Document: NUREG-0800
Document ID: 8ebc2326-697f-4c5e-986b-6686da2507d0
Document Type: srp
Title: MINIMUM CONTAINMENT PRESSURE ANALYSIS FOR EMERGENCY CORE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600405.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.5
CFR Part: 
CFR Title: 

Content:
pability studies: 6.2.1.5-4 Revision 3 - March 2007 A. Calculations of the mass and energy released during postulated LOCAs should be based on the requirements of 10 CFR Part 50, Appendix K. B. Branch Technical Position 6-2, "Minimum Containment Pressure Model for PWR ECCS Performance Evaluation," delineates the calculation approach that should be followed for a conservative prediction of the minimum containment pressure. Technical Rationale The technical rationale for application of these acceptance criteria to the areas of review addressed by this SRP section is discussed in the following paragraphs: 1. 10 CFR 50.46(a)(1)(i) requires plants to have ECCSs, the cooling performance of which is evaluated for the most severe postulated LOCA. 10 CFR 50.46(a)(1)(i) allows the ECCS evaluation to use a realistic model that describes the behavior of the reactor coolant system during a LOCA. Containment minimum pressure directly affects ECCS performance. Calculation and analysis of this parameter, therefore, is a part of the ECCS performance evaluation. RG 1.157 provides specific methods acceptable to the staff for meeting 10 CFR 50.46(a)(1)(i). This regulation assures that, in a LOCA, the ECCS will perform as predicted, meeting limits on maximum peak cladding temperature, maximum cladding oxidation, and maximum hydrogen generation and maintaining a coolable geometry. 2. 10 CFR 50.46(a)(1)(ii) requires plants to have ECCSs, the cooling performance of which is evaluated for the most severe postulated LOCA. As an alternative to the requirements of 10 CFR 50.46(a)(1)(i), 10 CFR 50.46(a)(1)(ii) requires for the ECCS performance evaluation a model based on 10 CFR Part 50, Appendix K, which provides specific calculation methods for evaluating ECCS performance and significant conservatisms to address the uncertainties of post-LOCA plant behavior. Containment minimum pressure directly affects ECCS performance. Calculation and analysis of this parameter, therefore, is part of the