Document: NRC Regulatory Guide
Document ID: c9ebcbb0-96c4-4d29-be51-5acae9cc858a
Document Type: regulatory_guide
Title: Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of Implementing Appendix I (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.113
CFR Part: 
CFR Title: 

Content:
om normal releases from nuclear power plants, it is necessary to locate water users, identify types of uses, and estimate usage to a distance of 50 miles from a site. Because of high usage rates along many streams and estuaries, it is also necessary to identify the effects of water usage on the spatial and temporal distribution of flows. In addition, water usage upstream of a nuclear power plant can alter flows at or downstream of the plant. The following is an acceptable meth odology to evaluate water usage and the consequences thereof on streamflows. This methodology provides a realistic evaluation of the liquid transport of normal releases of radionuclides from nuclear power plants along streams and estuaries. a. Users A schematic diagram of the river basin that locates the following features in relation to the plant site should be prepared: (1) surface water uses* upstream and downstream of the plant site, (2) major tributaries and their junctions, (3) streamflow gaging stations (including their period of record), and (4) major reservoirs and diversions upstream and downstream of the plant site. Approximate contributing drainage areas and types of water use for all points identified %hould be shown on the diagram or tabulated separately. An example schematic diagram Is shown SFigure 16. From the diagram, key diversion and streamflow stations should be selected to provide the basis for establishing reasonable spatial and temporal distributions of runoff patterns, upstream and downstream of nuclear power plant sites. Historical streamflows at major mainstem and tribu tary locations should be adjusted for historical diversions and reservoir effects to produce "natural" flows (e.g., flows independent of reservoir and diversion effects). Missing streamflow data (i.e., gaps in records) at critical stations may subsequently be synthesized by direct cor relation with nearby streamflow stations or by statistical correlation with many stations using models such as "HEC-4,