Module 6: Perform Environmental Sample Counting Using Proportional Counters
Table of Contents:
Module 6: Perform Environmental Sample Counting Using Proportional Counters 1
Resources Key 2
Module Readings and Homework 3
Primary Scenario “Determine Gross Alpha/Beta Activity in Air Exhaust” 3
Transfer Scenario “Determine Gross Alpha/Beta Activity in Environmental Samples” 3
Module Assessment Items 4
Primary Scenario “Determine Gross Alpha/Beta Activity in Air Exhaust” 4
Suggested Labs 5
ACAD References 6
Lesson Plan…………………………………………………………………………………………………………………….7
Notes for Powerpoint Presentation………………………………………………………………………………10
Appendix 1 …………………………………………………………………………………………………………………..39
Resources Key
This refers to: / This reference:ACAD / National Academy for Nuclear Training, Uniform Curriculum Guide for Nuclear Power Plant Technician, Maintenance, and Nonlicensed Operations Personnel Associate Degree Programs, ACAD 08-006.
DOE-SG / Office of Environmental, Safety and Health: Radiological Control Technician Training Site Academic Training Study Guide Phase I, Project Number TRNG-0003
Available at: http://nsedu.rnet.missouri.edu/docshare/. File is located under the Docs/General Curriculum/DOE materials folder.
G. / Gollnick, D. (2006). Basic Radiation Protection Technology, 5th Ed. Pacific Radiation Corporation, Altadena, CA.
Spectrum / Spectrum Spectroscopy Techniques Lab Manual (Instructors and Student Versions)
Supl. Lab / Supplemental Lab Manual (instructors and Student Versions)
Module Readings and Homework
Primary Scenario “Determine Gross Alpha/Beta Activity in Air Exhaust”
Core Concept: Alpha/Beta Gross Counting Using Proportional CounterHomework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 254-260
DOE SG 1.13-14 through 1.13-17
DOE SG 2.19-7 though 2.19-8 / N/A / DOE SG 2.19.01
Core Concept: Alpha/Beta Particle Discrimination Using Proportional Counter
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 254-260
DOE SG 1.13-14 through 1.13-17
DOE SG 2.19-7 though 2.19-8 / N/A / G., Chap. 7, #12
DOE SG 2.19.01
Core Concept: Air Particulate Monitoring
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 10, 416-427
DOE SG 2.06-6 through 2.06-20 / DOE SG 2.06.09 / DOE SG 2.06.03 through 2.06.08
Core Concept: Calculation of Air Concentrations
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 10, 423
DOE SG 2.06-6 through 2.06-20 / DOE SG 2.06.09 / N/A
Transfer Scenario “Determine Gross Alpha/Beta Activity in Environmental Samples”
Refer to readings and homework for primary scenario above.
Module Assessment Items
Note: If instructors wish to increase the difficulty of any item, then we suggest you use it as the basis for an in-class discussion, and / or require students to write an explanation for why a particular choice is correct.
Primary Scenario “Determine Gross Alpha/Beta Activity in Air Exhaust”
Assessment Items
You are a Radiation Protection Technician at the Nuclear Maintenance Facility (NMF). This facility specializes in the maintenance of contaminated nuclear power plant equipment. The work spaces at the NMF are ventilated with fresh air which is discharged to the environment after passing through HEPA particulate filters. The effluent air flow is continuously sampled with an isokinetic sample probe providing a representative volume of air drawn through an effluent sample filter to collect particulate material. Every week the radioactivity collected on the sample filter is collected and analyzed approximately 72 hours later to determine the amount of radioactive particulate NMF discharges to the environment. One of your routine job tasks is to collect the effluent sample filters for analysis.
1. (Inference) While you are performing the sampling evolution, you accidentally drop the filter paper when removing it from the sample holder. It lands on the floor with the sample side down. You carefully pick it up and place it in the protective envelope for analysis. What is the most important consequence of this occurrence?
A.) The radioactive contamination on the floor is most important due to the radioactive particles on the filter being a significant source of contamination.
B.) The larger amount of radioactive particulate discharged to the environment is most important due to some of the radioactive material on the sample filter being lost to the floor.
C.) The smaller amount of radioactive particulate discharged to the environment is most important due to some of the radioactive material on the sample filter being lost to the floor.
D.) The accuracy of the amount of radioactive particulate discharged to the environment is most important due to the sample results being inaccurate.(Correct)
2. (Prediction) In a gas-filled detector operating in the Proportional Region, how would a change in the detector voltage affect the number of electrons produced in the detector?
A.) As voltage decreases, the number of electrons increase
B.) As voltage increases, the number of electrons increase (Correct)
C.) As voltage decreases, there is little or no change in the number of electrons.
D.) As voltage increases, there is little or no change in the number of electrons.
3. (Explanation) Which of the answers below best explains how alpha and beta radiation each impact the circuitry of a gas-filled proportional detector?
A.) Alpha radiation produces smaller pulses of current in the detector circuitry than beta radiation because if its lower penetrating ability.
B.) Beta radiation produces larger pulses of current in the detector circuitry than alpha radiation because of its higher penetrating ability.
C.) Alpha radiation produces larger pulses of current in the detector circuitry than beta radiation because of its higher ionization potential. (Correct)
D.) Beta radiation produces larger pulses of current in the detector circuitry than alpha radiation because of its lower ionization potential.
4.) (Inference) Given the conditions in the scenario described above, which type of detector system provides the most accurate measure of effluent air radioactivity?
A.) A gas-filled G-M detector system is best because it is portable and permits quick and immediate results.
B.) A gas-flow proportional detector system is best because it measures current instead of pulses.
C.) A gas-filled G-M detector system is best because it responds indiscriminately to most types of radiation.
D.) A gas-flow proportional detector system is best because it discriminates between different isotopes. (Correct)
5.) (Explanation) Explain why this sampling method (Isokinetic with 72-hour decay)does not measure the actual amount of radioactive material discharged from the facility in the effluent air flow?
A.) Isokinetic sampling is not representative of the effluent air flow.
B.) The upstream HEPA filters remove the radioactive isotopes before they are discharged.
C.) The sample only contains long-lived isotopes when it is analyzed (Correct)
D.) The sample analysis is masked by short-lived isotopes before they decay away.
6.) (Prediction) How would the number of calculated DACs in the effluent air change if an error in sample counting date resulted in the sample being counted one day early?
A.) The number of DACs would not change because only long-lived isotopes are being counted.
B.) The number of DACs would increase because there would be more activity due to short-lived isotopes.(Correct)
C.) The number of DACs would decrease because there would be less activity due to short-lived isotopes.
D.) The number of DACs would not change because only short-lived isotopes are being counted.
Suggested Labs
Supl. Lab #16: Alpha-Beta Discrimination in Proportional Counters, page 13
Supl. Lab #17: Measurement of alpha energy spectrum, page 20.
ACAD References
ACAD3.2.3 Radiological Survey and Analysis Instruments
· Identify the instruments available for performing contamination surveys such as the following
– Proportional counters
· Explain the operating characteristics and use of the following radiological survey and analysis instruments:
– Gross alpha counter
– Gross alpha/beta counter
3.3.15 Environmental Monitoring
· Explain the purpose of the plant environmental monitoring program.
· Describe the methods used to conduct environmental monitoring, such as:
– Air sampling
– Vegetation sampling
– Aquatic life sampling
– Water sampling
– Soil sampling
– Milk sampling
Lesson Plan
I. PROGRAM: Radiological Protection Technician
II. COURSE: Fundamentals Training
III. LESSON TITLE: Contamination Control
IV. LENGTH OF LESSON/COURSE:
V. TRAINING OBJECTIVES:
A. Terminal Objective:
Upon completion of this course, the participants will demonstrate their knowledge and understanding of the information presented during RADCON Technician training by obtaining a score of greater than or equal to 80% on a written examination. The information presented in this lesson plan may be part of an overall exam or be the only information for which the student is examined.
B. Enabling Objectives:
Standards and conditions apply to all enabling objectives. They include under the examination ground rules, without the use of training materials or outside assistance, and utilizing information presented in this lesson plan. Upon completion of this lesson each participant will be able to:
1. Define contamination and list its sources, types and forms.
2. List and describe the two types of survey techniques, media, and instrumentation used for loose contamination.
3. Describe the proper technique and instrumentation used for fixed contamination surveys.
4. Discuss "Hot Particles" and the proper survey techniques.
5. Discuss the mechanism utilized to determine alpha limits and survey requirements.
6. State the limits for smear, wipe, and direct surveys.
7. Describe the identification and control requirements for an item/object exceeding the limits.
8. Describe the identification and control requirements for a plant area exceeding the limits.
9. Explain the proper control requirement and survey for items exiting a "Contamination Area".
10. State the limit for personnel contamination and describe proper utilization of personnel monitoring devices.
11. Describe the monitoring and release requirements for personnel and items leaving the "Radiologically Controlled Area".
12. Discuss contamination control to include determining source of contamination, stopping the release of contamination, limiting the spread of contamination, and protection/monitoring of personnel.
13. Identify the types of personnel contamination protection utilizing protective clothing and devices to include the deposition of these items and contamination limits for reuse.
14. Discuss plant area decontamination techniques.
15. Discuss item/equipment decontamination techniques.
16. Discuss personnel decontamination techniques, documentation, and pathway surveys
VI. TRAINING AIDS:
A. Computer and projection system with power point capabilities.
VII. TRAINING MATERIALS:
A. Attachment A: HPT001.015 Power point presentation, P:\Training\Technical Programs and Services\Radcon\Initial Program\Lesson Plan Library\Library\HPT001.015 Contamination Control
B. Appendix 1: Just-in Time Operating Experience
VIII. REFERENCES:
A. 10 CFR 20, January 2001.
B. TVAN Standard Programs and Processes, SPP-5.1, Radiological Controls, revision 5.
C. TVAN Standard Department Procedure, RCDP-1, Conduct of Radiological Controls, revision 2.
D. TVAN Standard Department Procedure, RCDP-10, Conduct of Radiological Controls, revision 3.
E. Martin, Alan and Harbison, Samuel A., An Introduction to Radiation Protection, 3rd Edition, Chapman and Hall, 1986.
F. Moe, H. L., Operational Health Physics Training, Argonne National Laboratory, 1988.
G. Shapiro, Jacob, Radiation Protection – A Guide for Scientist and Physicians-Third Edition, Harvard University Press, 1990.
Notes for Powerpoint Presentation
IX. INTRODUCTION:
In a nuclear power plant, radioactive material is present in the primary piping systems as a result of the fission process. Fission and activation products produced provide a source of contamination if the radioactive material escapes the piping in which it is contained. This lesson will explain the types of contamination and their sources, contamination survey techniques, contamination limits and identifications, contamination control, personnel contamination protection and detection, and decontamination. In addition, the hazards associated with contamination and necessary actions to limit personnel exposure to these hazards will be explained. Your knowledge of these hazards will allow you as a Radcon technician to make the appropriate decisions and provide the necessary guidance to other nuclear plant workers.
A. Contamination Definition and Survey Techniques1. Contamination is radioactive material in an unwanted place. / Objective 1
Slide 2, 3
2. The sources of contamination are fission products, activation products, and activated corrosion products produced in the reactor core and reactor coolant of the nuclear power plant.
a. Reactor coolant, coolant gases, fission products and activation products which circulate through the primary system and its support systems will become contamination when they escape the system piping or components.
b. Contamination escapes a system through
1) System breaches for maintenance or testing
2) Reactor coolant spills
3) Reactor coolant leaks from:
a) Valves
b) Flanged connections such as manways, closures, pipe-caps
c) Defective pump gaskets
d) Defective welds
e) Boric acid corrosion through piping
3. Contamination is defined in two types based upon the decay process of the isotopic mixture.
a. Alpha contamination – the isotopic makeup of the contamination releases alpha during the decay process / Slide 3
b. Beta/gamma contamination – the isotopic makeup of the contamination releases beta and/or gamma during the decay process
4. Contamination exists in 3 forms
a. Loose
b. Fixed
c. Airborne / Slide 4
5. Loose contamination is removable, smearable, transferable.
a. Loose surface contamination is detected by indirect surveys through transference of the contamination to smears or wipes when swiped across the surface. / Defn – Survey - the process of monitoring for ionizing radiation, analyzing the results in regard to establishing protection standards, and defining or evaluating any radiological hazard which may exist.
b. The smears or wipes are monitored for the contamination present as a representation of the amount present on the item surveyed. / Objective 2
Show smear, wipe and frisker.
c. Wipes are utilized when contamination is not expected for verification of non-contamination.
1) Wipes are chemically treated cloths, attached to a mop handle and lightly pushed across the floor. / Slide 5
Note – Due to the oil present in wipes alpha contamination cannot be detected – wipes are not used for alpha contamination surveys.
2) Wipes are taken over a 100 ft2 (10 x 10 ft) area to indicate the presence of beta/gamma loose surface contamination. / Demonstrate wipe survey technique to include frisker checks and use.
3) Wipes will be folded when removed from the mop to contain any potential contamination present while in route to survey instrument. / Human performance - STAR