Document: NUREG-0800
Document ID: 6de5c1bb-88d0-4d17-8255-a248a8db304a
Document Type: srp
Title: SUBCOMPARTMENT ANALYSIS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070487.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.2
CFR Part: 
CFR Title: 

Content:
from the design basis when analyses reviewed and approved by the staff demonstrate that the probability of fluid system piping rupture is extremely low. Demonstration of extremely low probability pipe rupture requires fracture mechanics analysis that evaluates the stability of postulated through-wall flaws in piping and the ability to detect leakage through a flaw before the flaw could grow 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 rupture in the design basis of SSC, the staff will continue to require consideration of the global effects of postulated pipe ruptures for the design of subcompartment enclosures since the global effects provide a convenient and conservative design envelope. Containment subcompartments contain high energy piping that, if ruptured, could cause collapse of the subcompartment, generation of missiles, and creation of harsh local environmental conditions. Meeting GDC 4 will help ensure that the structural integrity of containment subcompartments is maintained and that the containment structure and systems are protected from the effects of a high energy line break. 2. GDC 50 requires the containment structure and associated heat removal system to be designed with margin to accommodate any loss-of-coolant accident such that the containment design leak rate is not exceeded. A loss-of-coolant accident potentially causes the greatest pressure surge and release of fission products when compared to any other accident. Since it is the most severe challenge expected, containment and its subcompartments must be designed to definitively withstand this accident. Providing 6.2.1.2-5 DRAFT Rev. 3 - April 1996 design margin will assure that the design can meet all postulated accidents regardless of unanticipated factors. Following GDC 50 will provide assurance that the structural