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)