Data testing ENDF/B IV dosimetry data

Phase II testing of the Evaluated Nuclear Data File/B Version IV (ENDF/B IV) neutron cross section data set for dosimetry applications was updated. The update involved folding energy-dependent reaction cross section data with the updated version of the neutron spectrum for the Coupled Fast Reactivity Measurement Facility (CFRMF). The new spectrum was calculated from transport theory by using a full core representation of the CFRMF and ENDF/B IV data. The derived integrated reaction rates were compared with respective measured values to determine the accuracy and limitations of the ENDF/B IV dosimetry data. The CFRMF is designated as a ''benchmark'' neutron field for data testing, not only on dosimetry data, but also fission product and actinide cross section data as well. A comparison of the updated version of the CFRMF spectrum, with the earlier spectrum is shown. The most pronounced change between the two spectra occurs at energies greater than 1 MeV where the new spectrum is consistently higher than the older version. This change has resulted in a significant improvement in the data testing results for the primary threshold reactions. Calculated reaction rates from three versions of the CFRMF spectrum are compared to the measured values. ENDF/B IV dosimetry reaction data were used in all calculations. 1 figure, 2 tables