Development and validation of the MAVR-TA code for analyzing the release and transport of fission products during a severe accident at a VVER NPP. Part 3 – Modelling of the release of fission products from the melt

Abstract

The MAVR-TA code is designed for modelling of fission product release from fuel and melt, as well as fission products transport in the primary circuit and in the containment during a severe accident at a NPP with VVER. The third part of the work provides information on the models of the MAVR-TA code related to modelling of fission products release from the melt due to evaporation from the melt surface and due to molten core concrete interaction. The paper describes the models and approximations implemented in the code, as well as experimental tests used to validate the models of fission product release in the MAVR-TA code. The results obtained during validation are described and analyzed.