Analysis of transients for NPP with VVER-440 using the code SiTAP

The report contains results of the analysis of the transients "Loop connection" and "SG tube rupture" for NPP with VVER-440 type reactors. To obtain detailled informations about NPP's dynamic characteristics, various variants of initial and boundary conditions are considered.
Calculation of these transients was performed with use of the code SiTAP developed at the Nuclear Safety Institute of Russian Research Centre "Kurchatov Institute". SiTAP is a multi-functional computer tool for fast analysis of transient and accidental processes of VVER type reactors for engineers working in the field of NPP dynamics.
SiTAP can be used for comparative analysis of several variants of accident scenarios to find out the conditions leading to the most severe consequences from safety point of view. For this cases, additional analyses using best-estimate codes should be carried out.
The results from SiTAP for faulty loop connection leading to a boron dilution accident are intended to be used as boundary conditions for a more detailled analysis by the help of the three-dimensional reactor core model DYN3D, developed in the Research Centre Rossendorf for the simulation of reactivity initiated accidents.