DOE-HDBK-1132-99, Design Considerations

TS NOT MEASUREMENT SENSITIVE DOE-HDBK-1132-99 April 1999 DOE HANDBOOK DESIGN CONSIDERATIONS U.S. Department of Energy AREA EDCN Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from ES&H Technical Information Services, U.S. Department of Energy, (800) 473-4375, fax: (301) 903-9823. Available to the public from the U.S. Department of Commerce, Technology Administration, National Technical Information Service, Springfield, VA 22161; (703) 605-6000. DOE-HDBK-1132-99 TABLE OF CONTENTS PARAGRAPH PAGE iii ACRONYMS AND ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii PART I: DESIGN CONSIDERATIONS INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-3 SECTION 1: SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-7 1.1 CONFINEMENT SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-7 1.1.1 Introduction and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-7 1.1.2 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-8 1.1.3 Primary Confinement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-9 1.1.4 Secondary Confinement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-14 1.1.5 Tertiary Confinement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-16 1.1.6 Confinement Ventilation Systems . . . . . . . . . . . . . . . . . . . . . . . . . I-16 1.2 CONFINEMENT SYSTEM DESIGN ASPECTS BY FACILITY TYPE . . . . . I-23 1.2.1 Plutonium Processing and Handling Facilities and Plutonium Storage Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-23 1.2.2 Unirradiated Enriched Uranium Storage Facilities . . . . . . . . . . . . I-25 1.2.3 Uranium Processing and Handling Facilities . . . . . . . . . . . . . . . . . I-26 1.2.4 Irradiated Fissile Material Storage Facilities . . . . . . . . . . . . . . . . . I-29 1.2.5 Reprocessing Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-31 1.2.6 Uranium Conversion and Recovery Facilities . . . . . . . . . . . . . . . . I-33 1.2.7 Laboratory Facilities (Including Hot Laboratories) . . . . . . . . . . . . . I-36 1.3 EFFLUENT CONTROL AND RADIATION PROTECTION . . . . . . . . . . . . . . I-39 1.3.1 Introduction and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-39 1.3.2 Shielding Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-40 1.3.3 Airborne Radiation Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-41 1.3.4 Contamination Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-42 1.3.5 Radiation Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-42 1.3.6 Airborne Effluents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-43 1.3.7 Effluent Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-45 1.3.8 Effluent Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-45

SECTION 2: SPECIAL FACILITIES AND ACTIVITIES . . . . . . . . . . . . . . . . . . . . . . I-47 INTRODUCTION AND SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-47 2.1 PLUTONIUM PROCESSING AND HANDLING FACILITIES . . . . . . . . . . . . I-47 2.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-47 2.1.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-47 2.2 PLUTONIUM STORAGE FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-58 2.2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-58 2.2.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-58 DOE-HDBK-1132-99 TABLE OF CONTENTS PARAGRAPH PAGE iv 2.3 UNIRRADIATED ENRICHED URANIUM STORAGE FACILITIES. . . . . . . . I-61 2.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-61 2.3.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-61 2.4 URANIUM PROCESSING AND HANDLING FACILITIES. . . . . . . . . . . . . . . I-63 2.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-63 2.4.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-64 2.5 IRRADIATED FISSILE MATERIAL STORAGE FACILITIES . . . . . . . . . . . . I-65 2.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-65 2.5.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-66 2.6 REPROCESSING FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-68 2.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-68 2.6.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-69 2.7 URANIUM CONVERSION AND RECOVERY FACILITIES. . . . . . . . . . . . . . I-71 2.7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-71 2.7.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-71 2.8 RADIOACTIVE LIQUID WASTE FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . I-74 2.8.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-74 2.8.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-74 2.9 RADIOACTIVE SOLID WASTE FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . I-81 2.9.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-81 2.9.2 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-81 2.10 TRITIUM FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-86 2.10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-86 2.10.2 Sources of Tritium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-87 2.10.3 The Relative Abundance of Tritium . . . . . . . . . . . . . . . . . . . . . . . . I-89 2.10.4 The Radioactive Decay of Tritium. . . . . . . . . . . . . . . . . . . . . . . . . I-90 2.10.5 The Chemical Properties of Tritium . . . . . . . . . . . . . . . . . . . . . . . . I-93 2.10.6 Modeling the Behavior of Tritium . . . . . . . . . . . . . . . . . . . . . . . . . I-97 2.10.7 The Development of Tritium Technology . . . . . . . . . . . . . . . . . . I-109 2.10.8 Confinement Systems vs. Containment Systems . . . . . . . . . . . . I-112 2.10.9 Tritium Removal Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-120

2.11 FUSION TEST FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-127 2.11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-127 2.11.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-128 2.12 DESIGN OF FACILITIES TO FACILITATE ULTIMATE DECONTAMINATION AND DECOMMISSIONING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-129 2.12.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-129 2.12.2 Equipment Selection and Location. . . . . . . . . . . . . . . . . . . . . . . I-130 2.12.3 Building Layout (to Facilitate Decontamination and Decommissioning) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-131 2.12.4 Coatings to Facilitate D&D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-132 2.13 D&D AND ENVIRONMENTAL REMEDIATION PROJECTS . . . . . . . . . . . I-132 2.13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-132 2.13.2 Decommissioning and Decontamination . . . . . . . . . . . . . . . . . . . I-135 2.13.3 Hazards Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-139 DOE-HDBK-1132-99 TABLE OF CONTENTS PARAGRAPH PAGE v 2.13.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-141 2.13.5 Environmental Remediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-142 2.14 VITRIFICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-144 2.14.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-144 2.14.2 General Vitrification Processes and Steps to Consider. . . . . . . . I-144 2.14.3 Waste Extraction from Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . I-144 2.14.4 Feed Delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-146 2.14.5 Feed Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-146 2.14.6 Feed Make-up and Chemical Addition . . . . . . . . . . . . . . . . . . . . I-147 2.14.7 Feed Holding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-147 2.14.8 Feed to Melter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-148 2.14.9 Acceptable Glass Compositions. . . . . . . . . . . . . . . . . . . . . . . . . I-148 2.14.10 Melters and Melter Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . I-148 2.14.11 Melter Life/Keeping Melters Hot/Not Cycling . . . . . . . . . . . . . . . . I-149 2.14.12 Off-Gas Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-150 2.14.13 Material Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-151 2.14.14 Process Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-151 PART II: GOOD PRACTICES INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1 1. ARCHITECTURAL CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

1.1 Facility Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-2 1.1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-2 1.1.2 Space Allotment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-3 1.1.3 Hazards Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-5 1.1.4 Hazardous Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-5 1.2 Equipment Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-6 1.2.1 Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-6 1.2.2 Air Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-7 1.2.3 Diesel Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-8 1.2.4 Auxiliary Lifting Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-8 1.2.5 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-9 1.2.6 Site Considerations for Outdoor Equipment. . . . . . . . . . . . . II-10 1.3 Piping Design and Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-10 1.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-10 1.3.2 Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-11 1.3.3 Vents and Drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-11 1.3.4 Lined Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-12 1.3.5 Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-12 1.3.6 Piping at Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-13 1.3.7 Expansion Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-13 1.3.8 Piping Containing Radioactive Materials . . . . . . . . . . . . . . . II-14 1.3.9 Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-16 DOE-HDBK-1132-99 TABLE OF CONTENTS PARAGRAPH PAGE vi 1.4 Special Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-18 1.4.1 Radioactive Waste Transfer Lines . . . . . . . . . . . . . . . . . . . . II-18 1.4.2 High-Activity Drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-18 1.4.3 Non-Fire Protection Penetration Seals . . . . . . . . . . . . . . . . . II-18 1.5 Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-19 1.5.1 General Jumper Design Considerations . . . . . . . . . . . . . . . . II-19 1.5.2 Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-20 1.5.3 Pipe Stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-20 1.6 Structural Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-21 1.6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-21 1.6.2 Metals-Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-21 1.6.3 Foundation Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-21 1.6.4 Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-21 1.6.5 Equipment Support Resonance . . . . . . . . . . . . . . . . . . . . . . II-22 1.6.6 Creep and Shrinkage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-22 1.6.7 Environmental Concrete Storage Structures . . . . . . . . . . . . II-22

2. ELECTRICAL SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-23 2.1 Basic Electrical Materials and Methods. . . . . . . . . . . . . . . . . . . . . . . . II-24 2.2 Exterior Electrical Utility Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-28 2.3 Special Facilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-30 2.4 Interior Lighting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-31 2.5 Exterior Lighting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-31 2.6 Special Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-32 3. MECHANICAL SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-33 3.1 Piping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-33 3.1.1 Piping Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-33 3.1.2 Piping Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-35 3.1.3 Buried Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-35 3.1.4 Steam and Condensate Systems . . . . . . . . . . . . . . . . . . . . . II-36 3.1.5 Water Hammer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-37 3.2 Purge Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-37 3.2.1 Systems Design: General Purge Systems Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-38 3.2.2 Components Design Considerations: Storage Tanks . . . . . . II-38 3.2.3 Pressure Buildup Coils Design Considerations . . . . . . . . . . II-38 3.2.4 Vaporizer Design Considerations . . . . . . . . . . . . . . . . . . . . . II-39 3.2.5 Service Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-39 3.2.6 HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-39 3.3 Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-39 3.4 Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-39 DOE-HDBK-1132-99 TABLE OF CONTENTS PARAGRAPH PAGE vii 4. INSTRUMENTATION AND CONTROLS CONSIDERATIONS . . . . . . . . . . . . II-40 4.1 Control Centers/Control Rooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-40 4.2 Distributed Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-41 4.2.1 Component Modularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-41 4.2.2 Input/Output Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-42 4.2.3 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-42 4.2.4 Data Highways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-42 4.2.5 Failure Mode Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.6 Operator Workstations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.7 System Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.8 Real Time Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.9 Data Historian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.10 Acceptance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-43 4.2.11 System Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-44

4.3 Programmable Logic Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-44 4.4 Alarm Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-45 4.5 Electrical Noise and Wiring Practices . . . . . . . . . . . . . . . . . . . . . . . . . II-46 4.6 Lightning Protection for Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . II-47 4.7 Analyzers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-48 4.8 Solenoid Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-48 4.9 Instrument Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-49 4.9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-49 4.9.2 Instrument Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-49 4.9.3 Pressure Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-50 4.9.4 Temperature Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . II-51 4.9.5 Flow Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-52 4.9.6 Level Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-52 4.9.7 Leak Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-52 4.9.8 Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-52 5. MATERIALS CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-53 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-53 5.2 Basic Considerations for Material Selection for Process Service . . . . II-56 5.3 Welding, Fabrication, Examination, and Testing . . . . . . . . . . . . . . . . II-57 5.4 Material Corrosion and Material Degradation by Radiation . . . . . . . . . II-58 ADDITIONAL REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1 DOE-HDBK-1132-99 viii INTENTIONALLY BLANK DOE-HDBK-1132-99DOE-HDBK-1132-99 ix ACRONYMS ACGIH American Conference of Governmental Industrial Hygienists ACI American Concrete Institute ADP automated data processing AHJ authority having jurisdiction ALARA as low as reasonably achievable ANS American National Standards ANSI American National Standards Institute ASHRAE American Society of Heating, Refrigerating, and Air Conditioning Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing & Materials AWG American wire gauge AWS American Welding Society BP&V Boiler and Pressure Vessel CAD computer-aided design CADD computer-aided design and drafting CAM continuous air monitors CFR Code of Federal Regulations D&D decontamination and decommissioning DC direct current DCS distributed control system DNFSB Defense Nuclear Facilities Safety Board DOE Department of Energy DOE-EM Department of Energy, Office of Environmental Management DOE-RW Department of Energy, Office of Civilian Radioactive Waste Management dpm disintegrations per minute ER environmental remediation FIPS Federal Information Processing Standards HEPA high-efficiency particulate air (filter) HID high-intensity discharge HPS high-pressure sodium HVAC heating, ventilation, and air conditioning I/O input/output IAEA International Atomic Energy Agency IEEE Institute of Electrical and Electronics Engineers IFM irradiated fissile material IFMSF irradiated fissile material storage facility ISA International Society for Measurement and Control (formerly Instrument

Society of America) LET linear energy transfer MIC microbiological-influenced corrosion NFC National Fire Code NFPA National Fire Protection Association NPH natural phenomena hazards NRC Nuclear Regulatory Commission PLC programmable logic controller PPHF plutonium processing and handling facility DOE-HDBK-1132-99DOE-HDBK-1132-99 x ACRONYMS (continued) PSF plutonium storage facility plf pounds per linear foot ppm parts per million psf pounds per square foot psi pounds per square inch psia pounds per square inch absolute psig pounds per square inch gauge PTFE polytetraflouoroethylene PVC polyvinyl chloride R.G. Regulatory Guide RLWF radioactive liquid waste facility RSWF radioactive solid waste facility SNM special nuclear material SSC structures, systems, and components SST safe, secured transport STP standard temperature and pressure TSR technical safety requirement UCRF uranium conversion and recovery facilities UEU unirradiated enriched uranium UEUSF unirradiated enriched uranium storage facility UMTRA Uranium Mill Tailings Remedial Action UPHF uranium processing and handling facility UPS uninterrupted power supply ABBREVIATIONS ? resistivity µm micron EC degrees Centigrade Ar argon cal calorie Ci curie cm2 square centimeter cm3 cubic centimeter D deuterium g gram H hydrogen H2O water EK Kelvin keV kiloelectron volt (joule) kVA kilovolt-ampere kWh kilowatt-hour mCi millicurie (becquerel) m3 cubic meter DOE-HDBK-1132-99DOE-HDBK-1132-99 xi ABBREVIATIONS (continued) mg milligram min minute mm millimeter MW(e) megawatt (electrical) N2O nitrous oxide N2 nitrogen NO nitric oxide NO2 nitrogen dioxide O2 oxygen Pu(IV) plutonium polymer Pu238 plutonium-238 PuF4 plutonium tetrafluoride sec second T tritium (the hydrogen isotope of mass-3) UF6 uranium hexafluoride UO2 uranium oxide EF degrees Fahrenheit DOE-HDBK-1132-99DOE-HDBK-1132-99 xii INTENTIONALLY BLANK DOE-HDBK-1132-99DOE-HDBK-1132-99 xiii FOREWORD Over a period of more than 50 years, the Department of Energy (DOE) and its predecessor agencies developed considerable experience in designing and operating nonreactor nuclear facilities of many different types. Operation of these facilities has provided valuable insight into successful designs and opportunities for improving those designs. Through the years, some of this experience and information was incorporated into DOE 6430.1A, GENERAL DESIGN CRITERIA. In 1996, when DOE decided to simplify and revise its directives system, DOE 6430.1A was identified for cancellation. Deemed too prescriptive, the Order was to be replaced by two performance-based Orders: DOE O 420.1, FACILITY SAFETY, and DOE O 430.1, LIFE- CYCLE ASSET MANAGEMENT. As a result, DOE O 420.1 contains safety requirements and DOE O 430.1 contains life-cycle and programmatic requirements. In addition, Guides and other documents developed for use with DOE O 420.1 and DOE O 430.1 provide acceptable methodologies for satisfying requirements, including guidance on selecting industry codes and standards for aspects of design. During the development of DOE O 420.1, a team visited the major DOE sites to obtain recommendations from engineering organizations regarding content and format of the new Order. One recommendation was that, although DOE 6430.1A was confusing, contradictory, dated, and too prescriptive, it contained useful information on good design practices that should not be lost. Independently, the Defense Nuclear Facilities Safety Board (DNFSB) staff

made a similar suggestion. Accordingly, the purpose of this Design Considerations Handbook is to provide a compilation of DOE good practices from DOE 6430.1A in a nonmandatory fashion and to supplement them with additional lessons learned to assist current and future DOE facility designers. Although the writers reviewed all the information not captured in DOE O 420.1 and DOE O 430.1 that was previously contained in DOE 6430.1A, certain types of information were specifically not incorporated, as listed below: • Some of the 99 sections included requirements that address criteria for safety class structures, systems, and components (e.g., 0111-99.0.1 Structural Requirements). DOE-HDBK-1132-99DOE-HDBK-1132-99 xiv • DOE O 420.1 and DOE Standards 1020 through 1024 provide design evaluation guidance for natural phenomena hazards (NPH) design. Further guidance for NPH design is not included. • Division 15 included many details of mechanical equipment design. The Design Considerations Handbook, Part II, incorporates this information only to the extent that it is not included in national codes and standards. • The DOE M 440.1-1, DOE EXPLOSIVES SAFETY MANUAL, contains authoritative guidance for explosive facilities. No information is included in the Design Considerations Handbook related to explosives and explosives facilities. • Information related to physical protection and safeguards and security is not included. The writers also reviewed a number of other documents, many in draft form, that provide information that may be useful in designing facilities, as well as particular components and systems. Examples of these other documents include the following: • Draft Report dated October 9, 1997: “Waste Vitrification System Lessons Learned.” • Department of Energy Lessons Learned Information Services Home Page sponsored by DOE Office of Field Management. <http://www.tis.eh.doe.gov/others/ll/ll.html> • Good Practice Guides for Life Cycle Asset Management - Guidance on many areas of project and fixed asset management is provided. <http://www.fm.doe.gov/FM- 20/guides.htm> • Four volumes of a Handbook developed by the Backup Power Working Group. <http://www3.dp.doe.gov/CTG/bpwg/bpwg.htm> • Regulatory Guides issued by the U.S. Nuclear Regulatory Commission, included those previously mentioned in DOE 6430.1A. DOE-HDBK-1132-99DOE-HDBK-1132-99 xv The information contained in the handbook is presented in differing levels of detail. The material from DOE 6430.1A has been extracted from that document, edited to remove the mandatory tone and to remove safety requirements content (which is addressed in DOE O 420.1). Additional content has been included, when available from sources around the DOE complex, such as the tritium section (2.10), the D&D and environmental remediation section (2.13), the vitrification section (2.14), and Part II, Good Practices. No attempt has been made to edit this material to produce a document with a consistent level of detail throughout. In this regard, the handbook should be regarded as a compilation of available engineering design experience and advice. No attempt has been made to be complete and exhaustive in any one subject area. This handbook is intended for the use of designers with some level of experience as a reference to see how the design of existing DOE nuclear facilities have addressed the special issues inherent in these facilities.

Nuclear safety design criteria requirements are contained in DOE O 420.1. They are in the format of performance requirements rather than explicit and detailed specification requirements. Guidance on acceptable ways of satisfying the requirements of DOE O 420.1 is found in the associated Implementation Guides. Because design requirements are treated in DOE O 420.1 and because the material in this handbook is not a complete and exhaustive collection of material that a designer would need, the contents of this handbook are not intended to be referenced as requirements. Guidance in this handbook should not be used as justification of acceptable ways of satisfying requirements. The adequacy of a design should stand on its own merits. This handbook was prepared through the efforts of individuals from DOE Headquarters, DOE Field Offices, and contractor and subcontractor personnel. As additional relevant material is developed throughout the DOE complex and made available, revisions will be made to this handbook so that the content remains relevant and useful. Please provide suggestions for improvement and material for consideration for future revisions to the DOE Office of Environment, Safety and Health; attention: Rich Stark, DOE/EH-31. DOE-HDBK-1132-99DOE-HDBK-1132-99 xvi INTENTIONALLY BLANK DOE-HDBK-1132-99DOE-HDBK-1132-99 I-1 PART I: DESIGN CONSIDERATIONS INTRODUCTION Scope. The Design Considerations Handbook includes information and suggestions for the design of systems typical to nuclear facilities, information specific to various types of special facilities, and information useful to various design disciplines. The handbook is presented in two parts. Part I, which addresses design considerations, includes two sections. The first addresses the design of systems typically used in nuclear facilities to control radiation or radioactive materials. Specifically, this part addresses the design of confinement systems and radiation protection and effluent monitoring systems. The second section of Part I addresses the design of special facilities (i.e., specific types of nonreactor nuclear facilities). The specific design considerations provided in this section were developed from review of DOE 6430.1A and are supplemented with specific suggestions and considerations from designers with experience designing and operating such facilities. Part II of the Design Considerations Handbook describes good practices and design principles that should be considered in specific design disciplines, such as mechanical systems and electrical systems. These good practices are based on specific experiences in the design of nuclear facilities by design engineers with related experience. This part of the Design Considerations Handbook contains five sections, each of which applies to a particular engineering discipline. Purpose. The purpose of this handbook is to collect and retain the nonmandatory Department of Energy (DOE) good practices from DOE 6430.1A, GENERAL DESIGN CRITERIA, and to supplement those practices with additional lessons learned. Applicability. This handbook is a reference document that may be consulted during design of nonreactor nuclear facilities. Its provisions are not to be invoked as requirements. Because DOE-HDBK-1132-99DOE-HDBK-1132-99 I-2 design requirements are treated in DOE O 420.1 and because the material in the handbook is not a complete and exhaustive collection of material that a designer would need, the contents

of this handbook are not intended to be referenced as requirements. Guidance in this handbook should not be used as justification of acceptable ways of satisfying requirements. The adequacy of a design should stand on its own merits. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-3 REFERENCES DOE Orders and Standards DOE 5820.2A RADIOACTIVE WASTE MANAGEMENT DOE/EH 545 Seismic Evaluation Procedure DOE/EH-0256T DOE RADIATION CONTROL MANUAL DOE/EM-0142P DOE Decommissioning Handbook DOE/EM-0246 Decommissioning Resource Manual DOE-HDBK-1066 Fire Protection Criteria DOE-HDBK-1081 Primer on Spontaneous Heating and Pyrophoricity DOE-STD-1090 Hoisting and Rigging DOE-HDBK-1092 DOE Handbook on Electrical Safety DOE HDBK-1129-99 Tritium Handling and Safe Storage DOE M 440.1-1 DOE EXPLOSIVES SAFETY MANUAL DOE O 420.1 FACILITY SAFETY DOE O 430.1 LIFE-CYCLE ASSET MANAGEMENT DOE-STD-1020 Natural Phenomena Hazards Design and Evaluation Criteria for DOE Facilities DOE-STD-3013 Criteria for Preparing and Packaging Plutonium Metals and Oxides for Long-Term Storage DOE STD-3014 Accident Analysis for Aircraft Crash into Hazardous Facilities DOE-STD-3020 Specifications for HEPA Filters Used by DOE Contractors DOE-STD-3022 DOE HEPA Filter Test Program DOE-STD-3025 Quality Assurance Inspection and Testing of HEPA Filters DOE-STD-3026 Filter Test Facility Quality Program Plan DOE-HDBK-1132-99DOE-HDBK-1132-99 I-4 Other Government Documents 10 CFR 835 Occupational Radiation Protection 29 CFR 1910.134 Occupational Safety and Health Standards 40 CFR 264.193 Containment and Detection of Releases 40 CFR 265.193 Containment and Detection of Releases ERDA 76-21 Nuclear Air Cleaning Handbook NRC R.G. 3.10 Liquid Waste Treatment System Design Guide for Plutonium Processing and Fuel Fabrication Plants NRC R.G. 3.12 General Design Guide for Ventilation Systems of Plutonium Processing and Fuel Fabrication Plants NRC R.G. 3.18 Confinement Barriers and Systems for Fuel Reprocessing Plants NRC R.G. 3.20 Process Off-Gas Systems for Fuel Reprocessing Plants NRC R.G. 3.32 General Design Guide for Ventilation Systems for Fuel Reprocessing Plants NRC R.G. 3.49 Design of an Independent (Water Basin Type) Spent Fuel Storage Installation NRC R.G. 3.54 Spent Fuel Heat Generation in an Independent Spent Fuel Storage Installation NRC R.G. 8.8 Information Relevant to Ensuring that Occupational Radiation Exposures at Nuclear Power Stations Will Be as Low as Is Reasonably Achievable Non-Government Documents ACGIH 2090 Industrial Ventilation: A Manual of Recommended Practice ACI 224.1R Causes, Evaluation and Repair of Cracks in Concrete Structures ACI 224.2R Cracking of Concrete Members in Direct Tension DOE-HDBK-1132-99DOE-HDBK-1132-99 I-5 ACI 224.3R Joints in Concrete Construction ACI 318M Building Code Requirements for Reinforced Concrete ACI 349 Code Requirements for Nuclear Safety Related Concrete Structures AISC N690 Design, Fabrication, and Erection of Steel Safety-Related Structures for Nuclear Facilities ANS 6.4 Guidelines on the Nuclear Analysis and Design of Concrete Radiation Shielding for Nuclear Power Plants ANS 6.4.2 Specification for Radiation Shielding Materials ANS 8.3 Criticality Accident Alarm System ANSI N13.1 Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities ANSI N13.2 Administrative Practices in Radiation Monitoring (A Guide for Management) ANSI N13.4 American National Standard for the Specification of Portable X-

or Gamma-Radiation Survey Instruments ANSI S2.3 Immediate Evacuation Signal for Use in Industrial Installations Where Radiation Exposure May Occur ANSI Z88.2 Respiratory Protection ASHRAE HVAC Applications Handbook ASHRAE 62 Ventilation for Acceptable Indoor Air Quality ASME AG-1 Code on Nuclear Air and Gas Treatment ASME B31.3 Process Piping ASME B&PV ASME Boiler and Pressure Vessel Code ASME N509 Nuclear Power Plant Air-Cleaning Units and Components DOE-HDBK-1132-99DOE-HDBK-1132-99 I-6 ASME N510 Testing of Nuclear Air-Treatment Systems ASME NQA-1 Quality Assurance Requirements for Nuclear Facility Application ASTM A262 Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels ASTM D4258 Standard Practice for Surface Cleaning Concrete for Coating IAEA Manual on Safety Aspects of the Design and Equipment of Hot Laboratories (Safety Series No. 30) IEEE-1023 IEEE Guide for the Application of Human Factors Engineering to Systems, Equipment, and Facilities of Nuclear Power Generating Stations ISA RP60.3 Human Engineering for Control Centers NAVFAC DM-7.03 Soil Dynamics, Deep Stabilization, and Special Geotechnical Construction NFC NFPA 1 Fire Prevention Code NFC NFPA 101 Life Safety Code Fink and Beatty Standard Handbook for Electrical Engineers DOE-HDBK-1132-99DOE-HDBK-1132-99 I-7 SECTION 1 SYSTEMS This section of the handbook treats systems (e.g., confinement systems, radiation protection, and effluent monitoring and controls) typically used in nuclear facilities to control radiation or radioactive material. The specifics of designing these systems are developed in an iterative fashion by considering hazards and opportunities (alternatives) for prevention and mitigation of accidents involving the hazards. This section provides information based on experience, which the designer may use when developing the design. 1.1 CONFINEMENT SYSTEMS 1.1.1 Introduction and Scope. Safety ventilation and off-gas systems are generally designed to operate in conjunction with physical barriers to form a confinement system that limits the release of radioactive or other hazardous material to the environment and prevents or minimizes the spread of contamination within the facility. Confinement systems should be designed to— • prevent (if possible) or minimize the spread of radioactive and other hazardous materials to occupied areas; • minimize the release of radioactive and other hazardous materials in facility effluents during normal operation and anticipated operational occurrences; • minimize the spread of radioactive and other hazardous materials within unoccupied process areas; and • limit the release of radioactive and other hazardous materials resulting from accidents, including those caused by severe natural phenomena and man-made events. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-8 The specifics of confinement system design, as they relate to a particular facility, should be guided by an iterative process between safety analyses and design. Safety analyses define the functional requirements of the design, such as the type and severity of accident conditions that the confinement system must accommodate. The design should also consider sources of functional design requirements including maintenance, operability, and process requirements. This section discusses primary, secondary, and tertiary confinement systems, design of confinement ventilation systems, and aspects

of confinement system design by nuclear facility type. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) HVAC Applications Handbook provides general information regarding heating, ventilation, and air conditioning (HVAC) design for confinement systems. 1.1.2 General Considerations. Confinement system features, including confinement barriers and associated ventilation systems, are used to maintain controlled, continuous airflow from the environment into the confinement building, and then from uncontaminated areas of the building to potentially contaminated areas, and then to normally contaminated areas. For a specific nuclear facility, the number and arrangement of confinement barriers and their design features and characteristics are determined on a case- by-case basis. Typical factors that affect confinement system design are the type, quantity, form, and conditions for dispersing the hazardous material, including the type and severity of potential accidents. In addition, alternative process and facility design features may reduce potential hazards and the resulting requirements for confinement system design. Engineering evaluations, trade-offs, and experience are used to develop a practical design that achieves confinement system objectives. Because the number and arrangement of confinement systems required for a specific nuclear facility design cannot be predicted, this discussion describes a conservative confinement system design that uses the three principal confinement systems described below. The discussion assumes that three DOE-HDBK-1132-99DOE-HDBK-1132-99 I-9 levels of confinement are necessary or justified. Design decisions for a specific facility should address that facility’s hazards and other factors. • Primary confinement is usually provided by piping, tanks, gloveboxes, encapsulating material, and the like, and any off-gas system that controls effluent from within the primary confinement. It confines hazardous material to the vicinity of its processing. • Secondary confinement is usually provided by walls, floors, roofs, and associated ventilation exhaust systems of the cell or enclosure surrounding the process material or equipment. Except for glovebox operations, the area inside this barrier provides protection for operating personnel. • Tertiary confinement is provided by the walls, floor, roof, and associated ventilation exhaust system of the facility. Tertiary confinement provides a final barrier against release of hazardous material to the environment. 1.1.3 Primary Confinement System. Primary confinement consists of barriers, enclosures, gloveboxes, piping, vessels, tanks, and the like that contain radioactive or other hazardous material. Its primary function is to prevent release of radioactive or hazardous material to areas other than those in which processing operations are normally conducted. Primary confinement of processes that involve readily dispersible forms of material (e.g., solutions, powder or small fragments, gases) is provided by gloveboxes or other confining enclosures. Hoods are used when hazards are acceptably low, as indicated by the quantity of the material involved, the specific operation to be performed, and the hazardous nature and chemical form of material involved. The confinement philosophy described below should be applied to any component that serves a primary confinement function, such as

conveyor systems, material transfer stations, and ventilation/off-gas systems. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-10 Breaches in the primary confinement barrier that cannot be totally avoided or ruled out (e.g., due to glove or seal failure) should be compensated for by providing adequate inflow of air or safe collection of spilled liquid. Occasional breaches required for anticipated maintenance should be made only under carefully controlled conditions. Primary confinement should provide for storage of in-process material elsewhere, temporary alternative barriers, and adequate inflow of air to provide contamination control. The supply and exhaust ventilation system should be sized to maintain in-facility radiation doses at levels as low as reasonably achievable (ALARA) in the event of the largest credible breach. Process equipment and the process itself should be designed to minimize the probability of fire, explosion, or corrosion that might breach the confinement barrier. When handling pyrophoric forms (e.g., chips, filings, dust) of materials in the confinement enclosure, the guidance of DOE- HDBK-1081, Primer on Spontaneous Heating and Pyrophoricity, should be considered. Halon systems should not be used with pyrophoric metals due to the oxidizing reaction between halon and hot metal. Primary confinement barrier(s) should be provided between the process material and any auxiliary system (e.g., a cooling system) to minimize risk of material transfer to an unsafe location or introduction of an undesirable medium into the process area. Differential pressure across the barrier(s) should be used where appropriate. The effectiveness of each confinement barrier should be checked analytically against challenges it is expected to withstand without loss of function. This applies to any form of the hazardous material (gas, liquid, or solid) and its carrying medium (i.e., airborne or spilled in a liquid). To protect the integrity of process confinement systems, fire protection systems should include the following features: • Automatic and redundant fire detection devices. • A fire-extinguishing system that actuates automatically to— DOE-HDBK-1132-99DOE-HDBK-1132-99 I-11 – rapidly remove heat produced by fire to prevent or minimize pressurization of a process confinement and – rapidly extinguish a fire to minimize the loading of ventilation system filters with combustion products. (See DOE-STD-1066, Fire Protection Criteria, and DOE-STD-3020, Specifications for HEPA Filters Used by DOE Contractors.) • The introduction of the extinguishing agent in a way that does not result in overpressurization of the confinement barriers. • Provisions to collect liquid agents when a wet suppression agent is used. Enclosures (as primary confinement). Enclosures are physical barriers (e.g., cells, cubicles, gloveboxes, fume hoods, conveyor tunnels) that, together with their ventilation and operating systems, prevent the release of radioactive or other hazardous material to the work space or the environment. Accordingly, their structural and confinement integrity is a design consideration. [See the American Conference of Governmental Industrial Hygienists (ACGIH) Industrial Ventilation: A Manual of Recommended Practice (ACGIH 2090); American Society of Mechanical Engineers (ASME) Code on Nuclear Air and Gas Treatment (ASME AG-1); and Energy Research and Development Administration (ERDA) Nuclear Air Cleaning Handbook (ERDA-76-21).]

Enclosures should be designed to prevent exposure of personnel to airborne contamination and to implement ALARA concepts to minimize operator exposures. The enclosure system, including its internal and external support structures, should therefore be designed to withstand the effects of normal operating conditions, anticipated events, and accidents. Criticality considerations, when needed, should include water or other liquid sources, potential liquid level in the enclosure (during operations or fire fighting), drains to limit liquid level in the enclosure, and liquid collection in depressions, walls, and other areas. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-12 The following additional considerations should be addressed in designing enclosures: • Where practical, equipment not functionally required to operate directly in the presence of radioactive materials should be located outside the enclosure. Equipment that must be located within the enclosure should be designed to allow for in-place maintenance and/or replacement. • The design and operation of support and protection systems, such as fire protection, should not promote the failure of the enclosure system integrity or the loss of confinement. • Noncombustible or fire-resistant, corrosion-resistant materials should be used for enclosures and, to the maximum extent practicable, for any required radiation shielding. In no case should the total combustible loading located in a fire area exceed the fire resistance rating of the structural envelope. (See National Fire Protection Association (NFPA) Fire Protection Handbook for guidance on the relationship of combustible loading versus fire resistance rating.) • In conjunction with their ventilation systems, enclosures should be capable of maintaining confinement (i.e., negative pressure with respect to the surrounding operating area). • To reduce migration of contamination, closure devices or permanent seals should be provided on entrances to and exits from piping, ducts, or conduits penetrating confinement barriers. Such closures or seals should have an integrity equal to or greater than the barrier itself. • Where pertinent to safety, enclosure design should consider heat generation in the enclosure. Such heat sources may be from processes, lighting, chemical reactions, and the decay of radioactive material. Consideration of radioactive material as a heat source is particularly applicable to storage enclosures. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-13 • Consideration should be given to modular construction, versatility, relocation, and incorporation of shielding. Structural support should be provided to accommodate any anticipated loading resulting from shielding. The type of shielding used and its placement should allow for adequate fire-fighting access. Enclosure specifications should address the following standardized features, where applicable: • Windows and mountings. – Windows should be appropriately sized (and as small as practicable) and located to provide operators with visual access to the enclosure interior. – Windows should be constructed of noncombustible or approved fire-resistant materials. – Resistance of the selected material to impact and radiation damage should be considered. – The use of Mylar™ -glass laminates should be considered for use as viewing windows and lighting fixture covers in hydrofluoric acid environments. – Windows should be designed to minimize the risk of releasing

contamination to the working area during window replacement. – Window material should be selected based on specific process, combustible loading, and radiological safety considerations. • Glove ports (size, location, and height). – Glove ports should be located to facilitate both operations and maintenance work inside the enclosure. – Gloves should be flexible enough for operating personnel to access interior surfaces and equipment. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-14 – Gloves should be designed to allow replacement without losing contamination control and with minimum exposure to the operator. – When gloves are not in place, a noncombustible shield or cover for each glove port should be provided. • Exhaust air filters to minimize contamination of ductwork. • Ease of cleaning (radius corners, smooth interior and exterior surfaces, minimal protuberances, and accessibility of all parts). • Specific coatings for boxes containing halides to permit long life and ease of decontamination. • Adequate interior illumination (from fixtures mounted on the exterior where feasible). • Connections for service lines, conduits, instrument leads, drains, and ductwork. • Pressure differential monitors and heat detection. • Fire barriers and filter installation. • Sample removal ports for filter testing. Consideration should be given to incorporating transfer systems (such as double-door, sealed transfer systems or chain conveyors) for removal of hazardous material from a glovebox. Various types of removal and transfer systems are discussed in International Atomic Energy Agency (IAEA) Safety Series No. 30. These systems are designed to allow entry and removal of material without breaching the integrity of the glovebox. (See ERDA 76-21, Nuclear Air Cleaning Handbook, for additional information.) 1.1.4 Secondary Confinement. The secondary confinement system consists of confinement barriers and associated ventilation systems that confine any potential release of hazardous material from primary confinement. For example, when gloveboxes provide primary confinement for radioactive or hazardous DOE-HDBK-1132-99DOE-HDBK-1132-99 I-15 material processing, the functional requirements for secondary confinement refer to the operating area boundary and the ventilation system serving the operating area. Design features incorporated into the secondary confinement system should have been proven effective by extensive experience in similar applications or by formal prototype testing. Such design features include the following: • Continuous monitoring capability should be provided to detect loss of proper differential pressure with respect to the process area. Operating areas should also be continuously monitored. Commensurate with the potential hazards, consideration should be given to the use of redundant sensors and alarms. • Permanent penetrations of the secondary confinement (e.g., pipes, ducts) should have positive seals or isolation valves or double closure with controlled secondary to primary leakage on pass-through penetrations (e.g., personnel air locks and enclosed vestibules). • Ventilation systems associated with secondary confinement should be designed with adequate capacity to provide proper direction and velocity of airflow in the event of the largest credible breach in the barrier. • Secondary and tertiary barriers may exist in common such as a single structural envelope (e.g., walls, roof slab, floor slab), provided the barrier

can withstand the effects of external events, and does not contain access ways that allow the routine transfer of personnel, equipment, or materials directly to the exterior of the facility. Access ways into the interior of the single structural envelope should be designed so that the access way is entered from another level of confinement. • Special features (e.g., air locks, enclosed vestibules) should be considered for access through confinement barriers to minimize the impact of facility access requirements on the ventilation system and to prevent the release of radioactive airborne materials. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-16 • The use of stack-vented rupture disks, seal pots, or bubbler traps should be considered to prevent overpressurization and potential explosive disruption of the secondary confinement system. • When a pipe is used as the primary confinement barrier for materials, and the pipe exits a secondary confinement, the secondary confinement should be provided by a double-walled pipe of other encasement. In areas within the facility, the use of double-walled pipe should be considered. Leakage monitoring should be provided to detect leakage into the space between the primary pipe and the secondary confinement barrier. (See Resource Conservation and Recovery Act requirements in 40 Code of Federal Regulations (CFR) 264.193, Containment and Detection of Releases, and 40 CFR 265.193, Containment and Detection of Releases.) • When primary confinement includes ductwork, the considerations in the previous bullet should be applied to the ductwork. Transition from primary to secondary confinement typically occurs downstream of air cleaning devices, such as high-efficiency particulate air (HEPA) filters and adsorbers. 1.1.5 Tertiary Confinement. Tertiary confinement is provided by the building or outer structure of the facility. For some accidents, it represents the final barrier to release of hazardous material to the environment; for others, it is a barrier that protects other parts of the facility from damage. ALARA concepts should be incorporated in tertiary confinement system design to minimize exposure to operators, the public, and the environment. 1.1.6 Confinement Ventilation Systems. The design of a confinement ventilation system ensures the desired airflow at all times and specifically when personnel access doors or hatches are open. When necessary, air locks or enclosed DOE-HDBK-1132-99DOE-HDBK-1132-99 I-17 vestibules may be used to minimize the impact of open doors or hatches on the ventilation system and to prevent the spread of airborne contamination within the facility. Air cleanup systems provided in confinement ventilation exhaust systems are typically used to limit the release of radioactive or other hazardous material to the environment and to minimize the spread of contamination within the facility. To the extent practical, discrete processing steps should be performed in individual process confinements to reduce the amount of hazardous material that can be released by a single or local failure of the confinement system. The following general cleanup system features should be considered, as appropriate, for ventilation system design: • The level of radioactive material in confinement exhaust systems should be continuously monitored. Alarms should annunciate when activity levels above specified limits are detected in the exhaust stream.

Appropriate manual or automatic protective features that prevent an uncontrolled release of radioactive material to the environment or workplace should be provided. • Elevated confinement exhaust discharge locations can limit onsite doses and reduce offsite doses by enhancing atmospheric dispersion. An elevated stack should be used for confinement of exhaust discharge. Provisions should be made to provide an adequate ventilation exhaust discharge path in the event of stack failure. The stack should be located so that it cannot fall on the facility or an adjacent facility. Alternatively, the stack may be constructed to remain functional following accidents, including those caused by severe natural phenomena and man-made external events. Stack location and height should also consider intakes on the facility and adjacent facilities to preclude uptake. • Guidance for air sampling locations is provided in ACGIH/ASHRAE criteria. Sample collecting devices should be located as close to the DOE-HDBK-1132-99DOE-HDBK-1132-99 I-18 sampling probe as possible. Guidance for air cleaning device test port locations is provided by ASME N510, Testing of Nuclear Air-Treatment Systems. • The number of air filtration stages required for any area of a facility should be determined based on the quantity and type of radioactive materials to be confined. • Air filtration units should be installed as close as practical to the source of contaminants to minimize the contamination of ventilation system ductwork. • Ducts should be sized for the transport velocities needed to convey particulate contaminants to filter media while minimizing the settling of those contaminants in the ducts. • Ducts should be welded (transverse or longitudinal). Connections to equipment should be made using companion angle flanges. • Air filtration units should be located and provided with appropriate radiation shielding to maintain occupational doses ALARA during operations and maintenance. • Air filtration units should be designed to facilitate recovery of fissile material and other materials capable of sustaining a chain reaction . • The cleanup system should have installed test and measuring devices (see ASME N510) and should facilitate monitoring operations, maintenance, and periodic inspection and testing during equipment operation or shutdown, as appropriate. • Misters to cool inlet air and demisters to prevent soaking HEPA filters should be installed. Manual control of misters from the facility control DOE-HDBK-1132-99DOE-HDBK-1132-99 I-19 center should be considered. The inlet should have a temperature sensor with a readout on the facility control center monitor screen. • Where spaces, such as a control room, are to be occupied during abnormal events, filtration systems on the air inlets should be considered to protect the occupants. Control rooms should also be protected from the entry of smoke or other toxic gases through ventilation air intakes. Compressed (bottled) air storage could be used to pressurize the control room if toxic gases are present at the air intake. Alternatively, two intakes, separately located, could lessen the likelihood of toxic gas intake. • Either HEPA filtration or fail-safe backflow prevention for process area intake ventilation systems should be provided. • Consideration should be given to specify cadmium-free HEPA filters to avoid generating mixed waste.

• Roughing filters or prefilters upstream of a HEPA filter should be considered to maximize the useful life of the HEPA filter and to reduce radioactive waste volume. • When ducts with fire dampers penetrate the secondary confinement, boots may be needed for the clearance between the structure and the damper sleeve. Hot cell exhaust systems considerations are as follows: • Exhaust prefilters and HEPA filters should be installed to facilitate filter replacement and repair. Use of a bag-in/out type filter house can lessen personnel exposures. • Standby filters should be considered to provide backup protection and facilitate primary filter replacement without shutting down the exhaust DOE-HDBK-1132-99DOE-HDBK-1132-99 I-20 fans. Standby filters should be installed outside the cell and sealed in an acceptable enclosure for direct maintenance. Note: Air leakage through isolation valves/dampers should be evaluated to avoid the bypassing of filtration devices; the reduction of exhaust flow from recirculation through the standby filters; the exposure of personnel changing the isolated filter elements; and the premature loading of the standby filters. • Exhaust systems should have monitors that provide an alarm if the concentration of radioactive material in the exhaust exceeds specified limits. • If radioiodine may be present, consideration should be given to the installation of radioiodine-absorber units. In facilities where plutonium or enriched uranium is processed, the following are additional considerations: • Wherever possible, the designer should provide enclosures for confining process work on plutonium and enriched uranium. When these confinement enclosures are specified and designed, consideration should be given to whether room ventilation air for either a secondary or tertiary confinement can be recirculated. If a recirculation ventilation system is provided, the design should provide a suitable means for switching from recirculation to once-through ventilation. • If advantageous to operations, maintenance, or emergency personnel, the ventilation system should provide for independent shutdown. Such a shutdown should be considered in light of its effect on the airflow in other interfacing ventilation systems. When a system is shut down, positive means of controlling backflow of air to uncontaminated spaces should be provided by positive shutoff dampers, blind flanges, or other devices. • Equipment to continuously monitor oxygen levels should be provided for occupied working areas of facilities equipped with significant quantities DOE-HDBK-1132-99DOE-HDBK-1132-99 I-21 of inert or oxygen-deficient process glovebox lines. Allowable leakage rates for ductwork systems should be taken into consideration. • The supply of air to primary confinement, such as enclosures that confine the processing of plutonium and enriched uranium, should be filtered by HEPA filters at the ventilation inlets to the enclosures and area confinement barriers to prevent the transport of radioactive contamination in the event of a flow reversal. • If room air is recirculated, the recirculation circuit should provide at least one stage of HEPA filtration. The design should include redundant filter banks and fans. If recirculation systems are used, contaminated process enclosure air should be prevented from exhausting into the working area rooms. Process enclosure air (from hoods, gloveboxes, etc.) should be

treated and exhausted without any potential for recirculation to occupied areas. • The designer should specify and locate components in the exhaust systems to remove radioactive materials and noxious chemicals before the air is discharged to the environment. These components should be capable of handling combustion products safely. Exhaust system design should safely direct effluents through the appropriate ventilation ducts and prevent spread beyond the physical boundary of the ventilation system until treated. • HEPA filters should be installed at the interface between the enclosures that confine the process and the exhaust ventilation system to minimize the contamination of exhaust ductwork. Prefilters should be installed ahead of HEPA filters to reduce HEPA filter loading. The filtration system should be designed to allow reliable in-place testing of the HEPA filter and to simplify filter replacement. • Separate exhaust ventilation system ductwork and the initial two stages of filtration should be designed for exhaust air from enclosures that DOE-HDBK-1132-99DOE-HDBK-1132-99 I-22 confine the process (e.g., gloveboxes). These systems should maintain a negative pressure inside the enclosure with respect to the operating area. These systems should be designed to remove moisture, heat, explosive and corrosive gases, and other contaminants. These systems should also be designed to automatically provide adequate inflow of air through a credible breach in the enclosure confinement. • Enclosures that confine the process and are supplied with gases at positive pressure should have positive-acting pressure-relief valves that relieve the exhaust system to prevent over-pressurization of the process confinement system. • The design of air cleaning systems for normal operations, anticipated operational occurrences, and accident conditions should consider use of the following equipment as appropriate: – prefilters, – scrubbers, – HEPA filters, – sand filters, – glass filters, – radioiodine absorbers, – condenser distribution baffles, and – pressure and flow measurement devices. Airborne contaminant cleaning systems should be designed for convenient maintenance and the ability to decontaminate and replace components in the supply, exhaust, and cleanup systems without exposing maintenance or service personnel to hazardous materials. Filtration systems should be designed so that a bank of filters can be completely isolated from the ventilation systems during filter element replacement. Where the confinement system’s ventilation ducting penetrates fire barriers, fire dampers should be appropriately used to maintain barrier integrity. However, DOE-HDBK-1132-99DOE-HDBK-1132-99 I-23 the closure of such dampers should not compromise confinement system functions where the loss of confinement might pose a greater threat than the spread of fire. In such cases, alternative fire protection means (e.g., duct wrapping) should be substituted for fire barrier closure. In no case should a sprinkler system be considered a fire barrier substitute. (All penetrations of a fire barrier should be sealed, including conduit, cable trays, piping, and ductwork. In the selection of seals, requirements for pressure and water- tightness should be considered.) 1.2 CONFINEMENT SYSTEM DESIGN ASPECTS BY FACILITY TYPE The preceding discussions of primary, secondary, and tertiary confinement generally

apply to all nuclear facilities. The degree of applicability should be determined on a case-by-case basis. The following discussions provide some guidance on how to make these determinations as a function of facility type. A description of the facility types is included in Section 2. “Containment” is addressed in Section 2.10.8. 1.2.1 Plutonium Processing and Handling Facilities and Plutonium Storage Facilities (PSFs). The degree of confinement required is generally based on the most restrictive hazards anticipated. Therefore, the type, quantity, and form (physical and chemical) of the materials to be stored should be considered. For materials in a form not readily dispersible, a single confinement barrier may be sufficient. However, for more readily dispersible materials, such as liquids and powders, and for materials with inherent dispersal mechanisms, such as pressurized cases and pyrophoric forms, multiple confinement barriers should be considered. U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide (R.G.) 3.12, “General Design Guide for Ventilation Systems of Plutonium Processing and Fuel Fabrication Plants,” provides useful guidance that should be considered. Generally, for the most restrictive cases anticipated, three types of confinement systems should be considered: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-24 • primary confinement— established by the cladding or the storage container (e.g., canning); • secondary confinement— established by compartments with their ventilation systems; and • tertiary or final confinement— established by the building structure and its ventilation system. Exhaust ventilation systems are provided with HEPA filtration to minimize the release of plutonium and other hazardous material through the exhaust path. In addition, inlet ventilation to the secondary confinement systems should be provided with either HEPA filtration or fail-safe backflow prevention to minimize the release of plutonium and other hazardous materials through the inlet path. Primary Confinement System. Cladding or storage containers typically provide primary confinement during normal operation and anticipated operational occurrences, and for accidents. Cladding or storage containers should provide corrosion-resistant confinement for fuel assemblies and to prevent an uncontrolled release of radioactive material. Special design features should be considered to provide safe introduction, removal, and handling of stored plutonium. These handling systems and equipment should be designed to protect against the dropping of storage containers, fuel assemblies, and other items onto the stored plutonium. Secondary Confinement System. Compartments and their ventilation systems comprise the secondary confinement system. Secondary confinement barriers should have positive seals to prevent the migration of contamination. The use of positive seals should be considered for penetration of enclosures within the facility building to provide proper ventilation flow paths and to prevent the migration of contamination within the facility. Ductwork penetrations with fire dampers need clearance between the structure and the damper sleeve. Boots may be needed. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-25 The need for special ventilation systems for confinement purposes should be based on results of the safety analysis. In general, each compartment should be supplied with ventilation air from the building ventilation system. Each

compartment should also be provided with separate exhaust ventilation handled by a system with sufficient capacity to provide adequate ventilation flow in the event of a credible breach in the compartment confinement barrier. Pressure in the compartments should be negative with respect to the building ventilation system. Tertiary Confinement System. The facility building and its ventilation system comprise the tertiary confinement system. Penetrations of the building confinement barriers should have positive seals to prevent the migration of contamination. Air locks or enclosed vestibules should also be provided for access through confinement barriers. 1.2.2 Unirradiated Enriched Uranium Storage Facilities. The following provisions are typical for an unirradiated enriched uranium storage facility (UEUSF) confinement system. The actual confinement system requirements for a specific UEUSF should be determined on a case-by-case basis. The degree of confinement required is generally based on the most restrictive hazards anticipated. Therefore, the type, quantity, and form (physical and chemical) of the materials to be stored should be considered. For materials in a form not readily dispersible, a single confinement barrier may be sufficient. However, for more readily dispersible materials, such as liquids and powders, and for materials with inherent dispersal mechanisms, such as pressurized cases and pyrophoric forms, multiple confinement barriers should be considered. Generally, for the most restrictive case anticipated, the use of three confinement systems should be considered. The primary confinement should be the unirradiated enriched uranium (UEU) cladding or the storage container (e.g., canning). Secondary confinement should be established by compartments with DOE-HDBK-1132-99DOE-HDBK-1132-99 I-26 their ventilation systems. Tertiary or final confinement should be the building structure and its ventilation system. Primary Confinement System. UEU cladding or storage containers typically provide primary confinement during normal operation, anticipated operational occurrences, and accidents. Cladding or storage containers are used to provide a corrosion-resistant confinement for the fuel assemblies and other UEU to prevent an uncontrolled release of radioactive material. Special design features should be considered to introduce, remove, and handle UEU safely. These handling systems and equipment should protect against the dropping of storage containers, UEU assemblies, and other items onto the stored UEU. Secondary Confinement System. The compartments and their ventilation systems comprise the secondary confinement system. Penetrations of the secondary confinement barrier should have positive seals to prevent the migration of contamination. The use of positive seals should be considered for penetration of enclosures within the facility building to provide proper ventilation flow paths and to prevent the migration of contamination within the facility. The need for special ventilation systems for confinement purposes should be determined based on the safety analysis. In general, each compartment should be supplied with ventilation air from the building ventilation system. Separate exhaust ventilation should be handled by a system with sufficient capacity to provide adequate ventilation flow in the event of a credible breach in the compartment confinement barrier. Pressure in the compartments should be

negative with respect to the building ventilation system. Tertiary Confinement System. The facility’s building and ventilation system comprise the tertiary confinement system. Penetrations of the building confinement barriers should have positive seals to prevent the migration of contamination. 1.2.3 Uranium Processing and Handling Facilities. The following provisions are typical for a uranium processing and handling facility (UPHF) confinement DOE-HDBK-1132-99DOE-HDBK-1132-99 I-27 system. The actual confinement system requirements for a specific UPHF should be determined on a case-by-case basis. Generally, facilities that process and handle UEU have used two confinement systems. The primary confinement system encloses or confines the uranium materials being fabricated and the equipment used to process the uranium. The secondary confinement consists of the structures and associated ventilation systems that surround the operating areas that house the primary confinement system. The secondary confinement system barriers are those that separate the outside environment and free access areas, such as offices and lunch rooms, from potential contamination. Primary Confinement System. The primary confinement system includes barriers, enclosures (including their associated ventilation or atmosphere control systems), and process piping and vessels. Its principal function is to prevent the release of hazardous substances into the operating areas. The following features should be considered in the design: • Breaches of the primary confinement barrier (e.g., due to glove or seal failure) are acceptable if the off-gas treatment system is capable of maintaining an adequate inflow of air for the specified breach size and location. Some portions of the primary confinement may not form a complete physical enclosure. For these, primary confinement should be ensured by adequate airflow and appropriate process equipment design. • If needed, conveyors should be used to interconnect glove holes or other primary confinement enclosures to minimize introduction and removal of materials from the system. The primary confinement system criteria should be applied to these interconnections. • Special design features should be considered to safely introduce and remove materials from process confinements. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-28 • Process vessels that could contain uranium should vent to the process off-gas system, which in turn should pass through pretreatment, if needed, and HEPA filtration. Three types of metallurgical processes require special ventilation considerations: • Processes that use volatile or easily entrained organic liquids should have a ventilation system that provides sufficient air movement around the process area to prevent exposure of personnel to the hazardous liquid or vapor. The design should incorporate roughing filters and/or other types of traps to remove entrained organic liquid droplets from the process off-gas before the off-gas enters the main ventilation. As a result, the ventilation ducts should not become coated with the organic materials, which would create a fire hazard. • Processes that produce either finely divided particles of metal or small metal chips should have the same kind of front-end ventilation adaptations as for hazardous vapors and liquids to prevent metal accumulations in the off-gas ducting or in the final filtration train(s).

Roughing filters or centrifugal separators may be sufficient to remove metal particles from the off-gas. • Processes that use corrosive chemicals (e.g., acids, perchlorates) should use off-gas scrubbers to preclude damage to the exhaust air cleaning system (e.g., HEPA filtration train). Metallurgical processing equipment should have dedicated ventilation systems that exhaust to a common, final filtration train. If airborne particle capture is required, a high linear velocity will be necessary to ventilate these process areas due to the greater densities of metal particles. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-29 Ceramic processes involve oxide powder that is finely divided. The exposure of personnel to the powder inhalation hazard should be prevented. Processes that handle bulk ceramics such as pellets are not dust-free operations and thus, adequate ventilation should be provided. Secondary Confinement System. The secondary confinement system generally consists of the confinement barriers and associated ventilation systems that surround or confine the operating areas that house the process system and its primary confinement. The operating area compartments should have sensors that detect releases of hazardous materials from the primary confinement system and provide appropriate alarms. Commensurate with the potential hazard, the use of redundant sensors should be considered. Penetrations of the operating area confinement barriers should be minimized. When practical, equipment components not functionally required to operate directly in the presence of radioactive materials should be located outside the operating area compartments. Penetrations of the secondary confinement should have positive seals to prevent the migration of contamination out of the operating area. Each secondary confinement compartment should be supplied with ventilation air from the building ventilation system and should have exhaust ventilation with sufficient capacity to provide controlled ventilation flow as required in the event of a credible breach in the operating compartment confinement barrier. Pressure in the compartments should be negative with respect to the building ventilation system. 1.2.4 Irradiated Fissile Material Storage Facilities. The following provisions are typical for an irradiated fissile material storage facility (IFMSF) confinement system. The actual confinement system requirements for a specific IFMSF should be determined on a case-by-case basis. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-30 In general, primary confinement is the irradiated fissile material (IFM) cladding or canning. Secondary confinement is established by the facility buildings that enclose the dry storage area and/or the storage pool and auxiliary systems. Primary Confinement System. The IFM cladding or cans, as appropriate, provide primary confinement during normal and anticipated operational occurrences. The IFM cladding or canning are used to provide a corrosion- resistant confinement for the IFM material and to prevent an uncontrolled release of radioactive material. Secondary Confinement System. The facility building and ventilation system make up the secondary confinement system. Penetrations of the secondary confinement barrier should have positive seals to prevent the migration of contamination. The use of positive seals should be considered for penetration of enclosures within the facility building to provide

proper ventilation flow paths and to prevent the uncontrolled migration of contamination. Ventilation systems should include inlet air filtration (roughing filters) for the main storage building to prevent dust accumulation, thus reducing the load on other filters in the facility. Recirculated air in the main storage building should be filtered through a HEPA filter to reduce the build-up of radioactive material in the air. Areas with higher potential airborne radioactive contamination (e.g., pool water purification and waste treatment system areas) should use only once-through airflow. Supply air to these facilities should be drawn from the main storage building if such design is feasible. Exhaust air should be HEPA- filtered prior to release. Radioiodine adsorber units, such as activated charcoal or silver zeolite, should be considered for installation in the exhaust ventilation system when radioiodine releases are possible. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-31 Air should flow from areas of lower contamination to areas of higher contamination and areas of higher potential airborne contamination should be kept less than atmospheric pressure. 1.2.5 Reprocessing Facilities. The following provisions are typical for a reprocessing facility confinement system. Actual confinement system requirements for a specific reprocessing system should be determined on a case-by-case basis. The degree of confinement required in various locations of the facility depends on the potential hazards associated with the process being carried out and is generally based on the most restrictive case anticipated. Design should consider the characteristics of the hazardous material involved, such as type, quantities, forms (physical and chemical), dispersibility, and energy available for dispersion. In general, for the most restrictive case anticipated, the use of three confinement systems should be considered. In reprocessing facilities where processes require the use of corrosive or noxious materials, the process system should be totally enclosed and provided with its own ventilation system and off- gas cleanup system. In such cases, the process system should be treated as the primary confinement system. Secondary confinement should consist of the process cells and their ventilation system. Tertiary or final confinement should be the building structure and its ventilation system. In addition to these confinement systems, such features as change rooms and special access ways should be used to minimize the spread of contamination within the facility. If heat transfer systems are used that provide circulation between radioactive and nonradioactive areas, barriers to release due to contamination of the heat transfer fluids should be considered. Typically, confinement would be provided through the use of intermediate heat exchangers and the use of a “closed-loop” system. A leak monitoring system should be considered. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-32 Primary Confinement System. The primary confinement system consists of process systems equipment and the associated off-gas system. Process equipment failures should not cause failure of the secondary confinement system. Process equipment should operate under process conditions that prevent or minimize the probability of explosive chemical reactions. Secondary Confinement System. The secondary confinement system

consists of the process cell barriers and the ventilation systems associated with the cells. Design should consider the following features: • Secondary confinement areas should be equipped with sensors that detect abnormal releases of hazardous material from the primary confinement boundary and provide appropriate alarms. Commensurate with the potential hazard, the use of redundant sensors should be considered. • Penetrations of the secondary confinement should have positive seals to prevent the migration of contamination out of the secondary confinement area. • The ventilation system should be designed to maintain a negative differential pressure during the removal of cell covers and for normal in- leakage at cell cover joints. • Process cells should be supplied with ventilation air from the building ventilation system and with exhaust ventilation of sufficient capacity to provide controlled ventilation flow as required in the event of a credible breach in the secondary confinement barrier. • Pressure in the compartments should be negative with respect to the building ventilation system. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-33 • Special features (e.g., air locks, enclosed vestibules) should be considered for access through secondary and tertiary confinement barriers. Tertiary Confinement System. The process building and associated ventilation system comprise the tertiary confinement system. Penetrations of the building confinement barriers should have positive seals to prevent the migration of contamination. 1.2.6 Uranium Conversion and Recovery Facilities (UCRFs). To the extent practical, the primary confinement system should be constructed of fire-resistant materials, and the process equipment and process being confined should be designed to prevent potential flammable or explosive conditions. Confinement enclosures for flammable metals should be designed with self-contained fire protection and extinguishing equipment; in some cases, inert atmospheres may be desirable within the enclosures. Work that could subject personnel to possible inhalation exposures should be performed in process confinement enclosures. Gloveboxes should be the preferred enclosure, but are not always practical. Alternative systems may have to be considered. When gloveboxes are used, their design and construction should allow replacement of parts and/or relocation of the box(es) within the facility or system(s) with a minimum of contamination or exposure. To the extent practical, discrete processing steps should be performed in individual process confinements to reduce the amount of hazardous material that can be released by a single or local failure of the confinement system. Process and auxiliary system differential pressure should be maintained to inhibit backflow of hazardous materials into auxiliary systems. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-34 Generally, UCRFs have used two confinement systems. The primary confinement system encloses or confines the uranium materials being processed and the materials used to process the uranium. The secondary confinement consists of the structures and associated ventilation systems that surround the operating areas that house the primary confinement system. The operating areas include those areas that are not normally expected to become contaminated. The secondary confinement system barriers are those that separate the outside environment and free access areas, such as offices and

lunch rooms, from potential contamination. The actual confinement system requirements for a specific UCRF should be determined on a case-by-case basis. Primary Confinement System. The primary confinement system consists of barriers, enclosures (including their associated ventilation or atmosphere control systems), process piping and vessels, and so forth. Its principal function is to prevent the release of hazardous substances into the operating areas. The following considerations should be addressed in the design of primary confinement systems for UCRFs: • Breaches of the primary confinement barrier (e.g., due to glove or seal failure) are acceptable if the off-gas treatment system is capable of maintaining an adequate inflow of air for the specified breach size and location. Some portions of the primary confinement may not form a complete physical enclosure. For these, primary confinement function should be ensured by adequate airflow and appropriate process equipment design. • If needed, conveyors should be used to interconnect gloveboxes or other primary confinement enclosures to minimize introduction and removal of materials from the system. The primary confinement system criteria should be applied to these interconnections. • Special design features should be considered to safely introduce and remove materials from process confinements. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-35 • Process vessels that could contain uranium should be vented to the process off-gas system, which should route off-gas through pretreatment, if needed, and HEPA filtration. Typical pretreatment features include cyclone dust collection systems, different types of filters, cold traps, liquid condensers, solvent adsorption systems, and aqueous solution scrubbers. Nuclear criticality safety should be considered during the design of pretreatment and HEPA filtration systems. Secondary Confinement System. The secondary confinement system generally consists of the confinement barriers and associated ventilation systems that surround or confine the operating areas that house the process system and its primary confinement. The following considerations should be addressed in the design of secondary confinement systems for UCRFs: • Operating area compartments should be equipped with sensors to detect releases of hazardous materials from the primary confinement system and provide appropriate alarms. Commensurate with the potential hazard, the use of redundant sensors should be considered. • Penetrations of the operating area confinement barriers should be minimized. When practical, equipment components not functionally required to operate directly in the presence of radioactive materials should be located outside the operating area compartments. Penetrations of the secondary confinement should have positive seals to prevent the migration of contamination out of the operating area. • Each secondary confinement compartment should be supplied with ventilation air from the building ventilation system. Exhaust ventilation should be handled by a system with sufficient capacity to control ventilation flow as required in the event of a credible breach in the operating compartment confinement barrier. Pressure in the compartments should be negative with respect to the building ventilation system. The secondary confinement exhaust ventilation system should be equipped with HEPA filtration. DOE-HDBK-1132-99DOE-HDBK-1132-99

I-36 1.2.7 Laboratory Facilities (Including Hot Laboratories). The following provisions are typical for a laboratory facility confinement system. The actual confinement system requirements for a specific laboratory facility should be determined on a case-by-case basis. If radioiodine may be present, consideration should be given to the installation of radioiodine absorber units in the exhaust ventilation/off-gas system to reduce the radioiodine concentration in the effluent. Primary Confinement System. • In hot laboratories, primary confinement usually consists of items such as a hot cell, glovebox, process piping, tank, fume hood, etc.; the volume enclosed is normally contaminated. • The primary confinement volume and isolation systems, as appropriate, should be compartmentalized to isolate high-risk areas and to minimize the potential effects of accidents. • The primary confinement system(s) should operate under process conditions that prevent or minimize the potential for explosive chemical reactions and should use ALARA design principles to minimize exposures. • Design features for primary confinement for laboratory facilities and processes are facility-specific and should therefore incorporate the following features as appropriate: – Introduction and removal stations should provide for safe introduction and removal of material and maintenance equipment to and from the primary confinement. – Separate ventilation system or off-gas treatment system with appropriate air-cleaning capability (e.g., HEPA filtration, radioiodine absorbers, scrubbers) should be considered. The use of an inert gas atmosphere within the primary confinement is DOE-HDBK-1132-99DOE-HDBK-1132-99 I-37 necessary when handling pyrophoric material. Special considerations should be given to systems that handle tritium (see Section 2.10, Tritium Facilities). – Ventilation and cleanup systems associated with the primary confinement system should not be shared with secondary and tertiary confinement systems. – Tanks within the primary confinement system should vent to the off-gas treatment system. – The operating pressure in the primary confinement system should be negative with respect to the secondary confinement. • Gloveboxes should meet the following criteria: – Corrosive gases or particles from vats, scrubbers, and similar equipment should be neutralized prior to reaching HEPA off-gas filters. – A single filtered exhaust path should be acceptable when working with low-toxicity materials that do not require dilution or continuous cooling. – Exhaust flow rates (for air-ventilated gloveboxes) should confine in-box contaminants safely when an access port is opened or a glove ruptures. – If the glovebox is filled with an inert atmosphere, specific design criteria for emergencies (i.e., ruptured glove) should be incorporated on a case-by-case basis (e.g., pyrophoric materials). • Hot cells should meet the following criteria: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-38 – Space and equipment should be provided as needed to support accountability, process monitoring, and material control requirements. – Exhaust prefilters and HEPA filters should be installed to facilitate filter replacement and repair. – Standby filters should be incorporated for backup protection during filter changes so that filters can be changed without shutting down the exhaust fans. Standby filters should be

installed outside the cell and sealed in an acceptable enclosure for direct maintenance. – Exhaust systems should have alarms that will annunciate if the concentration of radioactive material in the exhaust exceeds the limits specified in the facility technical safety requirement. Secondary Confinement System . The secondary confinement system usually consists of the facility operating compartments and associated ventilation systems. The secondary confinement houses the hot cells, gloveboxes, fume hoods, etc. The following design features should be incorporated into secondary confinement systems for laboratory facilities: • design features to minimize the potential of the spread of contamination from within the laboratory facility operating areas to areas that are not normally contaminated; • the use of a ventilation system separate from the primary confinement ventilation system with appropriate air-cleaning capability (e.g., HEPA filtration, radioiodine absorbers, scrubbers); and DOE-HDBK-1132-99DOE-HDBK-1132-99 I-39 • measures to provide negative operating pressure in the secondary confinement with respect to the tertiary confinement, especially where variable flow primary confinement exhaust systems (fume hoods) are utilized. Tertiary Confinement System. The tertiary confinement system typically is the exterior laboratory building and its associated ventilation system. It is an area that is not contaminated and houses offices and other clean laboratory facilities. The following design features should be incorporated into tertiary confinement systems for laboratory facilities: • the use of a ventilation system separate from the primary confinement ventilation system with appropriate air-cleaning capabilities (e.g., HEPA filtration, radioiodine absorbers, scrubbers) and • measures to maintain operating pressure in the tertiary confinement negative with respect to the atmosphere. The secondary and tertiary confinement ventilation systems may be shared if safety analysis indicates that this type of design is acceptable. 1.3 EFFLUENT CONTROL AND RADIATION PROTECTION 1.3.1 Introduction and Scope . This section addresses aspects of facility design specifically intended to provide for effluent control and radiation worker protection. Included are shielding, radiation monitoring systems, contamination control, and effluent monitoring. This treatment is not exhaustive; many lessons learned in design have been translated into regulations, Orders, and guidance documents, especially 10 CFR 835, Occupational Radiation Protection; the DOE RADIATION CONTROL MANUAL; and DOE O 420.1 and its guidance documents. Design of nuclear facilities should minimize personnel exposures to external and internal radiological hazards, provide adequate radiation monitoring and alarm DOE-HDBK-1132-99DOE-HDBK-1132-99 I-40 systems, and provide adequate space for health physics activities. Primary radiation protection should be provided through the use of engineered controls (e.g., confinement, ventilation, remote handling, equipment layout, and shielding). Additional protection for workers should be provided through an effective radiation protection program that includes implementation of ALARA concepts. Additional considerations for specific facility types are included in this handbook; see Section 2, Special Facilities and Activities. 1.3.2 Shielding Design. The shielding design basis should minimize exposure of an

individual worker to ALARA levels. 10 CFR 835.1002 provides requirements in this area. In addition, appropriate shielding should be installed, if necessary, to minimize nonpenetrating external radiation exposures to the skin and lens of the eye of the worker. In most cases, the confinement barrier or process equipment provides this shielding. Shielding and other radiation protection measures should be provided for areas requiring intermittent access (e.g., to perform preventive maintenance, change components, and adjust systems and equipment). Straight-line penetration of shield walls should be avoided to prevent radiation streaming. American National Standard (ANS) 6.4, Guidelines on the Nuclear Analysis and Design of Concrete Radiation Shielding for Nuclear Power Plants, provides guidance regarding the design of concrete radiation shielding. ANS 6.4.2, Specification for Radiation Shielding Materials, provides guidance regarding material specifications, where it provides a critical confinement or structural function. American Concrete Institute (ACI) 318M, Building Code Requirements for Reinforced Concrete, provides general guidance for the structural design of concrete shielding. Straight-line penetration of shield walls should be avoided to prevent radiation streaming. Use of remote, shielded operations (i.e., through the use of handling equipment such as remote manipulators and lead glass windows) should be considered when exposures to extremities are anticipated to approach dose limits or where contaminated puncture wounds could occur. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-41 1.3.3 Airborne Radiation Control . Established airborne concentration limits for normal operating conditions should not be exceeded in occupied operating areas. 10 CFR 835.1002(c) provides requirements for limiting concentrations. ALARA principles should be used when designing confinement and ventilation systems to limit airborne contamination levels. Respirators should not be required during normal operations. Engineered controls and features should minimize potential inhalation of radioactive and other hazardous materials under all conditions. ASME N509, Nuclear Power Plant Air-Cleaning Units and Components, and ASME N510 provide guidance for the design and testing of nuclear facility HVAC systems. Monitoring systems should be calibrated at least annually using appropriate national standards. Radiation monitoring, alarm, and warning systems, which are required to function during a loss of normal power, should be provided with an emergency uninterruptible power supply (UPS) (internal or external on-line) unless it can be demonstrated that these systems can tolerate a temporary loss of function without losing needed data and that they are provided with standby or emergency (switched) power. Determination of the power supply type and quality should be based on the safety classification of the monitoring system or device. The sampling motivation (vacuum) type and quality should also be based on the safety classification. ANSI N13.2, Administrative Practices in Radiation Monitoring (A Guide for Management), provides guidance for administrative practices in radiation monitoring. Air monitoring and warning systems should be installed in work areas where hazardous materials are stored or handled or where hazardous airborne particles or vapors may be present. Air sampling heads should be located to

provide a representative sample of potential airborne radioactive or hazardous materials being breathed. ANSI N13.1, Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities, provides guidance for the design of air monitoring systems. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-42 Operation and maintenance of special facilities may lead to situations (e.g., accidents, special maintenance, spill recovery) where air-supplied respiratory protection is required. ANSI Z88.2, Respiratory Protection, and 29 CFR 1910.134, Occupational Safety and Health Standards, provide guidance for the design of breathing air supply systems. 1.3.4 Contamination Control . Use of devices to warn personnel of possible radioactive or other hazardous contamination should be evaluated and provided in accordance with the evaluation. Personnel monitoring devices, such as hand and foot counters, should be provided in the vicinity of workstations. Installed monitors (supplemented with personal monitoring methods) should be used to monitor personnel exiting an operating area. Continuous air monitors (CAMs) should be used to detect and alarm at prescribed airborne radioactivity levels. ANSI N13.4, American National Standard for the Specification of Portable X- or Gamma-Radiation Survey Instruments, provides guidance on personnel monitoring devices. Facility design should locate personnel decontamination facilities close to areas that represent potential contamination sources. Decontamination facilities should be designed to minimize the inadvertent spread of contamination during personnel decontamination activities. Change rooms should be provided for changing into and from protective clothing. These areas should be separate for male and female workers and be located adjacent to shower facilities. Change rooms should be designed to segregate clean clothing (e.g., personal clothing) and protective clothing. Storage of contaminated protective clothing should be controlled so that contamination does not spread. Change room exhaust air should be HEPA filtered if dispersible radionuclides are handled in the process areas it serves. 1.3.5 Radiation Monitoring. In the presence of ionizing radiation (due to process material, equipment, or operations), an area radiation monitoring and alarm system is used to alert personnel of unexpected increases in ionizing radiation levels. Warning and alarm systems should be designed, installed, and tested to DOE-HDBK-1132-99DOE-HDBK-1132-99 I-43 confirm that they can be heard in the ambient conditions of the area in which they are placed. ANSI N2.3 provides guidance for the design of evacuation alarm systems. If a criticality excursion could potentially occur, including a potential for personnel exposures, nuclear accident dosimeters should be installed. ANS 8.3, Criticality Accident Alarm System, provides guidance for criticality accident alarms. In addition to a local station alarm, radiation monitoring systems (i.e., criticality alarms, CAMs, alarms associated with stack monitoring systems) should have central (i.e., control room or radiation monitoring office) readout and alarm panels that are accessible after an accident so that internal conditions can be evaluated. 1.3.6 Airborne Effluents . For nonradioactive hazardous gaseous or airborne effluents, the point of release is the point at which the effluent exits the stack, vent, or other release points.

Exhaust ducts (or stacks) that may contain radioactive airborne effluents should be provided with effluent monitoring systems. The monitoring capability should cover the range from normal effluent concentrations to the maximum concentration expected from a credible accidental release. For exhaust outlets that may contain plutonium, uranium, enriched uranium, tritium, transuranics or fission products, and other radioisotopes above ambient levels, two independent monitoring systems should be considered. Backup capability for monitoring systems should be considered in the design of each system (e.g., redundant detectors, additional sample line ports, additional sampler trains, etc.). Continuous stack sampling and continuous radiation detection should also be considered. ANSI N13.1 provides guidance on designing sampling systems that provide accurate, representative sampling of effluent streams. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-44 Airborne effluents from confinement areas should be exhausted through a ventilation system designed to remove hazardous particulate material, vapors, or gases. ALARA should be implemented to minimize effluent concentrations and quantities released for hazardous materials. Isokinetic sampling should be provided for effluent streams that are expected to contain particulate radionuclides. After HEPA filter installations, anisokinetic sampling may be satisfactory, due to the small particle sizes in the effluent. Consideration should be given to including process confinement off-gas treatment systems to preclude the accumulation of potentially flammable quantities of hydrogen generated by radiolysis or chemical reactions within process equipment. Vent streams with the potential of containing significant quantities of radioactive material should be processed by an off-gas cleanup system before being exhausted to the environment. The following additional features should be considered in off-gas systems: • providing vents from liquid components with traps and drains to prevent inadvertent flooding of off-gas systems; • neutralizing corrosive gases and particles from vats, scrubbers, and similar equipment in gloveboxes before they reach the HEPA off-gas filters; • equipping vent streams containing UF 6 with chemical traps to remove radionuclides from the gases before they are vented to the atmosphere. The following vents are typically equipped with traps: – purge cascade, – cold recovery, – buffer seal exhaust stations, and – wet-air evaluation stations. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-45 Consideration should also be given to the need for equipment to provide meteorological parameters (e.g., wind speed, wind direction, humidity data, and wind direction frequencies for heights related to the estimated heights at which stack effluents and cooling tower moisture will be dispersed). As necessary, installation of special equipment for stack effluent dispersal and tracking should be considered. 1.3.7 Effluent Control . Generally, there will be statutory limits on facility effluents and concentrations at the point of discharge and/or the site boundary. These statutory requirements should be identified and their requirements implemented in design. Consideration should also be given to concentrations at neighboring facilities, and even to operations areas of the facility outside the building, especially for chemical releases. The design of monitoring and control systems

that reduce effluents released to the environment to ALARA levels should emphasize the use of features that employ the best technology economically available at the time of design. Confinement systems should minimize the release of radioactive and other hazardous materials in facility effluents during normal operation and anticipated operational occurrences. 1.3.8 Effluent Monitoring . Design for effluent monitoring should consider the following: • Sampling and monitoring systems provide adequate and accurate measurements under normal operations, anticipated operational occurrences, and accident conditions. Monitoring systems should be calibrated at least annually according to appropriate national standards. • Exhaust outlets that may contain radioisotopes other than ambient levels of those naturally occurring in the environment should be provided with monitoring systems. As necessary, special equipment for stack effluent dispersal and tracking should be considered for installation. Such monitoring provides data useful for dispersion analysis of effluent materials. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-46 • Stack monitoring systems should have central (i.e., control room or radiation monitoring office) readout and alarm panels that are accessible after an accident to evaluate internal conditions. Such data are useful for designing the most appropriate and efficient response to a release- related incident. • Radiation monitoring, alarm, and warning systems that must function during a loss of normal power should be provided with an emergency UPS (internal or external on-line). However, if it is demonstrated that these systems can tolerate a temporary loss of function without losing needed data and these systems are provided with standby or emergency (switched) power, the emergency UPS is not necessary. Determination of the power supply type and quality, including availability during and after events, should be based on the safety classification of the monitoring system or device. Emergency backup power systems are critical to the operation of monitoring, alarm, and warning systems in the case of a simultaneous power failure and radioactive release. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-47 SECTION 2 SPECIAL FACILITIES AND ACTIVITIES INTRODUCTION AND SCOPE This section of the Design Considerations Handbook provides design principles that the facility design team should consider for special facilities. These design principles have been developed as a result of design and operating experience with such facilities. These considerations should be consulted when designing facilities whose hazards and operations are similar to those discussed in this section. 2.1 PLUTONIUM PROCESSING AND HANDLING FACILITIES. 2.1.1 Introduction . A plutonium processing and handling facility (PPHF) is typically designed for the following functions involving plutonium: • shipping and receiving; • storage; • chemical processing; • recovery of scrap/residue; • characterization, control, and accounting; and • management of plutonium-contaminated wastes. Note that 238Pu presents special design challenges because of its high specific activity. Those considerations are not addressed here. 2.1.2 Design Considerations . The following sections provide specific design considerations for a PPHF. The design of PPHFs should consider the following features because of the special characteristics of plutonium and other materials

with high specific activity or radiotoxicity. Shipping and Receiving . A PPHF should be sited away from highly populated areas. It should also have reasonable access to major transportation networks, such as rail systems and interstate highways while maintaining safe distance. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-48 Because many state governments have the authority to designate traffic routes for shipment of radioactive material, close coordination with state and local agencies is recommended. The shipping and receiving area in a PPHF should accommodate the convoy of safe-secured-transport (SST), including its escort vehicles. The area should be free of any obstacles (other buildings and structures) during loading and unloading of the plutonium payload to establish a clear line-of-sight by site security forces. Radiation monitoring equipment should be available in the shipping and receiving area for surveying the radiation level on the surface of the SST and the containers during receipt of radioactive material from off-site. The shipping and receiving area may also be equipped with a decontamination port if a radiation survey indicates that the surface of a container is contaminated. Storage. A PPHF should include a storage facility (such as a vault-type room) in the process area to provide storage and staging functions. The following features should be considered in the design of the storage facility: • Operation of the storage vault should comply with the strict regulation of fire loading. • Packaging and unpackaging of plutonium in the storage vault area should provide for minimizing the build-up of packaging material. • Storage racks and shelves should be designed and constructed to meet seismic requirements. • Spacing between storage units should be sufficient to satisfy criticality controls. • Layout of storage racks should minimize radiation exposure to operating personnel and provide line-of-sight by safeguards and security. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-49 • Storage racks and shelves should be constructed of noncombustible material and designed to hold the storage containers securely in place and keep them properly separated. • Storage vault doors, racks, and containers should be designed to accommodate the application of tamper-indicating devices. • Design of the storage vault should facilitate the ease of performing periodic inventory. • Pyrophoric material should not be stored in a storage vault. Plutonium metal scraps (e.g., machine turnings, shavings, and fine chips) may be chemically reactive and should be processed to plutonium oxide before they are stored in the storage vault. [Because plutonium hydrides, carbides, oxycarbides, and nitrides are reactive and potentially pyrophoric, especially in finely divided form (powder), they should be handled in dry, inert (i.e., oxygen-free) atmosphere and should be converted to oxides for prolonged storage.] • Plutonium oxide is formed either by the reaction of the plutonium metal with oxygen in the air or by calcining plutonium compounds, such as the peroxide, oxalate, and nitrate. Plutonium oxide is generally a chemically inert powder and insensitive to self-radiation damage. However, plutonium oxide can absorb moisture from the air (depending on calcining condition), and incompletely calcined oxide could subsequently release gases, resulting in over-pressurization (bulging) a storage can. If

the plutonium compounds are not completely oxidized, the subsequent oxidation process could cause a decrease in the sealed container pressure, thereby imploding a storage can. To prevent or minimize these storage problems, plutonium oxides should be stabilized as prescribed by standards for packaging plutonium for storage. • The use of plastic bags in bag-in/bag-out operations could cause problems if the heat generated from radioactive decay melts the plastic bags after prolonged storage. The decomposition of the plastic bags DOE-HDBK-1132-99DOE-HDBK-1132-99 I-50 could release gases that could also bulge the can. State-of-the-art container packaging methods that either preclude or minimize the use of plastic bags should be considered, especially for long-term storage of plutonium containers. • Design of storage tanks for aqueous plutonium solutions should consider geometrically safe configurations with respect to nuclear criticality. Plutonium polymer [Pu(IV) solid] could be formed inadvertently under conditions of transient instability, and once formed, could be difficult to destroy. Polymerization in localized areas of low acidity could also occur if an acidic plutonium solution is diluted with water or steam. The plutonium polymers could clog transfer lines, interfere with ion-exchange separations, cause foaming, and constitute a criticality hazard. Detection of the build-up of polymers and means to remove these solids should be provided in aqueous plutonium storage systems. Prolonged solution storage of significant quantities of amorphous plutonium should be avoided. Chemical Processing. Plutonium processing operations should be conducted in the plutonium process area of the PPHF. The initial line of defense to protect workers in a process area is the confinement system, which includes enclosures, gloveboxes, conveyor lines, the ventilation system, and process piping. The primary confinement system should be designed to minimize the impact on workers and facilities. A secondary confinement barrier enclosing the primary confinement system provides contamination protection to plant personnel outside the area of secondary confinement. A tertiary confinement system, comprised of the building structure, encloses both the primary and secondary confinement barriers as well as the offices and other support areas, providing the final barrier between the potential contamination and the outside environment. Further design considerations for confinement systems are contained in Part I, Sections 1.1 and 1.2. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-51 The following design features should be considered for facilities that process chemicals: • The process area should be compartmented to isolate high risk areas, thereby minimizing productivity and financial loss if an accident occurs. Movement of personnel, material, and equipment between the process area and the uncontrolled area (such as the offices) should be through a controlled access area or an air lock. • The process area should permit ease of egress and material/equipment movement to allow rapid evacuation in the event of an accident. Consideration should be given to providing a ready room near or within the process area where maintenance, operating, and monitoring personnel could be readily available. The room should be located in a low background radiation area. • Indicators, auxiliary units, and supporting equipment control components

that do not have to be adjacent to operating/process equipment should be installed outside the radiation or contaminated areas. Equipment that requires periodic inspection, maintenance, and testing should be located in areas with the lowest possible radiation and contaminated levels. Equipment that is expected to be contaminated during operation should have provisions for both in-place maintenance and removal to an area of low radiation for repair. Maintenance areas for repair of contaminated equipment should provide for containment or confinement of radioactive material. • To the maximum extent practicable, the process area should provide sufficient space and versatility to accommodate equipment for programmatic changes and process modifications. It should also be designed to facilitate surveillance. Irregular plant layout (with obstacles) should be avoided where possible. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-52 Two different types of chemistry are generally employed for plutonium processing: the aqueous chemical process and pyrochemistry. Aqueous processes that are common to the plutonium production and chemical analysis are: dissolution, precipitation, liquid-liquid extraction, and oxidation-reduction reactions. The purex process, which has been the typical aqueous process used in plutonium production, involves the extraction and purification of plutonium with tributyl phosphate. Other processes are the production of plutonium tetrafluoride (PuF4) and the reduction of PuF4 using calcium and iodine. The purex process should include design features to deal with the use of flam mable liquids, the potential for radiolysis, the iron catalysis of hydrogen peroxide decomposition, and the potential generation of a large volume of plutonium- contaminated wastes. The design of facilities that employ an aqueous chemical process should consider the following features: • Systems, structures, and components for aqueous processing should be resistant to highly corrosive liquid and entrained vapors. Depending on the process to be used, stainless steel components are acceptable for nitrate-based systems. Because stainless steel is incompatible with chlorides, special coatings for gloveboxes (e.g., Kynar™ ) should be considered, along with Teflon™ or derivative polymer piping, valves, pump bodies, and vessels in systems that employ chloride chemistry. Selection of in-line process controls should consider materials compatibility. Automated ion-exchange systems have been used at Los Alamos with great success. • The sizing of process equipment is necessarily small to accommodate nuclear criticality requirements. In-process storage of feed solutions is efficiently handled in slab tanks or hollow cylindrical tanks. Pencil tanks have also been used; however, the array of such tanks is more complicated and subject to leaks. Selection of gasket, pump, and valve DOE-HDBK-1132-99DOE-HDBK-1132-99 I-53 material should recognize the corrosive nature of process solutions. Design of tankage should recognize the potential for post-precipitation and formation of a layer of solid precipitate on the bottom of the tank. Care should be exercised in agitating such a layer if it forms because a nuclear criticality could occur. Hence, tankage with small horizontal surfaces, such as hollow cylindrical tanks, is desirable. • Piping and valves should be located so that flammable, explosive, or toxic

gases or liquids that are necessary to the process can be isolated to prevent injuring workers if an accidental release occurs. The flammable gases should be provided by a hard-piped system with the gas supply located outside the facility in cylinders to limit the total quantity available in the event of a fire or explosion. • Radioactive liquid piping systems should be designed to avoid notches, crevices, and rough surfaces that might retain radioactive material. The piping system that collects contaminated liquids should be designed so that effluents from leaks in the system can be collected without releasing the liquids into the personnel access areas or to the environment. • Stainless steel should be used in radioactive waste and process system piping and equipment so that smooth, nonporous, corrosion-resistant materials are in contact with the contaminated, corrosive, and radioactive liquids. The piping system should be of welded construction whenever practicable. Flanges should be used only when absolutely necessary for servicing. • Piping or other conduits to convey plutonium solutions or plutonium- contaminated waste liquid should be double-walled or contained within an enclosure provided with a leak-tight barrier. Any potential leakage from the primary pipe should be collected in a geometrically safe sump or tank. Wherever possible, the piping system should be designed to avoid traps that could hold plutonium solutions. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-54 The process and equipment supporting the pyrochemical processing of plutonium should be designed to accommodate the pyrophoricity of plutonium metal and other materials used in molten salt and molten metal processing, button break-out, and the sampling operations. Features of the design should consider the minimization of dusting from operations. A criticality-safe service vacuum system may be used to clean up dusts. In addition to the features described above, facilities for the chemical processing of plutonium should address the following: • The process glovebox system should be designed to minimize moisture pickup by process materials. An inert atmosphere should be considered in gloveboxes where plutonium is processed. Bag-in/bag-out operations should be conducted without compromising glovebox atmosphere integrity. • The airborne radioactive effluents typically associated with PPHFs are furnace off-gas, airborne dust, off-gas from solvent processes, and corrosive vapor or mists from dissolvers. The design of airborne effluent systems should consider and minimize plutonium holdup at locations in off-gas and ventilation ductwork and include provisions to detect, monitor, and recover the build-up of such material. • The capability to service equipment should be provided. Equipment should be designed to minimize plutonium holdup. Provisions should be made to remove process material from equipment and to measure plutonium holdup with minimum downtime. • Because of the pyrophoric nature of plutonium metal, the plutonium process/handling glovebox system should be designed to accommodate glovebox fire safety. A leak detection system should be provided to detect the inleakage of air, which could change the glovebox atmosphere and lead to a plutonium fire. Certain glovebox construction components DOE-HDBK-1132-99DOE-HDBK-1132-99 I-55 are combustible— rubber gloves, plastic bags, polyvinyl chloride (PVC)

pipes, etc. Thus, the glovebox is vulnerable to involvement in fire, which, in turn, could cause the loss of glovebox integrity. • Facility design should provide for the continuous monitoring of external radiation exposure levels in process areas (e.g., hot cells and canyons) during maintenance or repair operations. Neutron shields in the form of water jackets should be capable of being monitored for water loss. • Gloveboxes should be equipped with quick couplings for dry chemical- type extinguishers. Recovery of Scrap/Residue . Plutonium scrap and residue should be recovered, processed, and accounted for— to the extent practical— according to the special nuclear material (SNM) accounting requirements. To prevent the accumulation of plutonium-containing scrap or residue, space should be provided for expeditious treatment or processing of these materials to allow their return to the main process. Plutonium could be recovered using various methods, depending on the chemical process employed. For the aqueous process, plutonium could be recovered by means of leaching and dissolution, followed by purification, evaporation, and concentration. For pyrochemistry, the recovery process would include salt flux remelting, hydriding, oxidation, and/or anion exchange. The following features should be considered to address the recovery and handling of scrap and residue: • Equipment for recovery and handling of scrap/residue should be designed to minimize dusting and physical losses or spillage. Vessels used for solution treatment, assay, or storage should be of geometrically safe design to preclude accidental nuclear criticality. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-56 • Provisions should be made for crucibles and molds removed or no longer serviceable to be processed to recover or remove residual plutonium before they are discarded. • Design should provide for the need to process plutonium scrap and residue before any subsequent disposition action is taken. Aqueous (chloride or nitrate system) and pyrochemical processing are required. Stabilization optimally involves separation of plutonium from matrix material in order to minimize the volume of material to be stored. Likewise, separation of plutonium from waste matrices will minimize the amount of transuranic waste to be shipped and placed in a waste repository. The final form of the concentrate should be a stable (but not necessarily highly purified) oxide or metal. The process includes acid dissolution (hydrochloric or nitric), some degree of purification (e.g., ion exchange), precipitation (typically as oxalate), calcining (to decompose the oxalate and produce plutonium oxide), and packaging. If a metal form is required as the end point, the temperature at which the oxalate is calcined should be kept as low as practical. Metal can be produced by direct oxide reduction with elemental calcium in a molten salt medium (calcium chloride). Means to regenerate the calcium chloride salt medium should be included in the process design. Characterization, Control and Accounting . Chemical sampling and analyses should be provided to support process and operations in the process area of the PPHF. Techniques employed for the characterization of plutonium include: metallography, electron microscope, X-ray diffraction, chemical analysis, thermal analyses, and isotopic. The most common detection technique employed is the

nondestructive assay detection system, which includes (1) radiation detection based on alpha, gamma radiation, and neutron activation, and (2) calorimetry, which measures the heat output of the radioactive materials. Several pyrochemical processes are likely to be used in plutonium processing. Molten salt extraction is used to separate americium from plutonium in aged plutonium items. A “saltless” extraction process has been developed at Los DOE-HDBK-1132-99DOE-HDBK-1132-99 I-57 Alamos that greatly reduces the amount of waste generated. Electrorefining is used to purify plutonium, leaving impurities behind in an anode “heel” that requires further processing, usually by aqueous means. Relatively pure plutonium oxide can be reduced to metallic form by direct oxide reduction, which requires dissolving plutonium oxide in a calcium chloride salt and introducing metallic calcium as the reducing agent. The resulting calcium oxide can be converted to calcium chloride by reacting with a chlorinating agent. Note that the media for pyrochemistry are typically chloride salts, and require special aqueous process equipment specifications to minimize corrosion. Likewise, the crucibles used to contain the melt also should be processed into a waste form or processed for extraction of plutonium. Exhaust ventilation, handling devices, and local furnace cooling should take thermally hot operations into account. Design of materials management and storage systems should attempt to achieve inventory extension to the maximum extent possible; that is, to minimize the frequency with which inventory must be taken and reconciled. This can be accomplished by use of a vault system with a long-term storage vault that can be locked down for a year or more, and a day vault that contains the items that will be used within the year. Sizing of process equipment should recognize the down-time required to complete inventory actions. These actions include cleaning out process equipment, wiping down gloveboxes, consolidating materials, conducting nondestructive assays, and reconciling inventory values. Management of Plutonium-Contaminated Wastes . Plutonium-contaminated and radioactive wastes generated from the PPHF should be managed and handled safely and effectively. The process system should be designed to minimize the generation of wastes at the source. The waste management system should be designed to limit the release of radioactive materials to the environment. Process liquid waste should be collected in the liquid waste treatment system and contained in geometrically safe vessels for temporary storage, sampling, and neutralization. Liquid waste should be concentrated by evaporation, and off-gas from the liquid waste evaporator should be sampled for radioactive materials and DOE-HDBK-1132-99DOE-HDBK-1132-99 I-58 hazardous chemicals before release to the environment. The concentrator bottom should be collected and solidified in containers with content meeting the waste acceptance criteria of existing or potential waste disposal site(s). Explosive or highly flammable materials should not be stored in proximity to these wastes. U.S. NRC R.G. 3.10, Liquid Waste Treatment System Design Guide for Plutonium Processing and Fuel Fabrication Plants, provides useful guidance that should be considered. 2.2 PLUTONIUM STORAGE FACILITIES. 2.2.1 Introduction . PSFs typically contain strategic amounts of plutonium. The

guidance contained in this section applies to facilities where strategic amounts of plutonium or significant quantities of other transuranic radionuclides, such as neptunium and californium, are stored. This section does not apply to “in process” or “in use” material, to material in assembly cells for use in weapons, or to material that is packaged in approved containers awaiting either transportation or disposition upon receipt. Note that 238Pu presents special design challenges because of its high specific activity. Those considerations are not addressed here. 2.2.2 Design Considerations . The design of PSFs should accommodate all planned plutonium handling and storage activities (e.g., analysis, shipping and receiving operations, packaging, and unpackaging). Provisions should be made to minimize the build-up of packaged materials or packaging materials. Receiving operations involving removal of radioactive material from protective shipping containers should be performed in an unpackaging room. Facility design, to the maximum extent practical, should: • provide sufficient versatility to accommodate equipment for programmatic changes and modifications and for multi-shift operations, DOE-HDBK-1132-99DOE-HDBK-1132-99 I-59 • provide sufficient spacing between compartments to facilitate relocation and maintenance of equipment in case of manual or automatic storage operations, and • facilitate expeditious identification, inventory, placement, and retrieval of storage containers. Facility layout should provide for efficient cleaning, maintenance, and ease of inspection and should consider the requirements for secure location of storage containers, traffic control, and segregation. Door locations should be coordinated with aisles to facilitate access to stored material, for loading and unloading of material, for use of fire fighting equipment, and for compliance with National Fire Code (NFC) NFPA 101, Code for Safety to Life from Fire in Buildings and Structures. Bumpers should be provided where necessary to minimize potential damage to the structure of racks from handling equipment. New storage facilities should be physically separated from process operations, storage of nonnuclear materials, flammable or explosive materials or equipment, and functions not directly required for storage operations. Combustible packaging materials should be stored in metal containers or structures outside a PSF in a location that will not endanger the storage facility or stored material if a fire occurs in the packaging material. No hazardous gases or liquids should be used in PSFs. No natural gas or other fossil fuels should be used for heating purposes unless the heating occurs in a separate building that is clearly isolated from the primary facility. The design should provide for sufficient spacing and arrangement of compartments and/or containers to facilitate the taking of inventories. Vault doors, racks, and containers should accommodate the application of tamper- indicating devices. Adequate space for measurement should be provided for the required inventory verification and/or confirmation. An automated vault surveillance system should be provided where excessive radiation exposure would result from entry for material control and accountability purposes. The design of the vault and/or system should facilitate inventory requirements. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-60

Those areas of the facility where SNM is stored (e.g., plutonium product storage) should be located in the least accessible (to an intrusion force) area of the plant. Design of storage tanks for aqueous solutions of plutonium should ensure that they are geometrically favorable with respect to nuclear criticality. When there is a tendency for solids to precipitate, vessels should be instrumented to detect the build-up of solids and designed to facilitate removal of solids. The ventilation system should be designed to provide adequate heat rejection capacity. DOE-STD-3013, Criteria for Preparing and Packaging Plutonium Metals and Oxides for Long-Term Storage, provides guidance regarding containers for storage of plutonium oxide and metal containing greater than 50 percent plutonium. Suitable physical compartmentalization should be considered to limit the quantity of stored materials in each compartment to safe levels, to provide the necessary access features and controls, and satisfy loss limitation criteria. Cautionary systems (e.g., visual or audible alarms or other warning systems) or interlocks should be considered to prevent inadvertent entry into hazardous areas. Safety alarm systems should annunciate inside and outside the PSF to identify hazardous areas to anyone present in either area. The need for visual alarm devices within the facility, in addition to audible alarm devices, should be considered. Storage racks should be noncombustible and designed to hold storage containers securely in place, maintain proper separation of storage containers, and maintain structural integrity under normal operational conditions, anticipated events, and accident conditions. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-61 2.3 UNIRRADIATED ENRICHED URANIUM STORAGE FACILITIES. 2.3.1 Introduction . UEUSFs are used to store unirradiated enriched uranium in a solid, liquid, or gaseous form. UEUSF activities may include shipping, receiving, handling, packaging, and unpackaging. 2.3.2 Design Considerations . The design should accomplish the following: • Accommodate planned UEU handling and storage activities (e.g., analysis, shipping and receiving operations, packaging, and unpackaging). The build-up of packaged materials or packaging materials should be minimized. Receiving operations involving removal of radioactive material from protective shipping containers should be performed in the unpackaging room(s). • Incorporate into the design ALARA concepts to minimize overall effects on workers, the public, and the environment. • Provide sufficient versatility to accommodate equipment for programmatic changes, programmatic modifications, and multishift operations. • Provide sufficient spacing between compartments to facilitate relocation and maintenance of equipment and ease of manual or automatic storage operations. • Facilitate expeditious identification, inventory, placement, and retrieval of storage containers. • Provide for sufficient spacing and arrangement of compartments and/or containers to facilitate the taking of inventories. Vault doors, racks, and containers should be designed to accommodate the application of tamper-indicating devices. Adequate space for measurement capability should be provided for the required inventory verification and/or DOE-HDBK-1132-99DOE-HDBK-1132-99 I-62 confirmation. The design of the vault system should facilitate inventory requirements. Those areas of the facility where SNM is stored should be

located in the least accessible area of the plant. To expedite recovery from accidents and provide facility versatility, modular construction concepts should be used, where feasible. No hazardous gases or liquids should be used in UEUSFs. No natural gas for heating purposes should be used unless the heating occurs in a separate building that is clearly isolated from the primary facility. New storage facilities should be physically separated from process operations, storage of nonnuclear materials or equipment, and functions not directly required for storage operations. Combustible packaging materials should be stored in metal containers or structures outside a UEUSF in a location that should not endanger the storage facility or stored material should a fire occur in the packaging material. The need to provide automatic fire suppression systems for these areas should be considered. Facility layout should provide for efficient cleaning, maintenance, and ease of inspection. Layout of floor and access areas should consider the requirements for secure location of storage containers, traffic control, and segregation. Suitable physical compartmentalization should be considered to limit the quantity of stored materials in each compartment to safe levels, to provide the necessary access features and controls, and to satisfy loss limitation criteria. Bumpers should be provided where necessary to minimize potential damage to the structure or racks from handling equipment. Design of storage tanks for aqueous solutions of enriched uranium should ensure that they are geometrically favorable with respect to nuclear criticality safety. When there is a tendency for solids to precipitate, vessels should be instrumented to detect the build-up of solids and designed to facilitate removal of solids. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-63 Cautionary systems (e.g., visible or audible alarms or other warning systems) or interlocks should be considered to prevent inadvertent entry into hazardous areas. Safety alarm systems should annunciate inside and outside the UEUSF to identify hazardous areas to anyone present in either area. The need for visual alarm devices within the facility, in addition to audible alarm devices, should be considered. Storage racks should be noncombustible and designed to hold storage containers securely in place, ensure proper separation of storage containers, and maintain structural integrity under normal operations, anticipated operational occurrences, and accident conditions. Door locations should be coordinated with aisles to facilitate access to stored material, for loading and unloading of material, for use of fire fighting equipment, and for compliance with NFC NFPA 101. Airborne radioactive wastes associated with UEUSFs that should be considered during the design include but are not limited to the airborne releases associated with the venting of storage containers. Cladding or canning failure during dry storage is also a source of such wastes. 2.4 URANIUM PROCESSING AND HANDLING FACILITIES. 2.4.1 Introduction . A UPHF is a facility that receives feed material from sources such as a conversion facility, a reprocessing facility, or fuel/target storage material. A UPHF processes, handles, and produces products such as UO 2, UF6, uranium metal, reactor fuel assemblies, target assemblies, and nuclear weapons components. This section is not process-specific. It is applicable to facilities that handle and

process uranium; however, it is principally directed at facilities that process and handle uranium enriched in 235U. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-64 2.4.2 Design Considerations . The design of processing facilities should consider inclusion of the design features described below. Design requirements vary significantly depending on the characteristics of the uranium, the type of processing and handling activities, and the characteristics of the site. • Materials of different uranium assays should be handled in physically different trains of equipment even though duplication of equipment results. If this is not possible, the equipment should be sized for criticality control of the most restrictive condition. • A definite isotopic specification for reactor returns should be established before facility design is started for refabrication of enriched uranium that has been irradiated and reprocessed. • Metallurgical processes and ceramic materials processing are the two principal types of processes for fabrication of uranium products. The hazards associated with each of these processes should be considered during the design of the fire protection, ventilation, and confinement systems. In addition, the chemical toxicity of uranium should be considered during the design of the facility. The design should provide specific control and isolation of flammable, toxic, and explosive gases, chemicals, and materials admitted to the areas of the facility. • The design should provide space for shielding, both permanent and temporary, of personnel and/or remote operations of equipment and processes. • The primary confinement system should be constructed of fire-resistant materials, and the process equipment and process being confined should be designed to prevent or minimize the probability of potential flammable or explosive conditions. Confinement enclosures for flammable metals should be designed with self-contained fire protection and extinguishing equipment; in some cases, inert atmospheres may be desirable within the enclosures. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-65 • To the extent practical, discrete processing steps should be performed in individual process confinements to reduce the amount of hazardous material that can be released by a single or local failure of the confinement system. Process and auxiliary system differential pressure should be maintained to inhibit back-flow of hazardous materials into auxiliary systems. • Process operations that involve oxide powder or that can generate powder or dust should be provided with special confinement to prevent the spread of contamination. Facility design should preclude the handling of uranium oxides in large open rooms. • Airborne radioactive wastes typically associated with UPHFs that should be considered during the design include but are not limited to airborne particulate material generated by fabrication processes (e.g., airborne grinding dust). Nuclear criticality safety should be considered in the design of the airborne effluent system. • When inert confinement system atmospheres are used, moisture removal systems should be considered to maintain long-term stability of packaged material. Small-volume process enclosures should be designed to prevent the enclosed atmosphere from being pressurized by rapid insertion of gloves into the enclosure. 2.5 IRRADIATED FISSILE MATERIAL STORAGE FACILITIES .

2.5.1 Introduction . IFMSFs are self-contained installations for storage of highly radioactive fissile material (e.g., spent fuel and target elements) that has been exposed to a neutron fluence, usually in a nuclear reactor. The irradiated material should be properly clad or canned when received so that leakage from the assemblies is minimized and remains within specified limits. The IFMSF stores the material in a manner that ensures the integrity of the cladding or canning. The stored material is shipped to facilities such as a hot laboratory or high-level solid radioactive waste facility. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-66 This section applies to a water-pool type of storage facility. Dry-type and spent fuel storage facilities that are part of a reactor facility are not covered by this section. 2.5.2 Design Considerations . The design of IFMSFs should consider inclusion of the design features described below. Design requirements vary significantly depending on the characteristics of the material, the type of storage, and the characteristics of the site. • The cooling water system for a water-pool type IFMSF should perform its required functions during normal and anticipated operating conditions and should be capable of limiting the maximum pool temperature. If pool boiling is used as an emergency cooling mechanism, the ventilation system design should consider the quantity of vapor being generated. Concrete and structural design should consider elevated temperatures. Drainage of condensate should be considered in the structure and equipment. • If the emergency makeup system is not permanently installed, the time required to implement its operation should be conservatively less than the time required to lower the pool water level to the minimum allowable depth or raise the pool temperature to boiling. • A pool water cleanup system should be provided to maintain water clarity, provide long-term cladding integrity, maintain structural integrity of the storage racks and other submerged structures, and minimize exposure rates and airborne contamination levels on the operating floor to ALARA levels. The piping configuration for the pool cooling water and cleanup system should be designed to eliminate the possibility of siphoning the pool water to a level below the minimum depth required for shielding and/or cooling. Cooling and cleanup systems should consider material deposition and plate-out in piping and equipment. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-67 • The design should also consider the inclusion of filters capable of being either remotely back-flushed or designed so that cartridges can be removed directly into a shielded container. Instrumentation for periodic functional testing of the pool-water cleanup system and heat-exchanger performance should be considered. The design should use containerized or modularized filters to reduce exposure during maintenance. Filter change-out prior to build-up of radiation levels should be considered. • The normal water level of the storage pool should be at or near the final design grade level. The water level necessary for in-storage radiation shielding should be at or below grade. • For water-pool type facilities, the design professional should consider providing the pool liner with a leakage collection system that will allow leakage detection and limit absorption of contaminated pool water by concrete structures.

• A system should be incorporated to detect leakage from stored IFM in the event of a cladding or canning failure that could allow the escape of fission products and other radioactive material greater than specified limits. This system should include the following: – Sampling of coolant allows identification of an individual leaking assembly. – System components, piping, and instrumentation are appropriately shielded to maintain operator exposures within guidelines and use ALARA design principles to minimize overall exposures. – The storage facility provides for the temporary storage of a leaky assembly. These provisions should limit the spread of contamination by a leaky assembly and provide adequate cooling and shielding of the assembly. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-68 • The IFMSF should provide for the interim canning of leaking assemblies until disposal. • Special design features should be considered for safe loading, removal, and handling of IFM. These systems and equipment should protect against the dropping of shipping casks, IFM assemblies, and other items onto the stored IFM. In water-pool type facilities, damage to the pool during loading and unloading operations should not allow the pool level to drop below the minimum allowable depth. Consideration should be given to features that will prevent breaching the pool integrity if a shipping cask is dropped. • Exhaust systems for pool areas should be HEPA-filtered. Other types of air-cleaning devices (adsorbers) should be considered. • Airborne radioactive wastes typically associated with IFMSFs that should be considered include but are not limited to airborne releases associated with the venting of transport casks and storage vessels. Cladding or canning failure during long-term wet or dry storage is also a source of airborne radioactive wastes. • Ventilation system design should consider the evaporation, mixing, and condensation of potentially tritiated sources in collection systems above and around pool areas. 2.6 REPROCESSING FACILITIES. 2.6.1 Introduction . A reprocessing facility is typically designed to recover uranium, plutonium, and other selected actinides and selected fission products from irradiated fissile fuel material and target material. The reprocessing facility is typically designed to separate these materials from each other and from any remaining actinides and fission products. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-69 2.6.2 Design Considerations . The design of reprocessing facilities should consider inclusion of the features described below. Design requirements vary significantly depending on the material (fuel) characteristics, the reprocessing technique, and the characteristics of the site. • Process system and auxiliary system differential pressure should be maintained to inhibit back-flow of contamination into auxiliary systems. The process equipment for transferring toxic and corrosive fluids should use vacuum and gravity where possible. Pumps and jets should have pressure capacity no greater than 10 percent above needed transfer capacity. • The integrity of process equipment off-gas treatment systems should be ensured for normal operations, anticipated operational occurrences, and accidents. • The use of directed airflow and back-flow prevention features to feed areas (i.e., shear and dissolver areas) should be considered. • Mechanical chopper and dissolver off-gas and other process vents should

be treated by an off-gas treatment system for removal of nuclides. As a minimum, the treatment system should be designed for particulate removal and should control the release of airborne radionuclides. In addition, the design should incorporate ALARA concepts to minimize impacts on operators and the public/environment. • Radioiodine adsorber units in the exhaust ventilation/off-gas system should be considered to reduce the radioiodine concentration in the effluent. Additionally, these releases should be ALARA. (See ASME AG-1 for adsorber selection considerations.) To reduce the amount of hazardous material that can be released if the process equipment fails, the following design provisions should be considered: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-70 • grouping or compartmentalizing process equipment to form units that can isolate the process inventory into modular units; • the capability to detect leakage from process equipment; and • selection of the method (e.g., manual, remote-manual, or automatic) of performing corrective actions (e.g., process shutdown) according to the potential hazards associated with a particular release. Design features that should be considered for maintenance of the confinement systems include the following: • the use of electrical equipment that precludes or minimizes the introduction of an ignition source in flammable or potentially flammable locations; • support and protection systems (such as fire protection systems) that do not promote the failure of the principal confinement systems; and • provisions for sprinklers, water fog, or other suitable systems within the secondary confinement to provide for rapid heat removal and minimum pressurization of the process cell or canyon and to minimize the loading of ventilation system filters with combustion products. Process equipment should be designed to operate under process conditions that prevent or minimize the potential for explosive chemical reactions (e.g., solvent vapor explosions, nitrate-solvent reactions). Process system design should provide for all fission product oxidation states expected during processing (e.g., suppression of the volatilization of ruthenium or the prevention of iodate formation). Systems should be provided to reduce the likelihood and consequences of pressurizing a primary confinement component as a result of an accident. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-71 Airborne radioactive effluents typically associated with reprocessing facilities that should be considered during the design include but are not limited to dissolver off-gas, process vessel vents, and high-level liquid radioactive waste collection and storage tank vents. Effluent system designs should preclude the holdup or collection of fissile material and other material capable of sustaining a chain reaction in portions of the system that are not geometrically favorable. Nuclear criticality safety should be considered in the design of airborne radioactive effluent systems. U.S. NRC R.G. 3.20, Process Off-Gas Systems for Fuel Reprocessing Plants, and R.G. 3.32, General Design Guide for Ventilation Systems for Fuel Reprocessing Plants, provide useful design guidance that should be considered. 2.7 URANIUM CONVERSION AND RECOVERY FACILITIES. 2.7.1 Introduction . UCRFs receive feed materials (such as UF6, uranyl nitrate, or UO3), process these materials chemically, and produce uranium metal, UO2, and

UF6. Uranium recovery facilities receive and handle scrap feed materials that are of different types, shapes, sizes, uranium contents, and enrichments. The kind of scrap and therefore the process to facilitate recovery of uranium may vary daily. This section is not process-specific, but is principally directed at facilities that produce feed materials for UPHFs and those facilities that recover uranium from scrap provided by UPHFs. 2.7.2 Design Considerations . The design of UCRFs should consider the features described below. Design requirements vary significantly depending on the material characteristics, the type of recovery and conversion processes used, and the characteristics of the site. • The design should provide special control and isolation of flammable, toxic, and explosive gases, chemicals, and materials admitted to the areas of the facility. • To the extent practical, the primary confinement system should be constructed of fire-resistant materials, and the process equipment and DOE-HDBK-1132-99DOE-HDBK-1132-99 I-72 process being confined should be designed to prevent or reduce the potential for flammable or explosive conditions. Confinement enclosures for flammable metals should be designed with self-contained fire protection and extinguishing equipment; in some cases, inert atmospheres may be desirable within the enclosures. • Work that could subject personnel to possible inhalation exposures should be performed in process confinement enclosures. Gloveboxes should be the preferred enclosure, but are not always practical. Alternative systems may have to be considered. • To the extent practical, discrete processing steps should be performed in individual process confinements to reduce the amount of hazardous material that can be released by a single or local failure of the confinement system. Process and auxiliary system differential pressure should be maintained to inhibit back-flow of hazardous materials into auxiliary systems. • Equipment design should include appropriate interlocks to prevent spills and cross-contamination. • The design of process systems should minimize the production of scrap and waste. • Geometric restrictions for nuclear criticality safety should apply to various units of equipment for the different processes used. In addition, other considerations, such as sufficient agitation in a process vessel to prevent the settling of uranium material, should be considered for nuclear criticality safety. • Leakage of enriched uranium material from processing equipment should be prevented. Design considerations should include, but not be limited to, the use of corrosion-resistant construction materials and features less vulnerable to leakage (e.g., of flanged and/or welded construction). DOE-HDBK-1132-99DOE-HDBK-1132-99 I-73 • Use of thermal insulation on the equipment that processes uranium solutions of high enrichment should be minimized because it absorbs the solution in the event a leak occurs. The uranium-impregnated insulation would be subject to scrap recovery operations. Because the insulation is considered a "full reflector," the equipment together with the insulation may not be geometrically favorable for highly enriched uranium solutions. • Storage tanks for aqueous solution of enriched uranium should be designed to ensure favorable geometry with respect to nuclear criticality safety. Where there is a tendency for solids to precipitate, vessels should

be instrumented to detect settling of solids and be designed to facilitate periodic removal of solids. • Airborne radioactive wastes typically associated with UCRFs that should be considered during the design include but are not limited to airborne particulate material generated during processing (e.g., airborne grinding dust) and vapors and gases used or generated during the processing. Nuclear criticality safety should be considered in the design of the airborne effluent system. Uranium Conversion Facilities . Piping systems, surge vessels, and control instruments with associated piping that carry UF6 gas should be equipped with heat tracing or heated enclosures wherever necessary to prevent solidification of UF6. Steam may be used as the primary heating agent where low-enrichment material (less than or equal to 2 percent 235U) is involved. At higher enrichments, a dry radiant heat source should be the preferred means of supplying the heating requirements. Uranium Recovery Facilities. The design of a uranium recovery facility should be approached on a case-by-case basis, considering possible forms of scrap and different assays of material that could be received for processing and possible methods that could be used for enriched uranium recovery. The following design features should be considered: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-74 • Materials of different uranium assays should be handled in physically different trains of equipment even though duplication of equipment results. If this is not possible, the equipment should be sized for criticality control of the greatest uranium enrichment. • For enriched uranium that has been irradiated and reprocessed, a definitive isotopic specification for the uranium should be adopted before facility design is begun. • In addition to provisions for handling uranium and other radioactive materials such as trace quantities of fission products and transuranics, the design should provide for the safe handling of other hazardous materials (e.g., acids, bases, organic solvents, fluorine, hydrogen, hydrogen fluoride, and magnesium) used or generated during recovery operations. 2.8 RADIOACTIVE LIQUID WASTE FACILITIES . 2.8.1 Introduction . Radioactive liquid waste facilities (RLWFs) store, treat, and dispose of radioactive liquid wastes generated by facilities and activities. This waste includes low-level, high-level, and transuranic-contaminated (to include enriched uranium and 233U) waste. An RLWF may be a separate facility or an adjunct to another facility. RLWFs may include waste treatment activities that separate solid and liquid waste constituents with provisions for disposing of noncontaminated waste. 2.8.2 Design Considerations . The design of RLWFs should consider the features described below. Design requirements vary significantly depending on waste characteristics, waste management techniques, and site characteristics. • The use of multiple barriers should be emphasized when necessary to restrict the movement of radioactive liquid waste that has the potential for human contact or for reducing groundwater quality below requirements. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-75 • Measurement and analysis capability should be provided to determine the volume and radioactivity of wastes fed to collection tank(s). Provisions should be made for analyzing liquids prior to transfer. Each transfer line should be identified individually. Instrumentation and control systems

should be used to provide monitoring and control capabilities associated with confinement, nuclear criticality safety, and/or radiation protection. • Individual lines should be used for each waste stream fed to central collection tanks, where necessary, to prevent chemical reactions or introduction of contaminants such as complexing agents that could interfere with waste decontamination. The use of traps in radioactive liquid waste lines should be avoided, and piping should be designed to minimize entrapment and build-up of solids in the system. Bypasses that would allow waste streams to be routed around collection tanks should be avoided. The radioactive liquid waste treatment system should contain no bypasses or drains through which waste may inadvertently be released directly to the environment. • Basic liquid waste treatment concepts include volume reduction, immobilization of radioactive material, change of composition, and removal of radioactive material from waste. The waste treatment concept(s) for a particular application should be selected on a case-by- case basis. To the extent practical, features should be included to allow volume reduction and/or waste solidification (immobilization) to forms required for long-term isolation. • Provisions should be made to adjust liquid waste characteristics prior to treatment to minimize adverse chemical reactions in the treatment system. • Recirculating closed-loop cooling systems should be used for facilities and equipment associated with the storage or treatment of high-heat, high-level radioactive liquid waste. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-76 • Provisions should be made for the continuous monitoring and recording of radioactivity, flow volume, pH, and other parameters required for material control and proper waste treatment operations while each volume of industrial waste is being received by an on-site treatment plant. This monitoring allows optimum control of waste treatment operations and helps prevent unintended off-site releases. • Liquid process wastes containing radioactive or other hazardous material should be collected and monitored near the source of generation before batch transfer through appropriate pipelines or tank transfer to a liquid waste treatment plant or area. Radiation, liquid level, or conductivity detectors should be provided in collection systems. Monitoring not only provides information useful for planning efficient waste treatment operations, but also can serve as an indicator of unintended fluctuations in process operations. • The airborne radioactive waste sources typically associated with RLWFs and RSWFs that should be considered during the design include but are not limited to radioactive liquid waste process vessel vents, high-level liquid radioactive waste collection and storage tank vents, airborne effluents from process system vents, and fission product gases. Effluent system designs should preclude the holdup or collection of fissile material or other material capable of sustaining a chain reaction in portions of the system that are not geometrically favorable. Nuclear criticality safety should be considered in the design of airborne effluent systems. • Provisions should be made to handle combustible gasses generated during waste handling and/or storage. • Consideration should be given to condensation and deposition of aerosols formed in vent lines. DOE-HDBK-1132-99DOE-HDBK-1132-99

I-77 Liquid Waste Confinement Systems . The following provisions are typical for an RLWF confinement system (see Table I). The actual confinement system requirements for a specific RLWF should be determined on a case-by-case basis. • The degree of confinement required in a RLWF is both storage-specific and process-specific, but in either case should suit the most restrictive case anticipated. • The primary confinement system consisting of the process equipment and/or primary storage tanks should operate under process conditions that prevent or minimize the potential of explosive chemical reactions. • Spills, overflow, or leakage from storage vessels or other primary confinement structures should be collected and retained within a suitable secondary confinement structure (e.g., secondary vessel, dike or berm, elevated threshold within a storage or process building, etc.). The secondary confinement structure should be able to retain the maximum radioactive liquid waste inventory that may be released by a spill, overflow, or leak from the primary confinement structure. For outdoor applications, the capacity must also include maximum predicted precipitation. The structure should also be designed to preclude overtopping due to wave action from the primary vessel failure and, in outdoor applications, to wind-driven wave action. The capability should exist to transfer collected liquid from the secondary confinement structure to a suitable storage location. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-78 TABLE I. Typical confinement provisions for RLWFs. Material being confined Primary Secondary Tertiary High-level liquid waste Primary storage vessel1 or treatment system equipment3 Secondary storage vessel1 or process cell Soil barrier2 or process building7 Low-level liquid waste Storage vessel4 or basin6 or treatment system5 Dike or berm8 around vessel or dike or berm None Transuranic waste Storage vessel4 or treatment system5 Storage building7 or process building7 None 1 Double-wall underground storage tanks and transfer piping are typically used to establish primary and secondary confinement barriers. Primary storage tanks have condensers and/or filters in their vent stream. The space between tanks is also ventilated and the exhaust is filtered. 2 Soil barrier is the engineered backfill material and natural setting surrounding the waste storage tanks. A monitoring capability should be available to detect leakage from the storage tanks into the soil. 3 Typical treatment equipment includes waste calciner, evaporator, or waste fractionization equipment. Treatment also occurs within the storage vessel (e.g., precipitation). 4 Single-wall storage tank. 5 Typical treatment concepts include volume reduction, immobilization of radioactive material, change of composition, and removal of radioactive material from waste. 6 Interim storage in retention or settling basins. 7 With elevated threshold or other means of confinement. 8 When dikes or berms are considered, use of an impervious membrane should be considered to minimize the cost of cleanup should a spill occur. High-Level Liquid Waste Confinement . Design of a high-level liquid waste confinement system should consider the following: • Tank and piping systems used for high-level liquid waste collection, treatment, and storage should be of welded construction to the extent practical. Construction materials should be selected to minimize all forms

of corrosion. Consideration should be given to stress relieving, welding parameter controls, etc., depending on the materials used. Fatigue failure should be a design consideration where temperature cycling is required (i.e., evaporator systems, etc.). • Potential nonuniform distribution of decay heat caused by solids in the waste should be considered in the design of storage tanks and any DOE-HDBK-1132-99DOE-HDBK-1132-99 I-79 associated cooling system. Agitation of tank contents should be provided, when necessary, to control waste temperature. • Double-walled piping, multi-pipe encasements, and double-walled tanks should be considered to establish the primary and secondary confinement boundaries in underground portions of high-level liquid waste systems. Provisions should be made to detect leakage from the primary confinement to the interspace. • Installation of spare pipelines between transfer points should be considered. Process and waste storage vessels should be vented through appropriate treatment systems that control the release of radioactive material in gaseous effluents, ensuring these releases are ALARA. Design of these systems should consider the following: • Off-gas should be suitably pretreated upstream of off-gas treatment equipment to remove or reduce the concentration of chemicals that may adversely affect system operation. • The venting system should prevent overpressure or vacuum conditions from occurring within vessels. • The venting system should prevent the build-up of hydrogen from radiolysis. • Tank overflows should be directed to collection systems. Integrity of the primary confinement boundary should be determined by some or all of the following measures: • vessel inventory monitoring (e.g., liquid level sensors); • on-line leakage monitoring for the interspace of double-walled vessels (e.g., airborne activity monitors, sump level sensors, conductivity cells); DOE-HDBK-1132-99DOE-HDBK-1132-99 I-80 • leakage monitoring outside confinement vessels (e.g., surveillance wells to detect leakage into ground water); • capability for periodic visual surveillance, including remote visual surveillance with closed-circuit television; • periodic evaluation of test coupons of primary tank construction materials installed before the tank was placed in service; and • other surveillance or testing measures, as appropriate. Low-Level Liquid Waste Confinement . The following should apply to the low- level liquid waste confinement system: • An impervious dike or berm around the process system should provide secondary confinement for low-level liquid wastes. • Process and waste storage vessel vents should be provided. • Retention basins should be lined, fenced, and posted with appropriate radiation warning signs. A system for monitoring radionuclide migration from the basin should be available. • An impervious berm or dike should be capable of retaining the maximum radioactive liquid waste inventory that may be released by a leak or failure of a primary confinement vessel. A capability should exist to transfer waste that has leaked into the secondary confinement. • A means of removing rain or snow from the secondary confinement area should be provided unless rain or snow is precluded from entry to the confinement area. Monitoring or testing of the removed rain or snow should be considered. Transuranic-Contaminated Liquid Waste Confinement . The following

features should be considered in the design of a transuranic-contaminated (to include enriched uranium and 233U) liquid waste confinement system: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-81 • A storage or process building should provide secondary confinement for transuranic-contaminated liquid wastes. • Tank and piping systems used for transuranic-contaminated waste collection, treatment, and storage should be of welded construction to the extent practical. Construction materials should be selected to minimize all forms of corrosion. Consideration should be given to stress relieving, welding parameter controls, etc., depending on the materials used. Fatigue failure should be a design consideration where temperature cycling is required (i.e., evaporator systems, etc.). • Process and waste storage vessel vents should be considered. Nuclear criticality safety should be considered in the design of primary and secondary confinement structures and components. 2.9 RADIOACTIVE SOLID WASTE FACILITIES . 2.9.1 Introduction . Radioactive solid waste facilities (RSWFs) are used to store, treat, and dispose of the range of solid waste generated by DOE facilities and activities. This waste contains high-level, low-level, and transuranic- contaminated solid waste including radioactive-mixed waste. An RSWF may be a separate facility or an adjunct to another facility. 2.9.2 Design Considerations . The design of RSWFs should consider the design features described below. Design requirements vary significantly depending on waste characteristics, waste management techniques, and site characteristics. • Cooling water systems or cooling air systems should be provided, where required, for facilities and equipment associated with the interim storage or treatment of high-level radioactive solid waste, and to maintain the long-term integrity of the primary confinement boundary. To the extent practical, passive cooling means should be used for air cooling systems. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-82 • Instrumentation and control systems should be required at an RSWF to provide monitoring and control capabilities associated with confinement, nuclear criticality safety, and radiation protection. High-Level Waste Disposal Facility Confinement . During the short-term period following emplacement when short-lived nuclides dominate the hazards associated with a disposal facility, the engineered system of barriers should remain effective and should contain the emplaced wastes. Typically, this time period is considered to include at least 300 years but not more than 1,000 years following permanent closure. Technical criteria associated with the engineered system of barriers should address the following: • establishment of a high-integrity confinement system during emplacement (to limit the rate of release of radionuclides from the system), • in situ stresses affecting the engineered system of barriers, • corrosion affecting the engineered system of barriers, • radiological effects on barrier integrity, and • contact with groundwater. During the long-term period, reliance should not be placed on the engineered system of barriers to contain emplaced waste. Confinement during the long- term period should be accomplished by the geologic setting. Technical criteria associated with the geologic setting should address the following: • leaching characteristics of waste and waste binders;

• site and soil characteristics, including fractures, porosity, hydraulic conductivity, sorption, hydraulic gradient, and thermal gradient; • long-term geologic stability; • groundwater travel time; • absence of resources that would be an incentive for human intrusion; and • stability of rock mass. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-83 The facility should allow retrieval of wastes during the 50-year period following emplacement and before permanent closure of the facility. Low-Level Waste Disposal Facility Confinement . Low-level solid waste that is disposed to the ground should be confined by a site-specific system of barriers that may include— but not necessarily be limited to— waste form, waste packaging, and the geologic setting. When site permeability characteristics do not provide the required confinement capabilities, the confinement system should be augmented by the following: • constructing low permeability walls around the low-level waste, • lining the walls and bottom of the excavated area with low permeability material, and • other suitable methods for reducing permeability. Means should be provided to minimize contact of emplaced low-level waste with water. Active water-control measures should not be required following permanent closure. Typical requirements for water control are as follows: • Placing a layer of highly permeable material (e.g., sand, gravel) beneath the low-level waste to channel any percolating water to a sump. • Mounding the soil surface to facilitate surface water runoff. • Use of a suitable low-permeability cover material (e.g., clay) over the disposal area to prevent contact of the waste by infiltrating rainwater. This cover material should be protected by a layer of overburden (e.g., sand, gravel, top soil). DOE-HDBK-1132-99DOE-HDBK-1132-99 I-84 • A site diversion system for surface water runoff during operation of the facility. (This system should not be required following site permanent closure.) • Temporary protective covers (e.g., a tarpaulin) before the completion of the natural in-place soil barrier over the low-level waste. • Revegetation of the overburden layer. • Other suitable and reliable means for minimizing water contact with low- level waste. Solid Waste Confinement Systems. The following provisions are typical for an RSWF confinement system. The actual confinement system requirements for a specific RSWF should be determined on a case-by-case basis. • In general, the primary confinement should be the radioactive solid waste process system equipment and associated off-gas or vent systems during the treatment stage of processing. In special cases, such as RSWF where the processes or storage include corrosive or noxious materials, the radioactive solid waste process or storage system should be totally enclosed and provided with its own ventilation system and off-gas cleanup system. In such cases, the radioactive solid waste process or storage system should be treated as the primary confinement system. Depending on the waste being processed and stored, the primary confinement and secondary confinement should consist of a site-specific engineered system of barriers (e.g., drums, liners, concrete casks). • Secondary confinement for radioactive solid waste during treatment should consist of a process cell or building and its ventilation system; secondary confinement for radioactive solid waste during interim storage

should be provided by a storage building or structure. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-85 • Tertiary confinements are not needed in most cases for radioactive solid waste during the treatment or interim storage phase of the radioactive solid waste management process. Tertiary confinement for radioactive solid waste is typically considered to be the geologic structure of the site. • In addition to these principal confinement systems, features such as change rooms and special access ways should be used to minimize the spread of radioactive contamination within the facility. Primary Confinement System. The primary confinement system consists of process system equipment and its associated ventilation and off-gas system, storage containers, or other waste and site-specific engineered barriers. Secondary Confinement System . The secondary confinement system consists of the process cell barriers and the ventilation systems associated with the cells or building, or a storage building or structure. In some cases, a drum, cask, or other waste and site-specific engineered barrier should provide secondary confinement. • Penetrations of the secondary confinement should have positive seals to prevent migration of contamination out of the secondary confinement area. • Process cells should be supplied with ventilation air from the building ventilation system, and should be provided with exhaust ventilation to control ventilation flow in the event of a credible breach in the secondary confinement barrier. Pressure in the compartments should be negative with respect to the building ventilation system. Special features (e.g., air locks or enclosed vestibules) should be considered for access through secondary and tertiary confinement barriers. Tertiary Confinement System. The natural geologic setting comprises the tertiary confinement system. The tertiary confinement system should meet the following performance objectives: DOE-HDBK-1132-99DOE-HDBK-1132-99 I-86 • following permanent closure, ongoing site maintenance should not be needed, and • in the absence of unplanned natural processes or human contact with a low-level waste disposal facility, calculated contaminant levels in groundwater at the site boundary should not exceed the maximum contaminant levels established in Federal statutes. 2.10 TRITIUM FACILITIES. The DOE Tritium Focus Group has issued DOE HDBK-1129-99, Tritium Handling and Safe Storage. This Handbook provides reference and background information that should be considered during the design of tritium handling and storage facilities. 2.10.1 Introduction . The design and operational philosophy of the older tritium facilities focused on worker protection. The tritium handling equipment was located in airflow hoods, and any releases from the equipment went into the ventilation system, up the stack, and directly into the environment. As long as local airflow requirements were maintained at the proper levels, exposures to workers were low to nonexistent. The high stacks maintained exposures to workers and personnel working or living downwind of such releases well below acceptable levels. By the mid-to-late 1960s, more modern operational philosophies began to emerge. The design philosophy changed and placed the equipment that handled substantial quantities of tritium into gloveboxes; the gloveboxes in turn were equipped with their own, individualized cleanup systems. Although the

initial intent of this type of change was to reduce tritium emissions to the environment to near zero by eliminating large releases, the tritium emissions were only reduced by some 10 to 25 percent. Thus, the primary lesson learned from this type of operational change strongly suggested that most tritium emissions to the environment did not come from large releases, but from the background releases from the facilities themselves. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-87 By the early 1970s, entirely new facility designs began to emerge. Having adapted to the lessons learned from the earlier operational changes, these newer facility designs also placed the bulk of the equipment that handled substantial quantities of tritium into gloveboxes. Rather than having individualized glovebox cleanup systems, the cleanup systems used in the newer facility designs heavily emphasized the use of a centralized cleanup system for glovebox operations. Evacuable covers were sometimes placed over glovebox glove ports to minimize the potential for permeation from the gloveboxes to the working rooms. Additional cleanup systems were installed to handle the emissions from the glove port covers and other vacuum systems that were not compatible with the centralized glovebox cleanup system. Real- time monitoring capabilities were added to the gloveboxes and cleanup systems to track their respective reliabilities. Rapid response, real-time monitoring capabilities were added to the room air monitoring capabilities to protect the worker further. Rapid response, real-time monitoring capabilities were also added to the stack exhaust monitoring capabilities to more reliably monitor releases to the environment. And, in some cases, specialized cleanup systems were added at the room air ventilation level to allow for the cleanup of large releases into a working room, before the tritium released into the ventilation system was finally released to the stack. With more than 25 years of operational experience with various types of newer facility designs, it is clear that the bulk of the emissions from all tritium facilities over the last 25 years have come from the background emissions of the facilities themselves. To better understand how these emissions come about, an appreciation for the behavior of tritium in the facilities is necessary. Once understood, prospective designers and engineers will begin to understand what they can and cannot control through design innovations and techniques. 2.10.2 Sources of Tritium. Tritium is the lightest of the naturally occurring radioactive nuclides. Tritium is produced in the upper atmosphere as a result of cascade DOE-HDBK-1132-99DOE-HDBK-1132-99 I-88 reactions between incoming cosmic rays and elemental nitrogen. In its simplest form, this type of reaction can be written as N + n 6 C + H . (1)7 14 0 1 6 12 1 3 Tritium is also produced in the sun as a sub-set of the proton-proton chain of fusion reactions. Although a steady stream of tritium near the surface of the sun is ejected out into space (along with many other types of particles) on the solar wind, much larger streams are ejected out into space during solar flares and prominences. Being much more energetic than its solar wind counterparts, tritium produced in this manner is injected directly into the earth’s upper atmosphere as the earth moves along in its orbit. Regardless of the method of

introduction, however, estimates suggest that the natural production rate for tritium is about 4 x 106 Ci/yr, which, in turn, results in a steady-state, natural production inventory of about 7 x 10 7 Ci. Tritium is also introduced into the environment through a number of man-made sources. The largest of these, atmospheric nuclear testing, added approximately 8 x 109 Ci to the environment between 1945 and 1975. Because the half-life of tritium is relatively short, much of the tritium produced in this manner has long since decayed. However, tritium introduced into the environment as a result of atmospheric testing increased the natural background levels by more than two orders of magnitude, and, in spite of its relatively short half-life, the natural background levels of tritium in the environment will not return to normal until sometime between the years 2020 and 2030. Tritium levels in the environment cannot truly return to background levels, however, because of a number of additional man-made sources. Tritium is also produced as a ternary fission product, within the fuel rods of nuclear reactors, at a rate of 1-2 x 104 Ci/1,000 MW(e). (Although much of the tritium produced in this manner remains trapped within the matrix of the fuel rods, estimates suggest that recovery of this tritium could reach levels of 1 x 10 6 Ci/yr.) Light-water and heavy-water moderated reactors produce another 500- DOE-HDBK-1132-99DOE-HDBK-1132-99 I-89 1,000 to 1 x 106 Ci/yr, respectively, for each 1,000 MW of electrical power. Commercial producers of radioluminescent and neutron generator devices also release about 1 x 106 Ci/yr. Thus, tritium facilities operate within a background of tritium from a variety of sources. 2.10.3 The Relative Abundance of Tritium . The isotopes of elemental hydrogen have long been recognized as being special— so special, in fact, that each has been given its own chemical name and symbol. Protium, for example, is the name given to the hydrogen isotope of mass-1, and the chemical symbol for protium is H. Deuterium is the name given to the hydrogen isotope of mass-2; the chemical symbol for deuterium is D. Tritium is the name given to the hydrogen isotope of mass-3. Its chemical symbol is T. Protium is by far the most abundant of the hydrogen isotopes. Deuterium follows next with a relative abundance of about 1 atom of deuterium for every 6,600 atoms of protium; that is, the D to H ratio (D:H) is about 1:6,600. Tritium is the least common hydrogen isotope. The relative abundance of naturally occurring tritium (i.e., tritium produced in the upper atmosphere and tritium injected directly by the sun) has been estimated to be on the order of 1 tritium atom for every 1018 protium atoms. The introduction of man-made tritium into the environment, particularly as a result of atmospheric testing, has raised this level approximately one order of magnitude so that the ambient T to H ratio is now approximately 1:1017. DOE-HDBK-1132-99DOE-HDBK-1132-99 I-90 The names, commonly used symbols, atomic masses, and relative natural abundances of the hydrogen isotopes are summarized in Table II. TABLE II. The isotopes of hydrogen. Name Chemical Symbol Atomic Mass Natural Abundance (Percent) Natural Abundance (x:H Ratio) Protium H 1.007 825 03 99.985 % 1:1 Deuterium D 2.014 101 78 0.015 % 1:6,600 Tritium T 3.016 049 26* very low 1:1017 * Calculated 2.10.4 The Radioactive Decay of Tritium .

Generic. As the lightest of the pure beta emitters, tritium decays with the emission of a low-energy beta particle and an anti-neutrino; i.e., 6 + + . (2)Η3 1 eΗ3 2 −β ν Tritium decays with a half-life of 12.3232 ± 0.0043 mean solar years or, using 365.2425 mean solar (days) per mean solar year, 4,500.96 ± 1.57 days. The specific activity of tritium is approximately 9,619 Ci/g, and/or 1.040 × 10 -4 g/Ci. In addition, the activity density (i.e., the specific activity per unit volume) for tritium gas (T2) is 2.589 Ci/cm3, under standard temperature and pressure (STP) conditions (i.e., 1 atmosphere of pressure at 0EC), and/or 2.372 Ci/cm3 at 25EC. Under STP conditions, it can also be shown that these values translate to 58,023 Ci/g-mole and 29,012 Ci/g-atom, respectively. Beta Emissions. Beta particles interact with matter by colliding with bound electrons in the surrounding medium. In each collision, the beta particle loses energy as electrons are stripped from molecular fragments (ionization) or promoted to an excited state (bremsstrahlung production). Because the rate DOE-HDBK-1132-99DOE-HDBK-1132-99 I-91 of energy loss per unit path length (linear energy transfer, or LET) increases as the velocity of the beta particle slows, a distinct maximum range can be associated with beta particles of known initial energy. The beta decay energy spectrum for tritium is shown in Figure 1. The maximum energy of the tritium beta is 18.591 ± 0.059 keV. The average energy is 5.685 ± 0.008 keV. The maximum range of the tritium beta (i.e., the mass attenuation coefficient) is 0.58 mg/cm2. The adsorption of energy from beta particles that emanate from a point source of tritium has been shown to occur nearly exponentially with distance. This is a result of the shape of the beta spectrum as it is subdivided into ranges that correspond with subgroups of initial kinetic energies. As a consequence, the fraction of energy absorbed, F, can be expressed as F = 1 - e-(µ/ )( )(x) , (3) where µ/ is the mass attenuation coefficient of the surrounding material, is the density of the surrounding material, and x is the thickness of the surrounding material. For incremental energy absorption calculations, Equation (3) can be restated as F = 1 - e-µx , (3a) where µ (i.e., the linear attenuation coefficient) is the product of the mass attenuation coefficient (µ/ ) and the density ( ), and x is the incremental thickness of choice. In gases at 25�C, at atmospheric pressure, for example, the linear attenuation coefficients for the gases hydrogen (H2), nitrogen (N2), and argon (Ar), are 1.81 cm-1, 11.0 cm-1, and 12.9 cm-1, respectively. A 5-mm thickness of air will absorb 99.6 percent of tritium betas. A comparable thickness of hydrogen (or tritium) gas will absorb only 60 percent of the tritium betas. Absorption coefficients for other media can be estimated by applying correction factors to the relative stopping power (the scattering probability) of the material of interest. For the most part, these will be directly proportional to ratios of DOE-HDBK-1132-99DOE-HDBK-1132-99 I-92 electron densities. Examples of tritium beta ranges are shown in Table III. The values shown for tritium gas and for air are stated as STP values. FIGURE 1. Tritium beta decay energy spectrum. TABLE III. Approximate ranges of tritium betas.

Material Beta Energy Range Tritium Gas Average 0.26 cm Tritium Gas Maximum 3.2 cm Air Average 0.04 cm Water (Liquid) Average 0.42 µm Water (Liquid) Maximum 5.2 µm Stainless Steel Average 0.06 µm DOE-HDBK-1132-99DOE-HDBK-1132-99 I-93 Photon Emissions. No nuclear electromagnetic emissions (gamma emissions) are involved in the decay scheme for tritium although it is worth noting that tritium does produce bremsstrahlung (braking radiation) as its beta particles are decelerated through interactions with nearby matter. 2.10.5 The Chemical Properties of Tritium . Generic. Although the chemical properties of tritium have been described in great detail, three distinctive types of chemical reactions and one underlying principle in particular are worth noting here. The reaction types are solubility reactions, exchange reactions, and radiolysis reactions. The underlying principle is Le Chatelier’s Principle. An overview of these types of reactions and Le Chatelier’s Principle is presented below. Solubility Reactions. Elemental hydrogen, regardless of its form (H2, D2, T2, and all combinations thereof), can be expected to dissolve to some extent in virtually all materials. On the atomic or molecular scale, hydrogen-like atoms, diatomic hydrogen-like species, or larger, hydrogen-like-bearing molecules tend to dissolve interstitially (i.e., they diffuse into the crystalline structure, locating themselves inside the normal lattice work of the internal structure). Schematically, such reactions can easily be described in terms of the generic reactions: H2 + Material 6 2H@Material , (4a) xHy + Material 6 xHy@Material , (4b) and + Material 6 @Material . (4c)1 3 H 1 3 H Theoretically, however, the underlying mechanics are much more complex. For example, of the generic reactions shown above, none are shown as being reversible. From a chemical perspective, none of these reactions is technically correct because, in most dissolution reactions, the solute that goes in can be expected to be the same solute that comes out. From an operational DOE-HDBK-1132-99DOE-HDBK-1132-99 I-94 standpoint, however, experience has shown that, regardless of the tritiated compound that enters into the reaction, an HTO (i.e., a tritiated water vapor) component can be expected to come out. Presumably, this is due to catalytic effects and/or exchange effects that derive from the outward migration of the tritiated species through molecular layers of water vapor that are bound to the surface of the material. Exchange Reactions . Driven primarily by isotope effects, exchange reacti