西安脉冲堆^(99)Tc、^(129)I热中子嬗变计算方法与实验验证

Calculation and Experimental Validation of ^(99)Tc、^(129)I Transmutation Rate in Xi'an Pulsed Reactor

为了研究利用西安脉冲堆(XAPR)热中子开展99Tc、129I嬗变的可行性,对乏燃料中长寿命裂变产物(LLFP)99Tc和129I核素的热中子嬗变计算方法进行理论与实验研究。利用NJOY程序,以ENDF/B VII.0库为基础,制作99Tc和129I在XAPR堆芯辐照温度下的蒙特卡罗程序(MCNP)截面库,并分析不同参数对截面数据的影响。采用ACE(A Compact ENDF)格式截面库和燃耗程序CINDER’90自带的63群活化截面,利用MCNP程序对ORIGEN2数据库中99Tc和129I的辐射俘获截面进行修正,用ORIGEN2程序分析一定规格的99Tc和129I靶件在XAPR内辐照后的嬗变情况。与实验结果值进行比较,截面数据的差异主要来自中子注量率测量值与实际值的误差,结果证明利用XAPR开展99Tc和129I嬗变是可行的。

The theoretical simulation and experimental methods related to Long Lived Fission Product （LLFP） of 99Tc and 129I transmutation in nuclear spent fuel were studied in order to develop the feasibility research on 99Tc and 129I transmutation in XAPR reactor. 99Tc and 129I ACE format cross libraries in XAPR were generated by NJOY code based on ENDF/B VII.0 library, different parameters were analyzed. MCNP code was used to modify 99Tc and 129I capture cross sections by adopting new generating ACE format and CIN- DER＇90 cross sections of 63 groups. Transmutation rates＇ calculations of 99Tc and 129I in XAPR were done by ORIGEN2 code, as well as comparison with experimental data, the difference between theoretical and experimental data mainly comes from the deviation of neutron flux used and the actual one. Conclusions were made that XAPR is effective in transmutation of 99Tc and 129I.