DOE-HDBK-1122-2009 Chg Notice 1, Part 5, Radiological Control Technician Training Site Academic Training Instructors Guide Phase I
Functional areas: Radiological Control, Technician Training, Site Academic, Instructor's Guide
This Handbook describes an implementation process for core training as recommended in chapter 14 to Implementation Guide G441.1-1C , Radiation Protection Programs for Use with Title 10, Code of Federal Regulations, Part 835, Occupational Radiation Protection, and as outlined in the DOE standard, Radiological Control (RCS). The Handbook is meant to assist those individuals within the Department of Energy, Managing and Operating contractors, and Managing and Integrating contractors identified as having responsibility for implementing core training recommended by the RCS. While this Handbook addresses the training requirements of 10 CFR 835.103 for Radiological Control Technicians, it must be supplemented with facility specific information to achieve full compliance. Superseded by Change Notice 2, dated 3-11-2011.
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Section 1
Part 5 of 9
Radiological Control Technician Training
Site Academic Training Instructor’s Guide Phase I
Coordinated and Conducted
for the
Office of Health, Safety and Security
U.S. Department of Energy
DOE-HDBK-1122-2009
Radiological Control Technician Instructor’s Guide
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Radiological Control Technician Instructor’s Guide
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Table of Contents
Page
Module 2.01 Radiological Documentation ............................................................................2.01-1
Module 2.02 Communication Systems ..................................................................................2.02-1
Module 2.03 Counting Errors and Statistics ..........................................................................2.03-1
Module 2.04 Dosimetry .........................................................................................................2.04-1
Module 2.05 Contamination Control .....................................................................................2.05-1
Module 2.06 Airborne Sampling Program/Methods .............................................................2.06-1
Module 2.07 Respiratory Protection ......................................................................................2.07-1
Module 2.08 Radioactive Source Control .............................................................................2.08-1
Module 2.09 Environmental Monitoring ...............................................................................2.09-1
Module 2.10 Access Control and Work Area Setup..............................................................2.10-1
Module 2.11 Radiological Work Coverage ...........................................................................2.11-1
Module 2.12 Shipment and Receipt of Radioactive Material................................................2.12-1
Module 2.13 Radiological Incidents and Emergencies..........................................................2.13-1
Module 2.14 Personnel Decontamination..............................................................................2.14-1
Module 2.15 Radiological Considerations for First Aid........................................................2.15-1
Module 2.16 Radiation Survey Instrumentation....................................................................2.16-1
Module 2.17 Contamination Monitoring Instrumentation.....................................................2.17-1
Module 2.18 Air Sampling Equipment..................................................................................2.18-1
Module 2.19 Counting Room Equipment..............................................................................2.19-1
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Radiological Control Technician Instructor’s Guide
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DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-1
Course Title: Radiological Control Technician
Module Title: Radiological Documentation
Module Number: 2.01
Objectives:
→ 2.01.01 List the types of records/reports that the Radiological Control group is responsible
for maintaining at your site.
→ 2.01.02 Describe the types of records and reports used at your site by the Radiological
Control Group, to include but should not be limited to:
a. Radiological Work Permits
b. Survey Reports
c. Analysis Reports
d. Radiological Deficiency Reports
e. ALARA Documentation
f. Exposure Reports
Section 2
→ 2.01.03 Explain the requirements for the records management system, such as QC,
auditability/retrievability, management information at your site.
References:
1. 10 CFR Part 835 (2007) "Occupational Radiation Protection".
2. "Radiological Control Standard," DOE-STD-1098-2008.
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-2
I. MODULE INTRODUCTION
A. Self Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
A good Radiological Control Program must have a sound
documentation process. RCTs are involved daily in
creating records through surveys, RWPs, and procedures
that give a history of actual conditions and operations.
C. Module Overview
1. Purpose and requirements
2. Radiological records management program
3. Radiological record keeping standards
4. Types of radiological records
5. Records management
6. Radiological reporting
D. Introduce Objectives
II. MODULE OUTLINE
NOTE: Most of the material for this section will come from
specific site procedures. The instructor must be
thoroughly knowledgeable in and have available for
student use, procedures for RWP's, Radiological
Occurrences, Records Maintenance, Inventories, and
O.H.: Objectives
DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-3
any other RC procedure related to administration. In
addition, any other procedure or procedural change can be
covered in this section.
A. Purpose/Requirements
Discuss the purpose and requirements for records and
reports at DOE facilities based on 10 CFR 835 and DOE
RCS. Discuss any additional site requirements.
B. Radiological Records Management Program
1. Discuss the types of radiological records that should
be included in the records management program.
a. Quality Control
b. Audits
c. Records retrieval
d. Management information
0. (Insert site specific information here.)
C. Radiological Record Keeping Standards
2. List the standards for record keeping.
3. Discuss the justifications for record keeping standards.
D. Types of Radiological Records
1. Identify and define the record categories:
a. Employment History Records
Objective 2.01.01
Ask the students why it
is considered necessary
to include facility,
specific location and
function on
documentation. Ask
trainees why it makes
sense to initial and date
corrections.
DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-4
b. Personnel Radiological Records
c. Medical Records
e. Radiological Training and Qualification Records
f. Instrumentation and Calibration Records
g. Radiological Control Procedures
2. (Insert site specific information here.)
E. Records Management
4. Discuss storage requirements
5. (Insert site specific information here.)
F. Radiological Exposure Reports
1. Purpose
2. Process
3. Examples of filled-out exposure reports
III. SUMMARY
A. Review major points
0. Purpose and requirements
1. Radiological records management program
2. Radiological record keeping standards
3. Types of radiological records
4. Records management
5. Radiological reporting
B. Review learning objectives
Objective 2.01.02
Objective 2.01.03
DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-5
IV. EVALUATION
Section 3
Evaluation should consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% should be the minimum passing criteria for
examinations.
DOE-HDBK-1122-2009
Module 2.01 Radiological Documentation Instructor’s Guide
2.01-6
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DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-1
Course Title: Radiological Control Technician
Module Title: Communication Systems
Module Number: 2.02
Objectives:
2.02.01 Explain the importance of good communication.
2.02.02 Identify two methods of communication and be able to determine
different types of each.
2.02.03 Describe different types of communication systems.
2.02.04 Describe the FCC and DOE guidelines regarding proper use of
communication systems.
2.02.05 Describe general attributes of good communications.
2.02.06 Explain the importance of knowing how to contact key personnel.
→ 2.02.07 Identify the communication systems available at your site and
methods available to contact key personnel.
→ 2.02.08 Describe the emergency communication systems available at your
site.
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Recommended - radio, telephone, pager, warning alarms, phonetic alphabet handout
5. Lessons learned
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-1
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Good communication skills are essential to an RCT. Each
RCT should develop an ability to communicate using both
verbal and non-verbal media. This skill will ensure important
information is transmitted to the proper individuals in a clear
and concise manner.
C. Overview of Lesson
1. Importance of communication
2. Methods of communication
3. Communication systems
4. FCC and DOE guidelines
5. General attributes of good communications
6. Contact of key personnel
7. Site communication systems
8. Site emergency communications
D. Introduce Objectives
O.H.: Objectives
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-2
II. MODULE OUTLINE
A. Importance of Communications
1. Clear
2. Understood
3. Received
B. Two Methods of Communication
1. Verbal
2. Nonverbal
C. Communication Systems
1. Public Address
2. Telephones
3. Two-way Radios
4. Pagers
5. Computer Mail Systems
6. Computer Bulletin Boards
D. FCC and DOE Guidelines
1. When using communication systems licensed by the
Federal Communications Commission and operated by
the Department of Energy, one cannot: Stress importance
of complying with these restrictions.
a. Use profane, indecent, or obscene language.
Objective 2.02.01
Objective 2.02.02
Ask the student to name
the two ways to
communicate and
examples.
Objective 2.02.03
Ask students to name
communication systems
available in everyday
use at home and work.
Objective 2.02.04
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-3
b. Willfully damage or permit radio equipment damage.
c. Cause malicious interference with any radio
communications.
d. Intercept and use or publish the contents of any radio
message without the permission of the proper
authorities.
e. Make unnecessary or unidentified transmissions.
Section 4
f. Transmit without first making sure that the
transmission will not cause harmful interference.
g. Make any adjustments, repairs, or alterations to a
radio transmitter without licensing by the FCC or
acceptable equivalent.
h. Transmit a call sign, letter, or numeral which has not
been assigned to your station.
i. Rebroadcast another transmission (i.e., radio station
music).
E. General Attributes of Good Communications
1. Minimize the use of abbreviations and acronyms.
2. Make all oral instructions clear and concise.
3. Ensure the identity of the person(s) is/are clearly
understood.
4. Use clear, precise terminology.
5. Repeat back messages, either paraphrased or verbatim.
6. Speak distinctly and deliberately.
Objective 2.02.05
Stress importance of
good habits and
technique.
See Table 1 - "Phonetic
Alphabet and Numbers”.
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-4
7. Acknowledge all communications.
F. Contacting Key Personnel
1. Getting knowledgeable people to locations is necessary
for routine, emergency, and non-routine circumstances.
2. Important for the protection of personnel, equipment and
to prevent radiological releases.
3. RCTs should be aware of communication equipment.
G. Site Communication Systems
(Insert site specific information here.)
H. Emergency Communication Systems
(Insert site specific information here.)
III. SUMMARY
A. Review major topics
1. Importance of communication
2. Methods of communication
3. Communication systems
4. FCC and DOE guidelines
5. General attributes of good communications
6. Contact of key personnel
7. Site communication systems
8. Site emergency communication
B. Review learning objectives
Objective 2.02.06
Objective 2.02.07
Objective 2.02.08
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-5
IV. EVALUATION
Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank,
matching and/or short answer questions. 80% should be the minimum passing criteria for
examinations.
DOE-HDBK-1122-2009
Module 2.02 Communication Systems Instructor’s Guide
2.02-6
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DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-1
Course Title: Radiological Control Technician
Module Title: Counting Errors and Statistics
Module Number: 2.03
Objectives:
2.03.01. Identify five general types of errors that can occur when analyzing radioactive
samples, and describe the effect of each source of error on sample measurements.
2.03.02. State two applications of counting statistics in sample analysis.
2.03.03. Define the following terms:
a. mode
b. median
c. mean
2.03.04. Given a series of data, determine the mode, median, or mean.
2.03.05. Define the following terms:
a. variance
b. standard deviation
2.03.06. Given the formula and a set of data, calculate the standard deviation.
2.03.07. State the purpose of a Chi-squared test.
→ 2.03.08. State the criteria for acceptable Chi-squared values at your site.
2.03.09. State the purpose of creating quality control (QC) charts.
→ 2.03.10. State the requirements for maintenance and review of QC charts at your site.
2.03.11. State the purpose of calculating warning and control limits.
2.03.12. State the purpose of determining efficiencies and correction factors.
Section 5
2.03.13. Given counting data and source assay information, calculate efficiencies and
correction factors.
2.03.14. State the meaning of counting data reported as x ± y.
2.03.15. Given counting results and appropriate formulas, report results to desired
confidence level.
2.03.16. State the purpose of determining background.
→ 2.03.17. State the method and requirements for determining background for counting
systems at your site.
2.03.18. State the purpose of performing sample planchet maintenance.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-2
→ 2.03.19. State the method and requirements for performing planchet maintenance for
counting systems at your site.
2.03.20. Explain methods to improve the statistical validity of sample measurements.
2.03.21. Define "detection limit," and explain the purpose of using detection limits in the
analysis of radioactive samples.
→ 2.03.22. Given the formula and necessary information, calculate detection limit values for
counting systems at your site.
2.03.23. State the purpose and method of determining crosstalk.
→ 2.03.24. State the criteria for acceptable values of crosstalk for counting systems at your
site.
2.03.25. State the purpose of performing a voltage plateau.
→ 2.03.26. State the method of performing a voltage plateau on counting systems at your site.
References:
1. Chase & Rabinowitz, "Principles of Radioisotope Methodology," 3rd Edition, Burgess
Publishing, 1987.
2. "Basic Radiation Protection Technology"; Gollnick, Daniel; 5th ed.; Pacific Radiation
Corporation; 2008.
3. "Radiation Detection and Measurement"; Knoll, Glenn F.; Wiley & Sons; 2000.
4. "Webster's New World Dictionary," 4rd College Edition, Webster's New World,
Cleveland & New York, 1999.
5. Moe, Harold, "Operational Health Physics Training," ANL-88-26; DOE; Argonne
National Laboratory, Chicago, 1988.
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-3
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Radiological sample analysis involves observation of a random
process, one that may or may not occur, and estimation of the
amount of radioactive material present based on that observation.
All over the country radiological control personnel are using the
activity measurements to make decisions that may affect the health
and safety of workers at those facilities and their surrounding
environments.
C. Overview of Lesson
1. This unit will present an overview of measurement processes,
and statistical evaluation of both measurements and equipment
performance.
2. In addition, this unit will address some of the actions to take to
minimize the sources of error in count room operations.
D. Introduce Objectives
II. MODULE OUTLINE
A. General Sources of Error
Assuming the counting system is calibrated correctly, there are five
general sources of error associated with counting a sample: self-
absorption, backscatter, resolving time, geometry, and random
disintegration (of radioactive atoms).
1. Self-absorption
a. When a sample has an abnormally large amount of
material on the sample media, it could introduce a
counting error due to self-absorption, with is absorption of
the emitted radiation by the sample material itself.
Section 6
O.H.: Objectives
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-4
b. Self-absorption could occur for:
1) Liquid samples with a high solid content
2) Air samples from a high dust area
3) Use of improper filter paper may introduce a type of
self-absorption, especially in alpha counting (i.e.,
absorption by the media, or filter).
c. Personnel counting samples should ensure the correct
sample media is used, and that the sample does not
become too heavily loaded with sample material.
d. Count room personnel should be routinely checking
samples for improper media or heavily loaded samples.
2. Backscatter
a. Counting errors due to backscatter occur when the emitted
radiation traveling away from the detector is reflected, or
scattered back to the detector, by the material in back of
the sample.
b. The amount of radiation that is scattered back will depend
upon the type and energy of the radiation and the type of
backing material (reflector).
c. The amount of backscattered radiation increases as the
energy of the radiation increases and as the atomic number
of the backing material increases.
d. Generally, backscatter error is only a consideration for
particulate radiation, such as alpha and beta particles.
Because beta particles are more penetrating than alpha
particles, backscatter error will be more pronounced for
beta radiation.
e. The ratio of measured activity of a beta source counted
with a reflector compared to counting the same source
without a reflector is called the backscatter factor (BF).
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-5
reflectorwithoutcounts
reflectorwithcountsBF
−−
−−
=
f. Normally, backscatter error is accounted for in the
efficiency or conversion factor of the instrument.
g. However, if different reflector materials, such as
aluminum and stainless steel, are used in calibration and
operation, an additional unaccounted error is introduced.
h. This additional error will be about 6% for stainless steel
versus aluminum. Count room personnel must be aware
of the reflector material used during calibration of the
counting equipment.
i. Any deviation from that reflector material will introduce
an unaccounted error and reduce confidence in the
analysis results.
3. Resolving Time
a. Resolving time is the time interval which must elapse after
a detector pulse is counted before another full-size pulse
can be counted.
b. Any radiation entering the detector during the resolving
time will not be recorded as a full size pulse; therefore, the
information on that radiation interaction is lost.
c. As the activity, or decay rate, of the sample increases, the
amount of information lost during the resolving time of
the detector is increased.
d. As the losses from resolving time increase, an additional
error in the measurement is introduced. Typical resolving
time losses are shown in Table 1 of the Study Guide.
e. Resolving time losses can be corrected by using the
equation:
1
o
o
RR
R τ
=
−
(Eq.2)
Refer students to
Table 1 in Study
Guide.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-6
where: R = "true" count rate, in cpm
Ro = observed count rate, in cpm
τ = resolving time of the detector, in minutes
("tau")
f. Count room personnel should be aware of the limitations
Section 7
for sample count rate, based upon procedures and the type
of detector in use, to prevent the introduction of additional
resolving time losses. This is especially true for counting
equipment that uses GM detectors.
4. Geometry
a. Geometry related counting errors result from the
positioning of the sample in relation to the detector.
b. Normally, only a fraction of the radiation emitted by the
sample is emitted in the direction of the detector because
the detector does not surround the sample.
c. If the distance between the sample and the detector is
varied, then the fraction of emitted radiation which hits the
detector will change.
d. This fraction will also change if the orientation of the
sample under the detector (i.e., side-to-side) is varied.
e. An error in the measurement can be introduced if the
geometry of the sample and detector is varied from the
geometry used during instrument calibration.
f. This is especially critical for alpha counting where any
change in the sample to detector distance also increases or
decreases the chance of shielding the alpha particles by the
air between the sample and detector.
g. Examples of geometry-related errors are:
1) Piling smears and/or filters on top of each other in the
same sample holder. Piling of the samples moves the
top sample closer to the detector and varies the
calibration geometry.
2) Using deeper or shallower sample holders than
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-7
those used during calibration changes the sample-to-
detector distance.
3) Adjusting movable bases in the counting equipment
sliding drawer changes the sample to detector distance.
4) Using too many or not using the appropriate sample
holder or planchet changes the sample to detector
distance. Sources not fixed in position can change
can change geometry and reduce reproducibility.
5) Plexiglass shelving in counting chamber is improperly
set.
5. Random disintegration
The fifth source of general counting error is the random
disintegration of the radioactive atoms and constitutes the
remainder of the lesson.
B. Statistics
1. Statistics is a branch of mathematics that deals with the
organization, analysis, collection, and interpretation of
statistical data.
2. No definition of statistical data is given. However, Webster's
does define a statistic as "an estimate of a variable, as an
average or a mean, made on the basis of a sample taken from a
larger set of data."
3. This last definition is applicable to our discussion of counting
statistics. After all, when we take samples, we use the data
derived from analysis of those samples to make determinations
about conditions in an area, in water, or in air, etc., assuming
that the sample is representative.
4. So, we have estimated conditions (a variable) on the basis of a
sample (our smear, water sample, air sample) taken from a
larger set of data.
5. Over the years, various methods and observations have
identified three models which can be applied to observations of
events that have two possible outcomes (binary processes).
7. Luckily, we can define most observations in terms of two
possible outcomes. (See table 2).
Refer students to
Table 2
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Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-8
7. For each of the processes that we want to study, we have
defined a trial (our test), a success and a failure (two possible
outcomes), and have determined the probability of observing
our defined success.
Section 8
8. Now, to study these processes, we can use proven, statistical
models to evaluate our observations for error.
9. Consider the possibilities when throwing two dice. There are
36 possible outcomes when throwing two dice, as indicated in
Table 3.
10. If, in our study of this process, we define a success as throwing
a number between 2 and 12, the outcome is academic. All
trials will be successful, and we can describe the probabilities
of throwing any individual number between the range of 2 and
12 inclusive would add up to 1.
11. If we define a success as throwing a particular number, we can
define the probability of our success in terms of the number of
possible outcomes that would give us that number in
comparison to the total number of possible outcomes.
12. If we were to take two dice, roll the dice a large number of
times, and graph the results in the same manner, we would
expect these results to produce a curve such as the one should
in Figure 1.
13. The area under the curve can be mathematically determined
and would correspond to the probability of success of a
particular outcome.
14. For example, to determine the probability of throwing a
particular number between 2 and 12 we would calculate the
area under the curve between 2 and 12. The results of that
calculation would be 36.
15. This is what statistics is all about; random binomial processes
that should produce results in certain patterns that have been
proven over the years.
16. The three models that are used are distribution functions of
binomial processes with different governing parameters.
These functions and their restrictions are:
Refer students to
Figure 1 in Study
Guide.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-9
a. Binomial distribution
1) This is the most general of the statistical models and
is widely applicable to all processes with a constant
probability.
2) It is not widely used in nuclear applications because
the mathematics are too complex.
b. Poisson distribution
1) A simplified version of binomial distribution is the
Poisson (pronounced "pwusówn") distribution, which
is valid when the probability of success, P(x), is small.
2) If we graphed a Poisson distribution function, we
would expect to see the predicted number of successes
at the lower end of the curve, with successes over the
entire range if sufficient trials were attempted.
3) Thus, the curve would appear as seen in Figure 2.
4) The Poisson model is used mainly for applications
involving counting system background and detection
limits, where the population (i.e., number of counts) is
small.
c. Gaussian distribution
1) Also called the "normal distribution," the Gaussian
(pronounced "Gowziun") distribution is a further
simplification which is applicable if the average
number of successes is relatively large, but the
probability of success is still low.
2) Note that the highest number of successes is at the
center of the curve, the curve is a bell shaped curve,
and the relative change in success from one point to
the adjacent is small.
3) Also note that the mean, or average number of
successes, is at the highest point, or at the center of
the curve.
Refer students to
Figure 2 in Study
Guide.
This will be discussed
in greater detail later.
Refer students to
Figure 3 in Study
Guide
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-10
Section 9
4) The Gaussian, or normal, distribution is applied to
counting applications where the mean success is expected
to be greater than 20.
a) It is used for counting system calibrations and
operational checks, as well as for normal samples
containing activity.
b) It may or may not include environmental samples
(i.e., samples with very low activity).
17. Application of Statistical Models
Application of specific statistical methods and models to
nuclear counting operations is termed counting statistics and is
essentially used to do two things:
a. Predict the inherent statistical uncertainty associated with
a single measurement, thus allowing us to estimate the
precision associated with that measurement.
b. Serve as a check on the normal function of nuclear
counting equipment.
18. Definitions
a. Mode - An individual data point that is repeated the most
in a particular data set.
b. Median - The center value in a data set arranged in
ascending order.
c. Mean - Average value of all the values in the data set.
19. Determination of mode, median and mean
a. Determination of the Mode: In the set of test scores in
Figure 4, a score of 95 occurs (i.e., is repeated) more often
than any other score.
b. Determination of the Median: In the same set of test
scores, this is the score in the middle - where one half of
the scores are below, and the other half are above the
median. The median for the test scores is 90.
Objective 2.03.02
Objective 2.03.03
Objective 2.03.04
Refer students to
Figure 4 in the Study
Guide.
DOE-HDBK-1122-2009
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2.03-11
c. Determination of the Mean: This is found by adding all of
the values in the set together, and dividing by the number
of values in the set. The mean of the test scores is 89.
Mean determination is often expressed using special
symbols, as illustrated in the following equation:
ixx
n
∑
= (Eq. 3)
where: x = mean (sometimes pronounced "x bar")
xi = data point with index i
n = number of data points
Σ = summation symbol
∑
=
n
i 1
xi = x1 + x2 + x3 + ...+ xn
20. Variance and Standard Deviation
Using the Gaussian distribution model depicted in Figure 5 of
the Study Guide, we need to define the terms "variance" and
"standard deviation" which are both used as discriptors of the
spread of the population (or the data set) in a normal
distribution.
a. Variance
1) The amount of scatter of data points around the mean
is defined as the sample variance.
2) In other words, it tells how much the data "varies"
from the mean.
b. Standard deviation
1) A more precise term is the standard deviation,
represented by σ (pronounced "sigma").
2) Mathematically, in a normal distribution, the standard
deviation is the square root of the variance.
3) The standard deviation of a population is defined
mathematically as:
Objective 2.03.05 a.
Objective 2.03.05 b.
Objective 2.03.06
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( )2
σ
ix x
n
∑ −
= (Eq.4)
where: σ = biased standard deviation of the population
xi = sample counts for each data point
x = mean
n = number of data points
4) If most of the data points are located close to the
mean, the curve will be tall and steep and have a low
numerical value for a standard deviation.
5) If data points are scattered, the curve will be lower
and not as steep and have a larger numerical value for
a standard deviation.
Section 10
6) In a Gaussian distribution, it has been determined
mathematically that 68.2% of the area under the curve
falls within the data point located at the mean ± (plus
or minus) one standard deviation (1 σ ); 95.4% of the
area under the curve falls between the data point
located at ± two standard deviations (2 σ ), etc.
7) What this means to us in terms of counting processes
is that if the distribution (as depicted in Figure 5) is
representative of a counting function with a mean
observable success >20 (Gaussian distribution):
a) 68.2% of the time the observed successes (or
counts) will be within ±1 standard deviation of
the mean.
b) 95.4% of the time the observed successes (or
counts) will be within ±2 standard deviations of
the mean.
c) 99.97% of the time the observed successes (or
counts) will be within ±3 standard deviations of
the mean.
8) Remember, the area of the curve represents the
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probability of success in a random process. In
radiation protection this random process is the decay
of a radioactive sample.
9) The known statistical distribution is used in radiation
protection when setting up a counting system and in
evaluating its operation by means of daily pre-
operational source checks.
10) In performing the calibration of the system, a
radioactive source with a known activity is counted
twenty times for one minute each time.
11) Using the data from the twenty counts, the mean and
standard deviation can be calculated.
a) The mean can then be used to determine the
efficiency of the system while allowing for a
certain number of standard deviations during
operation.
b) The twenty counts can also be used to perform
another required test of the system's performance,
the Chi-squared test.
21. Chi-squared Test
a. The Chi-squared test (pronounced "ki") is used to
determine the precision of a counting system.
1) Precision is a measure of exactly how a result is
determined without regard to its accuracy.
2) It is a measure of the reproducibility of a result, or in
other words, how often that result can be repeated, or
how often a "success" can be obtained.
b. This test results in a numerical value, called the Chi-
squared value (X2) which is then compared to a range of
values for a specified number of observations or trials.
c. This range represents the expected (or predicted)
probability for the chosen distribution.
Refer students to
Example 1 in Study
Guide.
Objective 2.03.07
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1) If the X2 value is lower than the expected range, this
tells us that there is not a sufficient degree of
randomness in the observed data.
2) If the value is too high, it tells us that there is too
much randomness in the observed data.
d. The Chi-squared test is often referred to as a
"goodness-of-fit" test. It answers the question: How well
does this data fit a Poisson distribution curve?
e. If it does not fit a curve indicating sufficient randomness,
then the counting instrument may be malfunctioning.
f. The Chi-squared value is calculated as follows:
( )2
2X
ix x
x
∑ −
= (Eq.5)
g. Criteria for acceptable Chi-squared values:
(Insert site specific information here.)
Assuming a given set of data passes the Chi-squared test,
the data can than be used to prepare quality control charts
for use in verifying the consistent performance of the
system.
Section 11
C. Quality Control Charts
1. Quality control charts are prepared using source counting data
obtained during system calibration. The source used for daily
checks should be identical to the one used during system
calibration.
2. Obviously since this test verifies that the equipment is still
operating within an expected range of response, we cannot
change the conditions of the test in mid-stream.
3. QC charts, then, enable us to track the performance of the
system while in use.
Refer students to
Example 2 in Study
Guide.
Objective 2.03.08
Objective 2.03.09
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4. Data that can be used for quality control charts include gross
counts, counts per unit time, and efficiency. Most nuclear
laboratories use a set counting time corresponding to the
normal counting time for the sample geometry being tested.
If smears are counted for one minute, then all statistical
analysis should be based on one-minute counts.
5. When the system is calibrated and the initial calculations
performed, the numerical values of the mean ± 1, 2, and 3
standard deviations are also determined.
6. Using standard graph paper, paper designed specifically for
this purpose, or a computer graphing software, lines are drawn
all the way across the paper at those points corresponding to
the mean, the mean plus 1, 2, and 3 standard deviations, and
the mean minus 1, 2, and 3 standard deviations. The mean is
the center line of the paper.
7. Quality control charts should be maintained in the area of the
radioactivity counting system such that they will be readily
accessible to those who operate the system.
8. These charts can then be used by operators to determine if
routine periodic checks (typically daily) have been completed
before system use.
(Insert site specific information here.)
9. System Operating Limits
a. The values corresponding to ±2 and ±3 standard
deviations are called the lower and upper warning and
control limits, respectively.
b. The results of the daily source counts are graphed daily in
many countrooms.
c. Most of the time our results will lie between the lines
corresponding to ±1 standard deviation (68.2%).
d. We also know that 95.4% of the time our count will be
between ±2 standard deviations and that 99.97% of the
time our count will be between ±3 standard deviations.
e. Counts that fall outside the warning limit (±2 σ ) are
Objective 2.03.10
Objective 2.03.11
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not necessarily incorrect. Statistical distribution models
say that we should get some counts in that area.
1) Counts outside the warning limits indicate that
something may be wrong.
f. The same models say that we will also get some outside
the control limits (±3 σ ). However, not very many
measurements will be outside those limits.
g. We use 3 σ as the control, a standard for acceptable
performance. In doing so we say that values outside of ±3
σ indicate unacceptable performance, even though those
values may be statistically valid.
h. True randomness also requires that there be no patterns in
the data that are obtained; some will be higher than the
mean, some will be lower, and some will be right on the
mean.
i. When patterns do show up in quality control charts, they
are usually indicators of systematic error. For example:
1) Multiple points outside two sigma
Section 12
2) Repetitive points (n out of n) outside one sigma
3) Multiple points, in a row, on the same side of the mean
4) Multiple points, in a row, going up or down.
j. The assumption is made that systematic error is present in
our measurements, and that our statistical analysis has
some potential for identifying its presence.
k. However, industry assumption is that systematic error that
is present is very small in comparison to random error.
D. Counter Efficiency
1. A detector intercepts and registers only a fraction of the total
number of radiations emitted by a radioactive source.
2. The major factors determining the fraction of radiations
Objective 2.03.12
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emitted by a source that are detected include:
a. The fraction of radiations emitted by the source which
travel in the direction of the detector window
b. The fraction emitted in the direction of the detector
window which actually reach the window
c. The fraction of radiations incident on the window which
actually pass through the window and produce an
ionization
d. The fraction scattered into the detector window
3. All radiation detectors will, in principle, produce an output
pulse for each particle or photon which interacts within its
active volume.
4. The detector then would be said to be 100 percent "efficient,"
because 100 percent of the activity was detected and reported.
5. In practice, because of the factors outlined above, the actual
(or total) activity emitted from the source is not detected.
6. Therefore, there is only a certain fraction of the disintegrations
occurring that results in counts reported by the detector.
7. Using a calibrated source with a known activity, a precise
figure can be determined for this fraction.
8. This value can then be used as a ratio in order to relate the
number of pulses counted to the number of particles and/or
photons incident on the detector.
9. This ratio is called the efficiency.
It can also be referred to as the detector yield, since the
detector yields a certain percentage of the actual counts.
10. The detector efficiency gives us the fraction of counts detected
per disintegration, or c/d.
11. Since activity is the number of disintegrations per unit time,
and the number of counts are detected in a finite time, the two
rates can be used to determine the efficiency if both rates are in
the same units of time.
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12. Counts per minute (cpm) and disintegrations per minute (dpm)
are the most common.
13. Thus, the efficiency, E, can be determined as shown in
Equation 6. Used in this manner the time units will cancel,
resulting in counts/disintegration (c/d).
cpm cE
dpm d
= = (Eq.6)
a. The efficiency obtained in the formula above will be in
fractional or decimal form.
b. To calculate the percent efficiency, the fraction can be
multiplied by 100.
1) For example, an efficiency of 0.25 would mean 0.25 ×
100, or 25%.
14. By algebraic manipulation, Equation 6 can be solved for the
disintegration rate (see Equation 7).
15. The system efficiency is determined as part of the calibration.
When analyzing samples, a count rate is reported by the
counting system.
16. Using Equation 7, the activity (A) of the sample can then be
determined in dpm, and then converted to any other units of
activity (e.g., Ci, Bq).
Section 13
dpm
cpm cpmdpm A
E E
= ⎯⎯→ = (Eq.7)
17. As seen in Equation 7 above, the net count rate is divided by
the efficiency.
Objective 2.03.13
Review Example 3 in
Study Guide with
students.
Review Example 4 in
Study Guide with
students.
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18. A correction factor (CF), which is simply the inverse of the
efficiency, is used by multiplying it by the net count rate to
determine the activity, as in Equation 8.
1CF
E
= (Eq.8)
19. This count-rate correction factor should not to be confused
with a geometry correction factor used with some radiation
instruments, such as the beta correction factor for a Cutie Pie
(RO-3C).
E. Error Calculations
1. The error present in a measurement governed by a statistical
model can be calculated using known parameters of that model.
2. Nuclear laboratories are expected to operate at a high degree of
precision and accuracy. However, since we know that there is
some error in our measurements, we are tasked with reporting
measurements to outside agencies in a format that identifies
that potential error.
3. The format that is used should specify the activity units and a
range in which the number must fall. In other words, the
results would be reported as a given activity plus or minus the
error in the measurement.
4. Since nuclear laboratories prefer to be right more than they are
wrong, counting results are usually reported in a range that
would be correct 95% of the time, or at a 95% confidence level.
5. In order to do this, the reported result should be in the format:
x.xx ± yy (K σ ) (Eq. 9)
where: x.xx = measured activity, in units of dpm, Ci, or
Bq
yy = associated potential (or possible) error in
the measurement
K = multiple of counting error
Review Example 5 in
Study Guide with
students.
Objective 2.03.14
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σ = standard deviation at stated confidence
level (CL)
Note: Use of K σ is only required for confidence levels other
than 68% (see Table 6).
Therefore:
σ = 1× σ 68% CL (optional)
1.64 σ = 1.64 × σ 90% CL (sometimes used)
2 σ = 1.96 × σ 95% CL (normally used)
6. For example, a measurement of 150 ± 34 dpm (2 σ ) indicates
the activity as 150 dpm; however, it could be as little as 116
dpm or as much as 184 dpm with 95% confidence (at 2 σ ).
7. The calculations of the actual range of error is based on the
standard deviation for the distribution.
8. In the normal (or Gaussian) distribution, the standard deviation
of a single count is defined as the square root of the mean, or
σ = x
9. The error, e, present in a single count is some multiplier, K,
multiplied by the square root of that mean, i.e., some multiple
times the standard deviation, K σ .
10. The value of K used is based on the confidence level that is
desired, and is derived from the area of the curve included at
that confidence level (see Figure 5).
11. Common values for K are given in Table 4.
12. To calculate the range to the point at which you would expect
to be right 95% of the time, you would multiply the standard
deviation by 1.96, and report the results of the measurement as
x.xx dpm ± yy dpm (2 σ ).
13. Note that using a 68% or 50% confidence level introduces an
expected error a large percentage of the time. Therefore, for
reasonable accuracy a higher confidence level must be used.
Section 14
Refer students to
Table 4 in Study
Guide.
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14. The simple standard deviation (σ ) of the single count (x) is
usually determined as a count rate (counts per unit time). This
is done by dividing the count rate (R) by the count time (T).
Subscripts can be applied to distinguish sample count rates
from background count rates.
σ RK
T
= (Eq.8)
F. Background
1. Determination of Background
a. Radioactivity measurements cannot be made without
consideration of the background.
b. Background, or background radiation, is the radiation that
enters the detector concurrently with the radiation emitted
from the sample being analyzed.
c. This radiation can be from natural sources, either external
to the detector (e.g., cosmic or terrestrial) or radiation
originating inside the detector chamber that is not part of
the sample.
d. In practice, the total counts are recorded by the counter.
This total includes the counts contributed by both the
sample and the background.
e. Therefore, the contribution of the background will produce
an error in radioactivity measurements unless the
background count rate is determined by a separate
operation and subtracted from the total activity, or gross
count rate.
f. The difference between the gross and the background rates
is called the net count rate (sometimes given units of ccpm,
or corrected counts per minute).
g. This relationship is seen in the following equation:
S S B BR R R+= − (Eq.11)
where: RS = net sample count rate (cpm)
Objective 2.03.15
Review Example 6 in
Study Guide with
students.
Objective 2.03.16
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RS+B = gross sample count rate (cpm)
RB = background count rate (cpm)
h. The background is determined as part of the system
calibration by counting a background (empty) planchet for
a given time.
i. The background count rate is determined in the same way
as any count rate, where the gross counts are divided by
the count time, as seen in Equation 12 below.
B
B
B
NR
T
= (Eq.12)
where: RB = background count rate (counts per time,
i.e., cpm)
NB = gross counts, background
TB = background count time
j. For low-background counting systems two background
values must be determined: one for alpha and one for
beta-gamma.
These two values are used to determine background
alpha and beta-gamma sample count rates,
respectively, during calibration and when analyzing
samples.
k. In practice, background values should be kept as low as
possible.
As a guideline, background on automatic counting
systems should not be allowed to exceed 0.5 cpm
alpha and 1 cpm beta-gamma.
2. Reducing background
a. Typically, the lower the system background the more
reliable the analysis of samples will be.
b. In low-background counting systems the detector housing
is surrounded by lead shielding so as to reduce the
background.
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c. Nonetheless, some background still manages to reach the
detector. Obviously, little can be done to reduce the actual
source of background due to natural sources.
On many systems a second detector is incorporated to
detect penetrating background radiation. When a sample
is analyzed the counts detected by this second detector
during the same time period are internally subtracted from
the gross counts for the sample.
Section 15
d. Background originating inside the detector chamber can
be, for the most part, more easily controlled. The main
contributors of this type of background are:
1) Radiation emitted from detector materials
2) Radioactive material on inside detector surfaces
3) Radioactive material on the sample slide assembly
4) Contamination in or on the sample planchet or
planchet carrier
e. There are, unfortunately, trace amounts of radioisotopes in
the materials of which detectors and their housings are
made. This is simply a fact of life in the atomic age.
1) However, the contribution to background from this
source is negligible, but should nonetheless be
acknowledged.
f. Radioactive material can be transferred from contaminated
samples to the inside surfaces of the detector chamber
during counting.
1) This usually occurs when samples having gross
amounts of material on them are counted in a low
background system.
2) During the insertion and withdrawal of the sample
into the detector chamber, loose material can be
spread into the chamber.
3) In order to prevent this, these samples should be
counted using a field survey instrument or a mini-
scaler.
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4) Low-background systems are designed for counting
lower-activity samples. Counting of a high-activity
sample on these systems should be avoided unless it is
a sealed radioactive source.
g. Radioactive material can also be transferred from
contaminated samples to the slide assembly upon which
samples are inserted into, and withdrawn from, the
detector chamber.
1) This can be prevented in the same way as stated above.
In addition, when loading and stacking samples for
counting, ensure that the slide assembly cover is in
place.
2) The slide assembly should also be cleaned on a
routine basis (e.g., weekly).
h. When loading and unloading samples into and from
planchets, material from the samples can be spread to the
planchet and/or the carrier.
1) Most smears and air samples are 47-mm diameter and
are counted in a planchet that is almost the same size.
2) The planchet is placed in a carrier which surrounds
and supports the planchet and allows for automatic
sample exchange by the counting system.
3) When a sample is counted, the entire carrier is placed
under the detector window inside the detector
chamber.
4) Any contamination on the carrier (or in the planchet)
is counted with, and attributed to, the sample.
5) A paper disc can be placed in the bottom of the
planchet as a step in preventing transfer of material
from samples to the planchet.
6) Care should be taken when loading and unloading
samples such that material remains on the sample
media.
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(Insert site specific information here.)
3. Planchet maintenance
a. Planchets and carriers should be inspected, cleaned, and
counted on a routine basis.
1) All in-use planchets and carriers must read less than
established site limits.
2) Planchets exceeding these limits should be
decontaminated and recounted as necessary.
b. By maintaining planchets clean and as free from
contamination as possible, sample result reliability will be
increased because the amount of error introduced in the
sample analysis will be reduced.
(Insert site specific information here.)
G. Propagation of Error
Section 16
1. The error present in a measurement includes the error present
in the sample count, which contains both sample and
background, and the error present in the background count.
Rules for propagation of error preclude merely adding the two
errors together.
2. The total error in the measurement is calculated by squaring
the error in the background and adding that to the square of the
error in the sample count, and taking the square root of the sum,
as shown in Equation 13.
22
BBSs eee += + (Eq.13)
where: eS = error present in the measurement (sample)
eS+B = error in sample count (sample plus
background)
eB = error present in background count
3. Since we normally use this equation in terms of a count rate,
the formula is slightly modified as follows, and the error stated
as the sample standard deviation (σ S):
Objective 2.03.17
Objective 2.03.18
Objective 2.03.19
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S B B
S
S B
R RK K
T T
σ += + (Eq.14)
where: RS+B = gross sample count rate (sample plus
background)
RB = background count rate
TS = sample count time
TB = background count time
K = confidence level multiple (see Table 4)
4. The error in the sample count is the standard deviation of the
count, which is the square root of that count (see Equation 13
above). If we square a square root we get the number we
started with.
5. If the sample counting time and the background counting time
is the same, the formula can be simplified even more to:
S B B
S
R RK K
T
σ + +
= (Eq.15)
H. Improving Statistical Validity of Count Room Measurements
1. Minimizing the statistical error present in a single sample
count is limited to several options. If we look at the factors
present in the calculation below (same as Equation 14), we can
see that there are varying degrees of control over these factors.
2. The standard deviation is calculated here in terms of count rate.
S B B
S B
R Rrate
T T
σ += +
a. RS+B is the sample count rate. We really have no control
over this.
b. RB is the background count rate. We do have some control
over this.
Review Example 7 in
Study Guide with
students.
Review Example 8 in
Study Guide with
students.
Objective 2.03.20
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1) On any counting equipment the background should be
maintained as low as possible.
2) In most of our counting applications, however, the
relative magnitude of the background count rate
should be extremely small in comparison to the
sample count rate if proper procedures are followed.
3) This really becomes an issue when counting samples
for free release or environmental samples.
4) However, some reduction in error can be obtained by
increasing the background counting time, as discussed
below.
c. TB and TS are the background and sample counting times,
respectively. These are the factors that we have absolute
control over.
1) In the previous section we talked about the reliability
of the count itself. We have been able to state that a
count under given circumstances may be reproduced
with a certain confidence level, and that the larger the
number of counts the greater the reliability.
2) The condition we have been assuming is that our
count is taken within a given time. In order to get
more precise results, many counts must be observed.
Therefore, if we have low count rates, the counting
time must be increased in order to obtain many counts,
thereby making the result more precise (or
reproducible).
Section 17
d. The total counting time required depends upon both the
sample and background count rates.
1) For high sample activities the sample count time can
be relatively short compared to the background count
time.
2) For medium count rates we must increase the sample
count time in order to increase precision.
3) As the sample activity gets even lower, we approach
the case where we must devote equal time to the
background and source counts.
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a) In other words, by counting low activity samples
for the same amount of time as that of the
background determination, we increase the
precision of our sample result.
b) However, we must never count a sample for a
period of time longer than that of the system
background.
3. In summary, by minimizing the potential error present, we
improve statistical validity of our measurements.
I. Detection Limits
1. The detection limit of a measurement system refers to the
statistically determined quantity of radioactive material (or
radiation) that can be measured (or detected) at a preselected
confidence level.
This limit is a factor of both the instrumentation and
technique/procedure being used.
2. The two parameters of interest for a detector system with a
background response greater than zero are:
a. LC Critical detection level: the response level at which the
detector output can be considered "above background"
b. LD Minimum significant activity level, i.e., the activity
level that can be seen with a detector with a fixed level of
certainty
3. These detection levels can be calculated by the use of Poisson
statistics, assuming random errors and systematic errors are
separately accounted for, and that there is a background
response.
4. For these calculations, two types of statistical counting errors
must be considered quantitatively in order to define acceptable
probabilities for each type of error:
a. Type I
1) occurs when a detector response is considered above
background when in fact it is not
2) associated with LC
Objective 2.03.21
Refer students to
Figure 6 in Study
Guide.
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b. Type II
1) occurs when a detector response is considered to be
background when in fact it is greater than background
2) associated with LD
5. If the two probabilities (areas labeled I and II in Figure 6) are
assumed to be equal, and the background of the counting
system is not well-known, then the critical detection level (LC)
and the minimum significant activity level (LD) can be
calculated.
6. The two values would be derived using the equations LC = kσB
and LD = k2 + 2kσB, respectively.
7. If 5% false positives (Type I error) and 5% false negatives
(Type II error) are selected to be acceptable levels, i.e., 95%
confidence level, then if for example k = 1.645 and the two
equations can be written as:
1.645 B B
C
B S
R RL
T T
= + (Eq.16)
where: LC = Critical detection level
LD = a priori detection limit [minimum
significant activity level]
k = Poisson probability sum for I and II
(assuming I and II probabilities are equal)
RB = background counts
T = count time (sample and background)
8. The minimum significant activity level, LD, is the a priori
(before the fact) activity level that an instrument can be
expected to detect 95% of the time.
a. In other words, it is the smallest amount of activity that
Section 18
can be detected at a 95% confidence level.
b. When stating the detection capability of an instrument,
this value should be used.
9. The critical detection level, LC, is the lower bound on the 95%
detection interval defined for LD, and is the level at which there
is a 5% chance of calling a background value "greater than
background."
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a. This value (LC) should be used when actually counting
samples or making direct radiation measurements.
b. Any response above this level should be counted as
positive and reported as valid data. This will ensure 95%
detection capability for LD.
10. If the sample count time (TS) is the same as the background
count time (TB), then equations 16 and 17 can be simplified as
follows:
2.32 B
C
RL
T
= (Eq.18)
2.71 4.65 B
D
RL
T
= + (Eq.19)
11. Therefore, the full equations for LC and LD must be used for
samples with count times differing from the background
determination time (95% CL used).
These equations assume that the standard deviation of the
sample planchet/carrier background during the sample count
(the planchet/carrier assumed to be 0 activity) is equal to the
standard deviation of the system background (determined
using the background planchet/carrier).
12. The critical detection level, LC, is used when reporting survey
results.
a. It is used to say that at a 95% confidence level, samples
above this value are radioactive.
b. This presupposes, then, that 5% of the time clean samples
will be considered radioactive.
13. The minimum significant activity level, LD, [also referred to as
the LLD (Lower Limit of Detection) in some texts] is
calculated prior to counting samples.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-31
a. This value is used to determine minimum count times
based on release limits and airborne radioactivity levels.
b. In using this value we are saying that at a 95% CL,
samples counted for at least the minimum count time
calculated using the LD that are positive will indeed be
radioactive (above the LC). This presupposes, then, that
5% of the time samples considered clean will actually be
radioactive.
(Insert site specific information here.)
J. Crosstalk
1. Discrimination
a. Crosstalk is a phenomenon that occurs on proportional
counting systems (such as a Tennelec) that employ
electronic, pulse-height discrimination, thereby allowing
the simultaneous analysis for alpha and beta-gamma
activity.
b. Discrimination is accomplished by establishing two
thresholds, or windows, which can be set in accordance
with the radiation energies of the isotopes of concern.
c. Recall that the pulses generated by alpha radiation will be
much larger than those generated by beta or gamma.
1) This makes the discrimination between alpha and
beta-gamma possible.
2) Beta and gamma events are difficult to distinguish;
hence, they are considered as one and the same type
by such counting systems.
d. In practice, the lower window is set such that electronic
noise and ultra-low-energy photon events are filtered out.
e. Any pulse generated whose size is greater than the setting
for the lower window is considered an event, or a count.
f. The upper window is then set such that any pulses which
surpass the upper discriminator setting will be considered
an alpha count.
Review Example 9 in
Study Guide with
students.
Objective 2.03.22
Section 19
Objective 2.03.23
Refer students to
Figure 7 in Study
Guide.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-32
g. For output purposes, the system routes each count to a
series of channels which simply keep a total of the counts
routed to them.
1) Channel A is for alpha counts
2) Channel B is beta-gamma counts
3) Channel C is total counts. As a sample is being
counted, all valid counts registered (i.e., those which
surpass the lower discriminator setting) are routed to
the C-channel.
h. In addition, if the count was considered an alpha count
(i.e., it surpassed the upper discriminator setting) it is
routed to the A-channel; else it is tallied in the B-channel.
i. In effect, what occurs is that the number of beta-gamma
counts (Channel B) are determined by subtracting the
number of alpha counts (Channel A) from the total counts
(Channel C), or B = C - A.
2. Origin of Crosstalk
a. Now that we understand the process involved, there is a
dilemma that stems from the fact that events are identified
by the system as either alpha or beta-gamma according to
the size of the pulse generated inside the detector.
b. The system cannot really tell what type of radiation has
generated the pulse.
c. Rather, the pulse is labeled as "alpha" or "beta-gamma" by
comparing the size of the pulse to the discriminator setting.
It is the setting of the discriminator that poses the dilemma.
d. Alpha particles entering the detector chamber generally
are attenuated by the detector fill-gas because of their high
LET, thereby producing a large pulse.
e. Low-energy beta particles and photons will also lose all
their energy within the detector gas, but nevertheless
produce a smaller pulse because of their lower energies.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-33
f. High energy beta particles can still retain some of their
energy even after having produced a pulse while
traversing the detector volume.
1) Rather than leaving the detector, as would a photon,
the beta is reflected off of the detector wall and
reenters the volume of gas, causing ionizations and
generating a second pulse.
2) These two pulses can be so close together that the
detector sees them as one large pulse.
3) Because of the large pulse size it can surpass the
upper discriminator setting and is, therefore, counted
as an alpha, and not as a beta.
g. The result is that alpha activity can be reported for a
sample when in fact there was little or no alpha present.
h. Conversely, if a true alpha-generated pulse is not large
enough so as to exceed the upper discriminator, it would
be counted as a beta-gamma event. This is crosstalk.
i. The solution is not a simple one. The setting of the upper
discriminator depends on the radiations and energies of the
sources and samples being analyzed.
1) If high energy beta radiations are involved, a
significant portion of them could be counted as alpha
events if the setting is too low.
2) If the setting is too high, lower-energy alpha events
could be counted as beta-gamma.
j. Typically, the setting of the discriminator will usually be
some "happy medium."
k. A discussion of how this can be dealt with is in order.
3. Calibration Sources and Crosstalk
a. For calibrations of Tennelec counting systems, the
manufacturer provides the following general
recommendations for discriminator settings:
Section 20
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-34
b. First, using a Strontium-90 beta source, set the upper (α)
discriminator such that there is 1% beta-to-alpha crosstalk.
c. Then, using a Polonium-210 alpha source, set the α+β
discriminator such that there is less than 3% alpha-to-beta
crosstalk.
d. Energies of sources used to calibrate counting systems
should be the same as, or as close as possible to, the
energies of isotopes in the samples analyzed.
e. Wherever possible they should be a pure emitter of the
radiation of concern.
f. For beta-gamma sources the most popular isotope in
radiation protection is Sr-90.
1) It has a relatively long half-life of 29.1 years, but
emits betas of only 546 keV.
2) However, Sr-90 decays to Yttrium-90, another beta
emitter which has a short half-life of only 2.67 days
and emits a 2.281 MeV beta.
3) Y-90 decays to Zirconium-90m which emits a 2.186
Mev gamma almost instantaneously to become stable.
4) The daughters reach equilibrium with the strontium
parent within a number of hours after source assay.
5) Hence, for every Sr beta emitted a Y beta is also
emitted, thereby doubling the activity.
6) These sources are often listed as Sr/Y-90 for obvious
reasons.
7) This makes Sr/Y-90 sources an excellent choice and
are used by many sites for calibrations and
performance testing.
g. Po-210 is essentially a pure alpha emitter. This is
primarily the reason why it is recommended for
calibrations and performance testing.
1) It yields a strong alpha, but it also has a short half-life.
A comparison of some alpha emitters is given in
Table 5.
Refer students to Table 5 in
Study Guide.
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-35
(Insert site specific information here.)
K. Voltage Plateaus
1. Very simply put, a voltage plateau is a graph that indicates a
detector's response to an isotope with variations of high
voltage.
a. The x-axis represents the high voltage and the y-axis the
response (i.e., counts).
b. The resulting curve gives an indication of detector quality,
and can indicate problems with the counting gas should
they be present.
c. The curve can also be used to determine the optimum
operating high voltage for the system.
2. Most automatic low-background counting systems provide
several different analysis modes. These modes count samples
at certain pre-determined voltages.
3. Counting systems generally provide three analysis modes:
• Alpha only
• Alpha then Beta
• Alpha and Beta (simultaneous)
4. There are usually two voltage settings used in conjunction with
these analysis modes:
• Alpha voltage (lower)
• [Alpha plus] Beta voltage (higher)
5. Recall that in a proportional counter the amount of voltage
determines the amount of gas multiplication.
6. Because of the high LET of alpha radiation, at a lower voltage,
even though the gas amplification will be lower, alpha pulses
will still surpass the lower discriminator and some will even
pass the upper discriminator.
7. Because of the lower gas amplification beta-gamma pulses will
not be large enough to be seen. Therefore, any counts reported
for the sample will be alpha counts.
Objective 2.03.24
Objective 2.03.25
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-36
8. In the Alpha only mode, the sample is counted once, at the
alpha voltage. Counts may appear in either the A or B
channels.
Section 21
a. Upon output, the A and B channels will be added together
and placed in Channel A and, therefore, reported as alpha
counts; the B channel will be cleared to zero, thereby
resulting in no beta-gamma counts.
9. In the Alpha then Beta mode, the sample is counted twice.
a. The first count interval determines the alpha counts using
the alpha voltage.
b. The second count is done at the beta voltage.
c. The determination of alpha and beta-gamma counts in this
mode is based strictly on the operating characteristics of
the detector at the different voltages.
d. For this reason, the A and B counts are summed during
both counting intervals to attain the total counts.
e. The separation of alpha and beta-gamma counts is then
calculated and reported according to the following
formula:
( )
1 1
α
2 2
α
β α
A B
CF
A B
+
=
= − −
(Eq.20)
where: α = reported gross alpha counts
β = reported gross beta-gamma counts
A1,B1 = accumulated channel counts respectively,
1st interval
A2,B2 = accumulated channel counts respectively,
2nd interval
CFα = alpha correction factor (ratio of alpha
efficiency at alpha voltage to efficiency at
beta voltage)
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-37
10. In the Alpha and Beta (simultaneous) mode, the sample is
counted once using the beta voltage.
a. Alpha events are reported in the A channel, while beta-
gamma counts are reported in the B channel.
b. This is the mode used most often.
11. As can be seen, the setting of the two voltages will have a
direct impact on the number of counts reported for a given
sample.
12. The determination of what these voltage settings should be
must be done such that the optimum performance of the
detector is obtained for those voltage regions. This is the
purpose of a plateau.
(Insert site specific information here. The information that
follows may be used as applicable.)
13. In conjunction with initial system setup and calibration by the
vendor, two voltages plateaus are performed--alpha voltage
and beta voltage.
14. For P-10 gas the alpha plateau is started at about 400 volts and
the beta plateau at about 900 volts.
15. Alpha and beta plateaus are defined by the isotope being used
and not by the channel being used to accumulate the counts.
16. More appropriately, the gross counts are accumulated and
plotted for each type of isotope.
17. Each time that a count is completed, the high voltage is
incremented a specific amount, typically 25 to 50 volts, and
another count is accumulated.
18. This is repeated until the end of the range is reached, typically
about 1800 volts.
19. With the high voltage set at the starting point, few or no counts
are observed because of insufficient ion production within the
detector.
20. As the voltage is increased, a greater number of pulses are
produced with sufficient amplitude to exceed the discriminator
threshold, and are then accumulated in the counter.
Objective 2.03.26
DOE-HDBK-1122-2009
Module 2.03 Counting Errors and Statistics Instructor’s Guide
2.03-38
21. There will be a high voltage setting where the increase in
counts levels off (see Figure 8).
22. This area is the detector plateau. Further increases in high
voltage result in little change in the overall count rate.
23. The plateau should remain flat for at least 200 volts using a
Sr/Y-90 source, and this indicates the plateau length.
24. Between 1750 and 1850 volts the count rate will start to
Section 22
increase dramatically. This is the avalanche region, and the
high voltage should not be increased any further.
25. The region where the counts level off is called the knee of the
plateau.
26. The operating voltage is chosen by viewing the plateau curve
and selecting a point 50 to 75 volts above the knee and where
the slope per 100 volts is less than 2.5%.
27. This ensures that minor changes in high voltage will have
negligible effects on the sample count. Poor counting gas or
separation of the methane and argon in P-10 can result in a
very high slope of the plateau.
28. Upon initial system setup and calibration the vendor
determines and sets the optimum operating voltages for the
system. Thereafter, plateaus should be generated each time the
counting gas is changed.
III. SUMMARY
This unit addressed the measures used to minimize error, fundamentals
of binomial statistics and application of these fundamentals in a nuclear
counting environment.
IV. EVALUATION
Evaluation should consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% should be the minimum passing criteria for
examinations.
[If used, refer students to
Beta voltage figure in
student guide]
DOE-HDBK-1122-2008
Module 2.04 Dosimetry Instructor’s Guide
2.04-1
Course Title: Radiological Control Technician
Module Title: Dosimetry
Module Number: 2.04
Objectives:
2.04.01 Identify the DOE external exposure limits for general employees.
2.04.02 Identify the DOE limits established for the embryo/fetus of a declared pregnant female
general employee.
→ 2.04.03 Identify the administrative exposure control guidelines at your site, including those for
the:
a. General Employee
b. Member of the Public/Minor
c. Incidents and emergencies
d. Embryo/Fetus
→ 2.04.04 Identify the requirements for a female general employee who has notified her employer
in writing that she is pregnant.
2.04.05 Determine the theory of operation of a thermoluminescent dosimeter (TLD).
2.04.06 Determine how a TLD reader measures the radiation dose from a TLD.
2.04.07 Identify the advantages and disadvantages of a TLD compared to a film badge.
→ 2.04.08 Identify the types of beta-gamma TLDs used at your site.
→ 2.04.09 Identify the types of neutron TLDs used at your site.
→ 2.04.10 Determine the requirements for use of TLDs used at your site.
→ 2.04.11 Determine the principle of operation, and the types used, for the personnel neutron
dosimeters used at your site.
→ 2.04.12 Determine the principle of operation of self-reading dosimetry (SRD) used at your site.
→ 2.04.13 Determine the principle of operation, and guidelines for use, for the alarming dosimeters
used at your site.
→ 2.04.14 List the types of bioassay monitoring methods at your site.
2.04.15 List different uses of area monitoring dosimeters.
DOE-HDBK-1122-2008
Module 2.04 Dosimetry Instructor’s Guide
2.04-2
References:
1. "Basic Radiation Protection Technology"; Gollnick, Daniel; 5th ed.; Pacific Radiation
Corporation; 2008.
2. ANL-88-26 (1988) "Operational Health Physics Training"; Moe, Harold; Argonne
National Laboratory, Chicago.
3. "DOE Radiological Control Standard"; U.S. Department of Energy, 2008.
4. 10 CFR Part 835 (2007) "Occupational Radiation Protection".
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
Section 23
2.04-3
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
This lesson will introduce the types of instruments used to
measure external and internal radiation to people. Dosimetry is
the quantitative assessment of radiation received by the human
body. There are several types of dosimeters in use worldwide.
This material is valuable to all radiological control personnel
since dosimeters are the only direct method to measure and
document personnel radiation exposure and ensure regulatory
compliance with applicable limits.
C. Overview of Lesson
1. Dosimetry terms
2. DOE limits
3. Site administrative guidelines
4. TLDs
5. Site dosimetry
6. Bioassay assessment methods
D. Introduce Objectives
II. LESSON OUTLINE
A. DOSIMETRY TERMS
Understanding the terminology used in discussing dosimetry and
exposure to ionizing radiation is essential for RCTs to do their
job.
1. Absorbed Dose (D)
O.H.: Objectives
Majority from 835.2
Refer to the definitions
provided in the Study
Guide and review terms
with class.
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-4
2. Equivalent Dose (HT)
3. Whole Body
4. Extremity
7. Committed Equivalent Dose (HT,50)
8. Radiation Weighting Factor (wR)
9. Committed Effective Dose (E50)
10. Total Effective Dose (TED)
11. Annual Limit on Intake (ALI)
12. Derived Air Concentration (DAC)
13. Bioassay
14. In Vivo
15. In Vitro
16. Background
17. Declared Pregnant Worker
B. DOE LIMITS
1. Limits are the legal maximum values stated in 10 CFR 835.
To exceed these values is to violate the law. Programs must
be in place to ensure that exposures to ionizing radiation are
kept below these levels. To accomplish this Administrative
Control Levels are selected well below the regulatory limits.
These control levels are usually multi-tiered with increasing
levels of authority required to approve higher Administrative
Control Levels.
2. Annual dose limits are based on a calendar year (January 1st
through December 31st). For assigning internal equivalent
dose received from intakes (committed effective dose and
committed equivalent dose), the total 50-year committed dose
received is assigned to the time of the intake even though the
actual dose is proportionally received over the 50-year period.
3. See Table 3 for dosimetric equivalencies for circumstances
when an individual conducts multiple activities involving
both activities under 10 CFR 835.1(b)(1) and excluded
activities, e.g., activities involving NRC licensed activities.
Explain that the terms
were revised in the 2007
amendment to 10 CFR
835
Objective 2.04.01
See Table 2
See Table 3
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-5
a. General Employees
1) Whole body (internal + external) - 5 rems (0.05
sievert)
2) Lens of the eye - 15 rems (0.15 sievert)
3) Extremities - 50 rems (0.5 sievert)
4) Organ or tissue and skin - 50 rems (0.5 sievert)
b. Minors/Public - 0.1 rem (0.001 sievert)
c. Embryo/Fetus of Declared Pregnant Workers - 0.5 rems
(0.005 sievert) per gestation period
d. Emergency Exposures
e. Planned Special Exposures
C. SITE ADMINISTRATIVE GUIDELINES
1. Radiological Workers
(Insert site specific information here)
2. Non-Radiation Worker
(Insert site specific information here)
3. Exposure from Incidents or Emergencies
(Insert site specific information here)
4. Embryo/fetus
Section 24
(Insert site specific information here)
D. TYPES OF DOSIMETRY
1. As a result of irradiation, some solid substances undergo
changes in some of their physical properties.
2. These changes amount to storage of the energy from the
radiation.
3. Since the energy is stored, these materials can be used for
dosimeters. The features that have been studied include:
10 CFR 835.202
10 CFR 835.207 & .208
10 CFR 835.206
Objective 2.04.02
DOE G 151.1-4,
Chapter 7
10 CFR 835.204
Objective 2.04.03.a
Objective 2.04.03.b
Objective 2.04.03.c
Objective 2.04.03.d
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-6
a. Optical density changes
1) Optical density changes involve a change in the color
of some types of plastics and glass.
2) In glass, the dose range is 103 to 106 rads (10 to 104
gray). The range for plastics is 106 to 109 rads (104 to
107 gray).
3) An example, film badges, provides low range, 10 mR
to 10 R, for personnel and high range, 1 R to 1,000 R
for accident readings.
b. Thermoluminescence
1) Thermoluminescence (TL) is the ability of some
materials to convert the energy from radiation to a
radiation of a different wavelength, normally in the
visible light range.
2) There are two categories of thermoluminescence.
a) Fluorescence - This is emission of light during or
immediately after irradiation (within fractions of
a second) of the phosphor. This is not a
particularly useful reaction for TLD use.
b) Phosphorescence - This is the emission of light
after the irradiation period. The delay time can
be from a few seconds to weeks or months. This
is the principle of operation used for
thermoluminescent dosimeters.
3) The property of thermoluminescence of some
materials is the main method used for personnel
dosimeters at DOE facilities and will be discussed in
further detail.
E. TLD OPERATION
1. TLD's use phosphorescence as their means of detection of
radiation.
2. Electrons in some solids can exist in two energy states, called
the valence band and the conduction band. The difference
between the two bands is called the band gap.
3. Electrons in the conduction band or in the band gap have
more energy than the valence band electrons.
Example - TV or
computer monitor screen
Objective 2.04.05
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-7
4. Normally in a solid, no electrons exist in energy states
contained in the band gap. This is a "forbidden region."
5. In some materials, or if impurities are added, defects in the
material exist or are made that can trap electrons in the band
gap and hold them there. These trapped electrons represent
stored energy for the time that the electrons are held. This
energy is given up if the electron returns to the valence band.
6. In most materials, this energy is given up as heat in the
surrounding material, however, in some materials a portion of
energy is emitted as light photons. This property is called
luminescence.
F. TLD Reader
1. Basic principle of operation
a. Heating of the TL material causes the trapped electrons
to return to the valence band. When this happens, energy
is emitted in the form of visible light.
b. The light output is detected and measured by a
photomultiplier tube and a dose is then calculated.
c. A typical basic TLD reader contains the following
components:
1) Heater
2) Photomultiplier tube
3) Meter/recorder
2. Glow curve
a. Obtained from heating process.
Section 25
b. The light output from TL material is not easily
interpreted. Multiple peaks result.
1) As the material is heated, electrons trapped in
"shallow" traps are released. This results in a peak as
these traps are emptied. The light output drops off as
these traps are depleted.
See figure 1 - "Electron
Entrapment"
See figure 2 -
"Thermoluminescence"
Objective 2.04.06
See figure 3 - "TLD
Reader"
See figure 4 - "Glow
curve"
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-8
2) As heating continues, the electrons in deeper traps
are released. This results in additional peaks.
Usually the highest peak is used for calculations.
The area under the curve represents the radiation
energy deposited.
c. After the readout is complete, the TLD is annealed at a
high temperature. This process essentially zeroes the TL
material by releasing all trapped electrons. The TLD is
then ready for reuse.
G. ADVANTAGES AND DISADVANTAGES OF TLDs
1. Advantages (primarily as compared to film badges)
a. Able to measure a greater range of doses.
b. Doses may be easily obtained.
c. They can be read on site instead of being sent away for
developing.
d. Quicker turnaround time for readout.
e. Reusable.
2. Disadvantages
a. Each dose cannot be read out more than once.
b. The readout process effectively "zeroes" the TLD.
H. SITE BETA/GAMMA TLDs
(Insert site specific information here)
I. SITE NEUTRON TLDs
(Insert site specific information here)
J. DOE EXTERNAL DOSIMETRY GENERAL PROVISIONS
1. Dosimetry shall be provided to and used by:
a. General employee expected equivalent dose to the whole
body > 0.1 rem (0.001 sieverts); or > 10% of limits for
extremities, organs, and other tissues.
b. Declared pregnant worker expected to receive 0.05 rem
(0.0005 sievert) or more during the gestation period.
Objective 2.04.07
Objective 2.04.08
Objective 2.04.09
10 CFR 835
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-9
c. Minors likely to receive 50% of Occupational Dose
Limits or more in a year.
d. Public entering controlled areas likely to receive external
equivalent dose to the whole body of 0.05 rem (0.0005
sievert) or more in one year.
e. Individuals entering a high or very high radiation area.
2. Neutron dosimetry provided when applicable threshold is
likely to exceeded due to neutron radiation.
3. Issued to individuals knowledgeable of proper use and worn
only by assignee.
4. Issuance of dosimeters should be discouraged for individuals
other than those where there is a likelihood of being
occupationally exposed to levels above monitoring thresholds.
5. Dosimeters should be returned at required intervals.
Individuals not returning dosimeters should be restricted.
6. Primary dosimeters should be worn on the chest area or
between the waist and the neck.
7. Individuals should not be assigned multiple primary
dosimeters during different periods of the dosimeter process
year (exchange of primary dosimeter for multi-badging is
acceptable); and avoid exposure of dosimeter to non-
occupational sources.
8. When dosimeters are lost, damaged, or contaminated, the
individual should place work in a safe condition, exit and
notify the RCO. Reenter only after review and approval.
K. SITE REQUIREMENTS FOR USE OF TLDs
(Insert site specific information here)
L. SITE PERSONNEL NEUTRON DOSIMETERS
(Insert site specific information here)
M. POCKET AND ELECTRONIC DOSIMETERS
Section 26
1. Provide real time dose indication.
2. Shall be issued for entry into High or Very High Radiation
Area.
Objective 2.04.10
Objective 2.04.11
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-10
3. Should be issue when planned activity levels exceed 0.05 rem
(0.0005 sievert) or 10% of control levels.
4. Should be issued when required by RWP.
5. Worn with primary dosimetry and located on chest area, on
or between the waist and the neck.
6. Should be read periodically and should not exceed 75% of
full scale.
7. Authorized work should cease when supplemental dosimeter
indicates total dose or dose rate is > than expected.
8. When supplemental dosimeters differ by more than 50%
from primary dosimeters and the primary result is >0.1 rem
(0.001 sievert), an investigation should be initiated.
N. SITE SELF-READING DOSIMETERS
(Insert site specific information here)
1. Self Reading Pocket Dosimeters (SRPD)
a. Direct reading ion chamber.
b. Utilizes two electrodes:
1) Fiber electrometer (fixed and moveable components)
2) Metal frame
c. As chamber is ionized the charge is decreased on the
movable and fixed fiber.
d. The movement of the fiber is proportional to the dose
received.
O. SITE ALARMING DOSIMETRY
(Insert site specific information here)
P. INTERNAL DOSIMETRY REQUIREMENTS
Objective 2.04.12
See figure 5 - "SRPD"
Note: SRPDs with steel
walls are usually
insensitive to beta and
low energy gamma
See figure 6 -"SRPD
Reading"
Objective 2.04.13
Re-enforce difference
between "internal" and
"external" dose
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-11
1. Internal dose evaluation programs shall be conducted for:
a. General employees - likely to receive 0.1 rem (0.001
sievert) or more committed effective dose.
b. Declared pregnant workers - likely to receive an intake
resulting in an equivalent dose of 10% of the limit (or
0.05 rem [0.0005 sievert]).
c. Minors - likely to receive a committed effective dose in
excess of 50% of limit (or 0.05 rem [0.0005 sievert]).
d. Public - likely to receive a committed effective dose in
excess of 50% of limit (or 0.05 rem [0.0005 sievert]).
2. Estimation shall be based on bioassay results rather than air
concentration values unless air concentration values are more
reliable or bioassay results are unavailable.
3. Follow-up bioassay monitoring is typically required when
results indicate a committed effective dose of 0.1 rem (0.001
sievert) or more.
4. A bioassay program should be considered for personnel
routinely exposed to surface or airborne contamination or to
radionuclides readily absorbed through the skin.
5. Personnel are required to submit bioassay samples.
6. Personnel shall be notified of positive bioassay results.
Q. BIOASSAY ASSESSMENT METHODS
1. General
a. Today's technology has not produced a device that allows
accurate determination of internal exposure following the
entry of radioactive materials into the body.
b. The method that is used to determine internal dose
contributions relies on calculation of dose to affected
portions of the body based on the quantities of
radioactive materials in the body. Thus, the real problem
becomes one of quantifying the amount of material
present.
c. Bioassay is the term that is used to describe the
assessment of the quantity of radioactive material present
in the body. There are currently two types of bioassay
measurements employed in nuclear industries:
Section 27
10 CFR 835.402
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-12
1) In vivo - analysis of living tissue.
2) In vitro - analysis of excreted samples.
d. Bioassay programs are designed to fulfill two needs:
1) Evaluate effectiveness of contamination control
practices.
a) Routine bioassay programs utilize submission
and analysis of samples from workers in facilities
where the likelihood of intake exists.
b) Primarily limited to urinalysis due to ease of
sample collection.
c) Also includes initial, routine, and termination
whole body counts.
2) Evaluate potential consequences of accidental
inhalation or ingestion of large quantities of
radioactive materials.
a) Can involve all types of bioassay measurements
with collection and analysis of nasal, urine, and
fecal samples.
b) Whole body counts provide immediate
indications for given radionuclides if
individual(s) involved are free of external
contamination.
2. In vivo measurements
a. The amount of materials is estimated by counting
radiation emitted by radioactive materials in the body.
b. Only good for radioactive materials which emit gamma
radiation of sufficient abundance and energy to be
detected and statistically measured.
c. With use of expensive, sophisticated spectroscopy, most
contributors (radionuclides present) can be identified.
d. Site In vivo methods
(Insert site specific information here)
e. Advantages
Objective 2.04.14
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-13
1) No sample required.
2) Results obtained quickly.
3) Some equipment design allows field use.
4) Time and manpower requirements minimized.
f. Disadvantages
1) Limited to detection and measurement of gamma
emitters.
2) Individual must be free of external contamination.
3) Long count times for identification.
4) Effects of background.
5) Complex calibration procedure and calibration
equipment.
6) Expense.
7) Quantification error due to differences in tissue
structure from one person to another as compared to
calibration phantom.
3. In Vitro Measurements
a. The amount of material present in the body is estimated
using the amount of materials present in excretions or
secretions from the body.
b. Samples include urine, feces, blood, sputum, saliva, hair
and nasal discharges.
c. Calculation requires knowledge of and use of metabolic
models which allow use of activity in samples to be
related to activity present in the body.
d. Resulting dose calculations to quantify committed and
effective doses are estimates.
1) This is due partly to use of default values for
measurements that cannot be readily made such as
mass of particular organs, volumes of particular
fluids, etc., in lieu of actual values for individual
involved. Remember that reference man is an
average.
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-14
2) Another contributing factor is different metabolism
from one individual to another.
e. Types of analysis
1) Urinalysis - indicates intake of primarily soluble
material.
2) Fecal analysis - primarily indicates intake of
insoluble material. Provides relatively rapid
indication.
3) Sputum - may contain insoluble material initially
deposited in the lung and later eliminated by ciliary
action.
4) Saliva - may be use to estimate uptake of tritium
oxide.
5) Nasal discharge - indication of the deposition of the
coarsest inhaled particles in the nose.
Section 28
f. Site in vitro methods
(Insert site specific information here)
g. Advantages of in vitro measurements
1) Can be used for estimation of neutron doses using
activation product concentration in hair and blood
(32P and 24Na).
2) Can be used to quantify presence of materials which
decay by alpha and beta emission to allow detection
and measurement with external detector systems.
h. Disadvantages
1) Requires sample submission and analysis.
2) Time and manpower requirements.
3. Bioassay Scheduling Program
a. Contamination found at a given site will depend on the
materials that are used and produced at the site. Thus,
the materials that internal dosimetrists are primarily
concerned with will change from one site to another as
well.
Objective 2.04.14
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Module 2.04 Dosimetry Instructor’s Guide
2.04-15
b. Baseline/Routine/Exit Evaluations
(Insert site specific information here)
c. Special Evaluations
(Insert site specific information here)
d. Investigation Levels
(Insert site specific information here)
e. Medical Uses
(Insert site specific information here)
R. AREA MONITORING DOSIMETERS
1. Area monitoring dosimeters are often used to record and
document radiation levels in routinely occupied areas
adjacent to areas where radiation or radiological operations
exist.
Note: This type of monitoring does not apply when the
radiation hazard of concern arises from low-energy beta
sources (e.g., 14C, 3H).
2. Establishment and maintenance of a comprehensive area
monitoring program can demonstrate that doses outside
Radiological Buffer Areas are negligible, and help to
minimize the number of areas requiring the issuance/use of
personnel dosimeters.
Minimizing the number of personnel dosimeters issued saves
in the costs of operating the dosimetry program and reduces
costs associated with maintaining personnel with enhanced
training and qualifications.
3. Area monitoring dosimeters are also used to help characterize
workplace conditions to verify the effectiveness of physical
design features, engineering controls, and administrative
controls. In addition, area monitoring dosimeter results can
be used to support dosimetry investigations where personnel
express concerns about their work environments and
exposure to ionizing radiation.
4. Finally, area (and equipment) monitoring dosimeters are
useful for the determination of dose rates and/or integrated
doses for:
Objective 2.04.15
DOE-HDBK-1122-2009
Module 2.04 Dosimetry Instructor’s Guide
2.04-16
a. equipment and/or areas with suspected high dose rates;
b. devices emitting pulsed radiation not accurately
measured with portable survey instruments;
c. highly collimated beams of radiation; and
d. radiological incidents.
III. SUMMARY
A. Review major topics
1. Dosimetry terms
2. DOE limits
3. Site administrative guidelines
4. TLDs
5. Site dosimetry
6. Bioassay assessment methods
B. Review learning objectives
IV. EVALUATION
Evaluation shall consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% shall be the minimum passing criteria for
examinations.
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-1
Course Title: Radiological Control Technician
Module Title: Contamination Control
Module Number: 2.05
Objectives:
2.05.01 Define the terms "removable and fixed surface
contamination," state the difference between them
and list common methods used to measure each.
Section 29
2.05.02 State the components of a radiological monitoring
program for contamination control and common
methods used to accomplish them.
2.05.03 State the basic goal of a contamination control
program and list actions that contribute to its
success.
2.05.04 State the basic principles of contamination control
and list examples of implementation methods.
2.05.05 List and describe the possible engineering control
methods used for contamination control.
2.05.06 State the purpose of using protective clothing in
contamination areas.
2.05.07 List the basic factors which determine protective
clothing requirements for personnel protection.
References:
1. "DOE Radiological Control Standard"; U.S. Department of
Energy, 2008.
2. "The Health Physics and Radiological Health Handbook,"
Shleien; 1992.
3. 10 CFR Part 835 (2007) "Occupational Radiation
Protection".
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-2
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Contamination control is probably one of the most difficult and
challenging tasks the Radiological Control Technician will
encounter.
C. Overview of Lesson
1. Types of Contamination
2. Assessing Contamination Hazards
3. Basic Goal of Contamination Control
4. Contamination Control Measures
5. Basis for Establishing Protective Clothing Requirements
D. Introduce Objectives
II. MODULE OUTLINE
A. TYPES OF CONTAMINATION
Contamination is simply defined as radioactive material in an
unwanted location, e.g., personnel work areas, etc. Two types are
possible:
1. Fixed Contamination - Radioactive surface contamination
that is not easily transferred to other personnel or equipment
through normal contact.
2. Removable Contamination - Radioactive surface
contamination that is easily transferred to other personnel or
equipment through normal contact.
O.H.: Objectives
Objective 2.05.01
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Module 2.05 Contamination Control Instructor’s Guide
2.05-3
3. Removable contamination is measured by a transfer test
using a suitable sampling material. Common materials used
for the monitoring are the standard paper disk smear or cloth
smear. The standard technique involves wiping
approximately 100 cm2 of the surface of interest using
moderate pressure. A common sampling practice used to
ensure a 100 cm2 sample is to wipe a 16 square inch "S"
shape on the surface (i.e., four inches by four inches).
Qualitative, large area wipe surveys may be taken using other
materials, such as Masslin cloth or Kimwipe, to indicate the
presence of removable contamination. These are commonly
used when exact levels of contamination are not required.
4. Fixed contamination is measured by use of a direct survey
technique. This technique, commonly referred to as
"frisking," indicates the total contamination on a surface
apparent to the detector from both fixed and removable. To
evaluate the fixed component the removable level must be
subtracted from the total, when non-removable levels are to
be recorded.
Appendix D to 10 CFR 835 lists contamination levels in units
of dpm/100 cm2. Typical evaluation of fixed contamination
monitoring includes adjusting the portable instrument count
rate (counts per minute) to account for the area of the
monitoring instrument (probe area) and the instrument
efficiency to obtain units of dpm/100 cm2.
Section 30
Footnote 4 to Appendix D states that when “removable
contamination on objects of surface area less than 100 cm2 is
determined, the activity per unit area shall be based on the
actual area and the entire surface shall be wiped”. For
example, for an object with a total surface area of 50 cm2, the
entire object would be wiped and the count result would be
divided by the counting efficiency and multiplied by an area
adjustment factor of two (100 cm2/50 cm2) to get a result in
units of dpm/100 cm2. A similar approach may be used for
fixed contamination monitoring of objects with surface area
less than 100 cm2. However, care must be taken in
monitoring very small objects and the sensitivity of the
monitoring protocol should be evaluated.
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-4
B. ASSESSING CONTAMINATION HAZARDS
In order to acquire the radiological information necessary for
contamination control, the presence of contamination must be
identified. In order to achieve this, a radiological monitoring
program must be applied. The components are:
• Constant monitoring
• Area and equipment surveys
• External personnel surveys
• Personnel internal monitoring and bioassay
1. Constant monitoring - There are various types of constant
monitoring instruments installed throughout facilities to warn
personnel of radiation and contamination hazards. Identify
the types of instrumentation used in the constant monitoring.
a. Some instruments are permanently installed, and some
instruments are portable to allow movement from place
to place as deemed appropriate.
b. Continuous air monitor (CAM) - These instruments
sample the air in specific locations continuously for
radioactive contamination. Other methods of
continuously monitoring for airborne contamination are
also used.
Objective 2.05.02
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-5
1) Filter monitors draw air through a moving particulate
filter, which is then monitored by a detector system.
2) Direct monitors pull air flow through an internal
detector to directly identify radioactive materials
present.
3) CAMs can give both a visual and audible alarm to
warn personnel of the presence of airborne
contamination.
c. Process monitoring systems - These systems monitor
certain operations in various facilities to alert operators of
abnormal conditions which might lead to the release of
excessive amounts of radioactivity to the facility or
environment.
2. Area and equipment surveys - Surveys are conducted
routinely throughout facilities to locate sources of radiation
and contamination. Pre-job surveys are performed to
evaluate hazards and determine work limitations and physical
safeguards within locations identified.
a. Direct instrument surveys
1) Various types of portable survey instrumentation are
used to measure the presence of radioactive
contamination on a floor or surface.
2) This is the only method available to detect "fixed"
surface contamination.
b. Smear surveys
1) A disk smear is wiped over an area of 100 square
centimeters and counted with proper instrumentation
to determine the activity of the nuclides present in
units of dpm/100 cm2.
a) Disk smears are small so they are usually used in
an area of suspected contamination.
b) Experience will dictate to the surveyor where
contamination is most likely to occur and hence
those areas that should be surveyed with disk
smears.
Section 31
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Module 2.05 Contamination Control Instructor’s Guide
2.05-6
2) Many routine contamination surveys are taken
with a chemically treated cloth called a masslinn.
a) Cloth is lightly pushed over a specified area and
scanned with an appropriate detector to detect the
presence of contamination.
b) If contamination is detected, a more thorough
disk smear survey should be performed.
c) Large area wipes are used only as an indication
of removable surface contamination.
d) Disk smears are required if contamination levels
are to be quantified.
3. External Personnel Surveys - Personnel surveys are either
performed by the individual (self-monitoring) using hand-
held or automated instruments or by a RCT. Monitoring by a
RCT is usually conducted whenever contamination of the
body or clothing is suspected, or as required by exit
monitoring when self-monitoring is not allowed. The
following describes the general types of hand-held or
automated instruments that are commercially available.
a. Personnel monitors - Sensitive hand held detectors used
by personnel to identify contamination on themselves
whenever contamination is suspected.
1) Portable Geiger-Mueller (GM) or scintillation
detectors that are installed at strategic locations
throughout the facilities.
2) These monitors are used whenever exiting
contaminated areas or RBAs.
b. PCMs (Personnel Contamination Monitors) provide
personnel with an external whole body monitoring
system.
1) PCMs are typically located at the RBA exits in
facilities with a high occupancy factor.
2) Contamination detectors within the monitors are
capable of performing a survey of the whole body in
a period of a few seconds, dependent upon
background radiation levels and the personnel
contamination limit of concern.
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
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3) These systems provide a more reliable method of
locating personnel contamination over hand-held
instruments.
c. Portal monitors - Portal monitors are "door frame" type
devices which provide a final monitoring point to ensure
contamination is not spread outside the facility to other
facilities or the general public.
Personnel are required to use (pause and walk through)
this type of monitoring system prior to exiting specified
areas.
d. Personnel surveys - These are performed by RCTs
whenever contamination of clothing or the body is
suspected, or as required when friskers or automated
instruments are not available.
1) The whole body should be surveyed with special
attention given to areas which are more likely to
become contaminated.
2) A minimum survey of the hands, arms, and front
portions of the body must be performed upon
completion of work or prior to leaving the area for
glovebox, laboratory fume hood, sample station, or
localized benchtop operations.
3) Contamination of the feet (shoes) would indicate
removable surface contamination on the floor just
traversed.
4) The nose and mouth should be surveyed upon
discovery of facial contamination or if airborne
contamination was detected in the work area to
determine if bioassay sampling is required.
5) The nose can be swabbed with Q-tips and the swab
counted in a smear counter.
6) Contamination of the nose or mouth may indicate
airborne contamination.
7) All open wounds must be monitored since
contaminants can be readily absorbed into the body.
Section 32
8) Upon detecting personnel contamination, follow-up
area and/or equipment surveys may be necessary to
determine the source of contamination and the extent
the contamination has spread, if any.
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-8
4. Personnel internal monitoring - A routine program of internal
contamination monitoring is conducted as a final check on
contamination control procedures.
Typical programs consist of external whole/partial body
counting and/or urinalysis.
a. In-vivo bioassay (whole/partial body counting) -
Individual is placed inside an array of very sensitive
detectors to measure the activity and energies of gamma
ray emissions from inside the body.
Information can be used to determine the amount and
identify the type of nuclides present.
b. In- vitro bioassays - Performed by collection of urine or
feces samples from an individual to determine type and
activity of the nuclides present in bodily waste.
1) Information is used to approximate the amount of
nuclides present in the body by their calculated rate
of elimination.
2) Can be used to assess the presence of non-gamma
emitting nuclides.
C. BASIC GOAL OF CONTAMINATION CONTROL
Once the presence of radioactive material has been located, the
basic goal underlying any effective contamination control
program is to minimize contaminated areas and maintain
contamination levels as low as reasonably achievable.
1. If the presence of removable contamination is discovered,
decontamination is a valuable means of control.
a. In some situations, this is not always possible.
1) Economical conditions: Cost of time and labor to
decontaminate a location out- weighs the hazards of
the contamination present.
2) Radiological conditions: Radiation dose rates or
other radiological conditions present hazards which
far exceed the benefits of decontamination.
3) Operating conditions: Some areas, e.g., hot cells,
will be contaminated due to normal operations.
b. Other means of control, such as engineering controls,
administrative procedures, or personnel protective
equipment, must be initiated when decontamination is not
possible.
Objective 2.05.03
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Module 2.05 Contamination Control Instructor’s Guide
2.05-9
2. "Good Housekeeping" is a prime factor in an effective
contamination control program. It involves the interactions
of all groups within the facility. Each individual must be
dedicated to keeping "his house clean" to control the spread
of contamination.
Every possible effort should be made in all operations to
confine the spread of radioactive materials to the smallest
possible area.
3. A sound preventive maintenance program can prevent many
radioactive material releases.
4. All material taken into or out of contaminated areas should be
controlled.
5. Regardless of the precautions taken, radioactive materials
will occasionally escape and contaminate an area.
6. Radiological Control Technicians should always be alert for
potential violations to the basic principle of contamination
control.
a. Use of improper contamination control methods
b. Bad work practices
c. Basic rule or procedure violations
d. Radioactive material releases or liquid spills
7. Radiological Control Technicians should always ensure that
the proper procedures to avoid the spread of contamination
are followed or implemented.
D. CONTAMINATION CONTROL MEASURES
Section 33
Controlling the spread of contamination is probably the most
difficult and challenging task the Radiological Control
Technician will encounter. The basic principles of contamination
control are:
• Access/Administrative Controls
• Engineering Controls
• Personnel Protective Measures
• Decontamination
• Preventive Methods
1. Access/Administrative Control
Objective 2.05.04
Objective 2.05.05
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-10
Once the location of contamination has been identified and
quantified and radiological areas have been established, we
must adequately control access to these areas.
Boundaries of radiological areas must be clearly marked.
This is accomplished by using radiological postings and tags
identifying entrances into these areas to restrict access.
Two basic access control points are used in contamination
control.
a. The primary access control point in a facility is the
entry and exit portal between the clean area and the
radiologically controlled area or RBA. The success of
a control program is based on controlling the movement
of personnel and equipment between these areas to
prevent release of contamination to a clean location.
b. Secondary access control points (perhaps the most
important) are set up within the RBAs to control access
between surface contamination areas and non-
contaminated areas. Yellow and magenta rope, tape,
chain, or similar barriers are used to identify boundaries.
Step-off-pads provide a recognizable demarcation to
personnel between the contaminated area and the RBA.
1) Special requirements will always be established for
entry and exit through these access control points.
2) When radiological conditions are severe, the access
control point will be continuously manned by
Radiological Control Technician.
3) Proper procedures must be established and observed
for crossing the SOP to prevent spread of
contamination out of the area.
4) All tools and/or equipment used in contaminated
areas which are unmonitored shall be placed in
plastic bags or securely wrapped in plastic before
being removed from the area.
5) All personnel and materials exiting the area shall be
monitored to ensure they are free of contamination.
2. Engineering Controls - There are several specific methods of
engineering control which can be utilized.
DOE-HDBK-1122-2009
Module 2.05 Contamination Control Instructor’s Guide
2.05-11
a. Ventilation - The design of permanent or temporary
ventilation systems needs to be such that air flow is from
clean areas to RBAs, to areas of moderate contamination,
to areas of high contamination, and finally to a exhaust
system capable of removing any contamination from the
air. Slight negative pressure is typically maintained in
buildings/rooms where potential contamination exists.
b. Containment - On jobs with very high contamination
potential, a plastic tent, (greenhouse or hut) can be built
around the work area to confine all contamination to as
small an area as possible.
1) A portable ventilation exhaust system (such as
HEPAs) may be used to control air flow in the
containment hut and remove airborne contamination.
2) Where possible, small containment devices, such as
glove boxes, glove bags, or hoods can be used to
contain the contamination depending on the nature
and location of the work being performed.
3) Contaminated tools or equipment are placed in
Section 34
plastic bags, or securely wrapped in plastic, before
being moved outside a contaminated area.
4) When possible, wrapping tools or equipment prior to
entry can help control contamination during use
inside the contaminated area.
c. Design and Control - Design of facilities should be such
that efficiency of maintenance, operations, and
decontamination is maximized.
1) Components should be selected that minimizes the
buildup of radioactivity.
2) Support facilities should be included that provide for
the donning and doffing of protective clothing and
for personnel monitoring.
3) Personnel traffic should be routed away from
contaminated areas.
3. Personnel Protective Measures - If engineering methods are
not adequate, then personnel protective measures, such as
protective clothing and respiratory equipment, will be used.
Objective 2.05.06
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a. The purpose of protective clothing is to keep
contamination off the skin and clothing of the workers.
1) Protective clothing allows personnel to work inside a
contaminated area with removable contamination and
to exit the area without spreading contamination to
uncontrolled areas.
2) Use of protective clothing alone will not guarantee
complete elimination of personnel contamination and
is not a substitute for implementing proper controls,
but if used properly, protective clothing will afford a
high degree of protection.
3) All personnel entering contaminated areas with
removable contamination will be required to wear
certain items of protective clothing.
4) Types of clothing required will vary depending upon
the contamination levels and the nature of the work
to be performed.
b. Some type of respiratory protective equipment will be
required for work in areas where very high contamination
levels exist or airborne contamination is present.
3. Decontamination - Line management is responsible for
ensuring prompt decontamination, where practical, of
facilities, tools, equipment, and material so that
contamination can be minimized in the workplace.
Reasonable efforts should be directed toward the
decontamination and unconditional release of these items
rather than their disposal as radioactive waste.
4. Preventive Methods - The following are practical methods
used for the prevention/control of contamination.
a. Identify and repair leaks before they become a serious
problem.
b. Establish adequate work controls before starting jobs.
c. While conducting pre-job briefs, discuss measures that
will help reduce or prevent contamination spread.
d. Change out gloves or protective gear as necessary to
prevent cross-contamination of equipment.
DOE-HDBK-1122-2009
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2.05-13
e. Pre-stage areas to prevent contamination spread from
work activities.
f. Cover piping/equipment below a work area to prevent
dripping contamination onto less contaminated areas.
g. Cover/tape tools or equipment used during the job to
minimize decontamination after the job.
h. Follow good work practices such as good housekeeping
and cleaning up after jobs.
i. Confine the spread of radioactive material releases by a
sound preventive maintenance program.
j. Control and minimize all material taken into or out of
contaminated areas.
E. BASIS FOR ESTABLISHING PROTECTIVE CLOTHING
REQUIREMENTS
1. The basic factors that determine the type and extent of
protective clothing required are:
Section 35
a. type and form of contamination
b. levels of contamination
c. type of work being performed
d. potential for increased levels of contamination
e. the area of the body at risk
f. competing hazards, i.e., asbestos, heat stress, etc.
2. Once the types of protection needed are established, the most
efficient protective clothing must be selected from the
different articles of protective clothing available for use.
a. Whole body protection
1) Laboratory coat
a) Provides protection from low levels of
contamination.
b) Only applicable when the potential for body
contact with contaminated surfaces is very low.
Objective 2.05.07
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Module 2.05 Contamination Control Instructor’s Guide
2.05-14
c) Lab Coats are generally worn for hands-off tours
and inspections in areas with removable
contamination at levels 1 to 10 times the values
in Table 2-2 of the Radiological Control
Standard.
d) Lab coats may also be worn during benchtop,
laboratory fume hood, sample station, and
glovebox operations.
2) Coveralls
a) Provides protection from low to moderate levels
of DRY contamination.
b) Protection is low when body contact with
contaminated surfaces is prolonged (since
contamination can be ground into the cloth).
c) Protection is low when the surface is wet.
d) Degree of protection can be increased by use of
more than one pair at a time to protect the body.
e) Not effective against radionuclides with high
permeation properties (gases, tritium, etc.).
3) Plastic coveralls
a) Provides protection from high levels of dry
contamination.
b) Provides protection from wet forms of
contamination.
c) Provides limited protection from tritium and
other highly permeating radionuclides being
transported through the coveralls to the skin
surface.
4) Disposable coveralls
a) Used for work involving mixed hazards, i.e.,
asbestos, PCBs, etc., where reuse is not desirable.
b) Types of suits are tyvek, gortex, etc. which
provide moderate protection from radioactive
contamination.
DOE-HDBK-1122-2009
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2.05-15
c) Disposable coveralls can be easily torn.
b. Hand protection
1) Surgical gloves
a) Minimal requirement
b) Normally used in only light contamination work
areas
c) High degree of dexterity
d) Fairly easily torn or punctured
2) Rubber gloves
a) Lightweight
b) Provides good gripping surface
c) Normally used in moderate to heavy
contamination locations
d) Greater puncture, abrasion and solvent resistance,
but afford a lower degree of dexterity than
surgical gloves.
3) Neoprene gloves
a) Synthetic rubber gloves mounted to various
containment devices to allow access by the
wearer into the device.
b) Used to provide protection for the wearer when
working inside a containment device in which
highly contaminated materials are present.
c) Usually of arm length attached to dry boxes,
glove boxes and bags, or other cabinets.
d) Provides a gas tight seal to the structure.
e) Gloves are normally taped to the sleeve of the lab
coat, coveralls, plastic suit, etc. and are tabbed to
permit easy removal.
4) Cotton glove liners
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Module 2.05 Contamination Control Instructor’s Guide
2.05-16
May be worn inside standard gloves for comfort, but
should not be worn alone or considered as a layer of
protection.
5) Leather or canvas work gloves
Should be worn in lieu of or in addition to standard
gloves for work activities requiring additional
strength or abrasion resistance.
Section 36
c. Foot protection
1) Booties: Used to protect lower leg area below
coveralls from contamination. Different
constructions used:
a) Plastic
b) Cloth (sometimes called cloth shoe covers)
2) Shoe covers: Worn over booties to provide a second
layer of protection and provide traction to wearer.
Normally are constructed of plastic or rubber.
3. Respiratory protection
a. Full-face masks: Used to filter particulate radionuclides
and/or radioactive Iodine from the breathing air of the
wearer when the surrounding atmosphere is not
immediately dangerous to the life and health of the
wearer.
b. Supplied air systems: Used to prevent inhalation of
particulate and gaseous radionuclides by the wearer in a
non-life threatening atmosphere.
c. Self-contained breathing apparatus (SCBA): Used to
provide a portable source of breathing air to the user
when entering an atmosphere which may be immediately
dangerous to life and health.
d. Medical approval, training, and fit testing are required
prior to respiratory protection use.
1) Systems should be in place to verify these criteria in
the field.
2) The wearer should be clean shaven in the area of fit.
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3.) The wearer should perform fit checks of their
respirators to ensure a proper seal.
4. Facility Protective Clothing Requirements
(Insert facility specific material here)
III. SUMMARY
A. Review major topics
1. Types of Contamination
2. Assessing Contamination Hazards
3. Basic Goal of Contamination Control
4. Contamination Control Measures
5. Basis for Establishing Protective Clothing Requirements
B. Review learning objectives
IV. EVALUATION
Evaluation should consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% should be the minimum passing criteria for
examinations.
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DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-1
Course Title: Radiological Control Technician
Module Title: Air Sampling Program/Methods
Module Number: 2.06
Objectives:
2.06.01 State the primary objectives of an air monitoring
program.
2.06.02 Describe the three physical states of airborne
radioactive contaminants.
2.06.03 List and describe the primary considerations to
ensure a representative air sample is obtained.
2.06.04 Define the term "isokinetic sampling" as
associated with airborne radioactivity sampling.
2.06.05 Identify the six general methods for obtaining
samples or measurements of airborne
radioactivity concentrations and describe the
principle of operation for each method.
a. Filtration
b. Volumetric
c. Impaction/impingement
d. Adsorption
e. Condensation/dehumidification
f. In-line/flow-through detection
2.06.06 Describe the general considerations for selection
of an air monitoring method.
2.06.07 State the purpose of the five primary types of
airborne radioactivity samplers/monitors:
a. Personal air samplers (breathing zone)
b. High volume/flow rate air samplers
c. Low volume/flow rate air samplers
d. Portable continuous air monitors
e. Installed continuous air monitoring
systems
2.06.08 List the factors that affect the accuracy of
airborne radioactivity measurements and
describe how these factors affect sample
accuracy.
Section 37
→ 2.06.09 Describe the site air monitoring program that
includes monitoring frequencies, calculational
methods, applicable derived air concentration
limits, and methods for determining radon
interference.
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Module 2.06 Air Sampling Program/Methods Instructor’s Guide
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References:
1. "Introduction to Health Physics"; Cember, Herman; 4nd
ed.; McGraw-Hill Medical; 2008.
2. "Basic Radiation Protection Technology"; Gollnick,
Daniel; 5th ed.; Pacific Radiation Corporation; 2008.
3. Moe Harold, Operational Health Physics Training, ANL-
88-26, Department of Energy, Argonne National
Laboratory, Chicago, 1988.
4. "Air Monitoring", Chapter 10 of Implementation Guide
for Use with 10 CFR 835, "Occupational Radiation
Protection".
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
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I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Before the proper internal exposure control methods can be
determined for personnel, an estimate of the airborne
radioactivity concentration must be obtained. Additionally,
airborne radioactivity measurements are necessary to ensure
that the control measures assigned are effective and continue to
be effective.
C. Overview of Lesson
1. Purpose and objectives of airborne radioactivity sampling
2. The nature of airborne radioactivity
3. Representative air samples
4. Basic sampling methods
5. Selection of the air sampling method
6. Primary types of air samplers
7. Basic air sample calculations
D. Introduce Objectives
II. MODULE OUTLINE
A. PURPOSE AND OBJECTIVES OF AIRBORNE
RADIOACTIVITY SAMPLING
1. Airborne radioactive contaminants are of concern to the
radiological control organization due to the biological
effects of the ionizing radiation emitted by those
contaminants.
O.H.: Objectives
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2. Inhalation of radioactive airborne particles is one of the
most important routes of entry of radionuclides into the
human body.
3. This represents a relatively complicated process that
depends on particle size distribution of the airborne particles,
their dynamical behavior in air, and the physical and
chemical properties of the particles after deposition in the
respiratory tract.
4. Air monitoring is performed to identify and monitor
airborne radioactive material in order to control the intake
of airborne radioactive material by workers.
5. Regulations govern the allowable or limiting doses to an
individual.
a. The total effective dose of an individual is determined
by combining the external and internal effective dose
values.
b. Typically, airborne radioactivity levels are maintained
well below allowable levels to keep the internal dose
contribution to the total effective dose small.
c. Confirmation that airborne radioactivity levels are
maintained low is accomplished by the airborne
radioactivity sampling program.
d. It is important to note that the individual equivalent
dose from internal sources is not normally determined
from air sampling analysis data, unless other
information, such as bioassay data, is unavailable,
inadequate, or internal dose estimates based on
representative air concentration values are
demonstrated to be as or more accurate.
Section 38
6. It is necessary to be aware that the air monitoring program
is only one element of a comprehensive radiation protection
program.
a. Individuals involved with the air monitoring program
should interact with personnel working in other
elements of the radiation protection program,
particularly with individuals involved in contamination
control and internal dosimetry.
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7. The primary objectives of an air monitoring program are:
a. To measure the concentration of the radioactive
contaminant(s) in the air by collection and analysis
b. To identify the type and physical characteristics of the
radioactive contaminant to help evaluate the hazard
potential to the worker
c. To evaluate the performance of airborne radioactivity
control measures
d. To assess air concentration data in order to determine if
bioassay sampling should be initiated to verify whether
an exposure has occurred, and if so, to determine the
magnitude of the exposure.
8. Additionally, the air monitoring program must demonstrate
that airborne radioactivity released to the general
environment is maintained as low as reasonably achievable
and below the allowable limits established by regulatory
agencies.
9. The primary goal of the air monitoring program is to
determine if the level of protection provided to the worker is
sufficient to minimize the internal equivalent dose.
a. Allowable concentration values, such as DACs, are
used as an index of the degree of control needed and
achieved.
b. Documented measurements of the airborne
radioactivity concentrations are required to demonstrate
that satisfactory control is achieved and maintained.
10. Air sampling is required when an individual is likely to
receive an exposure of 40 or more DAC-hours in a year.
Other situations requiring sampling are:
a. to establish the need for posting of airborne
radioactivity areas and to determine the need for
respiratory protection for workers.
b. to assess unknown hazards during maintenance on
systems contaminated with radioactive material or
when there is a loss of process controls.
Objective 2.06.01
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c. to assist in determining the type and frequency of
bioassay measurements needed for a worker.
d. to provide an estimate of worker exposures for
situations where bioassay measurements may not be
available or their validity is questionable.
e. to develop baseline airborne radioactivity levels and
verify containment integrity as necessary during startup
of a new facility or new operation within an existing
facility.
f. where respiratory protection devices for protection
against airborne radionuclides have been used.
g. real-time monitoring is needed as necessary to detect
and provide warning of increases in airborne
radioactivity levels that warrant immediate actions to
terminate the inhalation of airborne radioactive material.
B. THE NATURE OF AIRBORNE RADIOACTIVITY
1. Airborne radioactive contaminants are generally divided
into three categories, based on the physical state of the
contaminant.
a. Particulates
b. Gases
c. Vapors
2. Particulate contaminates are solid and liquid particles,
ranging upward from molecular sizes (approximately
10-3 um), suspended in the air.
a. Solids may be subdivided into fumes, dusts, and
smokes, which are distinguished mainly by their mode
of generation.
Section 39
b. Liquids are subdivided into mists and fogs, depending
on the dispersion of the liquid particulates.
c. The term "aerosols" is used to collectively refer to
relatively stable suspensions of either solid or liquid
particles in a gaseous medium.
Objective 2.06.02
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d. Generally, particulates are more readily retained in the
lungs than are gases, but retention of particulates is
highly dependent on particle size and solubility in the
lung.
e. While this suggests that particulate airborne
contaminant sampling should measure particle size, this
is not practically accomplished on a routine basis.
f. Certain sampling instruments utilize the characteristics
of particle size to separate larger particles from smaller
particles (e.g., impactors.)
g. This is an important factor in that the size range of
particles retained in the respiratory tract is generally 1-
10 um.
h. The retention of inhaled radioactive particles after
deposition in the pulmonary region of the lung is
strongly influenced by the dissolution characteristics of
the particles.
1) Dissolution in the lungs allows clearance into the
blood and the rest of the systemic circulation.
2) For this reason, the various chemical forms of
radioactive particles are classified with respect to
their potential solubility in the lungs.
3) These are Type S for the very insoluble particle
that takes years to clear from the lungs; Type M for
the somewhat more soluble particles that take
weeks to dissolve and clear into the systemic
circulation; and Type F for the relatively soluble
particles that dissolve in a matter of days in the
lung.
3. Gases are substances that, under normal conditions of
temperature and pressure, exist in the gaseous phase.
a. The retention of the gases in the body from poor
inhalation is so radioactive gases are usually treated as
an external source of exposure.
b. Radioactive gases typically found are the fission
product gases, such as xenon and krypton, and naturally
occurring radon.
c. While the gases contribute primarily to external
exposure, the particulate daughters to which they decay
can contribute to internal exposure.
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4. Vapors are considered the gaseous phase of a substance that
is normally a solid or liquid under normal conditions of
temperature and pressure.
a. Airborne vapor sampling is most commonly done for
radioiodine and tritium.
b. The contaminant may be dispersed in vapor form at
abnormal conditions of temperature and pressure.
c. However, as the temperature and pressure conditions
return to "normal," the contaminant will return to its
normal solid or liquid form, or become a particulate.
d. Sampling methods for vapors should isolate or measure
the contaminant regardless of whether the vapor or
particulate form is present.
C. REPRESENTATIVE AIR SAMPLES
1. To ensure that the sample is representative of the actual
conditions.
a. The airborne radioactivity concentration entering the
sample line must be representative of the airborne
radioactivity concentration in the air near the sampling
device.
b. The airborne radioactivity concentration entering the
sampling inlet must be representative of the airborne
radioactivity concentration at the point of concern, or
the air that is breathed, i.e., breathing zone.
Section 40
2. When obtaining an air sample, care must be taken to ensure
that the sample obtained is representative of the air around
the sampling device.
a. This is particularly important for sample lines that
directly sample an air flow, such as a stack or duct
monitor.
b. Air flow into sampling lines needs to be balanced with
respect to the flow of air around the probe or sample
inlet.
c. If there is not a relative balance between these
velocities, particles may be thrown in or out of a
sampling probe rather than being sampled in a
representative fashion.
Objectives 2.06.03
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2.06-9
d. To ensure the sample is representative, the flow rate in
the sample line or inlet must be the same as the flow
rate in the system, such as the duct or stack.
1) When the sample line velocity is equal to the
system velocity at the sample point, it is called
isokinetic sampling
e. If the velocities are not the same, or isokinetic, then
discrimination can occur for smaller or larger particles.
This occurs because the inertia of the more massive
particles prevents them from following an airstream
that makes an abrupt directional change.
1) If the velocity of the sample airstream is > the
velocity of the system airstream, then the larger
particles can not make the abrupt change and are
discriminated against in the sample, i.e., the
smaller particles are collected more efficiently.
2) If the velocity of the sample airstream is < the
velocity of the system airstream, then the small
particles do make the abrupt change and are
discriminated against in the sample, i.e., the larger
particles are collected more efficiently.
f. To minimize particle losses, sampling lines should be
as short (less than six feet preferred) and straight as
possible to avoid sample deposition along the walls of
the tube. When possible, sample lines should be
vertical instead of horizontal to prevent gravimetric
settling of large particles.
g. The sampling line should have no more than one bend
and be made of conducting material.
3. There are other factors to consider for maximizing the
efficiency of airborne radioactivity detection.
a. Self-absorption losses, e.g., dust loading, should be
minimized. This is especially critical for alpha
detection.
b. Air in-leakage between the sample intake and the
sample collection medium should be eliminated to the
greatest degree possible by instrument design.
Objective 2.06.04
See Fig. 1 - "Isokinetic
Sampling"
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c. The system and mechanisms within the instrument for
sample collection should be designed and constructed
to minimize deterioration and to facilitate
decontamination. This is more critical in areas with
corrosive atmospheres.
4. When obtaining an air sample, care must be taken to ensure
that the sample obtained is representative of the air at the
point of interest (the breathing zone).
a. Depending on the source of the airborne contaminant,
the concentrations within a work area can vary over
several orders of magnitude.
b. The sample taken should be representative of the air
entering the nose and mouth of the individual workers
since the data obtained may be used to estimate
potential worker intakes.
c. The best method to ensure a representative breathing
zone sample is to sample the air at the individual's nose
and mouth.
Section 41
d. This sampling method may not always be practical and
general work area sampling may be the alternative.
e. Care must be exercised in the selection of the number
and placement of the general area air samplers to ensure
that the sample is as representative as possible.
D. BASIC SAMPLING METHODS
1. Basically, three types of samples are collected:
a. A volumetric sample in which part of the atmosphere is
isolated in a suitable container, providing the original
concentration of the contaminant at a particular place
and time.
b. An integrated sample which concentrates the
contaminant on some collecting medium, providing an
average concentration over the collection time.
(Sometimes called a "grab" sample if collected in a
short period of time.)
c. A continuous sample where the sample air flow is
directed past or through a detection device providing a
measurement of the activity per unit volume of air.
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2. Breathing zone air monitoring should be performed
continuously in areas where workers are likely to exceed 40
DAC-hr exposure in a year.
Breathing zone air monitoring is used to identify possible
worker internal exposure and the need for follow-up
bioassay measurements.
3. Source-specific air sampling is performed near an actual, or
likely, release point in a work area.
This is typically used to verify containment integrity,
documenting airborne radioactivity levels, and providing
guidance on personnel protective measures (e.g.,
determining when respiratory protection is required).
4. Grab air sampling is used for temporary or nonroutine (e.g.,
emergency response) situations and as a backup for other
types of air sampling in the event of equipment failure.
a. Portable air sampling equipment is typically used for
operations requiring a grab sample.
b. Sample flow rates may vary depending upon the
specific application, but should always allow collection
of a sample volume adequate to ensure the minimum
detectable activity of the sampling and counting system
is no greater than 2% of an ALI.
5. There are six general methods for obtaining samples or
measurements of airborne radioactivity concentrations.
a. Filtration
b. Volumetric
c. Impaction/impingement
d. Adsorption
e. Condensation/dehumidification
f. In-line/flow-through detection
6. Filter samplers employ filtration of the air as the method of
concentrating the airborne radioactive particulate (aerosol)
contaminants.
Objective 2.06.05
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Module 2.06 Air Sampling Program/Methods Instructor’s Guide
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a. Filtration is the most common sampling method
employed for particulates because it is relatively simple
and efficient, but is ineffective as a sampling method
for gases and vapors.
b. The filter sampling technique employs an air mover,
such as a vacuum pump, to draw air through the
removable filter medium at a known flow rate for a
known length of time.
1) If the flow rate and sample time are known, the
total volume collected can be calculated.
2) After analysis of the filter medium to determine the
amount of radioactive material collected on the
filter at the time of the sample, the airborne
concentration can also be calculated.
c. The filtration medium selected for a sample depends on
Section 42
several factors: the collection efficiency required, the
flow resistance of the medium, and the mechanical
strength of the filter, pore size, the area of the filter, the
background radioactive material of the filter, cost, self-
absorption within the filter, and chemical solubility.
d. A wide choice of filters is available. The most common
types are:
1) Cellulose-asbestos filters
2) Glass fiber filters
3) Membrane filters
Membrane filters are manufactured with various
pore sizes and can be dissolved in organic solvents
and analyzed in a counter, e.g., a liquid scintillation
counter.
7. Volumetric samplers employ a sample container into which
the sample is drawn, by some method, and isolated for
analysis.
a. Several methods are employed to draw the sample into
the container.
1) The container may be evacuated by a vacuum
pump and isolated away from the sample location.
The container is opened at the sample location to
draw the air into the container. The sample is
sealed in the container and removed for analysis.
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2) An air mover, such as a vacuum pump, may be
employed at the sample location to draw a
representative atmospheric sample into the
container.
3) The container could be filled with water, isolated
and taken to the sample location. The water is
poured out of the container, drawing the air sample
into the container as the water pours out.
b. This method can be employed for particulates, gases,
and vapors.
8. Impingers or impactors concentrate particulate
contaminants on a prepared surface by abruptly changing
the direction of the sample air flow at some point in the
sampler.
a. Particles are collected on a selected surface as the
airstream is sharply deflected. Due to their inertia, the
particles are unable to follow abrupt changes in
airstream direction.
b. The surface on which the particles are collected must be
able to trap the particles and retain them after impaction.
Several methods are commonly used to trap the
particles, such as:
1) Coating the collection surface with a thin layer of
grease or adhesive.
2) Immersing the collection surface in a fluid, such as
water or alcohol, which is then analyzed after the
sample is collected.
c. Impingers and impactors may utilize several stages or
impingement distances to discriminate for or against
different particle sizes.
d. Impactors are frequently used to isolate particles larger
than the undesired smaller particles, such as
transuranics over radon daughters, or radon daughters
over fission products.
9. Adsorber sampling devices concentrate the contaminants by
causing them to adhere to the surface of the adsorption
medium.
a. Adsorption is the adhesion of a substance to the surface
of another substance through bonding.
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b. The adsorption medium is granulated or porous to
increase the surface area available for trapping of the
contaminant.
c. The technique employs an air mover to draw and
collect the sample through the adsorption media.
d. Adsorbers, such as activated charcoal, silica gel, and
silver zeolite, are commonly used to collect organic
vapors and non-reactive gases and vapors.
1) Activated charcoal is used primarily for radioiodine
sampling, but does trap noble gases, such as xenon,
krypton and argon.
2) Silica gel is primarily used for tritium oxide vapor
Section 43
sampling.
3) Silver zeolite is used for radioiodine sampling
when trapped noble gases would interfere with the
radioiodine analysis.
e. Particulates would be "filtered" by the absorption media
and must be filtered out before the adsorption process
to prevent interference during the analysis of the media.
10. Condensation or dehumidifier sampling devices employ a
"cold trap" to condense water vapors in the sampled
atmosphere and provide a liquid sample for further analysis.
a. Some means, such as liquid nitrogen or a refrigeration
unit is utilized to cool the condensation surface and
cause condensation of the water vapor as it passes over
the cold surface.
b. The collected water is frequently analyzed using a
liquid scintillation counter.
c. Calculations must include the relative humidity and
temperature of the air at the time the sample is taken to
determine the concentration of water vapor per unit
volume of air.
d. This technique is normally only applied for sampling
tritium oxide vapor (HTO or T2O).
11. In-line or flow-through samplers employ an air mover to
direct the sample air flow through or past the detection
device.
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a. This method is employed for radionuclides which are
difficult to collect or detect by other means.
b. Because the air flow passes directly outside the detector
or actually through the inside of the detector, the air
must be filtered for particulates or vapors that could
accumulate on or in the detector.
c. In-line detectors are used to measure gaseous activity
after filtration and adsorption have been accomplished.
d. Flow-through detectors are employed for radionuclides,
such as tritium, which emit low-energy radiation, that
could not otherwise pass through the detector window.
12. The various sampling methods may be combined into one
sampler or monitor.
a. Some samplers employ the filtration method for
particulates, the adsorption method for vapors and the
volumetric grab-sample method for gases (in that order).
Some advantages of combining these methods are:
1) One vacuum pump supplies the air flow for all the
samples.
2) All the samples are drawn at the same time to
minimize the amount of time spent by the
technician drawing samples.
b. In addition, some monitors have detectors installed to
monitor each sample and provide an immediate readout
as well as other capabilities, such as alarms, data
records, process controls, and trending.
E. SELECTION OF THE AIR SAMPLING METHOD
1. It is critical that the proper air sampling method and
equipment be selected because:
a. The data obtained must be meaningful and accurate to
adequately assign radiological control measures.
b. Improper selection and use may incorrectly indicate a
safe environment where an airborne radiological hazard
exists or leads to unneeded postings where no hazard
exists.
2. The general considerations for the selection of an air
sampling method include several factors.
Objective 2.06.06
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a. The environmental conditions in the area where the
sample is to be obtained.
1) Humid conditions may preclude the use of some
methods, such as paper filtration devices or
charcoal canisters, because water vapor loading of
the medium will change the collection efficiency
and flow rate.
2) High temperature environments may cause some
Section 44
samplers to overheat if run for long periods of time.
3) Explosive gases may be present which could
present an explosion hazard for samplers with
electric motors not designed for such environments.
4) Dusty areas could cause excessive sample loading
which will reduce sampler flow rates and
potentially overheat the sampler.
5) Corrosive environments may lead to the
deterioration of the sampling device.
b. The physical characteristics of the area in which the
sample is to be obtained.
1) An electrical outlet may not be available or close,
and a battery powered sampler would be better
suited.
2) Close spaces or passages may preclude the use of
movable CAMs or heavy samplers.
c. The energy and type of radiation of the radionuclide
being monitored. This will dictate the type of CAM or
analysis equipment required to determine the airborne
radioactivity concentration.
d. The expected concentration level. This will determine
the length of sample time and type of sampler required.
1) Low-level concentrations will require larger
volumes to reduce statistical errors and meet
minimum sensitivity levels of the analysis
equipment.
2) Large volume samples obtained over a long time
period are best obtained by samplers designed to
run for long periods.
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3) If immediate readout of information is needed, then
collection and analysis are done at the same time.
4) If not, then samples may be taken and removed to a
central analysis location.
e. The physical state of the airborne contaminant.
Dependent upon whether the contaminant is either gas,
vapor or aerosol, will dictate the type of sampler and
sample medium that is required.
f. The type of survey required. Specific methods, such as
breathing zone samples, routine general area samples,
general work area samples, general trending over time,
etc., also determines the type of equipment that is
selected.
g. Procedural requirements. This may dictate a particular
type of sample method and/or sample medium for a
given application.
1) Check the appropriate procedures prior to sampler
selection.
2) Ask supervision and experienced technicians for
their input.
F. PRIMARY TYPES OF AIR SAMPLERS
1. The five primary types of airborne radioactivity
samplers/monitors are:
a. Personal air samplers (breathing zone)
b. High volume/flow rate air samplers
c. Low volume flow rate air samplers
d. Portable continuous air monitors (CAMs)
e. Installed continuous air monitoring systems
2. Personal air samplers (PAS) provide an estimate of the
airborne radioactivity concentration in the air the worker is
breathing during the sampling period.
a. The PAS may also be used to determine if the
protection factor for respiratory equipment is exceeded,
to compare with other workplace air samples, and to
verify the effectiveness of engineered and
administrative controls.
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-18
b. Personal air samplers are small portable battery-
powered devices which sample the air in the breathing
zone of the worker's environment, making allowances
to eliminate interferences the sampler's themselves may
have on a worker's activities. Some characteristics are:
1) The device contains a small battery-powered pump
that is calibrated to a flow rate approximately 1/10
(2 liters per minute) the breathing rate of a worker
performing light activity.
Section 45
2) The sampling line terminates in a filter cassette
which contains the filtration medium for the
radioactive particulate contaminants.
3) The sample filter cassette is attached close to the
nose and mouth of the individual.
3. Portable high volume/flow rate samplers provide an
estimate of the airborne radioactivity concentration at a
particular location in a short period of time.
a. Portable high flow rate samplers are used to collect
airborne aerosols on a filter paper (filtration) or on a
greased planchet (impaction).
b. Portable high flow rate samplers can also be used to
collect radioiodine samples using activated charcoal
cartridges (adsorption) as long as the maximum flow
rate of the cartridge is not exceeded or a correction
factor is used.
c. These samplers do not have installed detectors and the
sample must be removed from the sampler and
analyzed on separate analysis equipment.
d. The high volume/flow rate samplers may be used to:
1) Provide a routine "slice of time" estimate of the
general area airborne radioactivity
2) Verify boundaries of areas posted for airborne
radioactivity
3) Or monitor the airborne radioactivity related to a
specific work activity.
e. High volume samplers typically use flow rates of at
least 10 cubic feet per minute (cfm).
See Fig. 2 - "High Volume
Sampler"
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-19
1) Although these samplers are noisy and not intended
for continuous duty, the shorter sample times allow
for greater sensitivity.
4. Low volume/flow rate samplers provide an estimate of
airborne radioactivity concentrations averaged over a longer
period of time at a particular location.
a. Portable low volume/flow rate samplers are used to
collect samples for aerosols on filter paper (filtration)
and radioiodine on an adsorption medium, such as an
activated charcoal cartridge.
b. Low volume/flow rate samplers may be used to provide
average airborne radioactivity estimates over a period
of time for:
1) Commonly traversed areas that normally have a
low probability of airborne radioactivity problems
2) Areas not commonly traversed with a higher
probability of airborne radioactivity problems
3) Backup samples in areas where airborne
radioactivity problems are discovered by other
means
4) Work maintenance activities normally
characterized by low airborne radioactivity
concentrations.
c. Low volume samplers generally have flow rates set at
approximately 20 lpm, the breathing rate of a worker
performing light activity.
1) Although these samplers must run longer for
reasonable sensitivity, they are generally quiet and
can be used for continuous duty.
5. Portable CAMs provide an estimate of airborne
radioactivity concentrations averaged over time at a
particular location, and provide immediate readout and
alarm capabilities for preset concentrations.
a. These air monitors are portable low flow rate (~20 lpm)
sampling systems, containing the necessary sampling
devices and built-in detection systems to monitor the
activity on the filters, cartridges, planchettes and/or
chambers in the system.
See Fig. 3 - "Low Volume
Sampler"
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-20
b. The system may provide a visual readout device for
each type of sample medium, a recording system for
data, and computer functions such as data trending,
preset audible and visual alarms/warning levels and
alerts for system malfunctions.
Section 46
c. Typical CAMs provide information on alpha and/or
beta/gamma particulates (filtration), radioiodine activity
(adsorption) and noble gas activity (volumetric
chamber or in-line detector).
d. Portable CAMs can be utilized as:
1) Low volume general area samplers
2) Monitors with alarm capabilities for areas where
airborne radioactivity conditions may quickly
degrade
3) Trending devices in selected areas
4) Devices to locate system leaks, if used with the
appropriate length hose or tubing.
6. Installed CAMs provide an estimate of airborne
radioactivity concentrations averaged over time at a fixed,
designated location, and provide immediate local and
remote readout and alarm capabilities for preset
concentrations.
a. These air monitors are fixed low flow rate sampling
systems, and contain the necessary sampling devices
and built-in detection systems to monitor the activity of
selected areas or airstreams.
b. The system may provide a local and remote visual
readout device, a recording system for data, and
computer functions such as data trending, preset
audible and visual alarms/warning levels and alerts for
system malfunctions.
c. Installed CAM applications include:
1) Fixed installations capable of sampling several
locations through valved sample lines.
2) Stack monitors
3) Duct monitors
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-21
7. Factors affecting the accuracy of airborne radioactivity
measurements include:
a. Sample is not representative of the atmosphere being
sampled
b. Sample is not representative of the air being breathed
by the worker
c. Incorrect or improperly installed sampling media for
the selected sampler, causing leak or improper flow
rates
d. Malfunctioning, miss-operated, or miscalibrated
sampling device, causing errors in flow rate
measurements
e. Accuracy and operation of the timing device, causing
errors in the time value
f. Accuracy and operation of the flow rate measuring
device, causing errors in the flow rate value
g. Mishandling of the sample media causing cross-
contamination or removal of sample material
h. Changes in the collection efficiency of the medium due
to sample loading, humidity and other factors
i. Improper use or selection of analysis equipment
j. Inherent errors in the counting process due to sample
geometry, self-absorption, resolving time, backscatter
and statistical variations
k. Mathematical errors during calculations due to
rounding of numbers and simple mistakes
l. Incorrect marking of samples and inaccurate recording
of data
8. It is important that the personnel performing the sample
collection and analysis minimize the magnitude of these
errors to ensure that accurate and reliable data is obtained
for the assignment of internal exposure control methods.
Objective 2.06.08
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-22
G. BASIC AIR SAMPLE CALCULATIONS
1. Once the air sample is collected and analyzed, calculations
must be performed to determine the amount of activity per
unit volume.
2. The specific calculations for particular sampling methods
are not covered in this lesson; however, some basics are
necessary for each calculation.
3. The analysis of the sample provides the activity of the
sample at the time of the sample analysis.
a. This value may be corrected for decay for the time
period between when the sample was taken to when it
was analyzed.
Section 47
1) This is especially true for short-lived radionuclides.
2) This correction may not be necessary for very long-
lived radionuclides.
b. The volume of the sample must be determined from the
sample data recorded, such as flow rates at the
beginning and end of the sample, and sample time
period.
c. The basic calculation listed below would also include
the conversions necessary for the desired units such as
dpm/liter to µCi/cc.
d. The calculation would also include correction factors,
as necessary, for:
1) Interference of other radionuclides, such as radon
and thoron daughters
2) Collection efficiency
3) Counter efficiency
4) Self-absorption by the sample media
5) Counter background.
6) Temperature and pressure as applied to flow rate
4. Many errors are inherent or induced in the sampling
analysis process and affect the accuracy of the resulting data.
DOE-HDBK-1122-2009
Module 2.06 Air Sampling Program/Methods Instructor’s Guide
2.06-23
5. The operator of the sampling and analysis equipment must
be aware of these points of error to ensure the resulting data
is as accurate as possible.
(Insert site specific material here)
III. SUMMARY
A. Review major points
1. Purpose and objectives of airborne radioactivity sampling
2. The nature of airborne radioactivity
3. Representative air samples
4. Basic sampling methods
5. Selection of the air sampling method
6. Primary types of air samplers
7. Basic air sample calculations
B. Review learning objectives
IV. EVALUATION
Evaluation should consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% should be the minimum passing criteria for
examinations.
Objective 2.06.09
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DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-1
Course Title: Radiological Control Technician
Module Title: Respiratory Protection
Module Number: 2.07
Objectives:
2.07.01 Explain the purpose of respiratory protection standards and regulations.
2.07.02 Identify the OSHA, ANSI, and DOE respiratory protection program requirements.
2.07.03 Identify the standards which regulate respiratory protection.
2.07.04 Describe the advantages and disadvantages (limitations) of each of the following
respirators:
a. Air purifying, particulate removing filter respirators
b. Air purifying, Chemical Cartridge and Canister respirators for Gases and
Vapors
c. Full-face, supplied-air respirators
d. Self-contained breathing apparatus (SCBA)
e. Combination atmosphere supplying respirators
2.07.05 Define the term protection factor (PF).
2.07.06 State the difference between a qualitative and quantitative fit test.
2.07.07 State the recommended physical functions the subject must perform during a
respirator fit test.
2.07.08 State how the term protection factor (PF) is applied to the selection of respiratory
protection equipment.
2.07.09 State the general considerations and considerations for the nature of the hazard
when selecting the proper respiratory protection equipment.
→ 2.07.10 Identify the types of respiratory equipment available for use at your site.
2.07.11 Identify the quality specification breathing air must meet.
References:
1. "Basic Radiation Protection Technology"; Gollnick, Daniel; 5th ed.; Pacific Radiation
Corporation; 2008.
Section 48
2. "Introduction to Health Physics"; Cember, Herman; 4nd ed.; McGraw-Hill Medical; 2008.
3. "Limits for Inhalation of Radon Daughters by Workers", ICRP Publication 32.
4. "Operational Health Physics Training Course", Moe, H.J., et. al., Argonne National
Laboratory, Argonne, 88-26.
5. "Radiation Detection and Measurement", Knoll, G., John Wiley and Sons, New York,
2000.
6. 10 CFR 835, "Occupational Radiation Protection", 2007.
7. "Practices of Respiratory Protection", ANSI Z88.2, 1992.
8. "Manual of Respiratory Protection Against Airborne Radioactive Material",NUREG-0041,
1976.
9. Respiratory Protection, Federal OSHA, 29 CFR 1910, 134.
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-2
10. DOE-STD-1167-2003, DOE Respiratory Acceptance Program for Supplied-Air Suits
11. CGA G7.1-1989, Breathing Air, Commodity Specification for Air
12. 10 CFR 851, “Worker Protection Programs”, 2007.
13. DOE Order 440.1B (2007), Worker Protection Management for DOE (including National
Nuclear Security Administration) Federal Employees
14. ANSI Z88.2 (1992)
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-3
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Internal dosimetry controls require the use of engineering
controls to prevent the internal deposition of radioactive and
non-radiological contaminants. However, when engineering
and administrative controls are not available or feasible,
respiratory protection may be necessary. The RCT should
know and apply the considerations used in determining the
respiratory protection equipment that is most appropriate for
the job. Inappropriate use of or the use of the wrong respiratory
protection equipment may result in undesirable health effects.
C. Overview of Lesson
1. Requirements and regulations
2. Types of equipment
3. Protection factors
4. Fit testing
5. Selection of respirators
6. Site respiratory equipment
7. Supplied air quality testing
8. Sorbents and protection against radioiodines
9. Communications
D. Introduce Objectives
O.H.: Objectives
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-4
II. MODULE OUTLINE
A. REQUIREMENTS AND REGULATIONS
1. DOE Requirements
10 CFR 851, for contractors, and DOE Order 440.1B, for
Federal employees, mandates the requirements for a
respiratory protection program contained in ANSI Z88.2
and 29 CFR 1910.134.
2. OSHA REGULATIONS - 29 CFR 1910.134
Purpose: Specify the minimal acceptable program which
must contain or address the following:
a. Written procedures and program
b. Respirator selection
c. The user shall be instructed and trained in proper use of
respirators
d. Respirators shall be cleaned and disinfected after each
use
e. Respirators stored in a clean, sanitary location
f. Respirators inspected routinely and replaced when
necessary
g. Appropriate surveillance of work area conditions and
degree of employee exposure or stress
h. Regular evaluation of program
i. Persons should be physically able to use respiratory
protection equipment as certified by a licensed health
care practitioner
j. NIOSH approved respirators shall be used
3. ANSI Z88.2 - 1992: Further specifies the minimal
acceptable program
Section 49
a. Individual exposures limited by both inhalation and
skin absorption
b. Air sampling and bioassays
Objective 2.07.01
Objective 2.07.02
Objective 2.07.03
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-5
c. Engineering controls are primary method
d. When an individual is exposed to greater than the
specified DAC or other exposure limits
e. Respiratory protection equipment must be NIOSH
approved
f. If allowance for use of respiratory protection equipment
is made,
1) Protection factor must be sufficient to limit the
annual dose considering the anticipated peak
exposure concentration and associated DAC
2) If exposure is later found to be greater than
estimated, corrected value shall be used
3) Surveys and bioassays conducted as appropriate to
evaluate actual exposures
4) Written procedures must be established
5) Determination by a qualified health care
professional of a user's physical capability
6) A written policy statement must be issued
a) Engineering controls
b) Routine, non-routine and emergency use
c) Periods of use
7) Each user must be advised upon failure of
equipment, physical stress or deterioration of
operating conditions
8) Equipment is appropriate for environment and
special equipment, such as communication devices
issued when needed
9) Emergency use equipment must be specifically
certified as such by NIOSH
If less than estimated, the
corrected value may be
used
Objective 2.07.04
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-6
B. TYPES OF EQUIPMENT
1. Air purifying, particulate-removing filter respirators
a. Description
1) Filtering action removes particulate
2) Operate in negative pressure (NP) mode
3) Exception is a special type of powered air purifying
respirator that is designed to never be negative
pressure.
b. Limitations
1) Do not provide oxygen
2) No protection against gases or vapors
3) Should not be used for abrasive blasting operations
4) Battery operated respirators are limited by battery
life
5) High humidity may increase breathing resistance as
paper elements become water saturated
6) Not to be used in IDLH atmospheres
2. Air Purifying, Chemical Cartridge and Canister Respirators
for Gases and Vapors
a. Description - use cartridges or canisters containing
chemicals to remove specific vapors and gases.
b. Limitations
1) Do not provide oxygen
"dust," "mist" or "fume"
respirators
NEVER to be worn in
oxygen-deficient
atmospheres
The difference between a
cartridge and a canister is
the volume of the sorbent.
Canisters have longer
capacity and are used in
gas masks.
NEVER to be worn in
oxygen deficient
atmospheres
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-7
2) Unless approved by DOE, no credit for protection
against radioactive gases and vapors
3) High humidity shortens life of the sorbent material
and increases breathing resistance
4) Not to be used in IDLH atmospheres
3. Atmosphere Supplying Respirators - Air
a. Description
1) Use central source of breathing air delivered to
wearer through a line or hose
2) Either tight-fitting facepiece or loose-fitting
hood/suit
3) Demand device - during inhalation there may be
negative pressure in the mask
4) Pressure demand device - positive air pressure
inside mask is maintained at all times
5) Continuous-flow air line - is designed to create
positive pressure in facepiece
Section 50
b. Limitations
1) Not used in IDLH atmospheres
2) Trailing air supply hose severely limits mobility
3) Length of hose, number of potential users and
pressure of the supply system are interdependent.
No more than five sections of hose with a
maximum length of 250 feet.
4) Control of air quality is essential
5) "Bubble suits" must be tested for exact conditions
of use
(not for emergency escape
or rescue)
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-8
c. Special Considerations
1) Follow all manufacturers instruction and written
facility/site procedures
2) If all hoses and fittings are same then a single
pressure gauge is appropriate
3) For situations where each user has different hose
lengths, different number of connection or different
air pressure requirements then a separate pressure
gauge should be used
4. Atmosphere Supplying Respirators - Self-Contained
Breathing Apparatus (SCBA)
a. Description
1) Allows the user to carry a respirable breathing
supply
2) There are two groups of SCBAs closed circuit and
open circuit
a) Closed circuit SCBAs - "rebreathing" device
b) Open circuit SCBA exhausts the exhaled air to
the atmosphere
c) Two types of open circuit SCBA are available,
"demand" or "pressure demand"
• Demand SCBA - air flows into facepiece
only on demand of the wearer
Pressure demand - maintains positive
pressure in facepiece at all times regardless
of "demand" of user
Air supply may last 3
minutes to four hours
Designed primarily for 1-4
hours use in toxic
atmospheres
Service life is shorter
When the person inhales
note: demand-type SCBA
does not provide any
higher degree of protection
against airborne
contaminants than air-
purifying respirator with
same facepiece, but it does
provide protection against
oxygen deficiency
Recommended for
emergency use, escape and
rescue
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-9
b. Combination atmosphere supplying respirators
1) Combination Pressure Demand Breathing
Apparatus provides respiratory protection for
personnel who must work in atmospheres that are
IDLH
2) Dual-purpose Breathing Apparatus combines all
capabilities of SCBA and an air line respirator in
one unit
c. Limitations of the pressure and demand SCBA
1) Air supply is limited
2) Bulky and heavy
3) Demand type not for fire fighting
d. Special considerations of the pressure demand SCBA
1) Only pressure-demand type SCBA should be
selected for emergency use, rescue and reentry into
contaminated area
2) Performance of SCBAs in high temperature
environments, such as fires may lead to rapid
deterioration of components
B. PROTECTION FACTORS
1. Overall protection afforded by a given respirator design is
defined in terms of its protection factor (PF)
2. An assigned PF is defined as the level of protection that
would be expected from a class or type of respirator to a
properly fitted and trained user.
3. Application of PFs
4. 29 CFR 1910.134 Protection Factors
Equipped with small air
cylinder in case primary
air supply (hose line) is
interrupted
10CFR20 Appendix R
Section H
Section 5.5 of NUREG
0041
Objective 2.07.05
Table 1 - “Assigned
Protection Factors”
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Module 2.07 Respiratory Protection Instructor’s Guide
2.07-10
C. FIT TESTING
1. Definitions
a. Qualitative fit test:
Test to determine if there is any mask leakage, usually
using irritant smoke
Section 51
b. Quantitative fit test:
Test to determine quantity of mask leakage and assign a
"fit factor," an oil or dust particles are the typical
challenge atmospheres used
2. Qualitative fit tests are sometimes performed in lieu of
quantitative fit tests
a. Can use challenge atmospheres such as Isoamyl Acetate
(banana oil) or irritant smoke (e.g. stannic chloride or
titanium tetrachloride)
b. A qualitative fit test uses the same series of exercises as
quantitative fit testing
c. An abbreviated qualitative “fit check” may be used
prior to entry into a contaminated area
3. At least a qualitative test must be performed - a negative
pressure type is typical.
4. Additional factors to be considered
a. Use of communication devices
b. Sorbent canisters with respirators
5. Respirator face pieces and cartridges must be periodically
tested
a. Test a portion of particulate cartridges upon
procurement
b. Test all particulate cartridges prior to re-use
c. Respirator facepieces are tested annually using:
1) Test head mannequin
Objective 2.07.06
Irritant smoke tests are
most effective
Minimum requirement -
each site may be more
restrictive
Penetration value of less
than or equal to 0.003% is
acceptable
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-11
2) Challenge atmosphere with a light scattering
photometer
3) Fit check by user
6. Fit testing of individual is normally quantitative
a. Involves measurement of a challenge atmosphere both
inside and outside respiratory facepiece
b. A "fit factor" is determined by dividing concentration
of challenge atmosphere outside respirator by
concentration inside facepiece
c. An oil mist may be used as a challenge atmosphere or
particle measuring instrument (e.g., Portacount)
d. Oil mist apparatus uses photometry as system for
measuring challenge and breathing zone atmospheres
e. Subject generally performs the following functions
during fit testing:
1) Normal breathing
2) Deep breathing
3) Moving head from side to side
4) Moving head up and down
5) Frown
6) Talking
7) Running in place
8) Normal breathing
D. SELECTION OF RESPIRATORS
1. Most critical factor: the protection factor for respirator
device to be used needs to be adequate to control radiation
dose, considering the work area concentration
2. Only NIOSH approved respirators shall be selected.
3. General considerations. The selection of a proper respirator
for any given situation shall require consideration of the
following factors:
Objective 2.07.07
Note: DOP has been
discontinued as a
challenge atmosphere
since it is a potential
carcinogen
Highlight significance of
functions as related to job
performance
Objective 2.07.08
29 CFR 1910.134
Objective 2.07.09
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
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a. The nature of the hazard
b. The characteristics of the hazardous operation or
process
c. The location of the hazardous area with respect to a
safe area having respirable air
d. The period of time for which respirator protection may
be provided
e. The activity of workers in the hazardous area
f. The physical characteristics, functional capabilities, and
limitations of respirators of various types
g. The respirator-protection factors and respirator fit
h. Requirement of facility/site written procedures
4. Nature of Hazard. The following factors concerning the
nature of the hazard requiring the use of respirators shall be
considered in respirator selection:
Section 52
a. Type of hazard
• Oxygen deficiency
• Contaminant
b. Physical properties
c. Chemical properties
d. Physiological effects on the body
e. Actual concentration of a toxic material or airborne
radioactivity level both average and peak
f. Whether the hazard is an immediately-dangerous-to-
life-or-health (IDLH) concentration
g. Warning properties
5. Recognition and evaluation of the respiratory hazard
(oxygen deficiency or contaminant(s)) shall be an essential
part of selecting a respirator except in emergency or rescue
operations. Initial monitoring of the respiratory hazard shall
be carried out to obtain data needed for the selection of
proper respiratory protection. The data should include:
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-13
a. Identification of the type of respiratory hazard
1) Oxygen deficiency
2) Specific contaminant(s)
b. Nature of contaminant(s)
1) Particulate matter
2) Vapor(s) or gas(es)
c. Concentration of respiratory hazard
6. The following factors concerning the hazardous operation
or process shall be taken into account in selecting the proper
respirator:
a. Operation or process characteristics both as-built and
modified
b. Work-area characteristics
c. Materials, including raw materials, end products, and
byproducts (actual and potential)
d. Worker activities
E. SITE RESPIRATORY EQUIPMENT
(Insert site specific material here)
F. SUPPLIED AIR QUALITY TESTING
1. Referenced in 29 CFR 1910.134
a. Compressed breathing air shall meet at least quality
specification for Grade D breathing air
b. Breathing air specifications are listed in Compressed
Gas Association G 7.1-1989
2. No explicit limit for water vapor but it is a contaminant
3. Acceptable analytical procedures for measuring the
respirable air components
Objective 2.07.10
Objective 2.07.11
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
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4. Frequency of performing air quality tests is recommended
by ANSI Z88.2-1992
a. For bottled air systems received from a supplier that
does not fill cylinders with any other gasses, the tests
should check 10% of the cylinders from each lot for
ppm CO and odor. In addition, if the supplier fills
cylinders with gas other than air, analyze all cylinders
for percent oxygen.
b. For facilities which generate respirable air, the
sampling should be performed:
1) Prior to each lot fill
2) Once during the lot fill
3) Once upon completion of the lot fill
c. For compressed air supply systems sampling frequency
is best performed prior to each use of a specific
manifold system
5. Separate breathing air supply and distribution system is the
ideal source or worker-supplied air
G. SORBENTS AND PROTECTION AGAINST RADIOIODINES
1. The regulations specifically prohibit the use of PFs for
canister sorbents as protection against radioiodine
atmospheres
The efficiency of the charcoal canister is dependent upon:
a. chemical form of the radioiodine,
b. humidity of the atmosphere,
c. and breathing rate of the user.
2. Approval may be obtained to use PF's for sorbent cartridges
3. Examples of limiting conditions of use (user must follow
manufactures instructions and DOE approval criteria):
a. Total challenge in the work place (radioactive iodine,
non-radioactive iodine or the halogenated compounds)
may not exceed 1 ppm
In cases of heavy usage
then a daily check of the
system may be more
appropriate.
Section 53
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-15
b. Temperature in the work area may not exceed 100 ΕF.
c. Respirator wearers must have demonstrated a fit factor
greater than 100 for half mask, 1000 for full face piece.
d. Service life is 8 hours maximum. This is calculated
from the time the canister is unsealed and includes
periods of non-use.
e. Canisters will not be used in the presence of organic
solvents, vapors, or chemicals.
f. Canisters must be stored in sealed humidity-barrier
packaging in a cool, dry environment.
H. COMMUNICATIONS
1. Conventional respirators distort the human voice to some
extent
2. Special attachments are often needed to ensure adequate
communications
a. Speaking diaphragm
b. Various methods of electronically transmitting and
amplifying speech through the respirator
c. Any communication device that is an integral part of
respirator must be part of NIOSH approval
IV. SUMMARY
A. Review major topics
1. Requirements and regulations
2. Types of equipment
3. Protection factors
4. Fit testing
5. Selection of respirators
6. Site respiratory equipment
7. Supplied air quality testing
DOE-HDBK-1122-2009
Module 2.07 Respiratory Protection Instructor’s Guide
2.07-16
8. Sorbents and protection against radioiodines
9. Communications
B. Review learning objectives
V. EVALUATION
Evaluation should consist of a written examination comprised of
multiple choice, fill-in the blank, matching and/or short answer
questions. 80% should be the minimum passing criteria for
examinations.
DOE-HDBK-1122-2009
Module 2.08 Radioactive Source Control Instructor’s Guide
2.08-1
Course Title: Radiological Control Technician
Module Title: Radioactive Source Control
Module Number: 2.08
Objectives:
2.08.01 Describe the requirements for radioactive sources per 10 CFR 835.
→ 2.08.02 Identify the characteristics of radioactive sources that must be controlled at your
site.
→ 2.08.03 Identify the packaging, marking, and labeling requirements for radioactive
sources.
→ 2.08.04 Describe the approval and posting requirements for radioactive materials areas.
→ 2.08.05 Describe the process and procedures used at your site for storage and
accountability of radioactive sources.
References:
1. 10 CFR 835, “Occupational Radiation Protection,” (2007).
Instructional Aids:
1. Overheads
2. Overhead projector/screen
3. Chalkboard/whiteboard
4. Lessons learned
DOE-HDBK-1122-2009
Module 2.08 Radioactive Source Control Instructor’s Guide
2.08-2
I. MODULE INTRODUCTION
A. Self-Introduction
1. Name
2. Phone number
3. Background
4. Emergency procedure review
B. Motivation
Radioactive sources are used for response checks in the field,
functional checks, and calibration of instruments and monitors
to traceable standards. To ensure the safety and welfare of all
personnel it is important to maintain control of radioactive
sources. Radioactive sources are controlled to minimize the
potential for:
• Spread of contamination
• Unnecessary exposure to personnel
• Loss or theft
• Improper disposal
C. Overview of Lesson
1. Requirements
2. Control of sources
3. Receipt
4. Radioactive Materials Storage Areas
5. Inventory and transfer
6. Surveys
7. Leak test
8. Source disposal
D. Introduce Objectives
O.H.: Objectives
DOE-HDBK-1122-2009
Module 2.08 Radioactive Source Control Instructor’s Guide
2.08-3
II. MODULE OUTLINE
A. 10 C