Document: NUREG-0800
Document ID: 22c713a3-851c-4195-8d52-e7a90bcbeed0
Document Type: srp
Title: LEAK-BEFORE-BREAK EVALUATION PROCEDURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600396.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.3
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for review of material engineering issues related to flaw evaluation and welding Secondary - None I. AREAS OF REVIEW 10 CFR 50, Appendix A, General Design Criterion (GDC) 4 allows the use of analyses reviewed and approved by the Commission to eliminate from the design basis the dynamic effects of the pipe ruptures postulated in Standard Review Plan (SRP) Section 3.6.2. The staff reviews and approves the plant-specific piping system submitted from licensees and applicants to eliminate these dynamic effects. A staff approved leak-before-break (LBB) analysis permits licensees to remove protective hardware such as pipe whip restraints and jet impingement barriers, redesign pipe connected components, their supports and their internals, and other related changes in operating plants. Likewise, requirements for plants under construction or being designed are similarly relaxed. The staff’s review ensures that adequate consideration has been given to direct and indirect pipe failure mechanisms and other degradation sources which could challenge the integrity of piping. The staff reviews the direct pipe failure mechanisms and fracture mechanics analyses. 3.6.3-2 Revision 1 - March 2007 The specific areas of review are as follows: 1. An evaluation over the entire life of the plant of the following for the plant piping system: a. Water hammer d. Corrosion b. Creep Damage e. Fatigue c. Erosion f. Environmental Conditions 2. A deterministic fracture mechanics and leak rate evaluation. The staff reviews the factors which contribute to the initial quality of the piping and the provisions adopted to maintain this quality. In addition, leak detection methods for the reactor coolant are examined to ensure that adequate detection margins exist for the postulated through wall flaw used in the deterministic fracture mechanics evaluation. The staff also evaluates indirect failure mechanisms, as defined in the plant Safety