Document: NUREG-0800
Document ID: ed948426-dd77-4047-be5e-2b7ab22de3f5
Document Type: srp
Title: FEEDWATER SYSTEM PIPE BREAK INSIDE AND OUTSIDE CONTAINMENT (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550009.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.2.8
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of transient and accident analyses for PWRs/BWRs Secondary - None I. AREAS OF REVIEW The steam and water release from a postulated feedwater line break results in a loss of secondary coolant which may result in a reactor system cool-down (by excessive energy discharge through the break) or a reactor system heat-up (from the loss of reactor system heat sink). A major feedwater line rupture is defined as a feedwater line break large enough to prevent the addition of sufficient feedwater to the steam generators to maintain shell side fluid inventory in the steam generators. If the break is postulated in the feedwater line between the isolation valves and the steam generator, fluid from the steam generator also is discharged from the break. (A break upstream of the feedwater isolation valves would affect the reactor system only as a loss of feedwater. This case is covered by SRP Section 15.2.7, “Loss of Normal Feedwater Flow.”) If a feedwater line rupture causes the water in the steam generator to be discharged through the break, the water will not be available for decay heat removal after reactor scram. The break location and size may prevent addition of any feedwater to the affected steam generator. An auxiliary feedwater system (AFWS) makes feedwater available to remove decay heat to prevent 15.2.8-2 Revision 2 - March 2007 over-pressurization of the reactor system. In one group of design, such as AP1000, the passive RHR (PRHR) may provide a safety related means of decay heat removal. The specific areas of review are as follow: 1. Evaluation of the applicant's postulated initial core and reactor conditions pertinent to the feedwater line break. The results of the analyses are reviewed for whether the values of pertinent system parameters, addressed in subsection II of this Standard Review Plan (SRP) section, are within expected ranges. The parameters of importance for these transients