Evaluation of thermal protection structure of KALIMER-600 reactor vessel

Reactor vessels of Liquid Metal Reactor (LMR) endures creep and thermal fatigue damages due to the high temperature operation condition above 500 .deg. C and the significant temperature gradient in the hot pool free surface regions of reactor vessel. The thermal protection mechanism of LMR reactor vessel should be designed for the high temperature structural integrity. Foreign large-scale LMR reactors adopt the cold sodium circulation mechanism. Hot sodium direct contact mechanism is applied in some LMR reactor for the design improvement. In small scale LMR, the hot sodium isolation mechanism using reactor baffle structure is selected. In this study, the thermal protection structures of foreign LMR reactor vessels are investigated for the high temperature structural integrity of KALIMER-600 reactor vessel and evaluated the proposed thermal protection system by thermal and stress analysis. Air cooling system is more effective for the reduction of thermal damage for KALIMER-600 reactor vessel. In the case of thermal insulation condition outside reactor vessel, the multiple thermal baffle structure can be applied for the reduction of thermal damages