Document: NUREG-0800
Document ID: 645cc743-c9e4-428c-b05d-ead2517eb3fa
Document Type: srp
Title: DETERMINATION OF RUPTURE LOCATIONS AND DYNAMIC EFFECTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070315.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.2
CFR Part: 
CFR Title: 

Content:
ASME Paper 69 HT-31, August 6, 1969. 7. NUREG-0609, "Asymmetric Blowdown Loads on PWR Primary Systems," resolution of Generic Task Action Plan A-2. 3.6.2-13 DRAFT Rev. 2 - April 1996 BRANCH TECHNICAL POSITION EMEB 3-1 (FORMERLY BTP MEB 3-1)50 POSTULATED RUPTURE LOCATIONS IN FLUID SYSTEM PIPING INSIDE AND OUTSIDE CONTAINMENT A. BACKGROUND This position on pipe rupture postulation is intended to comply with the requirements of General Design Criteria 4 of Appendix A to 10 CFR Part 50 for the design of nuclear power plant structures and components. It is recognized that pipe rupture is a rare event which may only occur under unanticipated conditions, such as those which might be caused by possible design, construction, or operation errors; unanticipated loads; or unanticipated corrosive environments. Our observation of actual piping failures have indicated that they generally occur at high stress and fatigue locations, such as at the terminal ends of a piping system at its connection to the nozzles of a component. The rules of this position are intended to utilize the available piping design information by postulating pipe ruptures at locations having relatively higher potential for failure, such that an adequate and practical level of protection may be achieved. Subject to certain limitations, General Design Criterion 4 allows dynamic effects associated with postulated pipe ruptures to be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate the probability of fluid system piping rupture is extremely low under design basis conditions. These analyses are commonly referred to as “leak- before-break” analyses. The application of leak-before-break to piping system design is reviewed in accordance with SRP Section 3.6.3 (later).51 In the ABWR and System 80+ design certification FSERs the Staff accepted an exemption to 10 CFR 100 Appendix A that the design of all safety-related SSCs consider OBE loads. In SECY 93-087