Neutron Cross-Section Evaluations of Fission Products in the Fast Energy Region

Abstract

Neutron cross-sections for 19 high priority fission products were evaluated from the unresolved resonance energy region up to 20 MeV. Evaluation procedures included optical model parameter search, followed by complete nuclear reaction model calculations with parameters carefully validated against experimental data. Calculations were done with the code Empire using the following models: spherical optical and coupled-channels deformed optical, multistep direct and multistep compound, preequilibrium exciton, and Hauser-Feshbach with width fluctuation corrections. Results were converted into the ENDF-6 format and detailed graphical comparisons with both CSISRS experimental data and ENDF files was performed. In most cases a considerable improvement over the current ENDF/B-VI library was achieved.

Keywords:

• neutron cross-sections
• nuclear data evaluation
• 19 fission products
• ⁹⁵Mo
• ⁹⁹Tc
• ¹⁰¹Ru
• ¹⁰³Rh
• ¹⁰⁵Pd
• ¹⁰⁹Ag
• ¹³¹Xe
• ¹³³Cs, ¹⁴¹Pr
• ^143,145Nd, ¹⁴⁷, ^149,152Sm
• ¹⁵³Eu, ^155,157Gd
• model calculations
• neutron energy 10 keV - 20 MeV
• ENDF-6 format
• comparison with CSISRS data
• comparison with ENDF files