Material movement in the bundle region during hypothetical accidents in FBR's (SIMBATH out of pile experiments and code development CALIPSO)

The SIMBATH program was initiated to investigate the physical phenomena of transient material movement and relocation during TOP and LOF - driven TOP accidents in LMFBR's. The energy release during the accident is simulated out of pile by the reaction of a thermite mixture. A series of single pin and several 7-pin experiments have been performed using flowing sodium. In all tests the transient material movement in both pin and coolant channel has been recorded by X-ray-cinematography at about 1000 frames per second. For the analysis of the experiments the code CALIPSO has been developed. A comparison between calculation and experimental results will be presented for a typical single pin test