Natural convection heat transfer in corium pools: A review work of experimental studies

During a severe accident in nuclear reactors, the core may melt and relocate into the lower head. The decay power in the accumulated melt pool will threaten the integrity of the reactor vessel if there is no effective cooling mechanism. Natural convection plays an important role in determining the heat flux distribution from the debris pool, which is directly relevant to the problem of retention of molten corium inside the lower plenum. Many experimental programs on natural convection heat transfer in corium pools have been performed under different conditions with multifarious research directions, thus a review work on this topic is necessary. Based on three different kinds of geometrical structures, this paper presents a comprehensive literature review of experimental methods and results. Influences of geometry, simulant material, heating method and layer stratification are also discussed. Conclusions and further research directions on natural convection heat transfer in corium pools are proposed.