Uncertainty quantification of total delayed neutron yields and time-dependent delayed neutron emission rates in frame of summation calculations

Abstract

To contribute to further improvements of the nuclear data related to delayed neutron emissions, uncertainty quantification calculations for total delayed neutron yields, ν¯d, and time-dependent delayed neutron emission rates after a burst fission have been carried out. Those are based on the summation calculations with fundamental nuclear data taken from JENDL/FPD-2011 and a partly-modified JENDL/FPY-2011. Sensitivities required for uncertainty propagation calculations are obtained efficiently by the help of the generalized perturbation theory for time-dependent problems.It is found that ν¯d and neutron emission rates after a burst fission obtained in frame of summation calculations generally agree with the JENDL-4.0 evaluations within 2σ of nuclear data-induced uncertainty. While further improvements of the fundamental nuclear data are crucial, application of the summation calculations to actual problems is now not unrealistic, and further efforts from the application side are helpful.