Validation and Comparison of KENO V.a and KENO-VI

This report documents the validation and comparison of KENO V.a and KENO-VI using the SCALE 27-group ENDF/B-IV and 238-group ENDF/B-V cross-section libraries against critical experiments. Experiments considered were primarily high- or low-enriched uranium systems. The results indicate that KENO V.a and KENO-VI Monte Carlo Criticality Programs accurately calculate a broad range of critical experiments. A number of the calculations showed a positive or negative bias in excess of 1 1/2% in k-effective (k{sub eff}). Classes of criticals that show a bias include 3% enriched green blocks, highly-enriched uranyl fluoride slab arrays, and highly-enriched uranyl nitrate arrays. If these biases are properly taken into account, KENO V.a and KENO-VI can be used with confidence for the design and criticality safety analysis of uranium-containing systems. KENO V.a and KENO-VI calculate the same k{sub eff} for a system within statistics and thus may be used interchangeably as long as the geometry of the problem can be modeled