AGNES Project. The applied codes, their validation, and results of the extended design basis accident analyses for the Paks NPP

The project launched for the Advanced, General, and New Evaluation of Safety (AGNES) deals with the safety of Paks NPP (Hungary) and is now completed. One of the main tasks was the deterministic analyses of design basis accidents extended to issues which are new and important for VVER-type reactors. The applied codes and their validation are summarized showing characteristic time functions to compare measured and calculated data for operational transients occurred at Paks NPP. Then the main results of the analyses are presented. An overall picture of the safety analysis is given by the methodical survey by groups of initial events. Examples for facilitating the comprehension of the most important processes with unexpected results are presented. The AGNES project motivated measures which can further improve the safety and make the high reputation even better. (author). 2 refs., 4 figs., 10 tabs