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:
such as 12 hours), (2) the containment activity (gas, particulate, tritium, and iodine) was preplanned, known, and very low (e.g., such that a bounding estimate of the radioactive material discharged indicated there would be no measurable impact relative to typical discharges), (3) the containment activity was monitored (e.g., by sampling or radiation monitoring equipment), and (4) an evaluation was completed to identify a preplanned limiting (or “trigger”) level of activity that would initiate remedial or mitigating action (e.g., close the equipment hatch to control gases escaping containment). In this example, the actions taken (i.e., preplanning and monitoring) before and during the evolution are sufficient to establish control of this discharge. As a result, this type of evolution should not be categorized as an abnormal discharge. 2. Effluent Sampling 2.1 Representative Sampling A typical schedule for radioactive effluent sample collection and analyses appears in NUREG- 1301 and NUREG-1302. Some licensees may have modified these sampling schedules (typically contained in the ODCM) as part of implementing Generic Letter 89-01 as approved by the NRC. Rev. 2 of RG 1.21, Page 18 Additional samples should be obtained as needed to characterize abnormal releases, abnormal discharges, or other significant operational evolutions. Samples should be representative of the overall effluent in the bulk stream, collection tank, or container. Representative samples should be obtained from well-mixed streams or volumes of effluent at sampling points by using proper equipment and sampling procedures. 2.2 Sampling Liquid Radioactive Waste Before sampling, large volumes of liquid waste should be mixed to ensure that sediments or particulate solids are distributed uniformly in the 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