DOE-STD-5506-2007, Preparation of Safety Basis Documents for Transuranic (TRU) Waste Facilities

DOE-STD-5506-2007 April 2007 DOE STANDARD Preparation of Safety Basis Documents for Transuranic (TRU) Waste Facilities U.S. Department of Energy Washington, D.C. 20585 AREA-SAFT DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. DOE-STD-5506-2007 ii Available on the Department of Energy Technical Standards Program Web Site at Http://tis.eh.doe.gov/techstds/ DOE-STD-5506-2007 iii Foreword This Standard provides analytical assumptions and methods, as well as hazard controls to be used when developing Safety Basis (SB) documents for transuranic (TRU) waste facilities in the U.S. Department of Energy (DOE) Complex. It also provides supplemental technical information that is specific to TRU waste operations, so that contractors can formulate, implement, and maintain safety bases for TRU waste operations in a consistent manner that is compliant with 10 CFR Part 830, Subpart B, requirements. Nothing in this Standard is intended to conflict with or modify the requirements for compliance with “safe harbor methods” in Table 2, Appendix A, of 10 CFR Part 830, Subpart B. In the case of an apparent conflict between this Standard and a safe harbor methodology for developing documented safety analyses, the language in the safe harbor Standard takes precedence, unless approval for an alternative methodology is requested and approved per Subpart B requirements. The information contained in this Standard is intended for use by all Department of Energy (DOE) and National Nuclear Security Administration (NNSA) sites and all contractors for DOE- owned or DOE-leased, Hazard Category 1, 2, or 3 nuclear facilities or nuclear operations that involve handling and remediation of TRU waste containers. DOE-STD-5506-2007 iv TABLE of CONTENTS PARAGRAPH PAGE 1. Introduction 1 1.1. Background 1 1.2. Scope 1 1.3. Purpose 2 1.4. Applicability 2 1.5. Use of the Words Must and Should 3 2. Acronyms 4 3. Identification and Evaluation of TRU Waste Events 6 3.1. Purpose 6 3.2. Hazard Identification and Standard Industrial Hazard Screening 6 3.3. TRU Waste Operations Minimum Set of Accidents 8 3.3.1. Fire Events 12 3.3.1.1. Fuel Pool Fires (Event 1) 12 3.3.1.2. Small Fire (Event 2) 12 3.3.1.3. Enclosure Fire (Event 3) 13 3.3.1.4. Large Fire (Event 4) 13 3.3.2. Explosion Events 13 3.3.2.1. Ignition of Fumes Results in an Explosion (Event 5) 13 3.3.2.2. Waste Container Deflagration (Event 6) 13 3.3.2.3. Multiple Waste Container Deflagration (Event 7) 14 3.3.2.4. Enclosure Deflagration (Event 8) 14 3.3.3. Loss of Confinement/Containment 14 3.3.3.1. Vehicle/Equipment Impacts Waste/Waste Containers (Event 9) 14 3.3.3.2. Drop/Impact/Spill Due to Improperly Handled Container, etc. (Event 10) 14 3.3.3.3. Collapse of Stacked Containers (Event 11) 15 3.3.3.4. Waste Container Over-Pressurization (Event 12) 15 3.3.4. Direct Exposure to Radiation Events (Event 13) 15 3.3.5. Criticality Events (Event 14) 15 3.3.6. Externally Initiated Events 15 3.3.6.1. Aircraft Impact with Fire (Event 15) 15 3.3.6.2. External Vehicle Accident (Event 16) 16 DOE-STD-5506-2007 v 3.3.6.3. External Vehicle Accident with Fire (Event 17) 16 3.3.6.4. External Explosion (Event 18) 16 3.3.6.5. External Fire (Event 19) 16

3.3.7. Natural Phenomenon Hazard Initiated Events 16 3.3.7.1. Lightning (Event 20) 16 3.3.7.2. High Wind (Event 21) 16 3.3.7.3. Tornado (Event 22) 17 3.3.7.4. Snow/Ice/Volcanic Ash Build-up (Event 23) 17 3.3.7.5. Seismic Event (Event 24) 17 3.3.7.6. Seismic Event with Fire (Event 25) 17 3.4. Expected Operational Events 17 4. TRU Waste Source Term Analysis 19 4.1. Purpose 19 4.2. Definition of Unmitigated Analysis 19 4.3. Bounding the Material-At-Risk 21 4.3.1. Data Uncertainties in Hazard and Accident Analysis 22 4.3.2. Defining a Bounding MAR for TRU Operations 22 4.4. Damage Ratios 24 4.4.1. Container Integrity 25 4.4.2. Container Deflagration Events 28 4.4.3. Fire Scenario Damage Ratios for TRU Waste Containers 32 4.4.4. Damage Ratios for Mechanical Insults 39 4.4.5. Natural Phenomena Damage Ratios for TRU Waste Container Storage 45 4.5. Airborne Release Fractions/Respirable Fractions 49 4.5.1. Deflagration Events 49 4.5.2. Fire Scenarios 49 4.5.3. Mechanical Insults 51 4.5.3.1. Spills 51 4.5.3.2. Impacts 53 5. Consequence Analysis 55 5.1. Purpose 55 5.2. Facility Worker Consequences 55 5.3. Collocated Worker and Public Consequence 56 6. TRU Waste Hazard Controls Selection and Standardization 59 6.1. Purpose 59 6.2. Risk Ranking and Control Selection Guidelines 59 6.3. Clarification of What Challenges the Evaluation Guideline 62 DOE-STD-5506-2007 vi 6.4. TRU Waste Controls 66 6.4.1. TRU Waste MAR Effects on Control Selection 68 7. Safety Basis Review and DOE Risk Acceptance 82 7.1. Purpose 82 7.2. Assurance of Adequate Protection 82 7.2.1. Assurance of Adequate Public Protection 82 7.2.2. Assurance of Adequate Worker Protection 83 7.2.3. Public Accident Analysis Versus Worker Hazard Analysis 84 7.2.4. Reasonable and Adequate Assurance 84 7.3. DOE Review 85 7.4. Summary 87 8. Verification of Safety Basis Implementation 88 8.1. Purpose 88 8.2. Implementation Verification Purpose 88 9. References 91 DOE-STD-5506-2007 vii LIST of TABLES 3.2.1 Hazard Sources and Potential Events 7 3.3-1 Minimum TRU Waste Activity/HE Event Matrix 11 4.3.2-1 Bounding MAR Limits for TRU Waste Operations 23 4.4.1-1 Payload Container Integrity Checklist, 27 4.4.2-1 Drum Deflagration Damage Ratios 31 4.4.4-1 Container Drop and Impact Damage Ratios 44 4.4.5-1 Damage Ratios for Containers Impacted by Seismic Debris 48 4.5-1 ARF*RF Value Applicable to TRU Waste Accidents 49 6.2-1 Consequent Levels and Risk Evaluation Guidelines 60 6.2-2 Qualitative Risk Ranking Bins 60 6.3-1 Uncertainties Associated with Source Term and Consequence Analysis Factors 63 6.4.1-1 Hazard Controls 70 LIST of FIGURES 4.4.3-1 Fire Damage Ratios (DRs) for Direct-Loaded Drums 36 APPENDICES A Results of Analysis of Plutonium Equivalent Curies (PE-Ci) data for Transuranic (TRU) Waste Containers from Multiple DOE Sites in Support of US DOE Environmental Management Programs A-1 B Container Deflagrations B-1 C Damage Ratios for Container Insults and Fire C-1 D Criteria for TRU Waste Drums Requiring Venting/Purging Due to Elevated Internal Hydrogen Concentration D-1 DOE-STD-5506-2007 1 1.0 Introduction 1.1 Background

The DOE is responsible for the safe handling, packaging and ultimate disposal of TRU wastes at the Waste Isolation Pilot Plant (WIPP) located near Carlsbad, New Mexico. Much of this waste, which is a result of legacy operations supporting the U.S. nuclear weapons mission, is now stored at numerous DOE sites located across the United States. These wastes can present significant hazards to workers, the environment, and the public if not adequately controlled. While numerous and located within multiple states, facility operations supporting the TRU waste management mission have shared similarities in terms of the hazards and scope of operations. However, facilities often employ a variety of different controls to manage the TRU wastes. Recognition of these inconsistencies led the DOE to develop this technical Standard, which lays out expectations for analyzing and controlling TRU waste hazards. To support this effort, DOE had to overcome several challenges. Chief among them was that TRU wastes are present at both large and small sites and involve wastes ranging from very low radioactive levels to those with significant radiological hazards. A one-size-fits-all approach could be overly expensive for smaller sites and not necessarily in line with relative lower actual risks. A second challenge was that TRU waste operations are conducted in a variety of newly designed structures and existing buildings originally intended for other DOE missions. These older facilities may not meet current facility design requirements, although they may be compliant with the code of record. Therefore, it was recognized that protective features designed into existing facilities are not always reliable or available as in new facilities. In such cases, alternative controls that include specific administrative controls may become the primary controls available. [NOTE: This does not relieve a new facility or major facility modification from DOE Order O 420.1B nuclear facility requirements.] To support these strategies, DOE collected hazard analysis and control data from all of its major TRU waste sites. This information was used to provide a baseline against which analytical methods and proposed controls could be evaluated, compared, and selected. It also highlighted inconsistencies among TRU waste sites that warranted further guidance. 1.2 Scope Based on the evaluation of existing SB information and input received from TRU waste operations personnel, analysts and DOE SB reviewers, the Standard focuses on topics related to hazard analysis, hazard controls, SB implementation, and the DOE review process. These topics are addressed in a level of detail that supports the existing framework of nuclear facility SB requirements and standards. DOE-STD-5506-2007 2 Specific topical areas covered in the Standard, and their associated Sections are as follows: • Section 2.0, Acronyms, provides easy access definitions to all acronyms used in the Standard. • Section 3.0, Identification and Evaluation of TRU Waste Events, discusses the types of hazards expected during TRU waste operations, defines a minimum set of accidents to be evaluated in the DSA, and addresses DSA provisions for addressing incidents that are inherent to normal operations such that operational impacts from their occurrence are appropriately minimized. • Section 4.0, TRU Waste Source Term Analysis, defines analytical methods and assumptions related to unmitigated analysis, Material-At-Risk, Damage Ratios, and Airborne Release Fractions/Respirable Fractions;

• Section 5.0, Consequence Analysis, addresses assumptions supporting qualitative evaluations of facility workers, as well as dispersion analysis assumptions supporting quantitative evaluations of onsite worker populations and offsite receptors; • Section 6.0, TRU Waste Hazard Controls Selection and Standardization, provides guidelines for standardizing the hazard control selection process and gives specific controls that are appropriate for TRU waste operations. • Section 7.0, SB Review and DOE Risk Acceptance, clarifies expectations for SB review and acceptance of risks. • Section 8.0, Verification of SB Implementation, describes general expectations for ensuring that new/revised SB documents are properly implemented. • Section 9.0 References, provides a list of all references cited in the main body of the Standard. Additional references are provided within each appendix. 1.3 Purpose This Standard provides detailed guidance for consistently analyzing hazards and selecting controls for TRU waste activities. The hazards analysis, accident analysis, and controls for TRU waste activities must be integrated into the overall SB documents for DOE Category 1, 2, or 3 nuclear facilities prepared in accordance with 10 CFR Part 830, Subpart B requirements (or alternate methodology where approved in accordance with the regulation). 1.4 Applicability The information contained in this Standard is intended for use by all DOE and National Nuclear Security Administration (NNSA) sites and all contractors for DOE or NNSA owned or leased, Hazard Category 1, 2, or 3 nuclear facilities or nuclear operations that involve retrieval, DOE-STD-5506-2007 3 handling, storage and processing of TRU waste containers. This Standard applies to Documented Safety Analyses (DSAs) complying with “safe harbor methods” in Table 2 to Appendix A of 10 CFR Part 830, Subpart B (or alternate methodology where approved in accordance with the regulation) and the associated TSRs. This Standard is not a safe harbor method as defined in 10 CFR Part 830, Subpart B. Nothing in this Standard is intended to conflict with or modify the requirements for compliance with safe harbor methodologies listed in 10 CFR Part 830. In addition, the Standard is not intended to conflict with requirements of 10 CFR Part 830.206 related to new Hazard Category 1, 2, or 3 nuclear facilities or major modifications. In the case of an apparent conflict between this Standard and a 10 CFR Part 830, Subpart B requirements, as well as supporting “safe harbor” standards in Table 2 of Appendix A of 10 CFR Part 830, Subpart B, the language in the “safe harbor” standard takes precedence, unless approval for an alternative methodology is requested and approved per the current DOE approval process for 10 CFR 830 exemptions or interpretations. The process used to justify deviations from methods prescribed in the standard should not be confused with the process used for exemptions from DOE nuclear safety requirements. In one case technical justifications for analytical methods or key assumptions are developed and submitted to the SB DOE Approval Authority for their approval of deviation from this Standard. Such deviations should be documented in the Safety Evaluation Report and not confused with the case where new or enhanced safety controls are needed because of a new activity or major modification, and those controls cannot meet current DOE design or other requirements. Where controls cannot meet current requirements, exemptions with appropriate compensatory measures are generally needed to authorize acceptability of not meeting the requirement. Depending on the requirement and its applicability to existing facilities, the SB DOE Approval Authority may not be the same person as the DOE authority for an exemption to current DOE Orders or other requirements. Furthermore, approval of exemptions to DOE Order requirements involving nuclear safety need concurrence of the DOE and/or NNSA Central Technical Authorities per the DOE exemption process in effect at the time of the request.

1.5 Use of the Words Must and Should The verbs "must" and "should" are used throughout this Standard. If this Standard is listed as a contract requirement or otherwise directed by DOE for a facility or project, the DOE contractor or other organization required to meet this Standard must comply with all of the applicable provisions that include the word "must." Provisions that use the word "should" are not required but they are recommended, particularly for complex or hazardous activities. DOE-STD-5506-2007 4 2.0 Acronyms AA Accident analysis AC AEGL Administrative controls Acute exposure guidance level AHJ AK ANSI ARF Authority having jurisdiction Acceptable knowledge American National Standards Institute Airborne release fraction BR CFR CH CVS Breathing rate Code of Federal Regulations Contact-handled Confinement ventilation system DBA DBE Design basis accident Design basis earthquake DCF DID Dose conversion factor Defense in depth DNFSB Defense Nuclear Facilities Safety Board DOE U.S. Department of Energy DOT U.S. Department of Transportation DR Damage ratio DSA Documented safety analysis DU DVS EG EM Depleted uranium Drum venting system Evaluation guideline (DOE Office of) Environmental Management EMHA Emergency management hazards assessment EPA Environmental Protection Agency FO (DOE) Field Office FR Facility Representative FSS Fire suppression system HA HC Hazard analysis Hazard class HEPA HGS ICRP IEEE ISMS High efficiency particulate air Headspace gas sampling International Commission on Radiological Protection Institute of Electrical and Electronics Engineers Integrated Safety Management System IVP Implementation verification process IVR Implementation verification review LCO Limited conditions for operations LEL Lower explosive limit LFL Lower flammability limit LMA LPF MAR Line manager assessment Leak-path factor Material-at-risk MOI Maximally exposed offsite individual NCSE Nuclear criticality safety evaluation NDA Non-destructive assay DOE-STD-5506-2007 5 NDE Non-destructive examination NFPA National Fire Protection Association NNSA National Nuclear Security Administration NPH Natural phenomena hazards ORR Operational readiness review OSHA U. S. Occupational Safety and Health Administration PC Performance category PE-Ci Plutonium equivalent curies PISA PMMA Potential inadequacy in the safety analysis Polymethyl methacrylate POC Pipe overpack container PPE RA Personal protective equipment Readiness assessment RCRA Resource Conservation and Recovery Act RF Respirable fraction RH Remote-handled RLC Removable Lid Canister SAC Specific administrative controls SB Safety bases SBD Safety basis document SC Safety Class SER Safety evaluation report SIH Standard industrial hazard SME Subject matter expert SMP Safety management program SSC Structures, systems, and components SSO Site Safety Office ST Source term SWB Standard waste box TBD TDOP To be determined Ten drum overpack TED Total effective dose TEEL Temporary emergency exposure level TRU Transuranic TSR Technical safety requirements UCL Upper confidence limit USQ Unreviewed safety question UTL Upper tolerance limit VOC Volatile organic compound WAC Waste Acceptance Criteria WIPP Waste Isolation Pilot Plant DOE-STD-5506-2007 6 3.0 Identification and Evaluation of TRU Waste Events 3.1 Purpose

This section provides guidance on identification of hazards expected during various types of TRU waste operations, as well as a minimum set of accident events that are applicable based on these hazards. The definition of Standard Industrial Hazards (SIH), as discussed in DOE-STD- 3009, is also clarified to help distinguish those hazards that do not require analysis within the DSA. Finally, this section provides a distinction for certain operational events that are to be expected during the course of normal TRU waste operations. 3.2 Hazard Identification and Standard Industrial Hazard Screening The identification of hazards inherent in TRU waste activities is necessary to provide a sound basis for identifying potential accident events and performing a hazard evaluation. The hazard identification process should result in a comprehensive list of hazardous materials and energy sources that are present in the facility or operation. This process must be conducted in accordance with the DOE-STD-3009 process for hazard identification and selection of accidents. Hazards commonly expected for TRU waste operations are identified in Table 3.2-1. This listing provides major hazard sources and material groups that could be potential initiators for specific accident events discussed in Section 3.3. Where these hazards are present in a given TRU waste operation, analysts must evaluate the applicability of the corresponding accident event(s). Hazards identified in Table 3.2-1 do not always result in accidental release of radiological materials or hazardous chemicals (i.e., as required to be evaluated by DOE-STD-3009). Depending on the location and specific characteristics of the hazard, it may be considered an SIH. DOE-STD-3009 defines an SIH as a hazard that is: . . . routinely encountered in general industry and construction, and for which national consensus codes and/or standards (e.g., OSHA, transportation safety) exist to guide safe design and operation without the need for special analysis to design safe design and/or operational parameters. Examples of SIH types that are common to TRU waste operations include radiography equipment that is governed by American National Standard Institute (ANSI) standards and heavy equipment hazards regulated by the U.S. Occupational Safety and Health Administration (OSHA). Further discussion and guidance on SIHs, as well as the hazard identification process in general, is provided in DOE-HDBK-1163, Integration of Multiple Hazard Analysis Requirements and Activities. It is not the intention of the DSA to provide analysis of SIH type of hazards. Rather, hazards in Table 3.2-1 are evaluated to the extent that they act as initiators and contributors to accidents that DOE-STD-5506-2007 7 result in a radiological or chemical release. Application of a hazard screening during the hazard identification process can be helpful in distinguishing between SIH hazards and those that must be evaluated in the DSA. Hazard screening is a simple evaluation used to identify those hazards that need no further consideration in the DSA. The screening process sorts through a comprehensive list of hazards based on the following considerations:

• Does the identified hazard have the characteristics of an SIH? Hazardous materials that are incidental to the process operation, such as those that are found in laboratories, or environmental circumstances such as the presence of insects, hanta virus, etc., can be screened from further consideration in the DSA, but should be considered in the preparation of job hazard analyses. Unique hazards cannot be screened and must be carried forward for further evaluation. In determining whether a hazard is unique, consider any variations from standard practice, the magnitude of the hazard, etc. • Does the hazard have the potential for significant interactions with nuclear hazards? Such interactions may not be addressed by consensus standards and require more thorough evaluation than screening would afford (i.e., to verify or determine appropriate controls). Some hazards are adequately controlled, but may still serve as initiators for a nuclear accident. Electrical power is an example. TABLE 3.2-1 Hazard Sources and Potential Events Hazard Source and Material Groups Potential Accidents Electrical Fires (Events 1-4) – In combination with combustible/flammable material Explosions (Events 5-8) – In combination with explosive material Thermal Fires (Events 1-4) – In combination with combustible/flammable material Explosions (Events 5-8) – In combination with explosive material Criticality (Event 19) – Increased concentration Pyrophoric Material Fires (Events 1-4) – Pyrophoric fire; may serve as ignition source for larger fires Explosions (Events 5-8) – In combination with explosive material Spontaneous Combustion Fires (Events 1-4) – May serve as ignition source for larger fires Explosions (Events 5-8) – In combination with explosive material Open Flame Fires (Events 1-4) – In combination with combustible/flammable material Explosions (Events 5-8) – In combination with explosive material Flammables Fires (Events 1-4) – In combination with ignition source Combustibles Fires (Events 1-4) – In combination with ignition source DOE-STD-5506-2007 8 Hazard Source and Material Groups Potential Accidents Chemical Reactions Fires (Events 1-4) – Fire or other thermal effect Explosions (Events 5-8) – Explosion or over-pressurization Loss of Confinement/Containment (Events 9-12) – Toxic gas generation Criticality (Event 19) – Increased concentration, precipitation of material Explosive Material Fires (Events 1-4) – As an ignition source Explosions (Events 5-8) – In combination with ignition source Loss of Confinement/Containment (Events 9-12) – Missiles (in combination with ignition source) Criticality (Event 19) – Loss of configuration or spacing Kinetic Energy (Linear and Rotational) Loss of Confinement/Containment (Events 9-12) – Impacts, acceleration/deceleration, missiles Criticality (Event 19) – Loss of configuration or spacing Potential Energy (Pressure) Loss of Confinement/Containment (Events 9-12) – Impacts, missiles Criticality (Event 19) – Loss of configuration or spacing Potential Energy (Height/Mass) Loss of Confinement/Containment (Events 9-12) – Impacts (falling objects), dropping Criticality (Event 19) – Loss of configuration or spacing Internal Flooding Sources Loss of Confinement/Containment (Events 9-12) – Ground/surface water runoff Criticality (Event 19) – Increased moderation Physical Loss of Confinement/Containment (Events 9-12) – Puncture, dropping Radiological Material All Events – Potentially releasable material

Hazardous Material All Events – Potentially releasable material Ionizing Radiation Direct Exposure (Event 13) – Direct exposure to worker Non-Ionizing Radiation Direct Exposure (Event 13) – Direct exposure to worker Other – May interfere with equipment operation Fissile Material Criticality (Event 14) Non-facility Events External Initiated Event (Events 15 – 19) – These events may be similar to Events 1 – 14 Vehicles in Motion (external to facility) External Initiated Event (Events 15 – 19) – These events may be similar to Events 1 – 14 Natural Phenomena Natural Phenomenon Hazard (NPH) Events (Events 20 – 25) – These events may be similar to Events 1 – 14 3.3 TRU Waste Operations Minimum Set of Accidents The following section represents the minimum set of accident events that must be addressed in the DSA hazard evaluation when the hazard identification indicates the presence of potential initiators that could lead to the accident event. If a particular event is not applicable for a facility TABLE 3.2-1 Hazard Sources and Potential Events - Continued DOE-STD-5506-2007 9 (e.g., volcanic ash does not apply to many DOE locations), then the basis for excluding the event should be developed and discussed with the local DOE Approval Authority. The applicability of a specific accident also depends on whether it is plausible during the TRU waste activity being conducted (e.g., a vehicle accident may not be plausible during glovebox repackaging activities). The following consolidated list of general TRU waste activities has been developed to facilitate an understanding and characterization of TRU waste accident events: • Characterization: Non-Destructive Assay (NDA), Non-destructive Evaluation (NDE), and Headspace Gas Sampling (HGS). These activities are those typically required for package acceptance and certification at WIPP. • Container Handling: Lifting and moving TRU waste containers with forklifts, cranes, drum handlers, etc.; stacking; banding; loading and unloading from waste container arrays; overpacking; and loading on transport vehicle until ready for transport. • Venting and/or Abating/Purging: Installing vents to release gases built up within the TRU waste container, allowing gases to passively vent, and purging the TRU waste container headspace. The purpose of these activities is to reduce the potential hydrogen concentration within the TRU waste container to a level at which the hydrogen no longer presents a deflagration hazard. • Staging and Storage: Static conditions which may include staging (temporary storage), storage, surveillance, and maintenance. Staging and storage may take place inside a facility with features such as fire suppression and ventilation, inside temporary structures such as tents that only protect the waste container from the elements, or outside of any physical structure. • Retrieval and Excavation: Excavation of buried waste and/or retrieval from original storage location. • Waste Repackaging: Intrusive material handling. May include sorting, visual inspection of waste, size reduction, compaction, invasive sampling, dewatering, repackaging, consolidation, conditioning or treatment of reactive material, and absorption or solidification of liquids. • Type B Container Loading/Unloading: Handling and storage/staging of Type B containers.

The minimum set of accident events presented in this Section addresses those events with the potential for consequences that could be significant enough to warrant explicit technical safety requirements (see additional discussion in Section 6). A matrix of the minimum accident events versus typical TRU waste activities discussed above is provided in Table 3.3-1. Areas of the table marked by “X’s” indicate potential applicability. DOE-STD-5506-2007 10 Accident events are presented according to broad categories that include fires, explosion events, loss of confinement/containment, direct radiation exposure, criticality, externally initiated events, and natural phenomena events. These events are applicable to both Contact-Handled (CH) and Remote-Handled (RH) TRU activities. The descriptions and causes of accidents may not be inclusive of certain hazards or operations that are unique to a given site. The hazard identification process, conducted in accordance with DOE-STD-3009, should identify those hazards not addressed by the standard. When an accident is applicable based on the facility’s hazard identification and the type of TRU waste activity being conducted, the accident must be covered in the DSA hazard evaluation. A subset of these accidents may also require formal accident analysis where required in accordance with DOE-STD-3009 (e.g., Hazard Category 2 facilities). DOE-STD-5506-2007 11 TABLE 3.3-1 Minimum TRU Waste Activity/Hazard Evaluation Event Matrix Hazard Evaluation Event 1 Character- ization Container Handling2 Venting &/or Abating/ Purging Staging and Storage Retrieval and Excavation Waste Repack- aging Type B Container Loading/ Unloading Fire Events Fuel Pool Fire (Event 1) X X X X Small Fire (Event 2) X X X X X X X Enclosure Fire (Event 3) X X X Large Fire (Event 4) X X X X X X X Explosion Events Ignition of Fumes Results in an Deflagration/Detonation (external to container) (Event 5) X X X X Waste Container Deflagration (Event 6) X X X X X Multiple Waste Container Deflagration (Event 7) X X X X X Enclosure Deflagration (Event 8) X X X Loss of Confinement/Containment Vehicle/Equipment Impacts Waste/Waste Containers (Event 9) X X X X X X Drop/Impact/Spill Due to Improperly Handled Container, etc. (Event 10) X X X X Collapse of Stacked Containers (Event 11) X X X Waste Container Over-Pressurization (Event 12) X X X X X Direct Exposure to Radiation Events (Event 13) X X X X X X X Criticality Events (Event 14) X X X X X X Externally Initiated Events Aircraft Impact with Fire (Event 15) X X X X X X X External Vehicle Accident (Event 16) X X X X X X X External Vehicle Accident with Fire (Combustible or Pool) (Event 17) X X X X X X X External Explosion (Event 18) X X X X X X X External Fire (Event 19) X X X X X X X NPH Initiated Events Lightning (Event 20) X X X X X X X High Wind (Event 21) X X X X X X X Tornado (Event 22) X X X X X X X Snow/Ice/Volcanic Ash Build-up (Event 23) X X X X X X X Seismic Event (Impact Only) (Event 24) X X X X X X X Seismic Event with Fire (Event 25) X X X X X X X 1 Transport activity accidents and control selection are done in compliance with DOE O 460.1B and 461.1. 2 Movement of TRU waste containers (not including Type B containers) is considered “container handling,” even when it is related to the completion of another type of TRU waste activity. When analyzing these events, one must consider the waste being handled as well as other stored/staged waste that may be impacted.

DOE-STD-5506-2007 12 3.3.1 Fire Events The magnitude of fire events provided below should be consistent with the assumptions of a facility’s fire hazard analysis. Fire sizes and types are generally defined below to facilitate the selection of controls in Section 6.0. In addition, the use of the term “facility” within the fire events does not necessarily mean the evidence of a structure, i.e., fires may occur inside or outside of a structure. 3.3.1.1 Fuel Pool Fires (Event 1) The analysis of liquid fuel fires, separate from other fires, is important because liquid fuel fires have the potential to result in pool fires that have a substantially higher source term than combustible material fires when TRU waste containers are involved in the event. Pool fires can cause rapid heating of containers. This heating can cause relatively small containers, such as 55- gal drums, to experience rapid pressure buildup, resulting in a lid failure and expulsion/ejection of material from the container. The ejected material would burn as unconfined material, resulting in a greater release than confined material. These potential fires are associated with the ignition of pools by various ignition sources, such as thermal energy from the equipment or sparks from moving containers. The fuel pool is formed from the leaking of equipment and/or vehicle flammable/combustible liquids or the spilling of the liquids during refueling, maintenance, or an impact from equipment/vehicles used to support TRU waste operations. The potential amount of fuel is dependent on the equipment/vehicles used within the facility footprint and may range from a few gallons to thousands of gallons. If this is the case, separate small and large fuel pool fire events must be included for complete hazard evaluation and control selection. Additionally, if the fuel pool fire event is initiated by an equipment/vehicle impact and postulated to impact uncontainerized and/or containerized waste; an additional fuel pool fire must be analyzed for complete hazard evaluation and control selection. 3.3.1.2 Small Fire (Event 2) Small fires may affect either one container during a container fire or one to several containers through exposure or direct impingement, but outside of any facility confinement enclosure (e.g., glovebox). This type of fire is limited in size and is contained within a fire zone. Additionally, the intensity of a small fire may be inadequate to result in automatic Fire Suppression System (FSS) activation. These fires, in general, will cause material in containers to burn as confined material. However, some containers (e.g., those with relatively significant quantities of liquids or reactive materials) may result in drum pressurization, lid failure, and ejection of some of the container contents. The ejected material would burn as unconfined material, resulting in a greater release than confined material. The event covers all small fires initiated within the facility, but outside of any facility enclosures. This fire is started from the ignition of combustible and/or flammable materials within the DOE-STD-5506-2007 13 facility as well as exposure fires from vehicles or other equipment within the facility. Fires of this type affect containers through exposure or direct impingement. Separate small fire events from hazards associated with various facility activities may be required to ensure a complete hazard evaluation. The propagation of these fires into a larger fire is addressed in a separate event (Event 4).

3.3.1.3 Enclosure Fire (Event 3) For facilities using enclosures such as gloveboxes or hot cells, this fire is addressed separately from other small fire events to ensure a complete hazard evaluation. This fire covers all internally initiated fires. The ignition source may be from pyrophoric or spontaneous combustion reaction, chemical reaction, or other source of internal heat generation. Flammable gas inside the enclosure may also result in a deflagration, which is addressed in a separate event. Additionally, if waste treatment activities not typically associated with TRU waste operations are conducted within an enclosure (e.g., stabilization of pyrophoric material through controlled oxidation), separate events may be required for complete hazard evaluation and control selection. 3.3.1.4 Large Fire (Event 4) This is a fire that propagates from any of the proposed smaller fire events. Propagated fires of different sizes may be proposed depending on the facility configuration (e.g., a large, multi-level facility may have a room fire, a level fire, and a full-facility fire). The size of the fire analyzed within the DSA will be dependent on assumptions addressed in the Fire Hazard Analysis (e.g., full facility fire may not be plausible because of non-combustible facility construction/design and lack of operational needs for combustible/flammable materials). 3.3.2 Explosion Events 3.3.2.1 Ignition of Fumes Results in an Explosion (external to container) (Event 5) This event is caused by hazards external to the waste matrix such as vehicle fuel/fumes, battery explosions, welding gases, or other explosive gases used in the facility. In addition to explosion overpressures, an explosion could produce missiles that could impact containers of waste. For waste in containers, the release mechanism would essentially be an impact. 3.3.2.2 Waste Container Deflagration (Event 6) This event is due to hydrogen or other flammable/explosive gases (e.g., off-gas from Volatile Organic Compounds [VOCs]) inside the container) in a suspect container. A suspect container is unvented (including those containers with inadequate vents, no vent, or plugged vents) and meets at least one of the following criteria: 1. Obvious indications of pressurization DOE-STD-5506-2007 14 2. Waste stream characteristics indicate a potential for generating concentrations of hydrogen or other flammable gas mixtures greater than or equal to the Lower Flammability Limit (LFL) 3. Waste stream data is either inadequate or unavailable to rule out the potential for generating concentrations of hydrogen or other flammable gas mixtures greater than or equal to the LFL Ignition sources include sparks, heat, etc., that can ignite gases escaping the container, as well as potential ignition sources in the waste, such as metal objects, pyrophoric material, and heat- generating chemical reactions. More than one waste container deflagration event may be required depending on the number of various facility activities and the similarity of the postulated event causes and potential controls. 3.3.2.3 Multiple Waste Container Deflagration (Event 7) This event is due to waste container deflagration propagating horizontally or vertically to initiate additional container deflagrations. This event requires two suspect containers (see the definition in Event 6) to be stacked, or of poor container integrity (see Section 4.4.1) to be stored or staged immediately adjacent to each other (e.g., on a pallet). This event is not required for newly generated drums (see Section 4.4.2 for further discussion).

3.3.2.4 Enclosure Deflagration (Event 8) For facilities using enclosures such as gloveboxes or hot cells, deflagrations within the enclosure are addressed as separate events to ensure a complete hazard evaluation. This event is due to hydrogen or other flammable/explosive gases inside an enclosure or within a container that has been placed inside and opened within an enclosure. Ignition sources include sparks, heat, etc. that can ignite gases as well as potential ignition sources in the waste, such as metal objects, pyrophoric material, and heat-generating chemical reactions. 3.3.3 Loss of Confinement/Containment 3.3.3.1 Vehicle/Equipment Impacts Waste/Waste Containers (Event 9) This event is due to operation of vehicles or equipment within the facility. These vehicles and equipment may or may not be used in close proximity to the TRU waste. The impact type will vary based on the impact source and may involve, for example, container puncture by forklift tines, or result in a stacked drum array falling. 3.3.3.2 Drop/Impact/Spill Due to Improperly Handled Container, etc. (Event 10) This event is due to mishandling of containers or to drops/impacts caused by equipment failure. If TRU waste containers may be dropped from elevated surfaces (e.g., drums falling from third tier or higher during removal), a separate event will be required to ensure a complete hazard evaluation. DOE-STD-5506-2007 15 3.3.3.3 Collapse of Stacked Containers (Event 11) This event is a collapse of a stacked array of containers. The collapse may be a failure of the containers, pallets, or other stacking media due to corrosion, defective construction, damage, or improper stacking (e.g., exceeding limits, unstable array). 3.3.3.4 Waste Container Over-Pressurization (Event 12) This event is due to a buildup of pressure inside of a container. The pressure buildup may be due to radiolysis of water or other hydrogenous material, thermal expansion of material/gases inside the container, or chemical reactions inside the container. This is typically a slowly developing event (on the order of months), although containers with unknown material or with the potential for chemical reactions may pressurize more rapidly (on the order of hours to days). 3.3.4 Direct Exposure to Radiation Events (Event 13) This event is caused by ionizing radiation from the waste. The exposure may be due to normal operational conditions (e.g., handling, cleaning up a spill) or due to an accident that causes the loss of shielding inherent to the container/activity. If the facility processes both CH and RH TRU waste, separate events for these waste types must be included for complete hazard evaluation. 3.3.5 Criticality Events (Event 14) Criticality events can occur due to many different causes. These are typically evaluated in a Nuclear Criticality Safety Evaluation (NCSE) consistent with DOE-STD-3007, Guidelines for Preparing Criticality Safety Evaluations at Department of Energy Nonreactor Nuclear Facilities. Events in the NCSE that require criticality controls should be explicitly presented in the DSA. Also, the NCSE events should be evaluated against other events in DSA to ensure that all potential upsets were considered in the NCSE. 3.3.6 Externally Initiated Events 3.3.6.1 Aircraft Impact with Fire (Event 15) This event occurs when a large commercial aircraft, small general aviation aircraft, or helicopter crashes into the facility and a fire ensues. Site over-flights and nearby airports are contributors to this event.

Aircraft impact events must be evaluated where deemed credible in accordance with DOE-STD- 3014. DOE-STD-5506-2007 16 3.3.6.2 External Vehicle Accident (Event 16) This event is due to a vehicle, not associated with facility activities, impacting the facility/waste containers. Traffic on nearby roads contributes to this event. This event differs from the vehicle impact from operations activities previously discussed in that the vehicle may be of a different type used in the facility (e.g., fuel tanker), traveling at a greater speed, and impact more containers. Additionally, if controls are necessary, the control set for this event may be different than that for operations-related equipment. 3.3.6.3 External Vehicle Accident with Fire (Combustible or Pool) (Event 17) This is a potential follow-on event for the external vehicle accident. After the vehicle accident, spilled combustible waste, and/or fuel from the vehicle ignite and burn. 3.3.6.4 External Explosion (Event 18) This event is similar to the explosion due to mechanical failure with missiles occurring within the facility that was discussed earlier. The hazard is primarily from vehicles/roadways near the facility or storage location, or from nearby locations with large quantities of explosive gas (e.g., nearby gas pipeline, propane tanks, pressurized gas used for characterization or welding, etc.). In addition to explosion overpressures, an explosion could produce missiles that could impact containers of waste. For waste in containers, the release mechanism would essentially be an impact. 3.3.6.5 External Fire (Event 19) This is a fire that begins outside of the facility and propagates to the facility. The external fire could be from wildland fires, other facilities, or another fire source. If TRU waste may be within and/or outside of a building, separate external fires must be addressed. 3.3.7 Natural Phenomenon Hazard Initiated Events 3.3.7.1 Lightning (Event 20) For facilities with electrical systems, a lightning strike may cause fires in the electrical system (e.g., ignition of wire insulation) that could ignite nearby material. Lightning strikes that cause fires outside of the facility are addressed as external fires. Additionally, lightning may strike a container or near stored/staged containers. The direct strike could cause rapid heating and pressurization of a container, with ejection of material. The nearby strike could cause small missiles (e.g., fragments of concrete). 3.3.7.2 High Wind (Event 21) This event is due to high winds causing impacts to both the facility and the containers via falling objects. The falling objects may be nearby trees, pole, cranes, or parts of the facility structure. DOE-STD-5506-2007 17 3.3.7.3 Tornado (Event 22) This event is due to a direct effect of a tornado, falling objects, or tornado-produced missiles causing impacts to both the facility and the containers. Missiles may be produced from various pieces of equipment or material (e.g., pallets). The falling objects may be nearby trees, poles, cranes, or parts of the facility structure. 3.3.7.4 Snow/Ice/Volcanic Ash Build-up (Event 23) Accumulation of snow, ice, or volcanic ash may cause the roof of a facility or structure to collapse, or may cause nearby objects, such as trees, to fall and impact the waste containers. 3.3.7.5 Seismic Event (Impact Only) (Event 24)

The seismic event can cause failure of the facility structure (partial or catastrophic, depending on the facility construction), failure of equipment inside the facility, or other structure failure, which impacts the waste. Additionally, the event can cause containers to fall and spill their contents. 3.3.7.6 Seismic Event with Fire (Event 25) The seismic event can cause failure of the facility, failure of equipment inside the facility, or failure of other structures, which impact the waste. Additionally, the event can cause containers to fall and spill their contents. The structural failure could involve damage to electrical systems that are not seismically qualified or involve other potential ignition sources (e.g., flammable materials or gas lines where present) that can ignite spilled combustible waste or other combustibles in the facility. 3.4 Expected Operational Events A facility’s DSA addresses normal, abnormal, and accident conditions as required by 10 CFR Part 830. A subset of the events evaluated in the DSA includes certain operational events that are expected to occur during the lifetime of a given TRU waste operation even with preventive controls in place. As used in this Standard, expected events are defined as planned occurrences encountered during normal operations that result from hazards inherent to the material and activities. This definition does not include events caused by personnel errors, since these causes involve a control failure that warrants some level of investigation. For example, incidental fires or reactions might be expected during retrieval and excavation of TRU wastes involving flammable/explosive atmospheres. In cases where an expected operational event occurs, it is prudent to validate that established protective measures function as intended, and then resume operations. This is similar in concept to initiating authorized required actions when a Limiting Condition of Operation (LCO) condition is entered. The DOE acknowledges the potential for the event and adequacy of the protective measures through approval of the DSA. Approval of a DSA in which response actions are cited for specified “expected events” effectively authorizes work to continue once the DOE-STD-5506-2007 18 event conditions are evaluated, reported (where necessary in accordance with DOE O 231.1A), and it is confirmed that the expected event occurred as planned and no unanticipated behavior or consequences were exhibited. For the purposes of this Standard, an expected operational event involves known hazards that are described in the DSA, and which does not result in significant consequences to workers or the public with preventive and mitigative controls in place. In other words, the protective features provided to perform operational processes ensure consequences are within the operational standards that apply to the work. For example, worker dose is limited to criteria established in 10 CFR Part 835. The DSA provisions for documenting expected operational events are as follows: • The event is documented in the facility process description of the DSA • The response actions following occurrence of the expected event are specifically documented in the DSA, although they may be as simple as evaluate and report the event to DOE (where necessary in accordance with DOE O 231.1A)

• The event is analyzed in the DSA hazard evaluation • Worker protection measures for the operational event are identified in the DSA A primary benefit of identifying expected operational events is to provide DOE with the means of pre-approving actions for continued operation should certain events that meet the conditions of an Expected event occur. Because these events are expected, appropriate protective measures and actions to ensure continuation of operations must be identified and in place prior to beginning the operation. DOE-STD-5506-2007 19 4.0 TRU Waste Source Term Analysis 4.1 Purpose This section defines assumptions for unmitigated analyses and provides guidance on source term development. The Source Term (ST) is the amount of airborne respirable radioactive material released to the environment. As specified in DOE-HDBK-3010, ST is determined by: ST = MAR· DR · ARF · RF · LPF Where, MAR = material-at-risk is the amount of radionuclides available to be acted on by a given physical stress. DR = damage ratio or fraction of the MAR that is impacted by the postulated accident scenario, unitless ARF = airborne release fraction, unitless RF = respirable fraction, unitless LPF = leak-path factor, unitless 4.2 Definition of Unmitigated Analysis For the purpose of this discussion, “unmitigated” means no credit is given to preventive and mitigative controls to reduce the frequency or consequence of potential accidents. The unmitigated accident scenario is intended to represent a reasonably conservative bounding analysis of potential consequences independent of their likelihood of occurrence (as long as these are physically plausible). Based on recent implementation experience at some DOE sites, the potential for “inherently credited controls” to define the scenario and frequency considerations, and the guidance of DOE-STD-3009, Appendix A, the following general features of an unmitigated analysis are required: 1. Consider material quantity, form, location, dispersibility, and interaction with available energy sources. The unmitigated release calculation represents a theoretical limit to scenario consequences assuming that all safety features including administrative controls have failed, so that the physical release potential of a given process or operation is conservatively estimated. The unmitigated release should characterize the energies driving the release and the release fractions in accordance with the physical realities of the accident phenomena at a given facility or process. NOTE: It is reasonable to assume that certain hazards are not expected to be introduced in the facility (e.g., flammable gases, explosives) if supported by the DSA facility process description and hazards identification. In those cases, unmitigated analysis need not assume their presence simply to ensure a bounding analysis. However, in those cases where unplanned hazards or activities have a real potential of being introduced into the facility (e.g., due to human error and the hazard exists elsewhere on the DOE site), they may need to be analyzed or their exclusion protected with TSR controls as an initial assumption of the analysis. It is also expected that the unreviewed safety question determination process will evaluate proposed introduction of new hazards or activities DOE-STD-5506-2007 20 before they are implemented in the facility, thus preserving the DSA assumption to not evaluate certain hazards.

2. Take no credit for active safety features such as ventilation, filtration systems, and process controls. In addition, do not credit passive safety features producing a leakpath reduction in building source term, such as building filtration. 3. Do not credit building wake in calculating the public or worker doses unless shown to yield more conservative or bounding results. There is considerable uncertainty associated with such analysis, e.g., concentration within the recirculation cavity or immediately downwind from the cavity depends on the release location from the building, size of building and structures around the facility, wind speed and direction, etc. Use of alternative dispersion methodologies than that described in Section 5.3 must have a valid basis and be discussed with and approved by the DOE Approval Authority. 4. The analysis may take credit for passive safety features where the capability is necessary to define a physically meaningful scenario. The effect of acknowledging passive features to define a meaningful accident scenario in the unmitigated analysis means that the unmitigated analysis is not necessarily a “parking lot release” expectation. In addition to those examples cited in DOE-STD-3009 Appendix A, another example for TRU waste operations is that credit may be taken for designed storage racks and fixed-aisle spacing, if these are to survive the postulated events and are not subject to change as part of the facility operations. It should be recognized that the presence of some design features could result in greater releases. As an example, if a facility interior contains heavy objects (e.g., equipment, concrete floors) on floors above the ground floor, the unmitigated seismic accident may have greater releases if this equipment were assumed to fall onto the ground floor than if it were assumed that no facility existed. This also applies to a postulated collapse of a concrete facility compared to the collapse of a lightweight metal type facility. However, it is important to note that such defining assumptions may warrant some level of safety Structures Systems and Components (SSC) designation to ensure that the assumptions remain valid in the future. 5. In general, credit must not be taken for administrative controls (e.g., combustible controls or restrictions). Based on experience within the DOE complex, an exception is application of a MAR control as an initial condition to preserve a Hazard Categorization (HC)-3 designation (e.g., for low-level waste storage) or an imposed HC-2 facility inventory. 6. The following guidance on assessing accident frequency is based on recent DOE experience: a. DOE-STD-3009 and 3011 caution that a frequency cutoff such as less than 10-6/yr (Beyond Extremely Unlikely) is not to be used as an absolute cutoff for DOE-STD-5506-2007 21 dismissing physically credible operational accidents without any evaluation of preventive and mitigative features in hazard analysis. b. Frequency estimates for Natural Phenomena Hazards (NPH) events generally have a lower initiating event frequency (e.g., Unlikely) and are based on design and evaluation criteria provided in DOE O 420.1B and its associated implementation in the DOE 1020 series of standards. Consideration should also be given to frequency of enabling events resulting from the NPH event. c. External manmade accidents are to be evaluated if the event can occur with a

frequency >10-6/yr as conservatively estimated, or >10-7/yr as realistically estimated. Frequency of aircraft events is determined based on DOE-STD- 3014, which uses a 10-6 per year frequency cutoff. d. The frequency of the unmitigated event is the product of the probabilities for independent initiating and enabling events that could cause a radiological release if preventive controls are not credited. An initiating event is the first in a sequence of detrimental events leading to an adverse consequence. Enabling events are those other intermediate events that link the initiating event with the outcome of an accident. Fortuitous circumstances, e.g., activities that are rarely performed, can be credited for the unmitigated analysis. However, failure of preventive controls, whether an active engineered safety feature or an administrative control, cannot be credited for the unmitigated analysis. e. If the failure is caused by human error, the unmitigated annual frequency of occurrence normally should be assumed to be Anticipated unless a rationale for supporting lower frequencies is provided (e.g., requires multiple independent errors of commission or omission, activity is rarely performed, etc.). f. Guidance on Expected operational events is provided in Section 3.4. 4.3 Bounding the Material-At-Risk The amount of hazardous material that is assumed to be at risk from a postulated accident scenario, or MAR, will directly impact the doses to both workers and the public. An overly conservative estimate of the MAR could very well lead to an over-designation of controls that could, in some circumstances, negatively impact safety. On the other hand, an optimistic (non- conservative) analysis could lead to major impacts on operations due to the discovery of discrepant as-found-conditions, Potential Inadequacies in the Safety Analysis (PISAs), preparation of multiple Unreviewed Safety Questions (USQs), and even potentially creating conditions that could lead to accidents. Thus, there is a need to balance the level of conservatism associated with the MAR definition. DOE-STD-5506-2007 22 4.3.1 Data Uncertainties in Hazard and Accident Analysis The purpose of determining MAR estimates during Hazard Analysis (HA) and Accident Analysis (AA) is to identify a bounding value for the scenario being evaluated. During HA, qualitative consequence severity categories are assigned to each of the postulated accident scenarios. Thus, there is a need for an understanding of the MAR expected to be involved. During AA, a more quantitative knowledge of the anticipated MAR is expected and is based on a quantitative assessment of the effects of the postulated release considering factors such as inventory, material form, and the energy sources involved with the release. Data uncertainties associated with the MAR depend on many variables, such as the quality of the current inventory data, whether the data represents Acceptable Knowledge (AK) for legacy waste or newly generated waste, and whether the inventory is based on actual characterization data. Most uncertainties associated with legacy waste stem from the fact that requirements for, and formality associated with AK documentation, have changed significantly, with the requirements for the older documentation being less stringent than current requirements. Thus, uncertainties associated with characterized waste are much less significant, (e.g., intrinsic uncertainties associated with NDA and NDE).

4.3.2 Defining a Bounding MAR for TRU Operations Table 4.3.2-1 summarizes the bounding MAR limits for TRU waste operations. The table provides an algorithm of MAR values based on the number of containers anticipated to be impacted by postulated scenarios (single container, payload, building, etc.), and inventory knowledge (e.g., whether the inventory has been partially or fully characterized). In cases where no characterization data is available, inventory estimates must be based on existing process knowledge or the use or extrapolation of characterization data from similar waste streams. The quantities of TRU material presented in Table 4.3.2-1 follow the general algorithm that a single container scenario assumes the presence of the single maximum loaded container (including instrument uncertainty), while multiple container accident scenarios assume the presence of some combination of containers containing the maximum container value, the 99th percentile value, the 95th percentile value, and the mean value quantities of TRU material, from the population of containers being evaluated. The algorithm also accounts for the extent of characterization associated with the inventory (limited or partial characterization, and fully characterized, e.g., WIPP compliant assay). The use of an additional 20% margin is recommended for single container events in which the container is not characterized or has limited characterization (e.g., not fully WIPP compliant or otherwise acceptably characterized). The methodology in Table 4.3.2-1 provides for additional conservatism to account for the increased uncertainty when the waste containers involved in the accident are not fully characterized. For those inventory populations with only limited or partial characterization, the MAR value should be based on the non-parametric estimate of the 95% upper tolerance limit (UTL95) for the specified percentiles and the 95% upper confidence limit (UCL95) for the mean (arithmetic average) (See Appendix A). Container populations, for which individual container DOE-STD-5506-2007 23 inventories have all been determined, through measurement (and documented), may be considered to be fully characterized for application of the algorithm in Table 4.3.2-1. The MAR methodology in Table 4.3.2-1 provides a reasonably bounding approach for typical TRU waste operations. However, this approach is not intended for the following situations: (1) operations that intentionally commingle containers with the highest distribution of radioactive material in a facility’s inventory (e.g., highest two or three containers in the same array that is impacted by an accident stress); (2) operations in which it can’t be distinguished whether containers with the highest distribution of radioactive material are commingled in a facility’s inventory (e.g., retrieval of legacy containers without data supporting such assumptions); or (3) containers that have been prepared for shipment in accordance with limits established in the WIPP waste acceptance criteria. In the first two situations, the term “commingling” is relative to the proximity of containers that are concentrated in an area that can be impacted by a single accident stress, e.g., intentionally concentrating together or segregating high-MAR drums from the general population of drums.

When using the MAR methodology in Table 4.3.2-1, assumptions regarding the scope of container movement activities should be clearly stated in the DSA. Special attention should be given to whether the scope of container activities could unintentionally concentrate problematic containers, thereby invalidating the MAR methodology. If this situation exists, an administrative control will be required to protect assumptions of the hazard analysis. TABLE 4.3.2-1 Bounding MAR Limits for TRU Waste Operations4 MAR Description Limited Characterization1 Fully Characterized 2 Single Container Maximum container +20% Maximum container Two Containers One at Maximum container, one at UTL95 for the 99th percentile One at Maximum container, one at 95 th percentile Three Containers One at Maximum container, one at UTL95 for the 99 th percentile, one at UTL95 for the 95 th percentile One at Maximum container, one at 95 th percentile, one at mean or median4 Four Containers One at Maximum container, one at UTL95 for the 99 th percentile, two at UTL95 for the 95 th percentile One at Maximum container, one at 95 th percentile, two at mean Greater than four containers One at Maximum container, one at UTL95 for the 99 th percentile, two at UTL95 for the 95 th percentile, Remainder at UTL95 for the mean each, Or Applicable Facility/area/payload Limit 3 One at Maximum container, one at 95 th percentile, remainder at mean each, Or Applicable Facility/area/payload Limit 3 TRUPACT-II Payload N/A Fourteen containers at WIPP WAC Limit3 DOE-STD-5506-2007 24 1 Waste has limited characterization data and relies on measures such as process knowledge. 2 Inventory is assumed to be fully characterized when contents of each container are known (e.g., meets requirements for WIPP compliant assay or other acceptable characterization of each container). 3 Bounding MAR limit determined based on operational needs and inventory profile. If the maximum container limit to be shipped is well below the WIPP Waste Acceptance Criteria (WAC) limit, then the 14 containers must be at the maximum inventory limit. 4 In cases where containers are intentionally grouped (e.g., separation of high or low inventory containers), statistics in this table must be applied to each grouped population of containers. As an alternative to using a statistical MAR approach, process areas with a known throughput of inventory (e.g., TRU staging pad) may establish a bounding MAR limit that is used in the unmitigated analysis. In these cases, any subset of the full facility inventory should be justified on the basis that it contains the maximum inventory that could be impacted by an accident stress. For example, if planned activities are such that a limit of 1,000 PE-Ci is sufficient to bound the MAR based on known container loadings to be staged in a given area, then the unmitigated MAR could be established at this limit. In such a case, the limit must be protected with a specific TSR inventory control. 4.4 Damage Ratios The DR is one of the parameters of the “five-factor formula” presented in the DOE-HDBK-3010 for estimating the airborne radiological release from an accident. The DR is defined in the Handbook as the “fraction of the MAR actually impacted by the accident-generated conditions.” However, there is a degree of interdependence between the definitions of DR and MAR. If only the MAR directly affected is used, then the DR is 1.0. If the MAR is the facility maximum operating limit, then the DR may well be less than 1.0 depending on the accident. What is important is that one convention is used consistently to avoid an obvious potential for assigning incorrect DR values.

The DR is estimated based upon engineering analysis of the response of structural materials and materials-of-construction for containment to the type and level of stress/force generated by the event. Standard engineering approximations are typically used. These approximations often include a degree of conservatism due to simplification of phenomena to obtain a useable model, but the purpose of the approximation is to obtain, to the degree possible, a realistic understanding of potential effects. A DR of 1.0 is often assumed, either for simplicity in performing the calculations as suggested in the DOE-HDBK-3010 or based on conservatism if the final radiological consequences do not drive the need for special TSRs to prevent or mitigate the accident. Section 7.3.6.2 of the DOE- HDBK-3010 provides a very important perspective on assigning DRs: In the examples in this handbook, DRs are typically bounded by assuming a value of 1.0 for the sake of simplicity. The above discussion indicates how conservative such a bound can be. It is important not to lose sight of the fact that the phenomena being examined are generally unlikely to highly unlikely. By the time a maximum MAR has been assumed, the DR has been maximized as 1.0, the bounding ARFs and RFs of this document have been applied, no leakpath is accounted for, and 95% or greater meteorology has been used for DOE-STD-5506-2007 25 dispersion, the answer obtained is extreme. Objectivity must be retained in the evaluation process so that a rote conception does not distract available resources from areas where greater real gains in safety can be made. As previously cautioned in this handbook, answers obtained are only as good as the decisions they lead to. That perspective should be kept in mind when DRs are justified for any specific accident scenario, natural phenomena event, or external events. The selection of appropriate DRs must support an overall conservative analysis consistent with the DOE-STD-3009 methodology (DOE 1994b). DRs must also be selected in context with the conservatisms of the other parameters in the “five factor formula,” i.e., MAR, bounding ARFs and RFs per DOE-HDBK-3010 as required by DOE-STD-3009 Appendix A, and Leakpath Factor (only for mitigated analysis). The following subsections address container integrity, and identify bounding DRs for drum deflagrations, fires, container impacts/spills, and natural phenomena events. 4.4.1 Container Integrity U.S. Department of Transportation (DOT) 7A or equivalent containers purchased for the packaging and storage of TRU waste provide containment of radioactive materials and minimize release of radioactive material to the public and workers. DOT 7A containers must meet the performance testing requirements specified in 49 CFR Part 173. This includes performance testing which demonstrates that the containers can withstand the following types of events: • Water spray test • Free drop test • Penetration test • Stacking test When purchased, TRU waste containers are certified to DOT specifications. However, containers can degrade over time, and DOT certification is only effective for one year after packaging. Legacy TRU waste containers greater than one year, therefore, have lost their DOT certification, but have not stopped performing their intended function. Type 7A containers that meet DOT specifications and conditions most applicable to DOE TRU waste activities are qualified to withstand an impact from a 4-ft drop onto a hard surface without being breached.

It is not reasonable to assume that the structural capability of drums, exceeding one year, has diminished significantly or that these containers will split open upon any impact. This is supported by field experience during handling, movement and storage evolutions. Although handling activities do not subject the drums to the same loads as does an impact from a drop, these activities, along with regular inspections, do provide some evidence that most of the drums have maintained structural capability. During storage, handling, and movement, TRU waste containers may be punctured, crushed, toppled, or dropped, causing failure of the container and release of material. Legacy container performance and the degree of damage from these accident stresses are largely dependent on the structural integrity of the container. Several individual drum drop and palletized drum drop tests DOE-STD-5506-2007 26 have been conducted and conclude that legacy drums will maintain confinement from a 4-ft drop, because any small degradation is likely to be less than the margin of safety in the original drum design. The WIPP CH WAC recognizes that most TRU containers are legacy and, therefore, provides an inspection checklist to document that a container meets the DOT 7A criteria. WIPP has established these criteria to address legacy drums and qualify them against new drum requirements. By applying the WIPP criteria to legacy drums, they can be deemed DOT Type 7A compliant. It is reasonable to conclude that containers that satisfy the WIPP container criteria and may be shipped as DOT compliant containers may also be credited as meeting DOT specifications during storage. The WAC states: Payload containers shall meet U.S. Department of Transportation (DOT) Specification 7A, Type A, packaging requirements. Payload containers must be made of steel and be in good and unimpaired condition prior to shipment from the generator/storage sites. To demonstrate compliance with the requirement that payload containers be in good and unimpaired condition, the exterior of all payload containers shall undergo 100% visual examination prior to loading into a TRUPACT-II or HalfPACT. The results of this visual examination shall be documented using the payload container integrity checklist. A payload container in good and unimpaired condition 1) does not have significant rusting, 2) is of sound structural integrity, and, 3) does not leak. Significant rusting is a readily observable loss of metal due to oxidation (e.g., flaking, bubbling, or pitting) that causes degradation of the payload container’s structural integrity. Rusting that causes discoloration of the payload container surface or consists of minor flaking is not considered significant. A payload container is not of sound structural integrity if it has breaches or significant denting/deformation. Breaching is defined as a penetration in the payload container that exposes the internals of the container. Significant denting/deformation is defined as damage to the payload container that results in creasing, cracking or gouging of the metal, or damage that affects payload container closure. Dents or deformations that do not result in creasing, cracking or gouging or affect the container closure are not considered significant.

These criteria have been assembled into a verification checklist as provided in Table 4.4.1-1. It should be noted that the WIPP WAC and container integrity checklist criteria are subject to change based on field experience and feedback. The Table 4.4.4-1 criteria are based on DOE/WIPP-02-3122 that was in effect at the time of development of this Standard. The most current criteria must be used to determine sound structural integrity of TRU containers. The use of damage ratios specified in the Standard that are based on containers with sound integrity (i.e., DR < 1) must meet these criteria. Application of these criteria assumes container integrity can be verified through an inspection program or process knowledge. Where this cannot be accomplished (e.g., TRU waste retrieval from a burial ground), a DR of less than 1 requires explicit justification. Additionally, in cases where a criterion is met in Table 4.4.1-1, the legacy container cannot be assumed to be of sound integrity. DOE-STD-5506-2007 27 TABLE 4.4.1-1 Payload Container Integrity Checklist Container Examination Discussion of Criteria 1. Is the payload container obviously degraded? Obviously degraded means clearly visible and potentially significant defects in the payload container or payload container surface. 2. Is there evidence that the payload container is, or has been, pressurized? Pressurization can be indicated by a fairly uniform expansion of the sidewalls, bottom or top. Past pressurization can be indicated by a notable outward deflection of the bottom or top. Verify that the drum is not warped. 3. Is there any potentially significant rust or corrosion such that wall thinning, pinholes, or breaches are likely or the load bearing capacity is suspect? Rust must be assessed in terms of its type, extent, and location. Pitting, pocking, flaking, or dark coloration characterizes potentially significant rust or corrosion. This includes the extent of the payload container surface area, covered, thickness, and, if it occurs in large flakes or built-up (caked) areas. Rusted payload containers may not be accepted if: • Rust is present in caked layers or deposits • Rust is present in the form of deep metal flaking, or built-up areas of corrosion products In addition, the location of rust should be noted; for example, on a drum: top lid; filter region; locking chine; top one-third, above the second rolling hoop; middle one-third, between the first and second rolling hoops; bottom one-third, below the second rolling hoop; and on the bottom. Payload containers may still be considered acceptable if the signs of rust show up as: • Some discoloration on the payload container • If rubbed would produce fine grit or dust or minor flaking (such that wall thinning does not occur) 4. Are there any split seams, tears, obvious holes, punctures (of any size), creases, broken welds, or cracks? Payload containers with obvious leaks, holes or openings, cracks, deep crevices, creases, tears, broken welds, sharp edges or pits, are either breached or on the verge of being breached. 5. Is the payload container improperly closed? Inspect the fastener and fastener ring (chine), if applicable, for damage or excessive corrosion. Check the alignment of the fastener to ensure that it is in firm contact around the entire lid and the payload container will not open during transportation. 6. Are there any dents, scrapes, or scratches that make the payload container’s structural integrity questionable or prevent the top and bottom surfaces from being parallel?

Deep gouges, scratches, or abrasions over wide areas are not acceptable. If top and bottom surfaces are not parallel, this would indicate that the container is warped. Dents should be less than ¼ inch deep by 3 inches long and between ½ inch to 6 inches wide. All other dents must be examined to determine impact of structural integrity. 7. Is there discoloration which would indicate leakage or other evidence of leakage of material from the payload container? Examine the payload container regions near vents, top lid fittings, bottom fittings, welds, seams and intersections of one or more metal sheets or plates. Payload containers must be rejected if evidence of leakage is present. 8. Is the payload container bulged? For the purposes of this examination, bulging is indicated by: • A fairly uniform expansion of the sidewalls, bottom, or top (e.g., in the case of a drum, either the top or bottom surface protrudes beyond the planar surface of the top or bottom ring, DOE-STD-5506-2007 28 Container Examination Discussion of Criteria • A protrusion of the side wall (e.g., in the case of a drum, beyond a line connecting the peaks of the surrounding rolling hoops or a line between a surrounding rolling hoop and the bottom or top ring), or • Expansion of the sidewall (e.g., in the case of a drum, such that it deforms any portion of a rolling hoop). 4.4.2 Container Deflagration Events This section addresses the DRs for a deflagration within a container from non-fire initiating events (e.g., internal spark during material handling, impacts to drums). The accident phenomenology is described in Appendix B, "Container Deflagrations", and along with a review of the literature, establishes conservative estimates of DRs for this event. The explosion ejects the drum lid and a fraction of the contents. Radioactive material is released to the environment from three accident stresses: • During the flexing in air • From assumed unconfined burning of a fraction of the material ejected • From assumed burning of the remaining materials inside the drum Appropriate ARFs and RFs for the different contributions are described in Section 4.5. The MAR associated with a single, bounding drum or a two drum deflagration must be consistent with the recommendations in Section 4.3. TRU wastes are actinide surface-contamination on combustible and noncombustible substrates. The contents of some drums are almost entirely combustible materials composed of cellulose and plastic substrates. The combustible materials are often found as multilayer wrapped, especially for most waste with highest potential inventory (e.g., from gloveboxes where waste, especially cellulose waste, is placed in a plastic bag and the air expelled before sealing for ease of handling and space considerations, and placed in a heavy-wall plastic sleeve during extraction from the glovebox). Other drums may be almost entirely of noncombustible items. Other forms of TRU wastes (e.g., sludge, decontaminated equipment, liquids absorbed on diatomaceous earth, etc.) are also found. There are also two categories of TRU drummed waste: “legacy” and WIPP WAC.

The radiolysis of hydrogenous materials by the alpha-activity present in TRU waste generates hydrogen gas that may accumulate in the drums. Based on drum characterization studies until recently, the oxygen content is simultaneously reduced, likely due to reaction with other materials present or hydrogen and oxygen forming water vapor, although this could be offset by inleakage past container seals due to breathing caused by barometric pressure and atmospheric temperature changes. However, recent characterization of drums at the Savannah River Site has demonstrated that sufficient levels of oxygen are present with levels of hydrogen that exceed its Lower Flammability Limit (see discussion in Appendix B). Three components are necessary for burning: fuel, oxidant, and an ignition source. Other factors will affect the ignition and combustion of hydrogen-air mixtures such as concentrations of the reactants, the location of the TABLE 4.4.1-1 Payload Container Integrity Checklist--Continued DOE-STD-5506-2007 29 ignition source, presence of water vapor, etc. Typically in the DOE-complex, the ignition source is assumed to be present. The fuel and oxygen must be mixed and at a sufficient level to support the combustion. Contained gases can explode (deflagrate or detonate) and result in loss of containment and ejection of surface-contaminated combustible and noncombustible contents. The energy release and the duration of the energy release is a function of the explosive reaction: deflagration or detonation. When the fuel and oxidant are in a gaseous state, the flammable mixtures deflagrate (fast burning), but under special conditions (such as proper concentration of the component gases, turbulent mixing, a strong ignitions source, an adequate length/diameter ratio, run-up distance, etc.), a deflagration can transition into a detonation (Deflagration to Detonation Transition). This phenomenon is addressed in Appendix B, which concludes that a deflagration in a drum will not transition to a detonation. There are many published experimental studies on the behavior of metal drums in the literature and those that are relevant and available are reviewed in Appendix B. Appendix B summaries hydrogen and oxygen concentrations measured in legacy TRU waste drums, provides the basis for the drum deflagration DRs, and covers the factors that influence the behavior of the contents (i.e., surface-contaminated combustible and noncombustible materials) of the 55-gal metal TRU waste drums. The Idaho drum deflagration tests discussed in Appendix B indicated that sympathetic deflagration of a drum on top of the initial deflagration occurred. However, the lower drum did not lose its lid due to the weight of the drum on top. No experimentation has been conducted nor observed on sympathetic deflagration of horizontally adjacent drums. Therefore, it is conservatively assumed that sympathetic deflagration is possible involving two suspect drums as defined by Event 7 in Section 3.3.2.3. Although additional sympathetic drum deflagrations may be possible depending on the staging configuration and other factors, modeling more than two drum deflagrations is not deemed necessary, because adequate insights from the two-drum deflagration should be sufficient to establish appropriate controls to protect the facility worker, other onsite (collocated) workers, the public, and the environment, and based on the likelihood of three or more sympathetic deflagrations being very low, this is not perceived to be a significant risk.

Sympathetic deflagrations need not be evaluated for the unmitigated analysis for TRU waste drum handling and staging/storage of newly generated drums associated with typical DOE Complex processes that generate contaminated, combustible wastes. Newly-generated drums are those generated per a site's waste packaging procedure with the intent to meet the WIPP WAC that was in effect since WIPP opened in the 1999, but may not be fully characterized as compliant to the current WIPP WAC. The assumption of not involving more than a single drum is based on the low likelihood associated with multiple upright drums, located adjacent or in nearby proximity to each other, having sufficient hydrogen-air concentration necessary for lid loss (i.e., exceeding approximately 15% hydrogen concentration with at least 7.5% oxygen, a small fraction of legacy drums based on characterization experience, and even lower chance that newly-generated drums would achieve such levels, as described in Appendix B). DOE-STD-5506-2007 30 The following DRs for deflagrations within a drum must be used, unless otherwise justified, for TRU wastes in metal drums: • Single, Bounding Drum o 40% ejected = 0.4 DR based on the maximum value cited in the Idaho experiment evaluated in Appendix B. This 0.4 DR applies to the flexing-in-air release and the unconfined burning outside the drum. Fraction of material that is released from the drum and burns in the ambient atmosphere as unconfined material: 0.05 DR of the mass of ejected combustibles that is ignited by heat generated by the combustion of a stoichiometric H2-air concentration in the drum. This includes the total energy generated by the deflagration of a 30-vol% hydrogen in air (that is assumed to contain a sufficient oxygen concentration for the complete combustion of the hydrogen) and ignoring any heat transfer to other components such as waste remaining in the drum or the drum itself and the possible extinguishment during its flight (see Appendix B discussion). o 0.6 DR for the remainder of the material in the drum that is conservatively assumed to burn, modeled as confined materials. • Two-Drum Deflagration o Both drums – use the values for the single, bounding drum deflagration (i.e., 40% ejected with 0.05 burn fraction), and 60% burning inside the drums, as discussed in Appendix B). In addition, the waste form influences the amount released (e.g., all combustible waste versus some noncombustible wastes). Where an individual site may be able to justify a specific ratio of combustible to noncombustible drum contents, that justification may be credited in the analysis. Releases from combustibles are assumed to be representative of cellulosic materials and surface- contaminated plastics, as discussed in Appendix B. Table 4.4.2-1 DRs for drum deflagrations must be used, unless otherwise justified, for TRU waste operations. DOE-STD-5506-2007 31 TABLE 4.4.2-1 Drum Deflagration Damage Ratios Number of Drums Involved Waste Form Percentage Release Phenomenon DR Fraction Burned Outside DR 1.A. Ejected flexing in air n/a 0.4 n/a 1.B. Ejected combustible waste burning outside 100% 0.4 0.05 1.C. Combustible waste burning inside drum 100% 0.6 n/a n/a – not applicable

The potential presence of prohibited items (cylinders of flammable/combustibles gases, VOCs) in legacy waste also can generate flammable gas mixtures. Appendix B concludes that the behavior of TRU waste drums filled with combustible waste containing a limited quantity of VOC is bounded by the drum behavior resulting from the deflagration of an internal stoichiometric H2-air mixture. This applies to both the ejection fraction and the amount of combustibles that could burn outside the drum. Although the quantity of the VOC is small, under most TRU waste drum situations, larger quantities are not anticipated. Under special circumstances for drums containing liquid VOC or large quantities of cellulose wetted with solvents used to clean glove box interior that are packaged, larger quantities of VOC may be found. This situation would not be bounded by the H2 drum deflagration due to the amount of solvent-soaked combustibles that could burn outside the drum, and the possibility that a larger fraction of wastes may be ejected. For combustible solid wastes with large quantities of VOCs, a DR of 1.0 is conservatively assumed for ejection of combustible wastes and unconfined burning due to the lack of experimental data and uncertainty of what can occur under these conditions. If the contents are radioactive flammable or combustible liquids and no combustible solid wastes, the release must be modeled per recommendations in the DOE-HDBK-3010, Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities assuming a DR of 1.0 for lid loss and subsequent burning of the liquid inside or outside the drum. Internal deflagrations for other container sizes are addressed as follows: • For a Standard Waste Box (SWB), lid loss will not occur for a container deflagration, because the lid is very heavy and bolted onto the body of the box. • Lid loss will not occur for a direct-loaded RH waste container with a welded lid, or the Removable Lid Canister (RLC) for the RH-TRU 72-B cask. The RLC has a very robust lid closure mechanism using grooved tabs (like the TRUPACT-II) and lock pins in lieu of bolting.1 • Overpacking a metal drum of sound integrity with a larger metal drum, a SWB, or a RH canister with nested metal drums can be credited to prevent lid loss and ejection of contents. • For the SWB, RH canister with nested metal drums, and the overpacked drum, a significant release from potential venting through the outer container seal is not expected. 1 See the latest WIPP procedure for more information DOE-STD-5506-2007 32 Any potential release from venting through the outer container would be bounded by the mechanical impact evaluations presented in Section 4.4.4 (e.g., spill-type release). Additionally, a subsequent fire will be limited by the availability of oxygen remaining after the deflagration or inleakage through damaged seals, and is bounded by the fire evaluations presented in Section 4.4.3. • For the Pipe Overpack Container (POC), pressure testing (see Appendix C) showed that even if a hydrogen deflagration should occur, its magnitude would not be enough to damage the pipe component or significantly degrade its filter. • For fiberglass reinforced wooden boxes of legacy TRU wastes, the Idaho test results discussed in Appendix B concluded that sufficient hydrogen buildup is not possible due to its lack of leak-tightness. • For other containers, specific analyses are required to credit their ability to prevent lid loss and/or ejection of materials.

4.4.3 Fire Scenario Damage Ratios for TRU Waste Containers This section addresses selection of DRs for fires in TRU waste container storage in existing facilities for the facility DSA. The technical bases, including conservative assumptions where direct experimental data are not available, for the DR values presented in this section are included in Appendix C, "Damage Ratios for Container Insults and Fires". The most common TRU waste storage container is the open-top, 55-gallon steel drum with a bolted lid locking ring, a DOT Type A container2. Other drum sizes may include 15-gal, 30-gal, 35-gal, 85-gal, and 100-gal. Waste may also be stored in SWBs, special purpose, and in some unique cases, DOT Type B containers. In this section, drums are the primary focus, because they are bounding with respect to vulnerability to release. The term “drum” as used in this section means that it is a metal container of sound integrity as described in Section 4.4.1, so that it provides a confinement safety function. Although SWB lids are bolted in place and are not expected to be lost, they are evaluated for releases from seal failure. This section also addresses overpacked containers (e.g., a metal drum of sound integrity nested within a larger metal drum or a SWB, or Ten Drum Overpack [TDOP]) and POCs. The RH canister is also evaluated for lid loss (direct loaded) and seal failure (overpacked drums). Drum storage areas include rooms within buildings, transportainers, and domed structures, as well as staging or storage outdoors. Fires may also occur in drum loading and unloading areas for transportation. For fire scenarios involving multiple drums, pallets, pads, or the inventory of a building, the general approach is to estimate DRs based on estimating the footprint of the design or evaluation bases fire to determine the area of impact of the fire (includes direct flame contact and the radiant heat and heat fluxes). From this area and the storage characteristics, the number of drums 2 Type A and Type B refer the robustness of the drums, as defined by meeting a series of tests (drop, fire, water, etc.) specified by the DOT. Type B is the more robust of the two, because Type B containers are required to survive a 30-min fire and 30-ft drop test. Type A containers have no requirements regarding fires and must survive only a 4-ft drop. DOE-STD-5506-2007 33 that could be impacted is estimated. Assumptions are made with respect to drums stacked on top of each other, to determine how they fail (i.e., seal failure venting or lid loss due to a fire). The potential for lid loss and ejection of contents is also considered. Extensive solid waste drum fire tests were performed by Hughes Associates, Inc. for the Hanford site and reported in Analytical and Experimental Evaluation of Solid Waste Drum Fire Performance, WHC-SD-TRP-233, and Solid Waste Drum Array, Fire Performance, WHC-SD- WM-TRP-246. These results were interpreted into a protocol to model drums exposed to flammable or combustible liquid pool fires and are published in the Fire Protection Guide for Waste Drum Storage Arrays, WHC-SD-SQA-ANAL-501. The general methodology outlined in Section 5 of that Fire Protection Guide is an acceptable methodology for fire modeling inputs and assumptions to determine the number of drums involved, extent of lid loss with ejected contents and seal failures, and to estimate the overall source term released. As an alternative to applying this Fire Protection Guide, the following simplified approach for flammable or combustible liquid pool fires and for ordinary combustible fires has been conservatively established to determine the extent of lid loss with ejection vs. seal failures and appropriate DRs for the different ARFs and RFs. Other site-specific fire modeling approaches based on drum fire testing results can be applied if technically justified for development of the control set.

4.4.3.1 Drums Exposed by Flammable Liquid Pool Fires Fire calculations to support the DSA analysis are required to determine the size of a pool fire or extent of sufficient radiant heat flux for non-pool fires, which in turn are used to define the number of drums involved. These calculations must be consistent with standard fire protection engineering methods for the bounding type of fires associated with the facility. DSA and fire hazard analysis modeling assumptions (e.g., pool burning characteristics and depth of an unconfined pool) must be consistent unless justified for the different objectives of the analyses (i.e., DSA unmitigated scenario versus a Maximum Possible Fire Loss scenario). Based on fire testing of drums, fires can cause release of radioactive and other hazardous materials from metal containers in two ways. First, fires can cause lid seals to fail, allowing unfiltered out-gassing at the interface between the lid and body of the container. Second, fires can cause the lid to be forcefully ejected (lid loss), possibly with an accompanying expulsion of material from within the container. Ejected materials are subject to the unconfined burning ARF of 1E-2 with a 1.0 RF as discussed in Section 4.5. Unlike the recommendation in Section 4.4.2 regarding unconfined burning of a fraction of the ejected wastes from a drum deflagration, all wastes ejected are assumed to burn unconfined due to the external fire source. Materials remaining in drums with lid loss are subject to the confined burning ARF 5E-4 with a 1.0 RF as discussed in Section 4.5. Seal failures are also subject to the confined burning ARF and RF. Since the different drum responses involving confined and unconfined burning result in significantly different estimates of airborne releases, damage ratios need to be addressed for both situations. To simplify the modeling approach, drum contents are assumed to be 100% combustible contaminated solid wastes. Appendix C discusses how to treat noncombustible contaminated DOE-STD-5506-2007 34 solid wastes if the site can justify bounding estimates for the distribution of combustible vs. noncombustible waste forms. The response of metal containers to fire depends on whether the heat transfer is through direct flame impingement or only through radiation. Lid loss can occur only if specific conditions are met (e.g., a “fast” fire growth rate, direct flame impingement, etc.). Engulfing fires are those fires in which burning liquid fuel (including melted drum liners) passes beneath the container (e.g., on a pallet) or surrounds it. These fires can cause lid loss to a fraction of the engulfed drums, which may expel a portion of the contents. From the fire testing experience described in Appendix C, not all unrestrained drums engulfed in a pool fire experienced lid loss. Twenty-five percent (25%) of the drums engulfed in the pool fire are conservatively assumed to experience lid loss and ejection of some contents, so that the analytical model more accurately represents the results of the fire tests. Some unrestrained drums adjacent to the fire that have direct flame impingement are also conservatively assumed to experience lid loss and ejection, therefore, apply the same 25% assumption. If containers are stacked, the drums on the lower layers are expected to retain their lids, as the weight of the upper layers will keep them in place. However, there are exceptions to this. In experiments with stacked drums, lid rupture was occasionally observed on levels other than the top level. In those cases, however, the lid was displaced, but not totally lost and there was little expulsion of material from within. For modeling purposes, it is sufficient to assume that lid loss occurs only on the top level, and some contents are ejected, as determined next.

For drums that experience lid loss, one-third of the contents (33%)3 are assumed to be ejected from the drum and burn as unconfined materials. The other two-thirds of the MAR are assumed to stay inside the drum and burn as confined materials. The DR is 1.0 for each portion, or this could be thought of as a DR of 0.33 of the total MAR for the expelled portion and 0.67 for the remainder in the drum. Those containers with direct flame impingement inside the pool or along the edge of the pool fire that do not lose their lids will most likely experience lid seal failure and experience confined material burning. If a container on the top tier in the second row outside the pool area is adjacent to a drum in the first row along the edge of the pool fire that loses its lid, seal failure and confined burning is also expected due to the likely magnitude of radiant heat flux from the pool fire and lack of shielding from the first row. Drums on lower tiers in the second row below the top tier do not experience seal failures due to assumed shielding from the first row of lower-tier drums and limited "view factor" from the flame. This approach does not consider toppling of stacked drums and potential for additional unconfined burning of scattered wastes. Rapid pressurization is not expected to topple higher- tier drums based on the Idaho hydrogen deflagration experiment described in Section 4.4.2. The Hanford fire tests did not observe toppling, however, the drums were banded to pallets that allowed the drums to slump vertically. Failure of metal pallets is much less likely and would require a sufficiently long duration fire to cause failure, not typically associated with potential facility fires in TRU waste storage areas, and must only be evaluated in the DSA if it is evaluated 3 See Appendix C discussion regarding how conservative this assumption is. DOE-STD-5506-2007 35 for the Fire Hazards Analysis based on the fixed and transient fuel loading associated with TRU waste operations. However, a fire would be expected to cause toppling of stacked drums on wooden pallets, which must be evaluated if this hazard exists at a site. FIGURE 4.4.3-1 illustrates the above approach to estimate the source term from a pool fire. It also summarizes the approach to calculate non-pool fire source terms as presented in the next section. DOE-STD-5506-2007 36 FIGURE 4.4.3-1 Fire Damage Ratios (DRs) for Direct-Loaded Drums Flammable or combustible liquid pool fire Ordinary combustible fire Use storage area maximum # drums if room flashover Determine # drums within critical heat flux (see Appendix 4.B) Determine # drums inside pool area (MAR) Determine # drums outside pool Define Design or Evaluation Basis Fire Fire Hazard Analysis or Documented Safety Analysis fire modeling Lose lids on 25% of top tier drums Source term from seal failure of remaining 75% of top tier and all lower tier drums: 0.75 DR, 5E-4 ARF, 1.0 RF Eject 1/3 contents Source term from confined burning of 2/3 contents inside drum: 0.25x0.67 DR, 5E-4 ARF, 1.0 RF Source term from flexing in air: 0.25x0.33 DR, 1E-3 ARF, 0.1 RF Source term from unconfined burning: 0.25x0.33 DR, 1E-2 ARF, 1.0 RF Source term from # drums (MAR) in 2nd row adjacent to 1st row drums that ejected contents: 1.0 DR, 5E-4 ARF, 1.0 RF Source term from # drums (MAR) adjacent to pool (1st row) – model the same as inside pool area Source term from < 10 drums (MAR): 1.0 DR,

5E-4 ARF, 1.0 RF Source term from ≥ 10 drums (MAR): 0.5 DR, 5E-4 ARF, 1.0 RF Source term from ≥ 10 drums (MAR): 0.5 DR, 5E-4 ARF, 1.0 RF Source term from < 10 drums (MAR): 1.0 DR, 5E-4 ARF, 1.0 RF D O E -ST D -5506-2007 36 DOE-STD-5506-2007 37 4.4.3.1 Drums Exposed by Ordinary Combustible Fires Non-pool fires are those that involve ordinary combustibles such as trash, wooden boxes, clothing, etc. This type of fire has a “moderate” fire growth rate. Fire experiments have demonstrated that lid loss and ejection of contents is not expected, so for modeling purposes, only seal failures are evaluated. This could include trash fires and wooden crate fires. For direct flame impingement on only one side of a container from an adjacent ordinary combustible fire, the container is not heated rapidly enough to cause lid loss and ejection of contents. When heat transfer is only through radiation, fires involving non-liquid fuel packages (e.g., trash) were determined to not result in lid loss. The heat output of the fire is insufficient to increase temperature and pressure inside the drum quickly enough to eject the lid before venting (seal failure) occurs. The container must be close enough to the fire such that it is exposed to a sufficient heat flux4. If room flashover is possible for the DSA unmitigated analysis, then all containers are subject to seal failures. An additional DR consideration for seal failures to account for incomplete combustion and other factors is appropriate when more than a few drums are involved. The use of a DR for an inventory of a single drum has not been substantiated through direct experimentation. The effect of incomplete combustion of the surface-contaminated solid combustible wastes is incorporated in the DOE-HDBK-3010-94 value in the experiments performed for waste burned in cardboard containers (i.e., the 5E-4 ARF presented in Section 4.5). Because the DR was not measured in the experiment, the relationship between the ARF and DR is unknown, introducing additional uncertainty upon application to other types of containers involved such as metal drums. But, it is reasonable to assume that the release of the same material, contained in a sealed metal drum, will be reduced by some factor due to the drum's effect and vapor and particle transport. However, due to uncertainties in how much of the contents burn and extent of seal failure versus lid loss, for any event that involves 10 or more drums, an assumption of a uniform-like surface contamination is acceptable and a DR of 0.5 is considered reasonably bounding. A DR of 1.0 is assumed for less than 10 drums due to this uncertainty regarding the amount burned and whether there is uniform contamination. Another type of fire that could cause a lid loss occurs when flammable/combustible liquid is present in the drum with other combustible solid wastes. A fire involving any type of fuel package may result in auto-ignition of flammable vapors inside the drum. For these mixed combustible wastes, based on assuming small amounts of the liquid, this phenomenon is modeled in accordance with assumptions presented in Section 4.4.2, unless otherwise justified. The Section 4.4.2 hydrogen deflagration modeling assumptions do not apply to drums of mixed wastes of combustible solid wastes with flammable or combustible liquids that exceed the small- quantity VOC assumption as described in Appendix B, "Container Deflagrations", or drums of radioactive flammable or combustible liquids. For combustible solid wastes with large quantities of VOCs, a DR of 1.0 is conservatively assumed for ejection of combustible wastes and unconfined burning due to the lack of experimental data and uncertainty of what can occur under these conditions. If the contents are radioactive flammable or combustible liquids and no combustible solid wastes, the release must be modeled per recommendations in the DOE- HDBK-3010-94, Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor

4 See Appendix C discussion DOE-STD-5506-2007 38 Nuclear Facilities assuming a DR of 1.0 for lid loss and subsequent burning of the liquid inside or outside the drum. It should also be noted that the Hanford fire tests concluded that an internal fire in a single drum is not expected to propagate to an adjacent drum5, whether the adjacent drum is to the side or above the drum with the internal fire.6 4.4.3.2 Fire Damage Ratios for Other Containers A similar DR for seal failures of SWBs is established based on physical consideration that four drums are approximately equivalent to one SWB. This results in a DR of 0.5 for more than two SWBs involved in a fire (i.e., 10 drums divided by 4 and rounded up). However, a DR of 1.0 is assumed for one or two SWBs involved in the fire. As discussed in Section 4.4.2 on deflagration within a container, overpacking a metal drum of sound integrity with a larger metal drum, a SWB or a TDOP, can be credited to prevent lid loss and ejection of contents and modeled as seal failures. In addition to preventing lid loss, overpacked containers provide an additional level of protection from fires that allows a lower DR than those for directed-loaded drums or SWBs. The dimensions of the SWB are nominally 5 ft long, 4 ft wide, and 3 ft tall, with rounded sides to fit within the TRUPACT-II container for shipments to WIPP. The walls are typically 10- to 12- gauge (about 0.1 in.) sheet metal, and the container is sealed with a gasket and lid with 42 bolts. The TDOP is constructed similar to a SWB and provides primary confinement to a large drum- like volume that can be loaded directly or as an overpack for 10 full 55-gal drums, up to 6 full 85-gal drums, or an SWB. Both the outer container and inner drums in an overpack assembly must have vents installed. For a radioactive material release to occur, the fire has to heat up the inside of the SWB/TDOP and also heat the inner contents of the 55-gal drums resulting in pyrolization of the drum contents and subsequent venting from both containers. The SWB/TDOP configuration presents a significant heat sink and pyrolization of drum contents would require a very long lasting fire or a very large fire. Another consideration is that the SWB/TDOP is large, therefore, it is not expected that all of the waste will be affected by a fire. Although the drum-in-drum overpack does not provide the same level of heat sink, the overpacked drum fire testing described in Appendix B.2.4, "Volatile Organic Compounds (VOCs)" concluded that the average mass loss for a drum overpacking was about a factor of five less than that of the direct-loaded drums that did not undergo "lid loss" (which only averaged about 10% mass loss). Therefore, a DR of 0.1 is assumed for overpacked drums of sound integrity whether overpacked in a larger drum, a SWB, or a TDOP. This applies to a single or multiple overpacked containers exposed to the radiant heat flux that causes seal failures. DRs presented in this section for “overpacked containers” do not apply to overpacked drums of suspect integrity, which must be modeled as a single, direct-loaded drum 5 Fire Protection Guide for Waste Drum Storage Arrays, WHC-SD-SQA-ANAL-501 6 The heat generated by a fire within a drum and possible “torches” via seal failure were not significant enough to heat adjacent drums to cause their failure. This is different than the sympathetic deflagration discussed in Section 4.4.2. DOE-STD-5506-2007 39

Direct-loaded RH canisters may experience lid loss depending on the design of the lid restrain, because it is only required to be qualified as a DOT Type A container. As discussed in Section 4.4.2 for hydrogen deflagrations within a RH canister, lid loss will not occur for a direct-loaded RH container whose lid is welded, or the RLC for the RH-TRU 72-B cask. Although RH canisters with nested drums are expected to behave similar to SWBs and not experience lid loss, the SWB DRs above can be applied to overpacked RH drums in a canister. For RH canisters or drums handled outside a hot cell facility in a shielded "facility cask" or onsite shipping cask that does not meet the DOT Type B criteria7, lower DRs may be appropriate. This can be justified based on a fire hazards analysis or DSA fire modeling to assess the extent of damage for bounding facility-specific fires or material-handling equipment fuel spills8. In the case of POCs, the containers are designed in a manner that precludes their failure during expected storage area fires. Four POCs were subjected to Type B protocol thermal tests as summarized in Appendix C. The associated 150 MW fuel pool fire caused the one outer 55- gallon drum of a POC package with a metal filter to experience lid loss9. This occurred within the first three minutes of the fire. Post-fire inspection showed the pipe component seal and filter gasket to be damaged. Associated leak rate testing of this POC showed a total leak rate of 24 cm3/s at a differential pressure of 87 kPa. This leak rate was later associated with an ARF of 6E- 6 for the bounding material type in POCs (i.e., powder)10. It should be noted that inspection of the POC packages remaining intact revealed that the POCs did not experience temperatures above 200 °F and remained leak tight. Therefore, POCs involved in storage and room fires need not be further evaluated in an accident analysis. However, engulfing fuel pool fires that last longer than 30 minutes exceed the testing conditions and may cause sufficient impact to POCs to warrant assessing the release. 4.4.4 Damage Ratios for Mechanical Insults This section addresses DRs for the steel drums of various sizes (e.g., 55, 85, 100-gal), SWBs, RH canisters, POCs, and overpacked containers (e.g., 55-gal drum of sound integrity nested within an 85-gal drum or four drums in a SWB; the TDOP, or RH canister with nested drums). Several tests have been performed for dropping 55-gal drums from various heights and with various weights and contents, and for crushing drums. These are described in Appendix C, "Damage Ratios for Container Insults and Fires". However, there has been no testing of the SWBs with “bolted down” lids, overpacked containers, or the TRUPACT-II double-stacked seven-pack drum configuration. Therefore, engineering judgment must be used to extrapolate the available test results to these configuration and accident scenarios. The term “drum” as used in this section means that it is a metal container of sound integrity as described in Section 4.4.1, so that it provides a confinement safety function. DRs presented in this section for “overpacked containers” do not apply to drums of suspect integrity, which must be modeled as a single, direct-loaded drum.

7 Casks that meet current Type B criteria normally are expected to survive facility fires typical of those that may occur in the DOE Complex where TRU wastes are stored or handled, unless a facility-specific hazard or accident can cause a mechanical breach of the cask or a much longer duration of fire is possible. 8 For example, see Damage Assessment of Waste Containers Involved in Accidents at the Waste Isolation Pilot Plant, PLG-1121. 9 The other POC packages had plastic filter seals, which melted during the fire. 10 See Appendix C discussion. DOE-STD-5506-2007 40 Drops and impact stresses on TRU waste containers will result in a wide range of damage depending on magnitude of these forces and condition of containers. Spills from a TRU waste container can result from severe shock and vibration stress, from impact events or dropping a container. Spills from a container can also result from the accidental falling or flowing of powders out of a confinement boundary resulting in an airborne release due to the free-fall of the powder in air. As stated in Section 4.4, the DR is that portion of the MAR that is affected by the accident stresses. For TRU waste containers, the materials are primarily contaminated combustible or noncombustible solid materials, solidified/vitrified sludges that do not contain free liquids, or may also be powders of radioactive compounds. Containers may be punctured, crushed, toppled, or dropped, causing failure of the container and release of the material. Dispersal of the material will occur from the kinetic energy from the accident initiator and from the fall of material from the container failure point to the ground. In the case of container failure due to corrosion, the energy for dispersal is provided by the fall of the material from the container failure point to the ground. Significant release of non-dispersible wastes, such as those that have been vitrified or solidified with concrete in metal containers, would require higher energy input to release the wastes than is available from mechanically initiated spills such as container punctures, drops, or falls. Examples of potential spill scenarios may include a spill from a metal container due to a forklift puncture or impact by a compressed gas cylinder missile, a spill of waste container(s) due to drops/falls, or a spill of waste container(s) resulting from impact with material handling equipment. Based on the Sandia, Hanford, and Rocky Flats experimental results of drum testing, each of these types of accidents are addressed in Appendix C to establish a range of DRs for various container types and waste forms. From this range of damages, DRs are established for other drop or impact events that can breach waste containers associated with heights typical of existing facilities in the DOE Complex that store and handle TRU wastes. Six broad categories were chosen to represent the range of damage ratios. Appropriate adjustments are made if the material form is contaminated solids versus sand-like material that may be free-flowing, as well as vitrified waste forms. An overview of Appendix C insights from drum and metal box testing performed by Sandia National Laboratories, Hanford, and Rocky Flats follows.

A majority of the reported drum tests were performed with DOT Type 17C drums with a rigid polyethylene liner containing bagged waste of various forms. However, generators will also ship drums that currently have the designation of Type 17H (thinner wall), and both types of drums will be shipped with and without liners. The type of drum and the presence of a liner within it cannot be readily distinguished once it is packaged. Type 17C drums are made from 16-gauge material, which have a nominal wall thickness of 0.059 inches. The Type 17H drums are made from 18-gauge material, which has a typical wall thickness of 0.039 inches. Based on simple calculations of compression stress in the wall and axial buckling performed in the PLG-1121 report, Type 17C drums are stronger than the Type 17H drums. Because both types of drums are to be handled and stored, the characterization of drum failure should be based on the more limiting case of Type 17H drums. DOE-STD-5506-2007 41 DOT Type A drums are only qualified for a 4-ft drop as discussed in Section 4.4.1. Drum drop testing and static axial crush tests indicated that they perform very well, but results are significantly affected by impact orientation and weight of the contents, among other variables. For example, no lid failures (and thus, no material releases) occurred for drop heights less than 44 ft (13 m) or impact velocities less than ~35 mph for the heaviest drum tested of 748 lb. However, all 1,000 lb drums landing such that the lid locking ring bolt struck the test surface failed at a drop height of 11 ft (3.4 m). Obvious (highly visible) damage to a drum is not necessarily an indicator of drum integrity. Extensive damage to the drum walls may not be indicative of container breach whereas a small amount of damage to the lid and upper sealing surface may cause lid separation and loss of container integrity. The testing concluded that drum deformation cannot be predicted by considering only the kinetic energy of the system; drum contents are important because different materials absorb various amounts of energy. The DRs are based on the amount of spillage of sand-like materials (powders) from test results increased to account for shock-vibration effects that could suspend particulates; a factor of two reduction is assumed for contaminated bulkier materials. The SWBs are made from 10-gauge material (minimum thickness of approximately 0.128 inches) and have a bolted lid. Because there are no tests for the SWBs, some insight is available from the results of the Rocky Flats DOT 7A welded metal box drop tests. There was no apparent failure of seams or closure welds and no contents were lost from either waste box for the 15-ft drop. For the 25-ft drop test, a pinhole leak was detected. Due to the bolted lid and gasket configuration of the SWB, its performance should be similar to the welded box. However, due to the lack of direct test data and that the container is only required to meet the DOT Type A drop test for 4 ft, and its much larger load capacity (4,000 lb), DRs for drops are established based on those for the 55-gal drum. This is also based on simple compression stress in the wall and axial buckling calculation performed in the PLG-1121 report, that concluded that Type 17C drums appear to be stronger than the SWBs, which in turn are stronger than the Type 17H drums. However, the lids for the SWBs are bolted to the body of the container implying that lid separation is much less likely for the SWBs than for the drums. DRs for forklift punctures are reduced by a factor of two due to the much larger size of the container as discussed in Appendix C, and for the accident involving falls equivalent to a fourth tier of drums (about 10 feet).

The RH waste canister for a 72-B shipping cask is a 0.25 inch thick carbon steel cylindrical vessel having 26 inches outside diameter and 121 inches in overall length. Standard vessel heads are welded to each end of the cylinder, or the top may have a mechanical lid such as the RLC described in Section 4.4.2. They are designed to DOT Type A criteria. It is reasonable to assume that their performance during drop and impact events would be at least as good as SWBs, therefore, the SWB DR recommendations apply to spill events involving RH waste canisters. This is also supported by structural calculations in PLG-1305. For RH canisters or drums handled outside a hot cell facility in a shielded "facility cask" or onsite shipping cask that does not meet the DOT Type B criteria11, lower DRs may be appropriate. This can be justified based on quantitative or qualitative arguments to credit the more robust container such as those 11 Casks that meet current Type B criteria normally are expected to survive facility mechanical insults typical of those that may occur in the DOE Complex where TRU wastes are stored or handled, unless a facility-specific hazard or accident is more severe than the testing requirements. DOE-STD-5506-2007 42 presented in the Appendix 3B of the Hanford Solid Waste Operation Complex Master Documented Safety Analysis (HNF-14741, 2005). For overpacked containers, there are no test data available. For the single package drop event, a factor of two credit is believed to be a reasonably conservative estimate, because two metal containers should provide some added protection for drop events. This applies to drums of sound integrity overpacked in another drum, SWB, TDOP, or RH canister, and does not apply to overpacked containers that do not meet the Section 4.4.1 container integrity requirements. The TRUPACT II payload configuration is a two seven-pack plastic-wrapped drum configuration. Based on the pallet drop testing, a DR of 0.5 is recommended, i.e., either the lower seven drums all breached (the more likely consequence), or half the 14 drums on either tier failed. The overall DR includes an adjustment for the type of contents which is based on test data for maximum spillage for two drums and average spillage for the other five drums, and rounding up to account for other shock-vibration effects and for conservatism. This approach is based on the concept similar to that for estimating a bounding MAR involving multiple containers as discussed in Section 4.3. The POC consists of a sealed pipe component (Schedule 40 pipe with 6-inch diameter or Schedule 20 pipe with 12-inch diameter), contained within a Type 17C 55-gal drum. The pipe component is separated from the drum by fiberboard packing material and a plastic liner. The lids of both the drum and the pipe component have filtered vents. The robustness of the POC was assessed by Rocky Flats12 based on data taken from reports of Type B protocol testing conducted at the Sandia National Laboratories (e.g., crush, 30-ft drop, and 30-min fire tests), pressure tests, and Finite Element computer modeling of crushing and puncturing. Rocky Flats concluded that the POC does not qualify as a DOT Type B container, because it was not subjected to the complete Type B protocol testing program and, because the pipe component is vented. However, the tests that were performed were passed and it is expected that the puncture test would also have been passed, based on computer modeling and comparison with similar containers that are certified as Type B. The POC far exceeded the DOT Type A test requirements.

For spill scenarios, POCs are vulnerable only to drops/falls from a distance of greater than 30 ft, structural collapse of substantial construction facilities (where falling structural concrete slabs impact POCs such as seismic collapse addressed in Section 4.4.5), and puncture by forklift tines. Stacked POCs could be toppled due to a forklift collision. The POCs would be expected to withstand the impact associated with the toppling of stacks of POCs, as the distance to fall is less than that in the Type B drop tests: a five-high drum-stacking configuration means that the top drum would fall a distance equal to the height of four drums plus the pallet separators – about 13 ft altogether, less than half the distance used in the drop test. Due to the fiberboard material (Celotex®) fill in the POC, the robust design of the Schedule 20 or 40 inner pipe, and the POC drop test performance, no release is expected from a cylinder missile impact, or from tornado/wind-generated missiles. The POC was determined by finite element modeling to be vulnerable to the forklift tine puncture due to the chisel design assumption and very small impact area. The frequency of a POC punctured by a forklift is Extremely Unlikely as discussed in 12 See Appendix B discussion. DOE-STD-5506-2007 43 Appendix C. This is not the case for other missiles impacting the 55-gallon POC drum with the fiberboard fill where no release is expected. Based on extrapolations and interpretation of the test data discussed in Appendix C as well as DOE Complex precedence established for SB development, the Table 4.4.4-1 DRs for container drops or impacts must be used, unless otherwise justified, for TRU waste operations. These DR recommendations apply a gradation based on energy imparted and container robustness for the range of container breaches presented. DOE-STD-5506-2007 44 TABLE 4.4.4-1 Container Drop and Impact Damage Ratios Damage Ratio (DR)d Accident Stress Drum SWB and RH canister POC Comments 1. Stress within container qualifications 0 0 0 Containers of sound integrity per Section 4.4.1 dropped from 4 ft or less (e.g., 2nd tiera in stacked array). 2. Minor stress causes breach, e.g.: - Single container or unbanded palletized containers dropped from 3rd tier in stacked array - Multiple containers impacted by low- speed vehicle (e.g., less than ~10 mph in congested or tight areas) - Containers containing closed pipes or welded containers that are dropped from 4th or 5th tier in stacked array 0.01 0.01 0 Considered a “spill” event as defined in Section 4.5.3.1 for ARFs/RFs. 3. Container(s) punctured by forklift tines: - Contaminated solids - Sand-like materials 0.1 1.0 0.05 0.5 0.05 0.1 See Appendix C discussion. Considered a “spill” or "low-energy impact" event as defined in Section 4.5.3.1 for ARFs/RFs. Forklift could puncture two drums. 4. Single container or unbandedb palletized containers dropped from 4th or 5th tier in stacked array: - Contaminated solids - Sand-like materials 0.1 0.5 0.1 0.25 0 0 4th tier falls are considered a “low- energy impact” event as defined in Section 4.5.3.1 for ARFs/RFs. 5th tier falls are considered a "high energy Impact" event as defined n Section 4.5.3.2. 5. Moderate to severe stress causes breach, e.g.: - Multiple containers impacted by a vehicle whose speed may be restricted by physical layout of the facility/site and associated obstacles, but whose speed can't reasonably be assumed to be < ~10 mph

- Vehicle crash affecting multiple containers, but not in the first row directly crushed by the vehicle (low or high speeds) 0.1 0.1 0 Considered a “low-energy impact” event as defined in Section 4.5.3.1 for ARFs/RFs, unless containers could be crushed as defined in Section 4.5.3.2 due to site-specific circumstances. 6.Catatrophic stress causes breach, e.g.: - Containers directly impacted by high- speed vehicle with crushing force - Container(s) impacted by compressed gas cylinder traveling long distance and/or airborne - Container(s) impacted by tornado- or wind-generated missile 1.0 1.0 0c Containers crushed by > ~25% volume reduction are considered a "high- energy impact" event as defined in Section 4.5.3.2 for ARFs/RFs. Cylinder and missiles are considered a “low- energy impact” event as defined in Section 4.5.3.1 and Appendix C. a Stacking height applies to 55-gallon drums stacked three or more high (i.e., typical drum height of 3 feet plus a nominal 4 inch pallet per tier). b Credit a factor of 2 reduction for banding 4 drums to a pallet, as discussed in Appendix C. c Use natural phenomena hazard DRs in Table 4.4.5-1 if severe crushing is possible. d For vitrified/concreted wastes in metal containers, a 50% reduction in the DRs associated with the metal container is generally recommended for contaminated solids. DOE-STD-5506-2007 45 4.4.5 Natural Phenomena Damage Ratios for TRU Waste Container Storage The following section addresses how to establish DRs for NPH for TRU waste container storage in existing facilities. The NPH discussion focuses on seismic events affecting existing TRU waste container storage facilities because they usually dominate the extent of potential damage and amount of material released, thus, the radiological consequences. High wind events and tornadoes may also cause extensive damage, including collapse of a structure. However, their radiological dose is much lower due to the higher winds causing dispersion of releases. The following seismic DRs can be used for the other facility-wide NPH events to the extent that the releases are caused by impact from structural debris. Other NPH events such as wind-driven or tornado-driven missiles have much smaller impacts that normally do not drive special TSRs that have common applicability to the DOE Complex. DRs for these missiles are addressed in Section 4.4.4. The technical bases for the DRs are from extrapolation of the DRs presented in Section 4.4.4 and precedence established in the DOE Complex during the development and approval of existing facility DSAs. The general approach is to estimate DRs based on whether or not a facility structure survives the event or collapses. For collapse events, a footprint of damage is defined to determine the number of drums impacted, and effect on stacked drums. If the facility does not collapse, waste containers may be impacted and breached by falling objects (e.g., lights, fire suppression sprinkler lines) and other overhead equipment not seismically rated in the structure that are not qualified to the “Code of Record” earthquake. Toppling of stacked containers is also considered for both events if the DOE requirements for a Design Basis Earthquake (DBE)13 is sufficiently large based on the site-specific evaluation. During an earthquake (and shortly thereafter), portions of a facility may fall onto containers of nuclear materials, breaching some of them, and containers may topple due to the earthquake causing a container breach. Three facility construction types are defined for use in damage assessment of containers and derivation of the corresponding values of DR. These are:

• Light construction (or none) includes tents, wood frame buildings, and open storage areas with no protective structure at all. • Medium construction includes structural steel framing with sheet metal siding and roof. This includes Butler® type buildings and cargo containers • Substantial construction includes buildings made of concrete, cinder block, etc. Because of the robust nature of the packaging used for containing nuclear waste materials (e.g., metal 55-gal drums and boxes), the collapse of a facility of light construction is not expected to breach the containers. Therefore, the analyst must assume DR = 0 for facilities of light construction for seismic events. For facilities of medium and substantial construction, the extent of damage to containers depends upon the magnitude of the earthquake. Various designations have been used for earthquakes of 13 Or "Derivative DBE" or "Evaluation Basis Earthquake" for evaluation of existing nuclear facilities. DOE-STD-5506-2007 46 different sizes. A Code of Record earthquake is one that a facility was originally designed and built to withstand. Thus, it is not expected to experience any structural damage that could cause significant radiological releases. An earthquake that causes collapse of the structure is called a “Collapse Earthquake” for the purposes of this DR discussion. During a Collapse Earthquake, 100% of the exposed packages may be assumed impacted by falling debris in a facility of substantial construction. This debris would include massive chunks of concrete from a ceiling or roof. All waste containers inside buildings are affected, because of impact from falling objects and collapsing building components such as walls, roofs, and structural I-beams, and/or toppling. For a medium construction building, the number of containers impacted by falling I-beams may be estimated by determining the I-beam area relative to the total floor area for a large size TRU waste storage building. The I-beam area for each building can be determined as follows: %I-beam area = [I-beam width (assumed to be 1 ft) × I-beam length (feet) × number of I-beams per building] / total area of building. Alternately, in lieu of the above calculation for a specific building design, the number of packages impacted may be conservatively assumed as 10%, based on DOE Complex-wide application of the above formula for typical TRU waste medium construction facilities. However, as discussed next, not all impacted containers are assumed to be breached. For both medium and substantial construction facilities, the amount of damage to an impacted package depends on its construction, as follows. • For drums, 10% of those impacted may be assumed breached (i.e., penetration of drum and internal packaging). This value is based on engineering judgment. It takes into account the strength of the drums and the types of overhead materials that may fall (i.e., they have to be heavy and fall with a sharp edge or corner hitting the package). Another interpretation as applied to a population of containers impacted by an accident, a DR of 0.1 represents: (1) 100% of the affected containers spilling 10% of their contents; (2) 10% of the affected containers spilling 100% of their contents; or (3) a combination of these two. A DR of 0.1 is considered reasonably conservative given the various mechanisms by which containers may be compromised (uplift, toppling, rolling and impact, equipment or building falling on the containers, missile strike). This value does not apply if only a couple of drums are impacted, where a 1.0 breach fraction must be assumed.

• For SWBs, the same 10% assumption as for drums applies. • For overpacked containers, a factor of two reduction from the drum DRs may be assumed breached, i.e., 0.05. This lower value is based on the configuration of the 55-gal metal drum nested within a larger metal container (e.g., four 55-gal drums inside a SWB or the TDOP, giving additional protection). This value does not apply if only a couple of drums are impacted, where a 0.5 breach fraction must be assumed. DOE-STD-5506-2007 47 • POCs afford even greater protection and only 1% of those impacted may be assumed breached in a substantial construction facility. However, a DR of zero is expected in a medium construction facility, as the falling debris would not be as massive as in a substantial-construction facility. POCs are vulnerable to being crushed by a collapsing concrete building, but not prefabricated metal buildings. The Rocky Flats report14 noted that finite element modeling of the impact of falling heavy objects was done only for the bare pipe components, not the complete POCs. Therefore, the results of these simulations can be used in either of two ways. First, the modeling results can be considered conservative, because the drum and its packing material absorb some of the impact, as was demonstrated by the Type B crush tests. For example, in the top-impact crush tests, 500 kg (1,100 lbm) steel plates were dropped on the POCs. The drums were shortened by about 13 cm (5 inches), but the pipe components were undamaged. The side-impact test also showed that the drum and its packing material absorbs some of the impact energy. • If direct loaded, RH canister performance should be similar to the SWB. Therefore, SWB DRs can be applied. RH canisters with nested drums must be modeled similar to overpacked containers. If the RH canister is handled outside a hot cell in a "facility cask" or onsite shipping cask that does not meet the DOT Type B criteria15, lower DRs may be appropriate, and can be modeled similar to mechanical spills discussed in Section 4.4.4. The NPH DR is the product of the fraction impacted times the fraction breached from the preceding discussion. For a substantial construction facility subject to a Collapse Earthquake, the NPH DR is 0.1 (i.e., 100% impacted x 10% breached) for drums and SWBs, and 0.01 (i.e., 100% impacted x 1% breached) for POCs. For a medium construction facility subject to a Collapse Earthquake, the NPH DR is 0.01 (i.e., 10% impacted x 10% breached) for drums and SWBs, and no release for POCs (i.e., DR = 0). DRs for the Code of Record earthquake are scaled down from those for the Collapse Earthquake based on engineering judgment. They are based on the assumption of limited amount of non- seismically qualified overhead mounted equipment (e.g., suspended space heaters, electrical distributions and lighting, fire sprinklers, etc.) that could fall and impact containers. This limited amount of damage is expected to result in at least a factor of 10 reduction from the NPH DRs applicable to the Collapse Earthquake. For the Code of Record earthquake, the DRs are for the exposed containers to the falling debris. If stacked, only the top tier is considered exposed. For example, four-high stacking means that only 25% of the containers are exposed.

Stacked drums can also topple during an earthquake of sufficient magnitude. In the event that stacked drums fall during an earthquake, only those from the third tier and above could possibly rupture due to the DOT Type A qualification of the drums to withstand a 4-ft drop. For the unmitigated analysis, the DR values presented in Table 4.4.4-1 based on stacked tier height are applicable to seismic-induced toppling, e.g., 0.1 DR for all fourth-tier drums and 0.01 for all 14 See Appendix C. 15 Casks that meet current Type B criteria normally are expected to survive facility mechanical insults typical of those that may occur in the DOE Complex where TRU wastes are stored or handled, unless a facility-specific hazard or accident is more severe than the testing requirements. DOE-STD-5506-2007 48 third-tier drums for contaminated solids (these are in addition to the above recommendations for releases from falling debris). These DRs do not consider the potential additional release from non-seismically qualified cranes that may be in TRU waste facilities. An additional evaluation of the extent of damage from the crane collapse should be performed in the DSA based on the facility-specific circumstances. If the drum banding (four drums to a pallet) is credited for the mitigated analysis, the chances of toppling are very small. The horizontal force would have to be great enough to cause the center of gravity of the stack to be displaced at least two feet from normal for the entire stack to topple. A site-specific structural engineering analysis should be performed to determine whether toppling is possible for unbanded and banded drums for the Code of Record and/or Collapse Earthquake being evaluated in the DSA. For the mitigated analysis crediting banding on pallets, the Table 4.4.4-1 DRs can be reduced by a factor of 2 (extrapolated from the Appendix C Hanford pallet drop test results). Based on the engineering evaluations discussed in Appendix C, stacks of SWBs, TDOPs, and TRUPACT-II payloads are not expected to topple (i.e., the DR would be zero) unless the site- specific engineering analysis determines otherwise. Finally, POCs are so robust that even if they toppled from five-high stacking, they would not be breached (DR = 0). Table 4.4.5-1 summarizes the DRs for seismic debris impacts that must be used, unless otherwise justified, for TRU waste operations. TABLE 4.4.5-1 Damage Ratios for Containers Impacted by Seismic Debris Building Construction Container Type Earthquake Type Substantial Medium Light Toppling Containers Code of Recorda 1E-2 1E-3 0 note (b) Drum Collapsee 1E-1 1E-2 0 note (c) Code of Recorda 1E-2 1E-3 0 0 [note (b)] SWB Collapsee 1E-1 1E-2 0 0 [note (d)] Code of Recorda 1E-3 0 0 0 [note (b)] POC Collapsee 1E-2 0 0 0 a Applies to containers exposed to falling debris. Use the "low-energy impact" ARFs/RFs from Section 4.5.3.1. b Earthquake magnitude is assumed not sufficient to topple containers for the Code of Record earthquake, unless site-specific engineering analysis determines otherwise as discussed in Section 4.4.5, then note (c) applies. c Use Table 4.4.4-1 DRs based on tiers and dispersible form of material. d Earthquake magnitude is assumed not sufficient to topple containers for the Collapse Earthquake unless site- specific engineering analysis determines otherwise as discussed in Section 4.4.5, then note (c) applies. e Use the "low-energy impact" or "high-energy impact" ARFs/RFs from Section 4.5.3 depending on facility-specific

circumstances and magnitude of the debris that can cause substantial crushing of containers. For POCs, use the "low-energy impact" ARFs/RFs based on its testing performance described in Appendix C. The impacts of NPH may also need to consider subsequent fires and explosions and associated DRs for those types of events. This is a facility-specific consideration based on the existence of DOE-STD-5506-2007 49 fixed and transient combustibles, ignition sources, and/or presence of flammable or combustible gases and liquids. 4.5 Airborne Release Fractions/Respirable Fractions The ARF and RF are key factors in estimating the amount of airborne materials generated from accidents involving solids, liquids, gases or surface contamination. ARF and RF values are given in DOE-HDBK-3010-94 (see the handbook for further discussion of values and assumptions referenced in the table). Pertinent values from DOE-HDBK-3010-94 as applied to TRU waste accidents are clarified in this section of the Standard. ARF and RF values vary according to the form of material and type of accident stress. A breakdown of TRU waste forms and accident types is discussed in this section of the Standard and summarized below in Table 4.5-1. The resulting product of ARF and RF values must be used, unless otherwise justified, for TRU waste operations. TABLE 4.5-1 ARF*RF Value Applicable to TRU Waste Accidents Mechanical Insults Waste Form1 (surface- contaminated) Explosion2 Over- Pressure3 Fire4 Spill5 Impact6 Ambient Atm. (see fire)7 --- 1E-27 --- --- In container (see fire) 1E-4 5E-4 1E-4 1E-4/2E-3 Combustible – cellulose, plastics In-flight 1E-4 --- --- --- --- Grout – cement, concrete 3E-4[ED]8, 9 <1E-6 7E-5 7E-4 Sludge or liquid slurries MR10 1E-4 2E-3 4E-5 MR11 Liquid MR10 2E-3 2E-3 1E-4 4E-5 Soil/Gravel, Powder, Granules 2E-49 7E-2 6E-5 6E-4 1E-3 Metal, Non-Combustible materials not subject to brittle fracture MR10 1E-312 6E-512 1E-412 1E-312 In-package 5E-4 HEPA filters Un-contained 1E-213 2E-3 1E-4 1E-2 1E-3 [ 1 The event is assumed to fail any additional layers of plastic wrapping. 2 Deflagration of H2-air stoichiometric mixture that ejects lid and some fraction of the contents. 3 Internal pressure that fails the container and expels some fraction of the contents at a pressure ≤500-psig. 4 Thermal stress that ejects lid and some of the contents. Some fraction of the ejected combustible contents may burn as well as the residual contents that remain in the open drum. 5 Some fraction of the contained powder and liquid contents are released from a location that is elevated to the equivalent of 3rd or 4th tier of stacked drums as defined in Table 4.4.4-1 and impacts a hard, unyielding surface. 6 The container is impacted with two possible levels of force. For lower energy impacts that do not crush the container, the "Spill" ARF*RF value of 1E-4 is applicable as discussed in Section 4.5.3.1. For impacts postulated that crush the container due to falling massive debris such as during a seismic event, or an errant blow from a high-speed vehicle crash that crushes the container, the cited value of 2E-3 is applicable as discussed in Section 4.5.3.2. The phenomena in this category are complex; and, provided a defensible technical basis is developed, other ARF & RF values are allowed. 7 For the fraction ignited from a container due to deflagration event or ejection from thermal effects that burns to completion. 8 Applied to the volume of grout/cement affected, ED = Energy Density, J/cm3. Note: ARF*RF values vary according to drop height and material density. The density of concrete is used to approximate ARF/RF values. A drop height of

DOE-STD-5506-2007 50 3 m is used to bound ARF*RF values for the “Spill” category. A drop height of 4 m (roughly 5th tier of array) is used to bound values for the “impact” category. 9 This form does not generate a combustible gas/vapor and the value only applies if this form is combined with a material that does generate a combustible gas/vapor. 10 Steindler and Seefeldt correlation for detonation on/or contiguous to material– Mass Ratio (MR) = mass inert, kg ÷ TNT Equivalent, kg. See Table 3-6, pg 3-46, in NUREG/CR-6410 for ARF & RF values. RF limited to RF of source material-of-concern. 11 The [ARF][RF] can be estimated by calculating the energy imparted to the slurry and assuming a free-fall and impact from the height that would insert that energy into the material. 12 Of loose, surface-contamination present. Metal fragmentation is not anticipated. 13 Assumes deflagration blast passes through the High Efficiency Particulate Air (HEPA) filter prior to failure of container. 4.5.1 Deflagration Events Deflagration accidents involve several types of accident stresses. The modeling of this event, as discussed in Section 3.3 and Section 4.4.2, is conservatively assumed to involve the ejection and ignition of combustible wastes. The fraction of wastes that is ejected and burns is modeled consistent with DOE-HDBK-3010-94 values for unconfined cellulosic or plastic materials. The bounding ARF is 1E-2 and RF is 1.0. The ejected material that is “in-flight” (i.e., traveling through the air) can shed particles due to the flexing of the substrate during the transmission. The ARF and RF cited in DOE-HDBK- 3010-94 for this phenomenon are 1E-3 and 0.1. These values must be applied to the same fraction assumed to be ejected from the drum. The surface-contaminated combustible material that remains in the open drum is also assumed to burn. The ARF and RF cited in DOE-HDBK-3010-94 for “packaged waste” are applied. The bounding values are 5E-4 and 1.0. 4.5.2 Fire Scenarios Airborne releases due to thermal stresses are primarily influenced by the form and combustibility of TRU waste materials and whether they are packaged or loosely strewn about. Cellulosic or plastic materials that are packaged must be modeled consistent with Section 5.2.1.1 of DOE HDBK-3010-94, which assigns bounding ARF and RF values of 5 E-4 and 1.0 for packaged wastes. The original experiments supporting these values were performed on wastes packaged in plastic bags and sealed in cardboard cartons. DOE-HDBK-3010-94 states that even waste placed together in a pile without bag containment forms a loosely agglomerate package of sorts. Therefore, combustion of TRU wastes that is contained in drums or boxes, meets the definition of packaged waste, even when these containers have suffered lid degradation or loss. Thermal stress on combustible cellulosic or plastic materials that are either ejected from containers or otherwise unconfined or packaged must assign bounding ARF and RF values from Section 5.2.1.2 of DOE-HDBK-3010-94, which are 1 E-2 and 1.0 respectively. These values must also be applied to the burning of unpackaged waste that is located in glovebox enclosures. The ARF value for plastics in DOE-HDBK-3010-94 is 5E-2. This is based upon the maximum measured value for a pile of ball-milled Depleted Uranium (DU) oxide powder lying on granular DOE-STD-5506-2007 51

Polymethyl Methacrylate (PMMA). The phenomenon that suspends the particles from burning PMMA, a thermoplastic material, requires energy to melt the plastic prior to ignition and burning of the vapors. In drummed TRU waste, the contaminant is incorporated into the matrix of material that is folded with contaminant inside or high-activity material from glovebox in additional layers of plastics. The single value cited in DOE-HDBK-3010-94 for the ball-milled DU powder lying under the granular PMMA, ARF 1E-2, is most representative of the conditions here, but probably still over-estimates the airborne release. Other plastic materials such as polystyrene, polycarbonate, and cellulose have bounding ARFs of 1E-2 with RF values less than 1.0. Thus, a more representative, but still bounding ARF for plastics under these conditions is ARF 1E-2. Because the ARF values for cellulose are 1E-2, the value is applied to all combustible material ejected from the drums that burn in the ambient atmosphere. Other forms of TRU waste that are noncombustible may include concrete or grout form, sludge or liquids, soils/gravel/powders, or solid metal forms. Values as described in Table 4.5-1 vary from 2E-3 for sludges and liquids (assumed to be at boiling point of water) to less than 1E-6 for grout forms. Noncombustible waste fractions of inventory that are assumed in the DSA should be conservatively assumed and supported by waste generator data. This assumption must not be used in single drum accidents due to the potential that average waste composition for an entire inventory may not be bounding for single drums. 4.5.3 Mechanical Insults TRU waste containers can be dropped or impacted by a variety of forces (seismic, forklifts, wind, and other vehicles). Where these forces are significant, containers can be breached and the contents dispersed. Many of the experiments for freefall spills, as described in DOE-HDBK- 3010, are based on a testing apparatus that dropped materials from a 10 to 12 ft distance. This distance closely approximates the height of the third tier in a stacked array of drums. Accidents that involve container drops substantially higher than the equivalent of a 3rd or 4th tier of drums (as defined on Table 4.4.4-1), as well as high-energy accident stresses from vehicle crushing impacts or structural collapse of a concrete building during certain seismic events (see Section 4.4.5), may not be bounded by [ARF][RF] values that are based on tests using the 10 to 12 ft drop testing apparatus. Therefore, mechanical stresses are presented according to categories that consider container drops from either 3rd and 4th tier falls and low-energy impacts, labeled as “Spills”, or from higher level drops and other higher-energy mechanical insults, labeled as “Impacts.” 4.5.3.1 Spills Cellulosic or largely cellulosic mixed wastes that become dispersed from breached containers due to a freefall spill, forklift puncture, 3rd or 4th tier falls (based on Appendix C drum drop tests), or experience lower energy impacts from falling ceiling-mounted debris but not structural DOE-STD-5506-2007 52 collapse or other stresses (e.g., low-speed vehicle accident as defined on Table 4.4.4-1, gas cylinder or windborne missiles) that do not substantially crush the containers as discussed in Section 4.5.3.2 of this Standard, are considered to be bounded by [ARF][RF] values for the suspension of loose surface contamination from shock/impact stresses. The basis for this phenomena and assumed bounding values are given in Section 5.3.3.2 of DOE-HDBK-3010-94.

Regarding impact events, the analyst must consider two levels of impact energies to assess the airborne release from impacts to containerized TRU waste. For lower impact energy that fails the container confinement, and dents the container or simply displaces the container location, the appropriate ARF and RF values are most closely modeled by the values cited on page 5-3 in DOE-HDBK-3010-94 of ARF 1E-3 and RF 0.1. These values are based on Langer’s experiments for shock-vibration of unconfined powders covered in Section 4.4.3.3.2 of the handbook, i.e., the same value that is recommended in Section 5.3.3.2 of the handbook for impact to a robust container. Although the experiments were performed on unconfined powders, some of the experiments involved powder in open cans that showed significantly smaller ARF and RF values relative to the experiments involving loose powder. This configuration is reasonably representative for the behavior of surface-contaminated waste due to shock-vibration forces and is conservative due to the additional difficulty of dislodging particles entrenched on the substrate matrix, and additional attenuation provided by the natural forces within the container that will reduce the amount of airborne particle prior to release (e.g., from deposition or agglomeration due to increased particle sizes). Higher energy impacts to containerized wastes are addressed in Section 4.5.3.2 of this standard. The DOE-HDBK-3010-94 does not specifically recommend the 1E-4 ARF*RF for seismic debris impacting TRU waste containers. However, it does extrapolate from the Langer tests with loose powders and those in cans, which is assumed applicable to TRU waste containers, as follows: There appears to be a significant decrease in the overall respirable release, due most likely to some combination of shielding of the powder and interaction between the powder and confining surfaces. As in the estimate for loose powder, there is considerable uncertainty associated with this data. If the highest ARF from the data set (1E-3 for uncontained Al2O3 powder) is used in conjunction with the largest RF from the contained experiments (rounded up to 0.1), the bounding values would be the same as that assessed for vibration shock of loose, clump powders, and the overall ARF x RF would be a factor of 5 greater than that measured in the experiment (1E-4 vice 2E-5). Accordingly, for powder held in cans failed by debris, an ARF of 1E-3 with an RF of 0.1 is assessed to be bounding. DOE-HDBK-3010-94 does not specifically address sludges, but this material form is considered to be bounded by experiments that measured ARF and RFs from the free-fall spill of slurries. The bounding ARF/RF values that are discussed in Section 3.2.3.2 of DOE-HDBK-3010-94 are 5E-05 and 0.8. The bounding [ARF][RF] for liquids is selected based on the airborne release of an aqueous liquid on impact after a freefall spill from and height less than 10 ft (2E-4 and 0.5). No experimentally measured [ARF][RF] values are available for TRU waste that is comprised of solid metal (e.g., equipment parts). No metal fragmentation is anticipated from freefall spills. Potential releases under accident stresses are assumed to consist of loose surface contamination DOE-STD-5506-2007 53 that is released through vibration and shock of the material substrate. These values (1E-3 and 0.1) are the same as described in Section 3.2.3.2 of DOE-HDBK-3010-94.

Nonmetallic or composite solids can be fragmented when impacted or crushed. DOE-HDBK- 3010-94, Section 5.3.3.2.1 provides a calculational method based on material density and energy imparted during the impact of the material with a hard, unyielding surface. Based on the density of typical grout and a fall height that approximates a third tier of a drum array, an [ARF][RF] value of 7E-5 is given to bound this material. This does not consider the energy absorption of the metal drum that adds to the conservatism of this calculation. The behavior of TRU waste in the form of soils or loose powders is approximated by experiments described in Section 4.4.3.1.2 of DOE-HDBK-3010. The bounding [ARF][RF] values for cohesionless powders are 2E-3/0.3. These values are applied to spills involving lower energy levels as opposed to “impacts” involving a higher distance drop of materials than 10 ft, seismically induced forces, or impacts from vehicle accidents. 4.5.3.2 Impacts As stated in the preceding section, the analyst must consider two levels of impact energies to assess the airborne release from impacts to containerized TRU waste. Impact energy that is higher than that associated with typical spills and low-energy impacts as described in Section 4.5.3.1 is characterized by internal volume reduction of more than ~25% (i.e. crushes the drum) and failure of drum confinement. This level of crushing is based on engineering judgment from the drum drop tests described in Appendix C. The Sandia tests concluded that drum deformation cannot be predicted by considering only the kinetic energy of the system. Drum contents are important because different materials absorb various amounts of energy. The Hanford tests concluded that obvious (highly visible) damage to a drum is not necessarily an indicator of drum integrity. Extensive damage to the drum walls may not be indicative of container breach whereas a small amount of damage to the lid and upper sealing surface may cause lid separation and loss of container integrity. The 1E-4 ARF*RF for impact to a robust container, e.g., a 55- gallon metal drum, discussed in Section 4.5.3.1 is not representative for severe stresses that substantially crush the drum, since it was based on the Langer 12 ft drop tests with 2 to 5 lb rocks. Section 4.4.3.3.2 of the DOE-HDBK-3010-94 acknowledged the limitation of the data as related to seismic debris impact to loose powders, as follows: The size and weight of the debris used and the fall heights appear to bound a number of phenomena in nonreactor nuclear facilities, including seismic vibration and impacts on large confinement structures such as gloveboxes. However, the size and weight of debris and the fall heights also appear to be unrealistically low for severe conditions in facilities such as a large building collapse, where large-sized debris from multiple levels may impact the released materials. In as much as the release mechanism appears to be air turbulence and shock- vibration, factors that can potentially increase with mass and size of debris and fall height. On the other hand, as the debris size increases, the impact effect is less likely to be fully concentrated in one area, and debris will provide cover for material that could limit releases. Since there are no experiments involving TRU waste containers under such severe stress, this phenomenon should be conservatively modeled in DOE-HDBK-3010 by suspension of bulk powders from shock impacts due to falling massive debris from structural collapse of a concrete

DOE-STD-5506-2007 54 building or external energy. It is stated in Section 4.4.3.3.2 of the handbook that “Due to the uncertainty in the test conditions, a conservative bounding value for the ARF is assessed to be 1E-2 with an RF of 0.2" for large debris and vibration from a seismic event. Thus, the [ARF][RF] is selected as 2E-3. This value is considered appropriate for the relatively higher levels of energy and container damage as compared to “spills.” Values apply to combustible and non-combustible solids not subject to brittle fracture. It does not apply to loose TRU wastes in gloveboxes or material forms that are not applicable including liquids, sludges or grout forms. It is recognized that the new approach for evaluating severe seismic stresses produces similar results to the traditional approach in DOE-HDBK-3010-94. Accordingly, use of the original DOE-HDBK-3010-94 basis for an ARF*RF of 1E-4 coupled with a damage ratio of 1.0 is also acceptable. This approach may also be extended to drums that will clearly be buried under a significant amount of debris as discussed in DOE-HDBK-3010-94, or drums stored outside of facilities. For solid materials that undergo brittle fracture (e.g., grout), the [ARF][RF] values are determined by the material mass and energy as discussed in Section 5.3.3.2.1 of the handbook. Due to the numerous variables such as weight of material and impact energy, a specific [ARF][RF] value is not given. For conservatism in cases where the calculational method is not used, a value of 7E-4 may be used for impacts to grout materials. This represents a one-order magnitude increase in spill events involving these materials, which is consistent with magnitude of increase for other materials in the Spill vs. Impact categories. Impacts on liquid-filled drums are postulated to fail the drums by compression and venting of the airborne liquid. The bounding [ARF][RF] values cited in DOE-HDBK-3010-94 for the venting of an aqueous solution at an internal pressure of <0 psig is 5E-5 and 0.8. DOE-STD-5506-2007 55 5.0 Consequence Analysis 5.1 Purpose This section provides guidance for evaluating accident consequences to all receptors. For facility workers, this section addresses qualitative guidelines for assessment of consequences. Accident scenarios typically postulate a release of radioactive material that is released into the atmosphere to the collocated worker and public receptors. For these receptors, this section provides an overview of atmospheric dispersion and consequence assessment methods. Receptors, as used in this Standard, are defined as follows: • Facility Worker – An individual who is impacted by an accident and is located within the facility boundary • Collocated Worker – The collocated worker is represented by a hypothetical onsite receptor located at a distance of 100 m from the point of release at which the maximum dose occurs. If the release is elevated, the onsite receptor is assumed to be at the location of greatest dose, which is typically where the plume touches down. • Offsite Public – The offsite public is represented by the Maximally-Exposed Offsite Individual (MOI), a hypothetical receptor located at or beyond the site boundary at the distance and in the direction from the point of release at which the maximum dose occurs. 5.2 Facility Worker Consequences

During the performance of hazards analysis, the hazards analysis team must consider the impacts of evaluated hazards on the facility worker. For each hazardous condition evaluated for the public and collocated worker in the hazards analysis, a qualitative evaluation of unmitigated consequence to the facility worker should be included. In accordance with DOE-STD-3009, quantitative consequence analysis should not be performed for the facility worker. The provided information is for the determination of facility worker safety-significant SSCs or Specific Administrative Controls (SACs) (i.e., meets the DOE-STD-3009 and DOE-STD-1186 “significant” criteria of prompt death, serious injury, or significant radiological or chemical exposure criteria.) Examples of conditions where a significant consequence to the facility worker should be considered for controls include the following: • Energetic releases of high concentrations of radiological or toxic chemical materials where the facility worker would normally be immediately present and therefore unable to take self-protective actions. • Deflagrations or explosions within process equipment or confinement/containment structures or vessels where grievous injury or death to a facility worker may result from DOE-STD-5506-2007 56 the fragmentation of the process equipment or failure of the confinement (or containment) in the vicinity of areas occupied by facility workers. • Chemical or thermal burns to a facility worker that could reasonably cover a significant portion of the facility worker body where self-protective actions are not reasonably available due to the speed of the event or where there may be no reasonable warning to the facility worker of the hazardous condition. • Exposures to radiological or toxic materials of sufficient magnitude that death or ongoing large-scale medical intervention may reasonably be expected to result. • Leaks from process systems where asphyxiation of a facility worker normally present may result. These and other unique conditions that may be "significant" for a specific process must be discussed by the hazard analysis team prior to initiating the hazards analysis process so that all members of the team may participate in the assessment of facility worker hazards. Lesser facility worker hazards may be evaluated and any results identified in the comments section for the hazardous condition. These lesser facility worker hazards are normally controlled through application of existing safety management programs (SMPs). 5.3 Collocated Worker and Public Consequence Doses to the collocated workers or MOI from postulated accident scenarios depend directly on the values and assumptions made with respect to determining the doses to these receptors. Even though qualitative consequence calculations are acceptable for collocated workers in the hazard analysis, these need to be supported by scoping calculations that implement the methodology described in this Section (this could be part of the hazard analysis and included as an attachment or appendix to the DSA). In order to comply with this Standard, this methodology must be used to support quantitative evaluations performed as part of the hazard or accident analysis. The potential doses to these receptors depend directly on the source terms from such scenarios, dispersion/transport of hazardous material, and assumptions with respect to exposure durations and release characteristics, among others. Following is a discussion of the major parameters that affect the doses to the collocated workers or MOI.

Simplistically, the dose to these receptors can be determined (assuming that the inhalation pathway is the predominant exposure pathway [this is mostly true for alpha emitters, such as plutonium]), by: Dose (rem) = ST · χ/Q · DCF· BR where: ST = respirable source term (Ci) χ/Q = atmospheric dilution factor (s/m3) BR = breathing rate (m3/s). DCF = inhalation dose conversion factor (rem/Ci) DOE-STD-5506-2007 57 The respirable source term calculation is described in Section 4.0. The atmospheric dilution factor, χ/Q, accounts for the effects of atmospheric dispersion of material released under postulated accident conditions at a specified receptor location. It is defined as the concentration in air per unit release rate of the material from an upwind source at a particular receptor location. The value of χ/Q is a function of the type of release (elevated, buoyant, ground level, etc.), release duration, wind speed, atmospheric stability class, and distance from the source (only centerline or under-centerline, ground-level values are considered). The duration of the release is assumed to conclude within two hours or proceed for up to eight hours for more slowly developing accidents, based on accident phenomenology. When evaluating consequences of exposure to hazardous materials, radiological and chemical consequences are evaluated differently. For radiological consequences, the analysis evaluates dose (time-integrated exposure) in units of Total Effective Dose (TED), because health effects are dose-driven. Consequences from hazardous chemicals are generally based on the concentration of the material to which an individual is exposed, rather than a time-integrated dose. For chemicals associated with TRU operations, the chemical atmospheric dilution factors are identical to those used for radiological consequence assessment (unless there are gases or vapors heavier than air). Radiological consequence modeling must be based on the following attributes listed below (may also apply to chemical dispersion analysis where noted) for unmitigated releases. Use of alternate dispersion methodologies or attributes discussed below must have a valid basis and be discussed with and approved by the DOE Approval Authority. Dispersion attributes are as follows. • The values of χ/Q used for radiological and chemical consequence analysis are generated using MACCS2 Computer Code (see DOE-EH-4.2.1-MACCS2-Code Guidance, MACCS2 Computer Code Application Guidance for Documented Safety Analysis). Use of other DOE-approved Toolbox Codes , or site-specific codes that have undergone appropriate validation and verification in accordance with DOE O 414.C requirements on software quality assurance, must be technically justified • Worst case meteorological assumptions (i.e., 95th percentile based on local site data) for onsite radiological and chemical releases (see STD-3009, Appendix A, for offsite evaluations) • Dry deposition velocity must be used at a value of 1 cm/s for all unfiltered, non tritium, non-noble gas species • Wet deposition must not be modeled • An surface roughness value of 3 cm must be assumed for radiological and chemical releases DOE-STD-5506-2007 58 • Building wake effects must not to be credited (modeled) unless shown to yield more conservative or bounding results. • Plume buoyancy may only be used when modeling fires that are outdoors or venting through a large breach in the facility (use of plume buoyancy should not be credited in a non-conservative manner)

• The breathing rate value, as specified in the DOE Toolbox Codes, is 3.3 x 10-4 m3/s. This value corresponds to the light activity breathing rate for adults and must be used in consequence assessment. • Inhalation dose conversion factors for the MOI evaluation must be consistent with ICRP 72, Age-dependent Dose to Members of the Public from Intake of Radionuclides: Part 5 Compilation of Ingestion and Inhalation Dose Coefficients, and optionally may use ICRP 68, Dose Coefficients for Intakes of Radionuclides by Workers, for the collocated worker evaluation. DOE-STD-5506-2007 59 6.0 TRU Waste Hazard Controls Selection and Standardization 6.1 Purpose This section of the Standard provides guidelines for standardizing the hazard control selection process and gives specific controls that are appropriate for the most common TRU waste accident events of concern. Section 6.2 presents evaluation guidelines that help grade the significance of accident events and safety classification of controls. Section 6.3 clarifies what is challenging to the Evaluation Guideline (EG) of DOE-STD-3009. Section 6.4 and the associated hazard control tables provide a set of preferred controls, as well as alternate controls that may be applied in certain situations. 6.2 Risk Ranking and Control Selection Guidelines DOE-STD-3009 encourages the use of hazard evaluation ranking mechanisms as a means of identifying the higher risk accidents that may warrant quantitative analysis and TSR controls. This section provides a risk ranking process and associated control selection guidelines that collectively give a qualitative tool to facilitate discussion between cognizant Subject Matter Experts (SMEs), including facility and operational staff, to enhance the judgment process inherent to selection of hazard controls. The numerical guidelines must be followed to comply with this Standard, but dose and frequency thresholds should not be construed as risk acceptance criteria. The risk ranking process bins the results of unmitigated hazard and accident analysis for the maximally exposed offsite individual, collocated workers onsite, and facility workers. Table 6.2- 1 identifies consequence levels and evaluation guidelines for each of these receptors. High, moderate and low consequence levels are quantitatively defined for the offsite public and collocated workers. High consequence levels are qualitatively established for facility workers consistent with DOE-STD-3009 guidelines for a significant worker consequence. Moderate and low consequence levels are not established for facility workers, because qualitative analysis would not yield results that provide a meaningful comparison to a distinguishable threshold. Table 6.2-2 identifies risk ranking bins that consider the consequence rankings from Table 6.2-1 together with the postulated accident frequency. Based on these factors, an accident is ranked as Risk Class I through IV. DOE-STD-5506-2007 60 TABLE 6.2-1: Consequence Levels and Risk Evaluation Guidelines Consequence Level Maximally Exposed Offsite Individual, Collocated Worker (at 100 meters Facility Worker Involved worker within facility boundary High Considerable offsite impact on people or the environs. CHALLENGE 25 rem TED or > AEGL-2/TEEL-2 Significant onsite impact on people or the environs. > 100 rem TED or > AEGL-3/TEEL-3 For Safety Significant designation, consequence levels such as prompt death, serious injury, or significant radiological

and chemical exposure, must be considered. Moderate Only minor off-site impact on people or the environs. ≥ 1 rem TED or > AEGL-1/TEEL-1 Considerable on-site impact on people or the environs. ≥ 25 rem TED or > AEGL-2/TEEL-2 No distinguishable threshold Low Negligible off-site impact on people or the environs. < 1 rem TED or < AEGL-1/TEEL-1 Minor on-site impact on people or the environs. < 25 rem TED or < AEGL-2/TEEL-2 No distinguishable threshold AEGL: Acute Exposure Guideline Level TED: Total Effective Dose Equivalent TEEL: Temporary Emergency Exposure Limit Minimally Exposed Individual: • Offsite consequences that challenge 25 rem must be protected with Safety Class controls independent of frequency. See Section 6.3 of this standard for further clarification of challenging the EG. • For elevated releases use location of highest dose Collocated Worker (at 100 meters) • For elevated releases use location of highest dose TABLE 6.2-2: Qualitative Risk Ranking Bins16 Consequence Level Beyond17 Extremely Unlikely Below 10-6/yr Extremely Unlikely 10-4 to 10-6/yr Unlikely 10-2 to 10-4/yr Anticipated 10-1 to 10-2/yr High Consequence III II I I Moderate Consequence IV III II II Low Consequence IV IV III III 16 Industrial events that are not initiators or contributors to postulated events are addressed as tndrd industrial hazards in the hazard analysis 17 For external events, frequency of occurrence below 10-6/yr conservatively calculated or 10-7/yr realistically calculated are Beyond Extremely Unlikely. DOE-STD-5506-2007 61 Risk Class I events for the public must be protected with safety SSCs, SACs (where appropriately justified in accordance with DOE-STD-1186) and associated TSRs. For offsite public protection, Safety Class SSCs, SACs (where appropriately justified in accordance with DOE-STD-1186) and TSRs are required for radiological events that challenge 25 rem TED offsite (regardless of frequency) in accordance with Appendix A of DOE-STD-3009, Change Notice 3. Events resulting in high offsite radiological consequences must be moved forward into accident analysis for determination of safety classification, without consideration of frequency. Safety Significant controls may also be warranted for protection of the public. Risk Class I events for the collocated worker or facility worker, and Risk Class II events for all receptors, must be considered for protection with Safety Significant SSCs, SACs (where appropriately justified in accordance with DOE-STD-1186) and associated TSRs. The consideration of control(s) should be based on the effectiveness and feasibility of the considered controls along with the identified features and layers of Defense In Depth (DID). Risk Class II events resulting in high offsite radiological consequence must be included in subsequent accident analysis for determination of safety classification, without consideration of frequency. Risk Class III events are generally protected by SMPs. These events may be considered for DID SSCs in unique cases. Risk Class IV events do not require additional measures. For facility worker protection, hazardous events with significant consequences must be considered for safety SSCs or SACs in accordance with DOE-STD-3009, Change Notice 3 and DOE-STD-1186. Activity-specific controls (e.g., Personal Protective Equipment [PPE] and hot work permit) are developed as needed based on job hazard analyses as part of the work control process, not as a specific TSR control. The TSR commitment to SMPs is relied upon to provide general worker protection. The actual implementation of work control process should be reviewed as part of the Integrated Safety Management System (ISMS) verification.

DID is a philosophy that ensures the facility is operated in a safe manner through multiple means. DID features include the entire suite of safety controls, encompassing Safety Class and Safety Significant SSCs, Administrative Controls (ACs), SMPs, and other engineered controls. Only the significant contributors to DID should warrant TSR designation. Those passive features that provide significant safety benefit are covered by the TSR Design Features section. Compensatory measures should be provided for those existing TSR Design Features that do not meet functional requirements. DOE G 423.1-1 provides additional guidance for consideration. Many important aspects of the DID strategy are implemented through the SMPs. The holistic approach embedded in the SMPs and their effective implementation as part of the ISMS must continue to optimize the intended safety benefits. The discipline imposed by the SMPs extends beyond simply supporting the assumptions made in the hazard analysis and is an essential part of DID safety posture. DOE-STD-5506-2007 62 6.3 Clarification of What Challenges the Evaluation Guideline Several DOE directives qualitatively address the issue of challenging the offsite Evaluation Guideline described in Appendix A of DOE-STD-3009. DOE G 420.1-1 and DOE O 420.1B define “challenge the Evaluation Guideline (EG)” as doses in the “rem range.” These directives apply to major modifications and new nuclear facilities, in which Design Basis Accidents (DBAs) are defined, developed, and quantified to derive design requirements for engineering SSCs. Safe harbor standards identified in Table 2, Appendix A, of 10 CFR Part 830 (e.g., DOE- STD-3009, DOE-STD-1120) are primarily intended to address existing facilities and activities, and these standards do not specifically define the term “challenge the DOE EG.” Most existing DOE facilities in the complex were not designed to a particular DBA. As such, any accident analysis for these facilities needs to be derived from assumptions made with respect to the operations and adequacy of the controls that may be available within these facilities (thus, the term evaluation basis accident, for these types of facilities). The term “challenging the EG” was developed to ensure that the 25 rem value would not be used as an acceptance threshold for potential consequences to the public. According to DOE G 420.1- 1, “it should emphatically be understood that 25 rem is not an acceptable criterion for safety design.” There is a potential for misusing this EG, in the sense that an unmitigated dose below, but close to the EG could be interpreted as not requiring Safety Class (SC) controls. Depending on the assumptions made with respect to source term and consequence analysis factors, uncertainties associated with dose estimates could be as high as two orders of magnitude. Thus, the key to determining whether a calculated dose “challenges” the DOE EG will depend on the conservatism in the values for each of these terms. Guidance contained in Chapters 4 and 5 ensures appropriate conservatism in the analysis to be performed for TRU waste operations, and thus results in a reasonably conservative estimate of dose consequences used for comparison to the EG. Table 6.3-1 presents the typical uncertainty associated with source term and consequence analysis factors, and summarizes recommendations addressed in the standard for each factor. DOE-STD-5506-2007 63

TABLE 6.3-1 Uncertainties Associated with Source Term and Consequence Analysis Factors Variable Typical Uncertainty Cause of Uncertainty Recommended Value MAR For accident analyses, the MAR developed in accordance with Section 4.3.2 is expected to be bounding; that is it represents a conservative accumulation of MAR in the number of containers involved in the accident scenario. This is accomplished by including the maximum drum and a number of 99th percentile and/or 95th percentile containers with the balance of the average containers. As a result, only a limited amount of uncertainty is associated with the generally conservative estimates of MAR for the containers in any accident scenario. Characterization based on some measurements, experience, training, and process knowledge in defining AK, for both newly generated and legacy waste introduces some statistical uncertainty associated with waste characterization. The MAR recommendations in Section 4 must be used for accident analysis; higher MAR values could be used for hazard analysis in order to ensure that no postulated scenarios are screened from further accident analysis in the DSA. χ/Q Standardized modeling parameters (DOE- EH-4.2.1-MACCS2-Code Guidance, MACCS2 Computer Code Application Guidance for Documented Safety Analysis; from hereon referred as “Tool Box Codes”), ground level release, default terrain (prairie grass), surface roughness, etc. Depending on the site, receptor location, and release characteristics, these variables could result in an uncertainty of about a factor of four. Terrain conditions, variability in meteorological conditions, site boundary distances, release characteristics (e.g., ground vs. elevated release), surface roughness, dispersion coefficients (relevance to site), deposition velocity, etc. Site-specific 95% based on meteorological data (DOE STD 3009) and using recommended values in the DOE Tool Box Codes (e.g., surface roughness, deposition velocity, ground release). The calculated χ/Q should be conservative, when the default or recommended values in the Tool Box Codes are used. The use of these default parameter values in determining χ/Q should be used for at least scoping calculations supporting the hazard analysis For accident analysis, alternate parameter values or assumptions can be made, if the site (complex terrain vs. flat) and the postulated release characteristics (e.g., filtered or volatile releases instead of unmitigated dispersible releases) are significantly different than those in the DOE Tool Box. Justification for values and assumptions different than those in the Tool Box Codes must be provided. D O E -ST D -5506-2007 63 DOE-STD-5506-2007 64 Variable Typical Uncertainty Cause of Uncertainty Recommended Value DCF The derivation of DCF values are based on a complex combination of metabolic, statistical, historical exposures, experimental, and human characteristics (e.g., age, sensitivity), among others. However, since these values are regulatory driven, they are assumed to be fixed for dose calculation purposes. N/A The latest recommendations of the International Commission on Radiological Protection (e.g., ICRP 68, 71, 72) are recommended for use in hazard and accident analysis BR While 3.33E-4 m3/s is the recommended breathing rate (BR) specified in the Radiological Health Handbook, some sites use values as high as 3.5E-4 m3/s. Values depend on the level of physical activity assumed during the accident condition.

The BR of 3.3 E-4 m3/s must be used for both hazard and accident analysis. This value is the recommended BR specified in the Radiological Health Handbook. DR Depending on the particular accident scenario and the number of containers involved, the uncertainty associated with this variable could be as high as one order of magnitude. Values are heavily dependent on the specific accident characteristics (e.g., type and magnitude of insult), type of containers, and model assumptions. The determination of the DR for a given accident scenario is heavily dependent on the magnitude of the scenario in question, container configuration during the accident, and number of containers involved. Results of experiments or tests have demonstrated high variability in the DRs. The DRs provided in Chapter 4 are based on empirical or analytically supported data (where available and represents “reasonable” conservative values for accident analysis. TABLE 6.3-1 Uncertainties Associated with Source Term and Consequence Analysis Factors--Continued D O E -ST D -5506-2007 64 DOE-STD-5506-2007 65 Variable Typical Uncertainty Cause of Uncertainty Recommended Value ARF*RF Provided that bounding values from DOE- HDBK-3010 are appropriately selected, the calculated doses (for safety analysis purposes) will be sufficiently conservative for derivation of adequate controls. Derivations of ARF/RF values reported in DOE-HDBK-3010 were based on a limited set of experiments, data gathering, and empirical correlations; thus, some uncertainty is expected. The bounding ARF/RF in the Handbook, however, represented in most cases the bounding values for the set of experiments or conditions being represented. Bounding ARF/RF values from DOE-HDBK-3010, with exceptions as noted in Chapter 4. LPF TRU waste facilities are relatively simple facilities (e.g., relatively low number of operational areas, ventilation zones, and fire areas), and in most cases do not rely on active ventilation to maintain confinement during accident scenarios; thus, a LPF of 1 is expected. For unmitigated dose estimates this represents a bounding condition, akin to a parking lot release scenario. Complex facilities, with multiple operating areas separated by different fires areas, ventilation zones, and evacuation pathways are expected to have LPFs less than 1.0, due to potential plateout, deposition, and filtration (among others) of particulates as these are transported throughout the facility, before these are released to the environment. For unmitigated dose estimates, a LPF of 1 represents the worst or most bounding value. A lower LPF can be used in mitigated analysis, but must be established using a technically derived basis. TABLE 6.3-1 Uncertainties Associated with Source Term and Consequence Analysis Factors-- Continued D O E -ST D -5506-2007 65 DOE-STD-5506-2007 66 In many cases, having an unmitigated MOI dose less than 10 rem (<40% of the EG) based on the recommended values above (Table 6.3-1) should still represent a reasonably low risk to be public and workers (assuming an adequate set of preventive and/or mitigative controls are implemented in the operation of these facilities). Thus, it is reasonable to expect that for existing facilities using the assumptions provided in this Standard, an unmitigated MOI greater than 10 rem should be considered sufficient to challenge the EG. 6.4 TRU Waste Controls

This section describes hazard controls that must be implemented for those accident events that warrant designation within the SB documents based on the results of the hazard/accident analysis and comparison to control selection guidelines presented in Section 6.2 (i.e., Risk Class I and potentially II types of events). The safety classification of controls (i.e., safety significant, safety class) is not specified in this section and is expected to vary at each DOE site depending on facility/container specific MAR and the results of consequence analysis as compared to thresholds specified in control selection guidelines. Though some accident events may not rise to a level of significance that warrants TSR controls, it still may be prudent to apply controls established in this section. Where applicable, recommended controls should be considered for accident events with consequences below the thresholds of concern. This is considered a good practice that is consistent with the control selection criteria. The hazard controls (Table 6.4.1-1) at the end of this section are presented according to each type of accident event. Events are identified with unique numbers that link to accident descriptions in Section 3. Where an accident event applies to multiple types of TRU waste operations, and the control set differs for each activity, the event is listed multiple times with each control set designated. If no specific TRU waste operation is designated in the accident description, then it applies to all TRU waste operations that are designated in Table 3.3-1 for the event. Minimal control functions are identified for each accident event. Each control function must be met. “Preferred” and “Alternate” controls are listed for each function and are separated in some cases by a semicolon, in which case all of the controls are required. In other cases, controls may be separated by “or” statements indicating that either control is acceptable. Preferred controls provide a high level of protection that gives precedence to the hierarchy of controls established in DOE-STD-3009 (i.e., passive over active, engineered over administrative, prevent over mitigate). The ordering of controls in Table 6.4.1-1 is presented in accordance with this hierarchy. Preferred controls may not always be available in existing facilities. Modifying facilities may require substantial operational impact. In such cases, consideration may be given to the “Alternate” set of controls listed in Table 6.4.1-1. The selected control set should also include some combination of Preferred and Alternate controls, when only a portion of the DOE-STD-5506-2007 67 Preferred controls can be met. In cases where preferred and alternate controls aren’t available or feasible to implement, other means for implementing stated control functions are acceptable if explicitly discussed and approved by the DOE Approval Authority. In those cases, technical justification for deviating from the Standard must be provided. With respect to TSR controls, the use of Alternate controls must be substantiated by a sound technical basis that is communicated and agreed upon with the DOE SB Approval Authority. The supporting rationale for selecting Alternate controls must demonstrate that Preferred controls are either not available or not appropriate for the given facility situation. The rationale must be documented in the DSA or in the hazard analysis document supporting the DSA.

A variety of controls may be available to control a hazard that requires safety class or safety significant controls. This set of potential controls could include both engineered controls and administrative controls. Engineered controls typically provide the most robust approach to address a hazard. However, for operations in older facilities, the engineered controls may not meet the current design requirements for safety class or safety significant engineered controls. In such cases, the tendency may be to specify an administrative control (designating it as a Specific Administrative Control) as the primary control having the safety class or safety significant function, even though the engineered features exist and are in place, and would appear to more adequately control the hazard. Where engineered controls exist that are most capable of accomplishing the needed safety function, those controls should be designated as safety class or safety significant rather than less robust administrative controls. If exemptions to requirements become necessary because of the designation, they must be obtained and appropriate compensatory measures proposed to ensure that the engineered controls provide protection commensurate with the protection warranted by the hazard. Specific Administrative Controls should not be proposed to avoid establishing an adequate set of engineered controls where it is possible to do so, and not cost-prohibitive. Though not indicated in the control sets for all accidents identified in Table 6.4.1-1 the use of MAR inventory limits is an acceptable approach for limiting consequences. However, this is not always prudent or feasible in TRU waste operations that must accept and process legacy containers. Where this approach is not operationally limiting and is used to limit consequences within facilities or designated areas, it must be listed as an initial condition of the hazard analysis and protected as a TSR specific administrative control. This concept also applies to other important initial conditions supporting the hazard analysis. It should be noted that some unique hazards that are limited to a single DOE site may not be covered by the controls listed in Table 6.4.1-1. Examples include highly dispersible forms of materials or unique waste treatment processes involving hazardous chemicals. Additionally, unique glovebox treatment activities beyond sorting and segregating may require consideration beyond those specified in this table (example, pyrophoric reaction fire). Consideration should be given to additional controls where these unique hazards are found. DOE-STD-5506-2007 68 6.4.1 TRU Waste MAR Effects on Control Selection The distribution of TRU waste MAR inventory at some DOE sites may be such that it is dominated by a small percentage of containers when compared to the overall population of containers (i.e., a few percent of the containers have radioactivity levels that are well above the majority of the remaining waste container population). The following example illustrates a case where MAR is dominant in only a few containers: Facility X has a population of approximately 4,000 containers. The drum with the highest radioactivity level contains 300 Plutonium-239 Equivalent Curies (PE-Ci). Only six containers have greater than 200 PE-Ci; 25 containers have greater than 100 PE-Ci; and less than one hundred containers have greater than 10 PE-Ci. Overall, 95% of the containers do not exceed 5 PE-Ci. MAR variability has been reported in finite characterized populations where the higher MAR containers are identifiable prior to handling. Conversely, it may be difficult to differentiate high MAR containers during waste excavation and retrieval operations if characterization data is not well known. It may not be prudent to apply preferred controls to an entire population of TRU waste containers when the risk is dominated by only a few containers with higher MAR content. The following guidelines apply to control selection under these conditions: 1. If the proposed operations can be practically conducted (limited operational impact) applying the controls driven by the high