基于D-D中子源开展^(238)U样品屏蔽积分实验研究  

Study on Shielding Benchmark Experiment of^(238)U Sample with D-D Neutrons

作　　者：丁琰琰 聂阳波[1,2] 胡志杰 赵齐 张环宇[1] 徐阔之 张时宇 潘欣怡 兰长林[2] 任杰[1] 阮锡超[1,2] DING Yanyan;NIE Yangbo;HU Zhijie;ZHAO Qi;ZHANG Huanyu;XU Kuozhi;ZHANG Shiyu;PAN Xinyi;LAN Changlin;REN Jie;RUAN Xichao(China Institute of Atomic Energy,Beijing 102413,China;Lanzhou University,Lanzhou 730000,China;China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]中国原子能科学研究院,北京102413 [2]兰州大学,甘肃兰州730000 [3]中国工程物理研究院,四川绵阳621900

出　　处：《原子能科学技术》2024年第5期970-981,共12页Atomic Energy Science and Technology

基　　金：国家自然科学基金(1177531,U2067205);稳定支持基础科研计划(BJ010261223282)。

摘　　要：利用中国原子能科学研究院的中子学屏蔽积分实验装置,通过飞行时间法分别测量了D-D中子源与不同尺寸^(238)U样品作用后在60°和120°的泄漏中子谱,样品表面积为30 cm×30 cm的板状样品,厚度分别为3、6和9 cm。利用蒙特卡罗程序对泄漏中子谱进行了模拟计算,其中^(238)U数据分别采用CENDL-3.2库、ENDF/B-Ⅷ.0库、JENDL-5.0库和JEFF-3.3库中的数据。通过对模拟结果与实验结果的比较,重点分析了CENDL-3.2库中^(238)U数据存在的不足和需要改进之处,结果表明:在裂变反应能区内,CENDL-3.2库计算结果与实验结果符合较好,但在弹性散射能区60°和120°均有较大的高估,尤其是120°,而在裂变反应和分立能级非弹性散射的混合能区1.5~2.5 MeV又有明显低估。^(238)U regarded as not only one of the important materials in the design of advanced nuclear energy system,but also significant components of the nuclear fuel cycle,especially constitutes more than 90%in power reactor.Improving the accuracy of evaluated neutron data for^(238)U is essential for the design of reactor and nuclear devices,and fusion neutron integral experiment is one of the effective means to check the accuracy of nuclear data.The idea of this approach is to find out differences and deficiencies between measurement and prediction of different evaluated libraries,which can provide guidance for the adjustment of evaluated data.The leakage neutron spectra were measured at angles of 60°and 120°after the interaction of D-D neutrons with^(238)U samples in different sizes by time-of-flight method using the shielding integral facility of China Institute of Atomic Energy.The samples were rectangular slabs with a 30 cm square base and 3,6 and 9 cm in thicknesses.A∅5.08 cm×2.54 cm BC-501A liquid scintillator was used to detect neutron in the measurement,and the gamma background can be removed by neutron-gamma discrimination.The leakage neutron spectra were simulated by Monte Carlo code using^(238)U data from the CENDL-3.2,ENDF/B-Ⅷ.0,JENDL-5.0 and JEFF-3.3 evaluated nuclear data libraries.The energy,angular flux and pulsed time distributions of source neutron were described carefully in the process of simulation,and the parameters of target structure material and detector efficiency were all taken into account.By comparing the calculated results with the experimental results,the shortcoming of^(238)U data in CENDL-3.2 library and the need for improvement were analyzed.The results show that the calculated result of CENDL-3.2 library in the fission reaction energy range is in good agreement with experimental result,but greatly overestimates in the elastic scattering energy range both at 60°and 120°,especially at 120°,there is also significant underestimation in the mixed energy range of 1.5-2.5 MeV for

关 键 词：泄漏中子谱 铀 D-D中子源 飞行时间法 评价核数据 

分 类 号：TL11[核科学技术—核能科学]