The CONTAIN-LMR code, which had been originally released from Sandia National Laboratories (SNL) in the U.S.A., has been developed in the Japan Atomic Energy Agency (JAEA) to evaluate ex-vessel severe accident progression in a liquid metal fast reactor (LMFR). As a part of several studies in JAEA, this paper mainly describes a state of the art of a debris-concrete interaction model. Since the debris-concrete interaction might be accompanied with concrete erosion, hydrogen generation and FP release etc., it is one of the most important phenomena in the ex-vessel accident. Stand-alone codes CORCON and VANESA, which were developed for the debris-concrete interaction calculation under a light water reactor (LWR) condition, have been incorporated into the CONTAIN-LMR code. Therefore, CORCON and VANESA have been improved to apply the LMFR condition in JAEA. Main topics of these works are followings; (1) addition of chemical reactions in the sodium pool, (2) consideration of heat conduction through the concrete, and (3) validation using SURC experimental data. As a result, improved CORCON and VANESA can represent the debris-concrete interaction behavior reasonably well.
