为校验次临界能源堆的概念设计，建立了贫化铀／聚乙烯球壳交替系统，采用活化法测量238^U的中子俘获率．贫化铀片置于系统内与入射D离子束成90°的方向上活化，用HPGe探测器测量230u俘获中子衰变产生的239^Np衰变产生的277．6keV特征γ射线计数，实验修正了贫铀片对277．6keVγ射线的自吸收，得到了交替系统中238^U（札，γ）反应率的径向分布，反应率的相对不确定度为3．5％-3．7％，并计算得到系统上整个贫铀区中23。U的总中子俘获率为2．24土0．09．用MCNP5程序在常用ENDF库下进行了模拟计算，238^U（n，γ）反应率分布计算与实验一般在5％以内符合，总俘获率在1％以内符合．%In order to check the conceptual design of subcritical reactor, an alternate depleted uranium/polyethylene-shell simulation device was established, to carry out uranium-238 neutron capture rate experiment using activation technique. The depleted uranium foils were activated at 90° to the incident. By measuring the 277.6 keV T-ray emitted from 239^Np generated by 2aSu （n, γ） 239^U reaction and correcting self-absorption of uranium experimentally, the 238^U （n, γ） reaction rate with an uncertainty between 3.5% and 3.7% and a total neutron capture of 2.24 ± 0.09 of the system were obtained. The experiment was simulated using MCNP5 code with ENDF libraries. The simulations and measurements accord within 5% for the 238^U （n, γ） reaction rate and within 1% for the total neutron capture rate of 238^U.
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