Considerable efforts are being continuously made by IRSN and GRS on the development of the source-term evaluation code ASTEC, ranging from the initial stage of core uncovery to the final situation of long-term corium stabilization, long-term containment integrity, and fission product retention or release to environment. Between 1999 and 2003, ASTEC has progressively reached a larger European dimension through projects of the European Commission Framework Program. The SARNET European Network of Excellence, coordinated by IRSN, has started in April 2004. It will provide an appropriate frame for achieving a sustainable integration of the European research capacities on Severe Accidents. SARNET will clearly become a reference in terms of research priorities in the field of Severe Accidents. In SARNET frame, a substantial effort is being made to disseminate ASTEC and to perform jointly-executed research activities with the ultimate objective of providing physical models for integration into ASTEC and making it the European reference integral code. These activities will focus on key safety issues such as: reflooding of a degraded core and in-vessel corium coolability; molten-corium-concrete interaction, particularly regarding long-term corium coolability; fission product behavior, especially iodine chemistry in circuits and containment; effects of high burn-up and MOX fuel on core degradation and fission product release. In parallel, the scope of application of the ASTEC code will be extended to reactor types other than PWR.
(1) : GRS