MotivationThe CRP on Reference Database for beta-delayed neutron emission has produced new evaluated half-lives T1/2 and delayed-neutron emission probabilities Pn for almost 300 precursors in the fission product mass region. These data need to be validated against macroscopic delayed-neutron properties, such as total delayed neutron yields (delayed nu-bar), average half-lives of the precursors, measured decay curves N(t) and group constants.
The purpose of the meeting was to compare the results of validation studies, reactor simulations and benchmark calculations using the new evaluated database. Participants agreed on the global trend observed with the new data and identified the most important fission product contributors for further careful analysis. New systematics on the precursor data were presented and used to identify outliers in the database. The need for proper treatment of uncertainties including correlations and unknown systematic effects was discussed. Results from measurements of total delayed neutron decay curves for a range of fast energies for U isotopes and other major and minor actinides were presented. New 8-group constants extracted from experimental decay curves, new systematics of average half-lives for U isotopes with predictive power, as well as the energy dependence of delayed nu-bars and the average half-lives extracted from these new measurements were shown and discussed.
Finally, the contents of the final publication of the CRP, related to the above mentioned work were discussed and agreed.
The Agenda is available here.
The minutes of the meeting are available here.