0～15MeV中子诱发^239Pu裂变产额能量关系的评价研究

Evaluation of dependence of cumulative fission yields on incident-neutron energy for ^239Pu（ n, f）

目的研究0～15MeV中子诱发^239Pu裂变产物的累积产额随人射中子能量变化的关系。方法使用加权平均和ZOTT评估的方法对裂变产物核的累积产额实验数据进行评价推荐，通过SPCC程序拟合和多模式模型理论首次得出产额能量关系。结果评价推荐了0～15MeV中子诱发^239Pu裂变的^85Kr^m、^87Kr、^88Kr和^138Xe 4个重要气体产物核的累积产额数据，给出了产额能量关系曲线。评价后的数据与国际上ENDF／B-VII、JENDL-3．1、JEF-2．2和CENDL-2等数据库的推荐数据进行了比较，使相关数据得以更新和补充。理论计算结果可以在定性上与实验拟合曲线进行比较。结论^87Kr和^88Kr的累积产额随能量增加呈上升趋势，而^85Kr^m和^138Xe呈现直线型的关系曲线。多模式理论计算结果可以定性地反映实验拟合曲线的趋势。

Objective To study the dependence of cumulative fission yields on incident-neutron energy for ^239Pu（ n, f）. Methods The experimental yield data were evaluated by using codes AVERAGE for weighted average and ZOTT for simultaneous evaluation. The multi-modal model was used to calculate the energy dependence of yields. Results The experimental yield data were evaluated at different neutron energies for gas fission products ^85 Kr^m , ^87 Kr, ^88r and ^138Xe resulting from the ^239Pu （ n, f） reaction. The energy dependence of the cumulative fission product yields on the incident neutron was presented and recommended. The evaluated curves of product yield versus neutron energy were compared with the results calculated by the TALYS code. Conclusions The energy curves of yieid showed the rising trend for ^87Kr and ^88Kr, but the linear functions for ^85Kr^m and ^138Xe. The muhi-modal model calculation may qualitatively describe the energy dependence of yields for the ^239Pu（n,f） reaction.