NRRPT Radiological Protection Standards 3 — Questions and Answers
Question 1: The annual occupational dose limit for the skin and extremities under 10 CFR Part 20 is:
- 5 rem (50 mSv)
- 15 rem (150 mSv)
- 25 rem (250 mSv)
- 50 rem (500 mSv) (Correct answer)
Correct answer: 50 rem (500 mSv)
10 CFR 20.1201 sets the annual occupational dose limit for the skin of the whole body and the extremities at 50 rem (500 mSv).
Question 2: A radiation worker receives an unplanned dose of 10 rem in one year. Under 10 CFR 20.1201, this would be:
- Within the annual limit; no action required
- A violation requiring immediate shutdown
- A violation of the 5 rem TEDE annual limit (Correct answer)
- Permissible if a planned special exposure was authorized
Correct answer: A violation of the 5 rem TEDE annual limit
The annual occupational TEDE limit under 10 CFR 20.1201 is 5 rem; receiving 10 rem unplanned constitutes a violation.
Question 3: Which radiation weighting factor (wR) is assigned to alpha particles under ICRP 103?
- 1
- 5
- 10
- 20 (Correct answer)
Correct answer: 20
ICRP Publication 103 assigns a radiation weighting factor of 20 to alpha particles due to their high linear energy transfer (LET).
Question 4: The 'negligible individual dose' (NID) defined by NCRP Report No. 116 is:
- 0.1 mSv/year
- 0.01 mSv/year (Correct answer)
- 1 mSv/year
- 0.001 mSv/year
Correct answer: 0.01 mSv/year
NCRP Report No. 116 defines the negligible individual dose as 0.01 mSv/year (1 mrem/year), below which individual protective actions are not warranted.
Question 5: Under 10 CFR Part 20, a 'declared pregnant worker' receives a dose limit of:
- 5 rem for the gestational period
- 0.5 rem for the entire gestation (Correct answer)
- 1 rem per trimester
- Same as non-pregnant workers
Correct answer: 0.5 rem for the entire gestation
10 CFR 20.1208 limits the dose to the embryo/fetus of a declared pregnant worker to 0.5 rem (5 mSv) during the entire gestation period.
Question 6: What document describes the NCRP's recommended basic radiation protection criteria for the U.S.?
- NCRP Report No. 39
- NCRP Report No. 93
- NCRP Report No. 116 (Correct answer)
- NCRP Report No. 147
Correct answer: NCRP Report No. 116
NCRP Report No. 116 (Limitation of Exposure to Ionizing Radiation, 1993) is the primary NCRP document recommending basic radiation protection criteria.
Question 7: In the context of radiological protection, 'deterministic effects' differ from stochastic effects because they:
- Have no threshold and increase in probability with dose
- Have a threshold dose and increase in severity with dose above the threshold (Correct answer)
- Only result from internal contamination
- Are caused exclusively by low-LET radiation
Correct answer: Have a threshold dose and increase in severity with dose above the threshold
Deterministic effects (e.g., cataracts, radiation burns) have a threshold below which they do not occur and increase in severity as dose exceeds the threshold.
NRRPT Radiological Protection Standards 3
The annual occupational dose limit for the skin and extremities under 10 CFR Part 20 is: