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:
ion resistance of piping be demonstrated can rely on investigations of the frequency and degree of corrosion in the specific piping systems under review. Modification to operating condi tions (as ýor example, controlling water chemistry) or design changes (as for example, replacing piping material) are measures that can be taken to improve corrosion resistance in piping. The staff recognizes that re medial residual stress improvement treatments are effective in reducing susceptibility to intergranular stress corrosion cracking. However, remedial stress improvement treatments of non-conforming materials alone do not provide a sufficient basis to support leak-before-break eval uations. The staff would, however, review such evaluations on a case-by-case basis if hydrogen water chemistry were used as an adjunctive measure with the remedial stress improvement treatments. The licensees' practices with regard to facility water chemistry would be an additional factor considered in the review. Non-conforming piping with any planar flaws in excess of the standards in the ASME Code, Section XI, Tables IWE-3514-1 and -2, would not be permitted to use leak-before-break anal yses. However, non-conforming piping that has been treated by two mitigating methods may qualify for leak-before-break if the piping contains no flaws larger than those permitted by the ASME Code Section XI without repair. 7. An assessment of potential indirect sources of pipe ruptures is required to demonstrate that indirect failure mechanisms defined in the plant FSAR are remote causes of pipe rupture. Compliance with the snubber surveillance requirements of the technical specifications assures that snubber failure rates are acceptably low. 8. The reviewer determines that the piping material is not susceptible to brittle cleavage-type failure over the full range of system operating temperatures (that is, the material is on the upper shelf). 9. The reviewer determines that the system(s) under evaluation do