The Management of Beyond Design Basis Accidents with Loss of Cooling at NPPs with WWER

The analysis of Ukrainian guidance on management of beyond design basis accidents at NPP is carried out. International experience on development regulatory documents in this area is considered. Directions for improvements of regulatory documents for NPPs with WWER are determined. For the analysis PSA results of the Ukrainian NPPs are used. It is shown that the primary circuit LOCAs are the dominant contributors of CDF. The set of symptoms for each LOCA group is developed. To develop the management algorithms for each accident group the approach to grouping of accident sequences on the basis of critical configurations of systems is submitted. Examples of necessary changes for improvement of guidance on management of beyond design basis accidents at NPPs with WWER are presented.(author)