Numerical simulation of PHEBUS FPT-3 experiment by using COMPASS code

As a part of the integrated severe accident code development project in Korea, KAERI (Korea Atomic Energy Research Institute) has been developing the stand-alone severe accident analysis code, COMPASS (COre Meltdown Progression Accident Simulation Software), which simulate the in-vessel severe accident phenomena including the core heat up, material melting and relocation, corium behavior in lower plenum, vessel failure. For the purpose of COMPASS code validation, the numerical simulation for PHEBUS FPT3 experiment has been conducted. In COMPASS code, the core and surrounding structure in a test section are consisted of two-dimensional node system, and the mass and energy equations are established for the main component in a core and surrounding structures. The temperature evolution of core and surrounding structure at the various location of a test section are pursued and compared with the experimental data as well as the numerical results of MELCOR code. The hydrogen generation rate and the final mass distribution are compared among the experimental data and the numerical results of COMPASS and MELCOR. Generally, COMPASS and MELCOR codes are well predicting the temperature evolution and hydrogen generation rate in the experimental. And, COMPASS are predicting a little bit smaller mass relocation compared with experimental data, while MELCOR has a larger mass relocation. (author)