The Basic Research on the Formation of the Neutron Irradiation Field for the Minor Actinides Transmutation

小锕系元素嬗变中子辐照场形成的基础研究

• 批准号: 11680520
• 负责人: SAKAMOTO Shigeyasu
• 金额: $ 1.79万
• 依托单位: TOKAI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680520/
• 关键词: minor actinides; transmutation; fission ratio; track-etch detector; neutron activation ooil; 放射化検出器; 核分裂断面積; 超ウラン元素; 放射化箔; 飛跡検出器; 臨界集合体

This study is a basic research on transmutation of minor actinide. By measuring relative nuclear fission rate rations of the minor actinide to the uranium in the irradiation fields, which have different neutron spectrums, it is to find that of adequate neutron field for transmutation of the minor actinide.Experiments were performed using polyethylene moderated, highly-enriched uranium cores at a solid moderated core in the KUCA. In order to systematically vary the neutron spectrum of the neutron field, the H/<235>^U ratio of the core has been systematically varied. Three cores were employed in this study; those cores were designated as EEE1, E1 and E3-core respectively. The neutron spectrum was evaluated in both of calculation and experiment using activation foil method.The fission rate ratio measurements have been performed using track-etch detectors put in a special irradiation apparatus used for the alternative of the back-to-back type double fission chamber.The ratio of the number of the effective atom on the target also used the track-etch detectors too. This agrees with the previous report value on the ratio of <237>^ Np and ^<235>U number of atoms in 13 : 1. At the center of the E1 core, the measured value of <237>^Np/<235>^U fission rate ratio was 0.016 is smaller than the previous report value about 30%. Data analysis of other core is now being performed.

本研究是次锕系元素嬗变的基础性研究。通过测量不同中子能谱辐照场中次锕系元素与铀的相对裂变率比，寻找适合次锕系元素嬗变的中子能谱。为了系统地改变中子场的中子谱，堆芯的H/<235>^U比已经被系统地改变。本研究中使用了三个核心;这些核心分别被指定为EEE 1、E1和E3-核心。用活化箔法对中子能谱进行了计算和实验评价，用径迹探测器测量了裂变率比，用径迹探测器测量了靶上有效原子数比。这与先前关于<237>^ Np和^<235>U原子数之比为13：1的报告值一致。在E1堆芯中心，<237>^Np/<235>^U裂变速率比的测量值为0.016，比以前报道的值小约30%。其他堆芯的数据分析正在进行中。