IAEA NULIFE VERLIFE - GUIDELINES FOR INTEGRITY AND LIFETIME ASSESSMENT OF COMPONENTS AND PIPING IN WWER NPPs DURING OPERATION

摘要

VERLIFE - ,,Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPPs during Operation" was developed within the 5th Framework Programme of the European Union in 2003 and later upgraded within the 6th Framework Programme ,,COVERS - Safety of WWER NPPs" of the European Union in 2008. This Procedure had to fill the gap in original Soviet/Russian Codes and Rules for WWER type NPPs, as these codes were developed only for design and manufacture and were not changed since their second edition in 1989. VERLIFE Procedure is based on these Russian codes but incorporates also new developments in research, mainly in fracture mechanics, and also some principal approaches used in PWR codes. To assure that VERLIFE Procedure will remain a living document, new 3-years IAEA project (in close co-operation with another project of the 6th Framework Programme of the European Union "NULIFE - Plant Life Management of NPPs") has started in 2009. Within this project, upgrading/updating of the VERLIFE procedure is practically finalized together with the extension by (at least) following procedures: Lifetime of reactor pressure vessel internals 1.Leak-before-break concept for WWER NPPs 2.No-break-zone for WWER NPPs Risk-informed ISI Qualification of NDT procedures Supports of components and piping Together with upgrading of some parts and Appendices, like Evaluation of radiation damage of RPV materials, Fatigue evaluation in primary water environment etc. Final document, was approved by expert groups of the IAEA and NULIFE in June 28-30, 2011, and will be issued as "IAEA/NULIFE Guidelines for Integrity and Lifetime Assessment of Components and Piping in WWER NPPs during Operation". The paper will describe these main principles and also future plans.