Document: NRC Regulatory Guide
Document ID: f4c5fb1d-efb9-4168-9804-5ad3f6f64d06
Document Type: regulatory_guide
Title: Reporting Procedure for Mathematical Models Selected To Predict Heated Effluent Dispersion in Natural Water Bodies
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML0037/ML003739535.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.4
CFR Part: 
CFR Title: 

Content:
May 1974 U.S ATOMIC ENERGY COMMISSION REGULATORY ( DIRECTORATE OF REGULATORY STANDARDS REGULATORY GUIDt 4.4 REPORTING PROCEDURE FOR MATHEMATICAL MODELS SELECTED TO PREDICT HEATED EFFLUENT DISPERSION IN NATURAL WATER BODIES A. INTRODUCTION In accordance with Appendix D, "Interim Statement of General Policy and Procedure: Implementation of the National Environmental Act of 1969"' of 10 CFR Part 50, "Licensing of Production and Utilization Facilities," and proposed Section 51.5 of 10 CFR Part 51, the Commission prepares an environmental impact statement for consideration in the licensing actions of certain nuclear facilities. In addition, each applicant for a permit to construct such a facility must submit an "Applicant's Environmental Report-Construction Permit Stage" (§51.20, 10 CFR Part 51), which discusses the probable environmental impact of the proposed facility. Should the proposed facility be a nuclear power plant, thermal effects from the release of condenser cooling water or dosed cycle blowdown to a natural water body can have a significant impact. Direct, quantitative measurements of environmental impact due to thermal discharge in natural water bodies an not possible during the preconstruction stages of proposed plants. Consequently, reasonable approximations to the interactions of thermal discharfs with the environment must be adopted .to provide a basis for impact aseument. The applicant may select mathematical models as one such means of approximation. Section 5.1 of Regulatory Guide 4.2, "Preparation of Environmental Reports for Nuclear Power Plants," suggests that details of mathematical modeling methods should be given in an appendix to the Environmental Report. This guide describes a procedure acceptable to the Regulatory staff for completing such an appendix. B. DISCUSSION As applied to nuclear power plants, thermal discharge mathematical modeling attempts to accurately 3UIDE simulate the dispersion of cooling water effluent within the receiving