Document: NRC Regulatory Guide
Document ID: 42f2dcf0-38ba-4f75-84d4-e60f4bbf9162
Document Type: regulatory_guide
Title: Assessment of Abnormal Radionuclide Discharges in Ground Water to the Unrestricted Area at Nuclear Power Plant Sites Appendix-Simple Ground Water Model for Estimating Offsite Tritium Activity Flux + HISTORY - HISTORY 12/2015 – DG-4025-Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1523/ML15237A388.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.25
CFR Part: 
CFR Title: 

Content:
d the vertical plane of the unrestricted area (surface or subsurface) (RG 1.21). flux The volumetric or mass discharge per unit cross-sectional area of medium over time (solids plus pores); called the Darcian flux when applied to water movement (ANSI/ANS 2.17-2010). ground water All water in the surface soil, the subsurface soil, or any other subsurface water. Ground water is simply water in the ground regardless of its quality, including saline, brackish, or fresh water. Ground water can be moisture in the ground that is above the regional water table in the unsaturated (or vadose) zone, or ground water can be at and below the water table in the saturated zone (RG 1.21). DG-4025, Page 11 residual radioactivity Residual radioactivity means radioactivity in structures, materials, soils, ground water, and other media at a site resulting from activities under the licensee’s control. This includes radioactivity from all licensed and unlicensed sources used by the licensee, but it excludes background radiation. It also includes radioactive materials remaining at the site because of routine or accidental releases of radioactive material at the site and previous burials at the site, even if those burials were made in accordance with the provisions of 10 CFR Part 20. uncontrolled discharge An effluent discharge that does not meet the definition of a controlled discharge. See the definition of controlled discharge (RG 1.21). uncontrolled release An effluent release that does not meet the definition of a controlled release. See the definition of controlled release (RG 1.21). unsaturated zone The zone immediately below the land surface where the pores contain both water and air, but are not totally saturated with water. These zones differ from an aquifer, where the pores are saturated with water. The unsaturated zone is synonymous with the vadose zone (U.S. Geological Survey Water Science Glossary, Ref. 31). vadose zone See unsaturated zone. DG-4025, Page 12 REFERENCES3 1.