Buckling and integral spectrum measurements in Pu239/BeO sub-critical assemblies

Abstract

The materials buckling of four BeO moderated Pu239/aluminium - alloy fuelled systems having BeO/Pu239 atomic ratios of 1707, 2499, 3749 and 4999 have been measured by the exponential method. Relative fission rates of U233, U235 and Pu239 were also measured in the equilibrium spectrum region of the same assemblies. Because of the heterogeneous nature of the assemblies, fine structure corrections were applied. Some calculations using the CRAM diffusion code, and some using the GYMEA code are included.