Validation for multi-physics simulation of core disruptive accidents in sodium-cooled fast reactors by COMPASS code

A five-year research project started in FY2005 to develop a code based on the Moving Particle Semi-implicit (MPS) method for detailed analysis of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). The code is named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis). Separated phenomena in CDAs are focused on: namely, (1) failure of fuel pins, (2) dispersion and freezing of molten core, (3) boiling of molten core pool, (4) failure of duct walls, (5) dynamic behavior of low energy disruptive core, (6) relocation of molten core, and (7) debris coolability. In the validation process of COMPASS, calculations using SIMMER-III are carried out to give boundary conditions and to provide reference results. In this paper, FY2007 results in the project are summarized. The validation is progressing corresponding to the separated phenomena in CDAs of SFRs. Dispersion and freezing of molten core was calculated to compare with the experimental data of GEYSER. Molten core material flowed up with freezing on the pipe inner surface. As a molten pool behavior, CABRI-TPA2 experiment was analyzed, where a sphere of solid steel was surrounded by solid fuel. Heat was injected to cause melting and boiling of the steel sphere. SCARABEE-BE+3 test was analyzed by COMPASS as a validation of failure of duct walls. Two types of damages of the duct walls, thermal and mechanical damages, were shown. (author)