NRRPT Radiation Shielding and ALARA Principles 2 — Questions and Answers
Question 1: Which NRC regulation establishes the annual occupational dose limit for the whole body?
- 10 CFR Part 20 (Correct answer)
- 10 CFR Part 50
- 10 CFR Part 61
- 10 CFR Part 35
Correct answer: 10 CFR Part 20
10 CFR Part 20 sets the NRC's standards for radiation protection, including the 5 rem/year occupational whole-body dose limit.
Question 2: What is the annual occupational effective dose limit (deep dose equivalent) set by the NRC?
- 1 rem
- 2 rem
- 5 rem (Correct answer)
- 10 rem
Correct answer: 5 rem
10 CFR 20.1201 sets the annual occupational total effective dose equivalent limit at 5 rem (0.05 Sv).
Question 3: Under ALARA, engineered controls are preferred over which type of control?
- Administrative controls
- Personal protective equipment
- Both A and B (Correct answer)
- Neither A nor B
Correct answer: Both A and B
The hierarchy of controls places engineering controls above both administrative controls and PPE in the ALARA framework.
Question 4: What is the primary purpose of a radiation work permit (RWP)?
- To record dosimeter readings
- To authorize and control radiological work activities (Correct answer)
- To request new shielding materials
- To document decontamination procedures
Correct answer: To authorize and control radiological work activities
An RWP formally authorizes specific work in radiological areas and communicates hazards, dose limits, and required controls to workers.
Question 5: Which action is an example of applying ALARA through the 'time' component?
- Erecting lead shielding around a source
- Rotating personnel to limit individual dose (Correct answer)
- Moving workers 10 feet farther from the source
- Using thicker concrete walls
Correct answer: Rotating personnel to limit individual dose
Rotating personnel limits the time any individual spends in a radiation field, reducing their cumulative dose.
Question 6: A tenth-value layer (TVL) reduces radiation intensity to what fraction of the original?
- 1/2
- 1/5
- 1/10 (Correct answer)
- 1/100
Correct answer: 1/10
A TVL is the thickness of material that attenuates radiation to one-tenth of its original intensity.
NRRPT Radiation Shielding and ALARA Principles 2
Which NRC regulation establishes the annual occupational dose limit for the whole body?