Development of integrated analysis code for sodium spill accident in multi-cell system in LMFBRs (HISLAC)

An integrated analysis code system HISLAC for a multi-cell sodium spill accident has been developed. HISLAC can analyze sodium spray and pool fires simultaneously and deal with concomitant sodium fires in multi-cells of up to 10. Realistic evaluations of sodium spill accidents have been made practical by considering the cooling effect with water or steam released from the surrounding concrete walls. HISLAC comprises four calculational modules: the sodium combustion calculation module, the mass transfer calculation model, the heat transfer calculation module and the temperature calculation module. Computer CPU time has been fairly shortened by selecting adequate time step sizes individually for each phenomenon. The sensitivity studies indicated that the effects of the time step size and the concrete wall mesh size are important analytical parameters for CPU time reduction