Document: NUREG-0800
Document ID: 8940dd69-2a01-4786-bbe6-f71794a60643
Document Type: srp
Title: LOSS-OF-COOLANT ACCIDENTS RESULTING FROM SPECTRUM OF POSTULATED PIPING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350156.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.5
CFR Part: 
CFR Title: 

Content:
BREAKS WITHIN THE REACTOR COOLANT PRESSURE BOUNDARY REVIEW RESPONSIBILITIES Primary - Reactor Systems Branch (RSB) Secondary - Accident Evaluation Branch (AEB) I. AREAS OF REVIEW Loss-of-coolant accidents (LOCA) are postulated accidents that would result from the loss of reactor coolant, at a rate in excess of the capability of the normal reactor coolant makeup system, from piping breaks in the reactor coolant pressure boundary. The piping breaks are postulated to occur at various locations and include a spectrum of break sizes, up to a maximum pipe break equivalent in size to the double-ended rupture of the largest pipe in the reactor coolant pressure boundary. Loss of significant quantities of reactor coolant would prevent heat removal from the reactor core, unless the water is replenished. General Design Criteria 35 (Ref. 1) requires each pressurized water reactor (PWR) and boiling water reactor (BWR) to be equipped with an emergency core cooling system (ECCS) that refills the vessel in a timely manner to satisfy the requirements of the regulations for ECCS given in 10 CFR Part 50, §50.46 and Appendix K to 10 CFR Part 50 (Ref. 2) and the applicable general design require- ments discussed in SRP Section 6.3 (Ref. 3). The analysis of ECCS performance has an impact on the design of the piping and support structures for the reactor coolant system, the design of the steam generators, the containment design, and the possible need for pump overspeed protection. The review of the applicant's analysis of the spectrum of postulated loss-of-coolant accidents is closely associated with the review of the ECCS, as described in SRP Section 6.3. As a portion of the review effort described in this SRP section and in SRP Section 6.3, RSB evaluates whether the entire break spectrum (break size and location) has been addressed; whether the appropriate break locations, break sizes, and initial conditions were selected in a manner that conservatively predicts the consequences of the