Comparison of Measured Neutron Reaction Rates in Fast Reactor Steels with Calculated Values Using FD5 Data

摘要

Measurements have been made in three Zebra assemblies of the gamma -activity of typical fast power reactor steel components. As a result of corrosion, these become important contributors to the activity of the primary coolant circuit during shut-down. Reaction rates were determined by dissolving irradiated samples and presenting them to a calibrated Ge-Li spectrometer and were expressed relative to Pu239 fission rates in positions near the samples. Calculated values for the reaction-rate ratios have been obtained using fluxes from standard Zebra calculations together with the activation cross-sections recommended for power reactor use. The measured and calculated reactor-rate ratios are compared for all the activities, and bias factors wtih uncertainties of less than 10% produced for the more important contributions to the steel activation. Calculated spectra in the 37-group FD5 structure are presented to allow any new activation cross-section data to be tested against the measured reaction rates. (ERA citation 10:006767)