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:
e number of material heats and weld procedures tested must be adequate to cover the strength and toughness range of the actual plant materials. Peason able lower bound tensile and toughness properties from the plant specific generic data base are to be used for the stability analysis of individual materials, unless otherwise justified. Industry generic data bases must provide a reasonable lower bound for the population of material tensile and toughness properties associated with any individual specification (e.g., A106, Grade B), material type (e.g., austenitic steel) or welding procedures. The number of material heats and weld procedures tested must be adequate to cover the range of the strength and tensile properties expected for specific material specifications or types. Reasonable lower bound tensile and toughness properties from the industry generic data base are to be used for the stability analysis of individual materials. If the data are being developed from an archival heat of material, three stress-strain curves and three J-resistance curves from that one heat of material is sufficient. The tests should be conducted at temperatures near the upper range of normal plant operation. Tests 3.6.3-6 should also be conducted at a lower temperature, which miy represent a plant condition (e.g., hot standby) where pipe break would present safety concerns similar to normal operation. These tests are intenaed only to determine if there is any significant dependence of toughness on temperature over the temperature range of interest. The lower toughness should be used in the fracture mechanics evaluation. One J-R curve and one stress-strain curve for one base metal and weld metal are considered adequate to determine temperature dependence. 1. There are certain limitations that currently preclude generic use of limit load analyses to evaluate leak-before-break conditions for eliminating pipe restraints. However, a modified limit-load analy sis can be used for austenitic