United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Question 105: How should demonstration be made of

compliance with the 2 mrem in an hour limit [10 CFR 20.1301

(a) (2)]? Is it adequate, for a nuclear power plant, to

demonstrate compliance by having effluent control (trip)

systems that prevent effluent releases from exceeding the

limits on the instantaneous release rates, and by

performing periodic surveys during radioactive material

storage and movements?

Answer: The 2 mrem in an hour limit is not new; it

appears in the old Part 20 in 10 CFR 20.105 (b) (1).

Therefore, methods for complying with this limit that have

been acceptable in the past will continue to be acceptable

under the new Part 20. The 2 mrem in an hour limit applies

to doses in an unrestricted area from radiation sources

located either inside or outside of that unrestricted area.

Therefore, compliance can be achieved by a reasonable

combination of appropriate controls, surveys, and

monitoring of sources, and potential sources. Such

controls, surveys and monitoring are not necessarily

limited to the "effluent control trip system" and "periodic

surveys during radioactive material storage and movements"

that are stated in the question. For example, controls and

surveys related to increased turbine shine at BWRs as a

result of hydrogen water chemistry must be included.

(Reference: 10 CFR 20.1301)

Page Last Reviewed/Updated Thursday, March 29, 2012