Uncertainty Estimation of Neutronics Parameters in Minor Actinides Transmutation Fast Reactors

The uncertainties of neutronics parameters such as effective multiplication factors, sodium void reactivity and minor actinides transmutation rates in minor actinides transmutation fast reactors are estimated using sensitivity analyses. The method to estimate the minor actinides transmutation rates has been introduced. The uncertainties are estimated for a 750 MWe class fast reactor with minor actinide content of 6.5%. From numerical calculations it is seen that the uncertainties for the multiplication factor and sodium void reactivity are slightly increased with the addition of minor actinides, but the main difference is the components of the uncertainties. The U-238 inelastic scattering cross-section has a large contribution for the uncertainty of the multiplication factor, and the Na-23 inelastic cross section has a large contribution for the uncertainty of the sodium void reactivity in the reactor with minor actinides. The uncertainties of the total minor actinides transmutation rates are estimated to be about 3%. It is seen that the uncertainties of the transmutation rates of Am-243 and Cm-244 are rather large. (authors)