United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Question 192: 10 CFR 20.1206 (e) says that licensees may

not authorize PSEs for workers whose doses from previous

PSEs and all "doses in excess of the limits" exceed certain

limits. (a) What and whose limits apply? (b) Does the

actual limit (e.g. 3 rem/quarter, 1.25 rem/quarter, etc.)

apply, or does the equivalent annual limit apply? (c) Do

doses from non-licensed sources (e.g., x-ray sources) that

were in excess of the facility's limits apply, especially

if the facility was not a licensee? (d) It appears that

overexposures will require the licensee to back-calculate

the dose in excess of the limits, particularly when that

dose was received from an intake of radioactive material.

However the Footnote 5 of 10 CFR 20.2106 says that

assessments of dose equivalent and records made using units

in effect before the licensee's adoption of this Part need

not be changed. Will the licensee have to, in fact,

convert the old doses in excess of the limits to committed

effective dose equivalent?

Answer: (a) The regulatory limits at the time and place

of the overexposure apply. If the individual worked for

the Department of Energy (DOE), then the DOE limits apply.

If the individual worked in a foreign country, then that

country's limits apply.

(b) The actual limit applies.

(c) Yes. It is the purpose of the regulation to control

licensed material in such a manner that the total dose to

an individual, from licensed and non-licensed sources, does

not exceed standards prescribed in the regulations.

d) Yes. (Reference: 10 CFR 20.1206, 10 CFR 20.2104, 10

CFR 20.1001, Regulatory Guide 8.35)

Page Last Reviewed/Updated Thursday, March 29, 2012