Leak-before-Break and other concepts of Break-Exclusion

Abstract

In the frame of knowledge management, it is important to transfer ideas and explanations regularly. Same terms can have several meanings, and this can be misleading. For break exclusion several national concepts exist: Leak-before-Break (LBB) according to the US Standard Review Plan 3.6.3 (SRP 3.6.3) and “Superpipe” for main steam line (MSL) between containment penetration fixed point and main steam valve (MSV) fixed point, Break Preclusion Concept (BPC) in Germany, French Break Preclusion Concept for European (or Evolutionary) Pressurized Reactor EPR (FA3/TSN), High Integrity Component (HIC) e.g. for EPR in the UK. All concepts with almost the same goal: support demonstration of safety while removing of dynamic effects of break from the design basis and safety demonstration. The meaning of LBB will be recalled. The several concepts for break exclusion will be summarized. An overview of the main efforts of the previous different concepts will be given. Finally, an overview of past and actual R&D with focus on LBB will be shown as well as an outlook of success and remaining challenges.