Delayed Neutron Yields for 39 Fissile Systems

Abstract

Accurate knowledge of absolute delayed neutron yields (vd) need to be improved.A method to derive the \( \bar{v}d \) is to do a summation calculation using cumulative fission yields (CU) and delayed neutron branching (Pn) for all precursors. For the “CU” we have taken the data from the JEF-2 file for 39 fissile systems. We have also done the calculations with the “CU” distributed by Wahl (3) for U233T, U235T and F , U238F, PU239T, PU241T.In JEF-2 we have “Pn” data for 156 precursors, almost 100 coming from experimental results and the others from a calculation by Klapdor (8).The results are compared with the last evaluations for the systems already measured. The relative uncertainty is three times higher for the “CU” than for the “Pn“.