Document: NRC Regulatory Guide
Document ID: a5cfec96-8785-464b-ada8-dc4424b90606
Document Type: regulatory_guide
Title: Quality Assurance for Radiological Monitoring Programs
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML0630/ML063060429.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.15
CFR Part: 
CFR Title: 

Content:
ements in particular. Sampling or measurements should be performed using equipment and methods that yield a result that is representative of the population in the particular environmental media. FIELD DUPLICATES are colocated spatially or temporally and should be collected periodically to check REPRODUCIBILITY. Chapter 10 of MARLAP discusses the field and sampling issues that affect laboratory measurements, including packaging, shipping, and storage of samples. DG-4010, Page 9 Some individual environmental samples are collected simply to confirm that radioactivity levels are below a specified (small) fraction of an established concentration limit. In those cases, the MINIMUM DETECTABLE CONCENTRATION of the method used should be below that specified fraction of the limit. Chapter 20 of MARLAP discusses detection limits, while Appendix C to MARLAP covers the relationship between the desired fraction of the limit that is important to detect and the uncertainty of the measurement method. In some cases, a series of measurement results will be averaged for comparison with BACKGROUND LEVELS or a regulatory limit. For such measurements, an appropriate MQO would be the MINIMUM QUANTIFIABLE CONCENTRATION (see Chapter 20 of MARLAP). For an isolated, well-mixed population, a single sample or measurement may be sufficient. It is more common, however, for spatial or temporal variations to exist. In that case, the frequency of sampling and number of samples and locations will depend on the level of variability and amount of radioactivity (compared with an established risk-informed limit). NUREG-1575, “Multi-Agency Radiation Survey and Site Investigation Manual” (hereafter referred to as MARSSIM), discusses the effect that such variability has on the number of samples that may be appropriate for SURVEYS. In general, the DQO process may be used together with specific statistical designs (EPA QA/G-9S-2006) to optimize the sampling. Continuous sampling or integrated measurements