Document: NRC Regulatory Guide
Document ID: 5f799693-27fd-4e13-a5e1-4c02f393d90a
Document Type: regulatory_guide
Title: Best-Estimate Calculations of Emergency Core Cooling System Performance + HISTORY –HISTORY 04/2013 – Periodic Review of Revision 0 – Reviewed with issues identified for future consideration 03/1987 – Draft RS 701-4, Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003739584.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.157
CFR Part: 
CFR Title: 

Content:
e uncertainty in that 1For the purpose of this guide, the terms "best-estimate" and "realis tic" have the same meaning. Both terms are used to indicate that the techniques attempt to predict realistic reactor system thermal-hydraulic response. Best-estimate is not used in a statistical sense in this guide. 2IThe term "evaluation model" refers to a nuclear plant system com puter code or any other analysis tool designed to predict the aggregate behavior of a reactor during a loss-of-coolant accident. It can be either best-estimate or conservative and may contain many correlations or models. MIhe term "model" refers to a set of equations derived from funda mental physical laws that is designed to predict the details of a specific phenomenon. 4The term "correlation" refers to an equation having empirically de termined constants such that it can predict some details of a specific phe nomenon for a limited range of conditions. The guides are issued In the following ten broad divisions: 1. Power Reactors 2. Research and Test Reactors 3. Fuels and Materials Facilities 4. Environmental and Siting 5. Materials and Plant Protection 6. Products 7. Transportation 8. Occupational Health 9. Antitrust and Financial Review 10. General Copies of issued guides may be purchased from the Government Printing Office at the current GPO price. Information on current GPO prices may be obtained by contacting the Superintendent of Documents, U.S. Government Printing Office, Post Office Box 37082, Washington, DC 20013-7082, telephone (202)275-2060 or (202)275-2171. Issued guides may also be purchased from the National Technical Infor mation Service on a standing order basis. Details on this service may be obtained by writing NTIS, 5285 Port Royal Road, Springfield, VA 22161. calculation. Methods for including the uncertainty in the comparisons of the calculational results to the cri teria of paragraph 50.46(b), in order to meet the re quirement that there be a high probability that the criteria