APPLICATION OF LEAK-BEFORE-BREAK CONCEPT IN VVER-440-230 RESULTS AND CONSEQUENCES FOR TACIS-PROGRAM-91 1.2/

The project TACIS 91/1.2 'Primary Circuit Integrity, Application of Le ak-Before-Break (LBB) Concept' was performed within the scope of the T ACIS-program (Technical Assistance for the Community of Independent St ates) of the European Community. The application of the LBB concept wa s carried out for the primary piping (main coolant lines (MCL) and sur gelines (SL)) of the first generation of the Russian VVER NPP's of the type VVER 440/230 of the nuclear power plants Kola 1 and 2 (K1, K2) a nd Novovoronesh 3 and 4 (NV3, NV4). The work was performed by the Cons ultant (Siemens, EdF, Framatome) and Russian subcontractors (headed by Vniiaes). The paper describes the comparison of the relevant safety c oncept, the scope of the LBB-program, the applied LBB-procedures (Germ an and NUREG 1061 procedure), the results obtained and the recommendat ions (analysis of seismicity, if necessary LBB analysis taking into ac count additional optimized seismic supports and their installation for NV3 and 4 adaption of inservice inspection (ISI) and leak monitoring systems (LMS)). Proposals have been made for future work to improve th e safety of these plants. This project was financed by the European Co mmunity's TACIS Programme, which provides grant finance for know-how t o foster the development of marked economies and democratic societies in the New Independent States and Mongolia. (C) 1997 Elsevier Science S.A.