Abstract: The design of core catcher of Tianwan nuclear power station comprehensively incorporates the exvessel containment facility,the cooling of the metallic surfaces of corium containment by passive water,reactor vessel melt-through and corium relocation into the core catcher is executed with the computer codes the improvement of corium properties by the sacrificial material and reducing density of heat flux.Analysis of the dynamic process of core degradation,debris relocation within the reactor vessel,molten pool formation,SCDAP/RELAP and MELCOR,and the reaction among the corium,the sacrificial material,and the metal material,as well as the thermal and hydraulic characteristic of heat exchanger is experimentally studied.