Post accident heat transfer of relocated fuel on the grid plate in a metal-fuelled FBR

Metal-fuelled fast reactor with U-Pu-Zr ternary alloy as fuel are now being considered with renewed research interest because of its high breeding gain and low doubling time. A Metal Fuelled Test Reactor is being designed at IGCAR. As part of safety analysis, transient thermal response of the grid plate to the decay heat generating molten fuel settling above it is studied by heat transfer computations. A whole core melt-down is assumed. Numerical analysis is done using in-house HEATRAN-1 code to obtain the temperature evolution in the grid plate. The paper summarizes the results obtained for a few possible configurations of core-melt on the grid plate by varying the extent of core-melt spreading on the grid plate and the boundary conditions as parameters. The results indicate that grid plate melt-through can happen in the worst case of whole core-melt settling upon the grid plate in the lumped form. (author)