Benchmark Eigenvalue Calculations of 233U and/or 232Th Critical Systems

This report summarizes the results of MCNP continuous energy Monte Carlo eigenvalue calculations performed for a variety of 233U and 232Th bearing benchmarks. Calculated eigenvalues, using ENDF/B-VII.0 cross sections, are generally accurate for unmoderated systems. For intermediate and thermal spectrum systems a decreasing trend in calculated eigenvalue is observed with increasing Above-Thermal Fission Fraction. This summary report was prepared as a contribution to an IAEA sponsored Consultants meeting to 'Review Benchmarking of Nuclear Data for the Th/U Fuel Cycle'. (author)