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:
he waste mixture. For example, a large tank may be mixed using a sparger system or recirculated three or more volumes to ensure that a representative sample can be obtained, as recommended by American Society for Testing and Materials (ASTM) D 3370-07, “Standard Practices for Sampling Water from Closed Conduits” (Ref. 24). If tank-mixing practices deviate from industry standards (i.e., those for recirculation or other), a technical evaluation or other justification should be provided. Sample points should be located where there is a minimum of disturbance of flow caused by fittings and other physical characteristics of the equipment and components. Sample nozzles should be inserted into the flow or liquid volume to ensure sampling of the bulk volume of pipes and tanks. Sample lines should be flushed for a sufficient period of time before sample extraction to remove sediment deposits and air and gas pockets. Generally, three line volumes should be purged (see ASTM D 3370-07) before withdrawing a sample, unless a technical evaluation or other justification is provided. Periodically, a series of samples should be taken during the interval of discharge to determine whether any differences exist as a function of time and to ensure that individual samples are indeed representative of the effluent mixture. In some instances, this may be accomplished by collecting one or more samples (either by “grab” or composite sampler) during the discharge and comparing with one or more samples taken before the discharge. If a series of samples are collected, these samples can be used to assess the amount of measurement uncertainty in obtaining representative samples. 2.3 Sampling Gaseous Radioactive Waste Although all licensees may not be committed to Regulatory Guide 4.15, American National Standards Institute (ANSI) N42.18-2004, “Specification and Performance of On-Site Instrumentation for Continuously Monitoring Radioactivity in Effluents” (Ref. 25), and ANSI/Health