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:
er (see paragraph below), then, for purposes of reporting discharges in the ARERR, there was no liquid discharge to the unrestricted area, and the spill need not be reported in the ARERR. However, the decommissioning file should be updated to include a description of the event as specified by 10 CFR 50.75(g). Licensees should review the decommissioning files before generating the ARERR to ensure that the ARERR includes the necessary information regarding leaks and spills. When evaluating areas that have been remediated, the licensee should survey for residual radioactivity. There may be times when the licensee wants to verify that an area contains no residual radioactivity. There is existing regulatory guidance and information on analytical detection capabilities. Licensees should ensure that surveys are appropriate and reasonable (as defined in 10 CFR 20.1501). Licensees should generally ensure that surveys are conducted using the appropriate sensitivity levels (e.g., refer to the environmental LLDs in NUREG-1301 and NUREG-1302, Table 4.12-1, “Detection Capabilities for Environmental Sample Analysis,” or LLDs determined by using the methodology outlined in NUREG-1576, “Multi-Agency Radiological Laboratory Analytical Protocols Manual,” (MARLAP) issued July 2004 (Ref. 14)). Additionally, licensees should apply plant-process-system knowledge when evaluating leaks and spills. For example, consider a hypothetical case of a leak in a condensate storage Rev. 2 of RG 1.21, Page 12 tank. Assume that the tank’s contents were analyzed 30 days before the leak and determined to contain 1.2x10-6 microcuries per milliliter (uCi/mL) of tritium (1,200 picocuries/liter (pCi/L)). Additionally, assume that historical records indicate that the tank contained detectable levels of tritium about 50 percent of the time, and that tritium concentrations never exceeded 2,000 pCi/L of tritium. In this example, the licensee discovers a leak in the tank and is able to fix the leak