Application of the Melcor 1.8.5 code to the analysis of severe accident scenarios for a VVER-1000/320 NPP analogous to Temelin

A research project started at University of Pisa supported by Austrian government to evaluate (independently and in addition to Czech Republic) the Safety and the safety margins of the Temelin Nuclear Power Plant in operation in Czech Republic at the borders with Austria. Temelin is a Soviet Union designed and built WWER-1000 (Water-cooled, Water –moderated Energy Reactor). University of Pisa was selected by Austrian government because of the competence in nuclear technology and of independence from (EU and Russian) nuclear industry. The present document deals with the analysis of selected severe accident scenarios by the MELCOR code. MELCOR code was developed at Sandia National Laboratories in New Mexico, US. The results of the activity, including the participation in joint Austria – Czech Republic meetings and Workshops contributed to smooth the political (and ‘technological’) tension between the two Countries.