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)