ATWS analyses for VVER-91 concept by the SMATRA code

This year, 7 different offers have been handed in for the fifth nuclear power unit of Finland. One of them is the VVER-91 plant concept of VVO Atomenergoexport (AEE). In cooperation with IVO International planning work has been made in order to fulfil the strict safety criteria of the Finnish authorities. Part of the accident analyses have been made by the Technical Research Centre of Finland (VTT). In Finland there is experience of the VVER type reactors. There are two VVER-440 reactors in Loviisa. A group of analyses made in VTT includes cases that belong to the class of Anticipated Transient Without Scram (ATWS). In this paper, methods and results of some loss of feedwater ATWS analyses are discussed