In-vessel transient analysis code INTRA for ITER accident analyses

The INTRA code is being developed to analyse integrated behaviours such as pressurisation, chemical reactions and temperature transients in case of accidents inside the plasma chamber and adjacent rooms of ITER. INTRA is based on the results of extensive research on containment safety analysis work for fission nuclear power plants. It is derived from the code RALOC, which was validated on a large scale and used in licensing procedures. INTRA is specified as an ITER reference code for in-vessel reactions and transport and distribution modelling within the vacuum vessel and its surroundings. First comparisons of INTRA calculations with the Japanese ICE/LOVA experiment shows good agreement. Results from one of the ITER category IV reference accident sequences also indicate, by inter code comparisons with the MELCOR code, that INTRA will be an important code for NSSR-2 analyses.