ENDF/B-VII nuclear data libraries for SCALE 6

Version 6 of the SCALE code system includes new ENDF/B-VII PW and MG nuclear data libraries for a variety of applications, including reactor lattice physics calculations, source term analysis, and spent fuel characterization. The codes and nuclear data libraries have been validated against critical experiments and isotopic measurements. Overall, LEU critical experiments are computed better with V7 than with earlier versions of ENDF/B. The k _eff values calculated with V7 for MOX criticals generally agree within the experimental error of measured results, except for the MCT-012 series which shows a wide variation compared to the values given in the ICSBEP. Much of the discrepancy is likely caused by uncertainties in the experiment specifications. Numerous HEU and Pu critical benchmarks were also analyzed and show similar good results. For the spent fuel isotopic measurements studied here, the major actinide concentrations are computed with the ENDF/B-VII libraries to an accuracy similar to that obtained with earlier SCALE computations using ENDF/B-V, which is acceptable agreement considering the experimental uncertainty. Curium isotopic results are greatly improved with ENDF/B-VII. Several important samarium, europium, and gadolinium fission product isotopes are also calculated significantly better with V7.