Development of a Fast Breeder Reactor Fuel Bundle-Duct Interaction Analysis Code BAMBOO: Analysis Model and Validation by the Out-of-Pile Compression Test

To analyze the wire-wrapped fast breeder reactor (FBR) fuel pin bundle deformation under Abundle-duct interaction (BDI) conditions, the Japan Nuclear Cycle Development Institute has developed the BAMBOO computer code. A three-dimensional beam element model is used in this code to calculate fuel pin bowing and cladding oval distortion, which are the dominant deformation mechanisms in a fuel pin bundle. In this work, the property of the cladding oval distortion considering the wire-pitch was evaluated experimentally and introduced in the code analysis. The BAMBOO code was validated in this study by using an out-of-pile bundle compression testing apparatus and comparing these results with the code results. It is concluded that BAMBOO Areasonably predicts the pin-to-duct clearances in the compression tests by treating the cladding oval distortion as the suppression mechanism to BDI.