A Review of Improvements of Evaluated Minor Transactinium Isotope Neutron Data, Their Qualification by Integral Experiments, and Remaining Data Requirements

The improvements of the neutron data for minor actinide (MINAC) isotopes in uranium-plutonium fuel cycles, the qualification of these data by integral experiments, and remaining data requirements are summarized. In the last 10 yr, there has been a successful worldwide effort to improve the neutron data base of MINAC isotopes. Most of the discrepancies that were observed in 1975 were reduced to an acceptable level in 1984. Tests of nuclear data in thermal and fast reactors before 1984 only revealed a few important discrepancies: the (n,2n) reaction on ²³⁷Np and the neutron capture in ²⁴³Am (mainly in thermal reactors). New measurements by N. V. Kornilov et al. on the ²³⁷Np(n,2n) reaction leading to the short-lived state of ²³⁶Np, presented in May 1984, solve the important discrepancies concerning this reaction.