Evaluation of WWER-440 Radiation Embrittlement Data Using the Semi-Mechanistic Model

The correct integrity assessment of reactor pressure vessel (RPV) is a main issue of NPP safety operation and the formula used up to now for WWER-440 material radiation embrittlement prediction does not always allow precise and conservative assessment. A large number of data points show systematically higher ATk experimental values when compared with prediction. Besides, a wide scatter is observed in correlation between measured and predicted data. Statistical methods are normally used for the evaluation of databases obtained on test results of irradiated Charpy specimens. In the present paper the statistical analysis of existing WWER-440 radiation embrittlement weld and base metal database has been carried out. In particular, the semi mechanistic model, which is an alternative model which based on additive contribution of three key mechanisms for RPV material radiation damage: direct matrix damage, precipitation (mainly copper) and element segregation (mainly phosphorus) is used in this paper for the WWER-440 RPV database evaluation and parameters are estimated.

ZHURKO D.;  KRASIKOV E.;  KRYUKOV A.;  DEBARBERIS Luigi; 

2006-09-26

EC-JRC-IE

JRC34041

https://publications.jrc.ec.europa.eu/repository/handle/JRC34041,