MC模拟中子探测器监测脉冲堆燃料元件破损响应特性  

Monte Carlo Simulation of Detector Response to Delayed Neutrons in Xi'an Pulsed Reactor

作　　者：杨宁[1] 张良[1] 张文首[1] YANG Ning;ZHANG Liang;ZHANG Wen-shou(State Key Laboratory of Simulation and Effect for Intense Pulse Radiation, Northwest Institute of Nuclear Technology,Xi'an 710024,China)

机构地区：[1]西北核技术研究所强脉冲辐射环境模拟与效应国家重点实验室,西安710024

出　　处：《核电子学与探测技术》2018年第4期491-494,共4页Nuclear Electronics & Detection Technology

摘　　要：为评估缓发中子探测器监测脉冲堆燃料元件破损的响应特性,建立了MCNP中子源模型和3He球形计数管探测器模型,应用MC方法计算给出了最佳监测位置和该位置处不同聚乙烯厚度下探测器对缓发中子的探测效率曲线。结果表明:最佳监测位置紧贴换热器外表面且偏向入口端,偏移距离和冷却剂贯穿换热器耗时有关,耗时越长,偏移越大;探测效率曲线的变化趋势取决于平均反应截面与中子注量率的积,采用聚乙烯慢化层在提高平均反应截面的同时会降低中子注量率,存在最优厚度4 cm使探测器对缓发中子探测效率最大,其值约为1.1×10-5。For assessing the response of the detector used for clad-failure monitoring in Xi'an Pulsed Reactor (XAPR),both a source model and a 3He spherical counter model were built in MCNP.The best monitoring place for detector installation was proposed,wherein the efficiency curve of the detector for the delayed neutrons was calculated using Monte Carlo method with the detector being coated by various thicknesses of polyethylene.It is shown that the best monitoring position is nearest to the heat exchanger outer surface in radial direction and some distance shifted to the inlet-end in axial direction,and the highest detection efficiency is 1.1×10^-5,which is realized when the detector is covered in 4cm thickness polyethylene.

关 键 词：缓发中子 破损 探测效率 MCNP 

分 类 号：TL352.27[核科学技术—核技术及应用]