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:
erican 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 Physics Society (HPS) N13.1-1999, “Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities” (Ref. 26), the documents contain the general principles for designing and conducting monitoring programs for airborne effluents. The cited references also contain recommendations for obtaining valid samples of airborne radioactive material in effluents and the guidelines for sampling from ducts and stacks. Licensees should use the appropriate licensing documents to evaluate the validity of representative samples (e.g., evaluate the potential for inaccurate sampling of gaseous effluents that may bypass a particulate filter and collect on an iodine collection cartridge) and to identify any inaccurate sample analyses configurations or counting geometries. 2.4 Sampling Bias Sampling and storage techniques that could bias quantitative results for effluent measurements should be evaluated and corrections applied as necessary. These biases include inaccurate measurement of sample volumes resulting from pressure drops in long sample lines and loss of particulates or iodine in sample lines resulting from deposition or plate-out. Samplers for gaseous waste should be evaluated for particulate deposition using ANSI N13.1-1999 (Ref. 26) or equivalent. Rev. 2 of RG 1.21, Page 19 2.5 Composite Sampling Composite samples should be representative of the average quantities and concentrations of radioactive materials discharged in liquid and gaseous effluents. Composite samples should be collected in proportion to the effluent flow rate 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