United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Question 138: Although it is extremely unlikely,

long-lived residual radioactive material in the body of a

female worker from her previous employment could deliver a

dose exceeding the limit to a subsequently conceived

embryo / fetus. For example, a former DOE worker who had

been involved in an accident could have a large americium

or plutonium body burden. 10 CFR 20.1208 makes no special

provision for this eventuality. What action would the NRC

expect the licensee to take?

Answer: The answer to this question is provided in

Regulatory Guide 8.36, "Radiation Dose to the

Embryo / Fetus," which indicates that if monitoring of a

declared pregnant woman is required, the existing body

burden must be included in determining the embryo / fetus

dose. If the licensee determines that the dose to the

embryo / fetus has exceeded 0.5 rem, or is within 0.05 rem of

the dose limit by the time the woman declares her

pregnancy, the licensee may allow the embryo / fetus to

receive an additional 0.05 rem during the remainder of her

pregnancy. If the prior body burden alone caused a dose to

the embryo / fetus in excess of the limit, that dose should

be recorded, but the NRC would not take enforcement actions

for this "overexposure" provided that the licensee does not

allow the embryo / fetus to receive more than 0.05 rem after

the woman has declared her pregnancy. See the answer to

the related Question 120. That answer states that the

intent of 10 CFR 20.1208 (d) is that the licensee should

not be in violation of the limit for the embryo / fetus as a

result of doses received by the embryo / fetus before the

woman declared her pregnancy or doses received as a result

of intakes before that declaration was made. (Reference:

10 CFR 20.1208).

Page Last Reviewed/Updated Thursday, March 29, 2012