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:
or in proportion to the volume of each batch of effluent discharges. 2.6 Sample Preparation and Preservation Methods of sample preparation and/or sample storage should minimize the potential for loss of radioactive material (i.e., deposition of analyte on walls of the sample container or volatilization of analyte). Composite sample storage time should be as short as practical to preclude deposition on the storage container, or sample stabilization should be considered. Before quantitative radionuclide analyses for liquid effluent composites, samples should be mixed thoroughly so that the sample is representative of the material discharged. Procedures should be instituted for handling, packaging, and storing samples to ensure that losses of radioactive materials or other factors causing sample deterioration do not invalidate the analysis. For example, filters should be stored carefully so as to prevent loss of radioactive material from the filter paper. 2.7 Short-Lived Radionuclides and Decay Corrections In the analysis of short-lived radionuclides (e.g., short-lived noble gases), measurements should generally be made as soon as practical after collection to minimize loss by radioactive decay. In other cases, when needed to improve the detection of the longer-lived radionuclides, time should be allowed for the decay of short-lived, interfering radionuclides. Some special considerations may be applicable in those instances where short-lived radionuclides are being measured. In general, sample collection (or analysis frequencies) should take into account the half-lives of the radionuclides being measured. This may have special applicability for continuous samples or composite samples. It is generally best to select a compositing interval (and analysis frequency) appropriate 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