The ASTEC integral code has been jointly developed by IRSN and GRS over the last several years for evaluating the various scenarios which may occur in a severe accident (SA) in a Light Water Reactor, the performance of mitigation measures and engineering devices, and eventually the source of radioactive products that may be released into the environment. The code should become the reference European integral code in the SARNET current Network of Excellence of the 6th Framework Programme. The version 1.2 models most of the physical phenomena near or at the state of the art. Important efforts are being made on validation by covering more than 30 reference experiments. Some examples of validation on the TMI2 accident and on VANAM M3 experiment, performed in the German Battelle facility, are shown. Twenty-seven SARNET partners are comparing the code to experiments and benchmarking it with integral codes on plant applications on PWR and VVER. Results of a calculation of a loss of steam generator feedwater sequence on a French 900 MWe PWR, from the initiating event up to the aerosol and iodine behaviour in the containment, are presented. Main efforts in 2006-07 will focus on multiplication of calculations of different reactor sequences and on modeling of reflooding of intact and degraded cores. In parallel, the advanced latest models of the ICARE2 core degradation mechanistic code (IRSN) are being implemented within ASTEC. Long-term improvements will concern the remaining safety key-issues such as corium coolability, iodine species behaviour in the primary circuit, long-term MCCI. Specifications to extend the application scope to other reactors than PWR and VVER are being prepared in SARNET frame.
(1) : GRS