Leak-Before-Break Evaluations
Leak-before-break (LBB) evaluations may be used to eliminate consideration of the dynamic effects of pipe rupture in nuclear reactor coolant piping systems, justifying either removal or non-installation of pipe-whip restraints and jet impingement barriers. The NRC's LBB evaluation criteria include demonstrating a low probability of pipe rupture by determining maximum critical flaw size via fracture mechanics analysis; performing thermal-hydraulic analysis to determine leakage for one half the critical size for normal plant operation; and finally demonstrating that there is adequate margin between predicted leakage and plant leakage detection capability. Structural Integrity Associates, Inc. (SI) has performed NRC-accepted LBB evaluations at numerous nuclear plants, including evaluations of piping as small as 6 inches in diameter. SI has also evaluated the effects of weld overlays on LBB performance.For information, please contact This e-mail address is being protected from spambots. You need JavaScript enabled to view it