Document: NRC Regulatory Guide
Document ID: 96baa826-d3bb-478b-8f38-e74500f6d433
Document Type: regulatory_guide
Title: 06/2009 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0911/ML091170109.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.21
CFR Part: 
CFR Title: 

Content:
natural attenuation), no one set of numerical values defines significant residual radioactivity. However, licensees may make remediation decisions based on their expectations of being able to meet the decommissioning criteria of 10 CFR 20.1402, “Radiological Criteria for Unrestricted Use,” at the anticipated time of decommissioning. Information that may be useful in this decision-making includes (1) NUREG-1757, Volume 1, Appendix H, “Memorandum of Understanding between the Environmental Protection Agency and the Nuclear Regulatory Commission,” (2) NUREG-1757, Volume 2, “Derived Concentration Guideline Levels in Table H.1,” and (3) the derived concentration guideline levels that have been authorized for decommissioned nuclear power plants. For a more detailed analysis, licensees may use the RESRAD computer codes available from Argonne National Laboratory (Refs. 17, 18, and 19) or equivalent. 1.6 Monitoring Continuous Releases For continuous releases, gross radioactivity measurements are often the only practical means of continuous monitoring. These gross radioactivity measurements are typically used to actuate alarms and terminate (trip) effluent releases, but by themselves, are generally not acceptable for demonstrating compliance with effluent discharge limits. The use of continuously indicating radiation monitoring system results may be combined with sample analyses to more fully characterize and quantify a discharge. This technique may have particular applicability when (1) a short-term, rapid upscale indication of a process radiation monitor occurs during a release or (2) when there is a desire to verify whether a preliminary grab sample is representative. In these instances the radiation monitor responses (i.e., the radiation monitor efficiencies) for various radionuclides should be well characterized. Grab samples should be collected at scheduled frequencies (see NUREG-1301 and NUREG-1302 or as approved in Generic Letter 89-01 submittals) to