Verification and validation of fast systems with ENDF/B data

An extensive and systematic verification, validation and data testing effort using diverse Monte Carlo and deterministic methods with ENDF/B data (Versions V.2 and VI.5) is in progress. Methods verification is obtained by comparing independent methods, including continuous-energy Monte Carlo methods using the VIM and MCNP codes and 1D and 2D transport calculations using multigroup cross section sets generated with the ETOE-II/MC-2 system combined with the TWODANT code. Each of these code systems relies on independently processed data libraries. Inter-comparison of these results is used for verification. Further verification is achieved by comparing and plotting the point-wise cross section libraries of VIM and MCNP. Where possible, benchmark models are taken from both the ICSBEP Handbook and the CSEWG Benchmark Specifications. Inter-comparison of these results quantifies the generally small differences between these references. Calculations are repeated with both ENDF/B-V.2 and ENDF/B-VI.5 data. Inter-comparison of these results quantifies their data dependence. Analyses of criticality and reaction rate ratios are used for the validation and data testing. Calculated neutron balances and neutron energy spectra are also obtained and analyzed to explain the observed differences