Document: NUREG-0800
Document ID: 9c7116dd-39cd-47a9-b121-dce6f51adc77
Document Type: srp
Title: SUBCOMPARTMENT ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070620009.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.2
CFR Part: 
CFR Title: 

Content:
construction permit (CP) preliminary safety analysis report (PSAR) or a factor of 1.4 should be applied to the peak differential pressure which is calculated in a manner acceptable to the reviewer for the subcompartment structure, and the enclosed components for use in the design of the structure and the component supports. For the review of the operating license (OL) final safety analysis report (FSAR), DC or COL FSAR, the peak calculated differential pressure should not exceed the design pressure. It is expected that the peak calculated differential pressure will not be substantially different from that of the construction permit. However, improvements in the analytical models or changes in the as-built subcompartment may affect the available margin. 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. GDC 4 allows the dynamic effects associated with postulated pipe ruptures in nuclear power units to be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping. Demonstration of extremely low probability pipe rupture requires fracture mechanics analysis to evaluate the stability of postulated through-wall flaws in piping and the ability to detect leakage through a flaw before the flaw grows to an unstable size. The concept underlying such analysis is referred to as “leak-before-break” (LBB). Although LBB technology allows applicants to eliminate consideration of local dynamic effects of postulated pipe ruptures in the design basis of an SSC, the staff will continue to require consideration of the global effects of postulated pipe ruptures for the design of subcompartment enclosures because the global effects provide a convenient and conservative design