Document: NUREG-0800
Document ID: d5452e7b-1e61-498b-9e3d-71073b3328ef
Document Type: srp
Title: LEAK-BEFORE-BREAK EVALUATION PROCEDURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0302/ML030280295.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.3
CFR Part: 
CFR Title: 

Content:
iance with the following factors necessary for an acceptable submittal to utilize leak-before-break technology. 1. The leak-before-break evaluation uses design basis loads and is based on the as-built configuration as opposed to the design configuration. Correct location of supports and their characteristics (such as gaps) are verified, as are the weights and locations of components such as valves. Particular attention is given to the reliability of snubbers whose failure could invalidate the stresses used in the fracture mechanics evaluations. 3.6.3-2 Compliance with the technical specifications can be used to demonstrate that snubber failure rates are maintained at a low level. Leak-before break technology cannot be applied to piping supported by masonry block walls unless compliance with Multi-Plant Action B-59 is achieved. 2. Degradation by erosion, erosion/corrosion, and erosion/cavitation due to unfavorable flow conditions and water chemistry is examined. Industry experience for specific piping systems plays a major role in the eval uation of these degradation mechanisms. Additionally, an evaluation of fabrication wall thinning of elbows and other fittings is undertaken to assure that Code minimum wall requirements are met. These evaluations must demonstrate that these mechanisms are not potential sources of pipe rupture. 3. Determination of leakage from a system under pressure involves un certainties and, therefore, margins are needed. Sources of uncertainties include plugging of the leakage crack with particulate material over time, leakage prediction, measurement techniques, personnel, and frequency of monitoring. Leakage detection systems are evaluated to determine that they are sufficiently reliable, redundant, and sensitive so that margin on detection of unidentified leakage exists for the throughwall flaws used in the deterministic fracture mechanics evaluation. Leak detection systems equivalent to Regulatory Guide 1.45 are required for the piping under