Deformation analysis of fuel pins within the wire-wrap assembly of an LMFBR

Abstract Deformation of fuel pins within the wire-wrap fuel assembly of a fast breeder reactor is analyzed by two computational codes, the subchannel deformation analysis code SHADOW and the thermal-hydraulic analysis code DIANA. Coupling these codes makes it possible to analyze percisely the mechanical interactions between all fuel pins in an assembly, and the deviation of coolant temperature distribution in deformed flow channels from the nominal distribution. In this paper, particular attention is paid to the effect on fuel pin deformation of the following factors: dimensional changes in the fuel assembly components, displacement of wrapper tube walls and changes in the radial power gradients.