Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPPs (VERLIFE)

Main goal of the project within the European Community 5^th Framework Program was in a preparation, evaluation and mutual agreement of a “Unified Procedure for Lifetime Assessment of Components and Piping in WWER Type Nuclear Power Plants”. This procedure should be based on former Soviet rules and codes, as WWER components were designed and manufactured in accordance with requirements of these codes and from prescribed materials. Then, critical analysis of possible application of some approaches used in PWR type components was performed and such approaches have been incorporated into the prepared procedure as much as possible with the aim of a harmonization of WWER and PWR Codes and procedures. Preparation of a Unified Procedure for WWERs operating in Finland, Czech Republic, Slovak Republic, Hungary and Bulgaria will increase the level of lifetime/integrity evaluation in these countries and will help to elaborate a unified approach and fully comparable results between individual plants and countries. Then, harmonization with PWR codes allows to obtain results that will be comparable, reliable and more sophisticated as similar approaches will be used in both types of reactors. The paper described main principles, approaches and achievements of the “Unified Procedure...”.