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:
timating aquatic dispersion to surface water Rev. 2 of RG 1.21, Page 21 bodies. However, the dispersion characteristics may be highly site dependent and local characteristics should be considered when performing dispersion modeling and dose assessments. 3.5 Spills and Leaks to the Ground Surface Liquid releases onto the land surface are transported and diluted as a function of site-specific hydrologic features, events, and processes and properties of the effluent. The releases may temporarily accumulate, pool, or runoff to natural and/or engineered drainage systems. During this process, water may also be absorbed into the soil (addressed in the next paragraph). Regulatory Guide 1.113 discusses the use of simple models to estimate transport through surface water bodies and considers water usage effects. Spills or leaks of radioactive material to the ground surface should initiate characterization of the runoff. The characterization activities should, at a minimum, satisfy (1) the requirements of 10 CFR 50.75(g), as well as (2) the effluent reporting requirements of NUREG-1301 and NUREG-1302 typically associated with planned effluents (e.g., sampling before discharge to unrestricted areas). Refer to Regulatory Positions 8.5.1, 8.5.2, and 8.5.9 in this guide for recommendations on the general format for reporting abnormal releases to on-site areas and abnormal discharges to unrestricted areas. 3.6 Spills and Leaks to Ground Water Liquid radioactive leaks and spills are sometimes released to on-site ground water or discharged to offsite ground water. Leaks and spills onto the ground surface can be absorbed into the soil. Once in the soil, some of the material in the leak or spill may, depending on the local soil properties and associated liquid flux of the release, eventually reach the local water table. The dispersion of this material depends on the local subsurface geology and hydrogeologic characteristics. Liquid releases into the subsurface will be transported as a