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:
mechanical induced fatigue is unlikely should be performed. Licensees and applicants must demonstrate that (a) adequate mixing of high and low temperature fluids occurs in the piping so that there is no potential for cyclic thermal stresses, and (b) there is no potential for vibration-induced fatigue cracking or failure. 11. The following steps constitute an acceptable deterministic LBB evaluation procedure: A. Material Specifications i. Identify the types of materials and materials specifications used for base metal, weldments, nozzles, and safe ends. Provide the materials properties including toughness and tensile data, long-term effects such as thermal aging. ii The piping materials toughness (J-R curves) and tensile (stress-strain curves) properties from the actual material heats should be determined at temperatures near the upper range of normal plant operation. B. Materials Properties and Testing i. The specimens used to generate the J-R curves should be large enough to provide crack extensions up to an amount consistent with J/T condition determined by the applicant’s or licensee’s analysis. Because practical specimen size limitations exist, the ability to obtain the desired amount of experimental crack extension may be restricted. In this case, extrapolation techniques may be used as described in NUREG-1061, "Report of the U.S. Nuclear Regulatory Commission Piping Review Committee, Evaluation of Potential for Pipe Breaks," Volume 3, or in NUREG/CR-4575, Papaspyropoulos, V., and others, “Predictions of J-R Curves with Large Crack Growth from Small Specimen Data,” September 1986. ii. The stress-strain curves should be obtained over the range from the proportional limit to maximum load. iii. Preferably, the materials tests should be conducted using archival material for the pipe being evaluated. If archival material is not available, plant-specific or industry-wide generic material data bases can be assembled and used to define the required material