Criticality Calculations for Uniform Water-Moderated Lattices

A procedure for calculating the neutron multiplication factor and few-group constants for water-moderated reactors has been developed. The intent of this development was to produce a calculational procedure which could be used with confidence in the engineering design of water-moderated reactors. Analytic procedures that require large amounts of computer time were excluded from consideration. The proposed procedure includes a heterogeneous treatment of the fast-fission effect, resonance absorptions and the thermal utilization. The results of the procedure agree well with more rigorous calculations requiring orders of magnitude more computer time. The procedures have been applied to 116 U-metal and UO₂ experimental lattices covering a wide range of parameters. The multiplication factor is calculated for all cases with a standard deviation about the mean of 0.86%.