Mathematic model of molten material in neighbor assembly in fast reactor

Running under the accident condition, the fuel pins of the LMFBR will melt, which then lead to the molten pool and boiling pool scenarios. When the molten material propagates into the neighbor subassemblies, the key point is that whether the neighbor subassembly will be total blocked radially. To make the penetration mechanism in neighbor subassembly clear, a conduction freezing model and a bulk freezing model are established which are validated on the UK SMPR experiment. the result shows that both conduction freezing and bulk freezing mechanism will be the reason of blocking; and when the pressure is low, the conduction is the prior mechanism; and the conduction freezing model is better than bulk freezing model in the prediction of the structure temperature and the crust growth. (authors)