NRRPT Radiological Control & Safety Procedures 4 ā Questions and Answers
Question 1: When must a radiation protection technician perform a pre-job briefing before radiological work?
- Only when working in very high radiation areas (VHRA)
- Before all work covered by a Radiological Work Permit (Correct answer)
- Only when new workers are present on the team
- Only when radioactive material is being handled directly
Correct answer: Before all work covered by a Radiological Work Permit
Pre-job briefings are required before all RWP-controlled work to ensure all workers understand radiological hazards, controls, dose limits, and emergency procedures.
Question 2: An 'extremely high radiation area' (EHRA) under 10 CFR 20 requires what additional physical control beyond standard HRA requirements?
- Written NRC approval before each entry
- Continuous air sampling during work
- Physical controls (not just administrative controls) that prevent inadvertent entry (Correct answer)
- Installation of a personnel dosimetry system
Correct answer: Physical controls (not just administrative controls) that prevent inadvertent entry
EHRAs require physical controls such as locked doors or gates that prevent inadvertent or unauthorized entry, beyond mere posting and administrative barriers.
Question 3: Which instrument is most appropriate for detecting and measuring low-energy beta contamination such as C-14 or H-3?
- Geiger-MĆ¼ller detector
- Sodium iodide scintillation detector
- Liquid scintillation counter for H-3; thin-window GM for C-14 (Correct answer)
- Ion chamber survey meter
Correct answer: Liquid scintillation counter for H-3; thin-window GM for C-14
H-3 emits very low-energy betas that require liquid scintillation counting, while C-14's betas require a thin-window GM detector because standard detectors cannot detect their low energies.
Question 4: What is the purpose of posting a 'Radioactive Material' area sign per 10 CFR 20?
- To indicate the area contains more than 10 times the quantity of radioactive material specified in Appendix C to Part 20
- To warn individuals that quantities of radioactive material exceeding certain thresholds are present (Correct answer)
- To alert workers that dose rates exceed 100 mrem/hr
- To designate areas where radioactive waste is stored pending disposal
Correct answer: To warn individuals that quantities of radioactive material exceeding certain thresholds are present
Radioactive Material area postings warn personnel that quantities of radioactive material above regulatory thresholds specified in 10 CFR 20 Appendix C are present.
Question 5: A worker's thyroid bioassay reveals an uptake of I-131 that results in a committed dose equivalent of 15 rem. Under 10 CFR 20, what is the occupational limit for thyroid dose?
- 5 rem per year
- 15 rem per year
- 50 rem per year (Correct answer)
- 75 rem per year
Correct answer: 50 rem per year
The occupational dose limit for the thyroid under 10 CFR 20.1201(a)(2) is 50 rem (0.5 Sv) committed dose equivalent per year.
Question 6: During radiological work planning, what is the primary benefit of performing a mockup or dry run of a task?
- To satisfy NRC documentation requirements for complex tasks
- To identify procedural inefficiencies and reduce actual timeāand therefore doseāin the radiation field (Correct answer)
- To verify that protective equipment fits correctly
- To calibrate dosimeters before actual exposure
Correct answer: To identify procedural inefficiencies and reduce actual timeāand therefore doseāin the radiation field
Mockups allow workers to practice a task and optimize their technique before entering the radiation field, directly reducing the time spent in the field and thus the total dose received.
Question 7: What action should a radiation protection technician take if a survey instrument reads unexpectedly high when entering a posted radiation area?
- Proceed cautiously while continuing to monitor
- Back out immediately, re-survey the area boundary, and investigate the discrepancy (Correct answer)
- Switch to a more sensitive instrument setting and continue
- Record the reading and notify the supervisor at end of shift
Correct answer: Back out immediately, re-survey the area boundary, and investigate the discrepancy
An unexpectedly high reading may indicate a changed radiological condition; the technician should exit, re-evaluate the boundary, and investigate before allowing work to proceed.
NRRPT Radiological Control & Safety Procedures 4
When must a radiation protection technician perform a pre-job briefing before radiological work?