VVER 1000 SBO calculations with pressuriser relief valve stuck open with ASTEC computer code

The objective of this paper is to present the results obtained from performing the calculations with ASTEC computer code for the Source Term evaluation for specific severe accident transient. The calculations have been performed with the new version of ASTEC. The ASTEC V2 code version is released by the French IRSN (Institut de Radioprotection at de surete nucleaire) and Gesellschaft für Anlagen-und Reaktorsicherheit (GRS), Germany.This investigation has been performed in the framework of the SARNET2 project (under the Euratom 7th framework program) by Institute for Nuclear Research and Nuclear Energy – Bulgarian Academy of Science (INRNE-BAS).

► We modelled the ASTEC input file for accident scenario (SBO) and focused analyses on the behaviour of core degradation.
► We assumed opening and stuck-open of pressurizer relief valve during performance of SBO scenario.
► ASTEC v1.3.2 has been used as a reference code for the comparison study with the new version of ASTEC code.