Document: NUREG-0800
Document ID: 491d2df9-2d17-45db-8189-4f489d8b306c
Document Type: srp
Title: - 15.3.4-2
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550012.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.3.3
CFR Part: 
CFR Title: 

Content:
Revision 3 - March 2007 after protective system actuation; the assumed reactions of reactor system components; the functional and operational characteristics of the reactor protection system in terms of how it affects the sequence of events; and all operator actions required to secure and maintain the reactor in a safe condition. The results of the applicant's analyses are reviewed to assess fuel damage and to ensure that values of pertinent system parameters are within expected ranges for the type and class of reactor under review. Fuel damage is assessed by the methods described in SRP Section 4.2. System parameters to be reviewed include the following: - core flow and flow distribution (including hydraulic instabilities), - channel heat flux (average and hot), - minimum critical heat flux ratio (or minimum critical power ratio), - departure from nucleate boiling ratio, - fuel centerline temperature - vessel two-phase level, - thermal power, - vessel pressure, - steam line pressure (BWR), - main steam flow (BWR), and - feedwater flow (BWR). The sequence of events described in the safety analysis report (SAR) is reviewed by the staff for PWR applications or BWR applications, as appropriate. The staff reviews concentrate on the need for the reactor protection system, the engineered safety systems, and operator action to secure and maintain the reactor in a safe condition. The analytical methods are reviewed by the staff to ascertain whether the mathematical modeling and computer codes have been previously reviewed and accepted by the staff. If a referenced analytical method has not been previously reviewed, the reviewer initiates a generic evaluation of the new analytical model. The values of all parameters used in a new analytical model, including the initial conditions of the core and system, are reviewed. It is the responsibility of reviewer to ensure that the appropriate physics and fuel data have been used in any staff calculations. The staff performs generic