RPT 113Instructional Resources
Module 1:Perform Dose Surveys using Ionization Chambers
Table of Contents:
Resources Key......
Module Readings and Homework......
Primary Scenario “Determine Dose Rates in a Nuclear Research Laboratory”......
Transfer Scenario “Determine Dose Rates in a Lay Down Area”......
Primary Scenario “Determine Pre- and Post-Job Dose Rates in a High Radiation Area”
Transfer Scenario “Determine Pre- During- and Post-Job Dose Rates for an Ion Filter Exchange Evolution”
Module Assessment Items
Primary Scenario “Determine Dose Rates in a Nuclear Research Laboratory”......
Primary Scenario “Determine Pre- and Post-Job Dose Rates in a High Radiation Area”
Suggested Labs......
ACAD References
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: 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 Dose Rates in a Nuclear Research Laboratory”
Core Concept: Gas-filled radiation detectorsHomework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 244-246 / N/A / DOE-SG-Mod. 2.16.01
Core Concept: Ionization chambers
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 246-254
DOE-SG-Mod 2.16-7 to 2.16-13 / G., Chap. 7,# 4 / G., Chap. 7,# 3, 6
DOE-SG-Mod. 2.16.02
Core Concept: Dose surveys using ionization chambers
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 12, 504-519 / N/A / N/A
Core Concept: Survey Meter Calibration
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 12, 494-496 / N/A / G., Chap 12, #1, 2
Transfer Scenario “Determine Dose Rates in a Lay Down Area”
Refer to readings and homework for primary scenario above.
Primary Scenario “Determine Pre- and Post-Job Dose Rates in a High Radiation Area”
Core Concept: High radiation dose areas using ionization chambersHomework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 246-254
DOE-SG-Mod 2.16-3 through 2.16-16
DOE-SG-Mod 2.16-19 through 2.16-22 / N/A / G., Chap. 7, # S-4
DOE-SG-Mod 2.16.03
Core Concept: Effect of environment on detector responses
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G.,Chap. 7, 253-254 / N/A / N/A
Transfer Scenario “Determine Pre- During- and Post-Job Dose Rates for an Ion Filter Exchange Evolution”
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 Dose Rates in a Nuclear Research Laboratory”
You have recently accepted a job as a radiation protection technician at the Johnson Radiological Research Facility (JRRF). After receiving an introductory tour of the facility, you have been asked to conduct a routine radiation survey of one of the research labs where samples containing various radioisotopes are used and counted. The radioisotopes used here emit alpha, beta, and gamma radiation. There are no high radiation or contamination areas in the lab. You are equipped with a personal monitoring device (TLD) and an electronic dosimeter (ED).
Use the scenario above for questions 1-5
1. (Inference) Which of the following is the most important to consider before conducting the survey to keep your dose ALARA?
A.) The anticipated contamination levels in the area
B.) The anticipated radiation levels in the area (Correct)
C.) The protective clothing needed to complete the survey
D.) The type of instrument needed to complete the survey
2. (Explanation) Which reason best explains your answer to Question 1?
A.) Contamination has a greater impact on your dose than radiation does.
B.) Radiation has a greater impact on your dose than contamination does. (Correct)
C.) Protective clothing will reduce your dose.
D.) The type of instrument you use will impact your dose.
3. (Inference) What type of radiation detector would you choose to use to perform this radiation survey?
A.) G.M. detector
B.) Scintillation detector
C.) Ionization detector (Correct)
D.) Electronic dosimeter
4. (Explanation) Which reason best explains your answer to question 3?
A.) GM detectors are gas-filled detectors and therefore provide a more accurate dose rate measurement.
B.) Electronic dosimeters are designed to accurately measure personal dose.
C.) Scintillation detectors accurately measure ionizations in air.
D.) Ion chamber detectors are air-filled detectors and therefore provide a more accurate dose rate measurement. (Correct)
5. (Prediction) While conducting the radiation survey, if the reading needle on the face of the instrument you are using suddenly were to become very erratic, bouncing back and forth from side to side, which of the following would you do first and why?
- Because rapidly changing radiation levels can cause rapidly fluctuating readings, I would check for any sources in the immediate vicinity that exhibit such characteristics.
- Because contamination on the detector can cause rapidly fluctuating readings, I would make sure the detector is free of contamination.
- Drained batteries make the needle bounce back and forth from side to side, so I would check to see if the batteries are charged in my instrument.
- A poor electrical connection can make the needle bounce back and forth from side to side, so I would check the electrical connection. (Correct)
Primary Scenario “Determine Pre- and Post-Job Dose Rates in a High Radiation Area”
1. (Explanation) As a Radiation Protection Technician at a nuclear power plant you have been asked to determine the beta dose rate 3 feet inside the man-way plane of a steam generator bowl (inlet side). You have selected an instrument with an ion chamber detector outfit with a beta window. Which of the following explanations describe how you will determine the beta dose rate?
A.) Open the beta window and take a reading. This is the beta dose rate.
B.) Close the beta window and take a reading. This is the beta dose rate.
C.) Take both an open-window reading and a closed-window reading and subtract the open-window reading from the closed-window reading to get the beta dose rate.
D.) Take both a closed-window reading and an open-window reading and subtract the closed-window reading from the open-window reading to get the beta dose rate. (Correct)
2. (Explanation) You are taking a radiation survey with an instrument equipped with a G.M. detector and digital readout. Which of the following explanations describe the effect of geotropism on the reading you will obtain?
A.) The reading will be lower than actual as you get closer to the earth.
B.) The reading will be higher than actual as you get closer to the earth.
C.) Geotropism will have an effect on the reading, depending on how you orient the instrument with the earth.
D.) Geotropism will have no affect on the reading. (Correct)
3. (Inference) You have been asked to conduct a radiation dose rate survey in an area with a typical dose rate range of 5 to 30 Rem/hr. You select a high-range instrument with an internal G.M. detector to take the survey with. How would you expect the survey results to compare with the actual dose rates?
A.) Survey results will be higher than actual dose rates. (Correct)
B.) Survey results will be lower than actual dose rates.
C.) Survey results will be the same as actual dose rates.
4. (Explanation) Which statement below best explains the reason for your answer to question 3
A.) G.M. detectors are very sensitive and tend to indicate erroneously high or saturate in high dose rate fields. (Correct)
B.) G.M. detectors are air-filled and therefore accurately measure exposure and dose.
C.) G.M. detectors measure ionizations in a gas rather than in air which causes the indicated dose rates to be lower than actual dose rates.
D.) G.M. detectors typically indicate higher than actual dose rates because they measure pulses produced from ionizations instead of current produced from ionizations.
5. (Prediction) You are using a dose rate meter with an ionization chamber detector. How would you expect the dose rate reading to change when you went from a normal environment to an environment with noble gas present?
A.) The reading would not change.
B.) The reading would be incorrectly low.
C.) The reading would be incorrectly high. (Correct)
D.) The instrument would not function.
Suggested Labs
Lab dose surveys using Teletrix SP418 simulated survey meters. No laboratory procedure given – at instructor’s discretion.
Supl. Lab #14: Calibration of G.M. Tube Survey Meter, page 3.
ACAD References
ACAD1.1.8 Radiation Protection and Detection
- Explain the principles and operation of radiation detection and monitors including the following:
3.2.2 Radiation Detection and Measurement Principals
- Explain the function of an ion chamber, proportional counter, alpha scintillation detectors, plastic scintillation detectors and Geiger-Mueller counter
- Draw and explain gas-filled detector six region curve, including gas amplification
3.2.3 Radiological Survey and Analysis Instruments
- Explain the operating characteristics and basic electrical circuitry of each survey instrument
- Perform and describe operational checks on survey instruments, such as battery, zero, source, response, background and calibration.
- Identify conditions that might affect survey instrument response, including the following:
–Extreme temperatures
–Geotropism
–High humidity
–Mixed radiation fields
–Noble gas atmospheres
–Off-scale reading
–Radiofrequency interference
- Explain the operating characteristics and use of monitoring devices including the following monitors:
- Identify unusual conditions that might affect counting and spectroscopy equipment response such as high humidity, abnormal background, electronic noise and extreme temperature
- Explain the operating characteristics and use of the following radiological survey and analysis instruments:
–Gamma survey instrument
- Identify unusual conditions that might affect radiation monitoring systems response such as high humidity, abnormal background, mixed radiation fields and temperature effects
3.2.5 Calibration Sources and Equipment
- Discuss the type of equipment required to calibrate plant survey instruments and radiation monitors.
- Describe the precautions associated with calibration procedures and calibration source handling.
- Identify the criteria for proper calibration of survey instruments and radiation monitors.
Module Perform Dose Surveys using Ionization Chambers
The Curators of the University of Missouri
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A Product of DOL Grant #HG-15355-06-60
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