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:
ate for the effluent (radionuclide) being analyzed. In cases where the compositing interval is selected appropriately, analytical bias is minimized. One way to avoid analytical bias is to decrease the composite sampling interval (and analysis frequency). To minimize bias in measurements, it may be necessary to decay correct analysis results for short-lived radionuclides. Licensees should be cognizant of those situations in which analytical bias may be introduced when analyzing short-lived radionuclides and should select appropriate methods to minimize such bias. 3 Effluent Dispersion (Meteorology and Hydrology) 3.1 Meteorological Data Gaseous effluents discharged into the atmosphere are transported and diluted as a function of (1) the atmospheric conditions in the local environment, (2) the topography of the region, and (3) the characteristics of the effluents. Licensees should consider the guidance in Regulatory Guide 1.23, “Meteorological Monitoring Programs for Nuclear Power Plants” (Ref. 27), in the development and implementation of site programs designed to collect site-specific meteorological data. The meteorological data do not need to be reported in the ARERR, but the data should be summarized and maintained as Rev. 2 of RG 1.21, Page 20 documentation (records). An annual meteorological summary report that provides the joint frequency distributions of wind direction and wind speed by atmospheric stability class (see Regulatory Guide 1.23) should be prepared and maintained on site for the life of the plant. In addition, hourly meteorological data should be recorded and available if needed for assessing abnormal gaseous releases. 3.2 Atmospheric Transport and Diffusion Site-specific meteorological data collected should be analyzed and used to generate gaseous effluent dispersion factors (χ/Q) and deposition factors (D/Q) in accordance with Regulatory Guide 1.111, “Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in