A simplified modeling technique for the thermal analysis of spent nuclear assemblies

A major design concern of a cask for the transport of spent fuel assemblies is the determination of the maximum fuel pin temperature. Normally the determination of the maximum steady state fuel pin temperature requires the thermal analysis (two-dimensional or three-dimensional) of the cask to be performed in conjunction with the fuel assemblies. This, in general, would require extensive effort and computer time. However, by performing a sensitivity analysis for fuel pin temperature for various boundary conditions it was possible to decouple the heat transfer analysis of the cask from that of the fuel assemblies. This paper presents the scaling law that was obtained for maximum fuel pin temperature as a function of emissivity, heat generation rate and assembly wrapper temperature for hex-shaped fuel assemblies