堆内自给能中子探测器信号电流计算方法研究  

Calculation of the signal current of self-powered neutron detectors in a nuclear reactor

作　　者：吴雄 张香菊 罗世杰 蒋洁琼[2] WU Xiong;ZHANG Xiangju;LUO Shijie;JIANG Jieqiong(University of Science and Technology of China,Hefei 230026,China;Institute of Nuclear Energy Safety Technology,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;China Nuclear Power Technology Research Institute Co.,Ltd.,Shenzhen 518031,China)

机构地区：[1]中国科学技术大学,合肥230026 [2]中国科学院合肥物质科学研究院核能安全技术研究所,合肥230031 [3]中广核研究院有限公司,深圳518031

出　　处：《核技术》2024年第3期84-92,共9页Nuclear Techniques

摘　　要：自给能中子探测器(Self-Powered Neutron Detectors,SPNDs)是核反应堆监测和保护系统的核心设备,其测量到的电流直接反映堆芯功率的大小和分布。探测器绝缘体是影响信号电流计算精度的主要因素,在SPND的研发设计中占有重要地位。为进一步提升SPND信号电流计算方法的精度,本文根据SPND电流产生机理以及绝缘体中固有的空间电场效应,提出了三种不同的中子、光子电流计算方法,并进行了详细的对比验证。结果表明:三种方法计算结果的差异小于1%,显示了相当的精度。此外,以反应堆工程中应用广泛的铑SPND为例,计算结果表明其信号电流主要由中子产生,光子引起的电流一般不超过5%。本文所提出的电流计算方法在反应堆上经过了大量的实验验证,理论和实验结果的差异均小于3%,证明了其有效性和精度。该方法已经应用于中国第三代先进大型压水反应堆——“华龙一号”,并具有通用性。它可用于不同类型自给能探测器的电流分析,也可为其他反应堆(如第四代快中子堆和后续的聚变堆)的堆芯监测系统提供有益的参考。[Background]Self-powered neutron detectors(SPNDs)are critical devices in the monitoring and protection systems of nuclear reactors,and their signal current directly reflects the value and distribution of the core power.Insulators play an essential role in the design of SPNDs and are the main factor affecting the calculation accuracy of the signal current.[Purpose]This study aims to improve the accuracy of the calculation method of the SPND signal current,ensuring that the measured currents accurately reflect the reactor conditions and meet the highest industrial standards.[Methods]Firstly,the signal generation mechanism of the SPND was thoroughly discussed,and three independent calculation methods of the current based on the inherent physical characteristics of the space electric field of an insulator were proposed.Then,high-fidelity simulations of the SPND were performed using the Monte Carlo code,and the three methods were validated based on the simulation results.In addition to the current caused by the neutrons,the current caused by the photons inside the reactor was quantitatively analyzed.Meanwhile,extensive radiation experiments on the various reactors have been performed to verify these three current calculation methods.[Results]The difference between the results obtained by using the three methods is less than 1%,demonstrating a considerable accuracy.In addition,the current of the rhodium SPND is primarily owing to the neutrons,whereas the photon-induced current is generally less than 5%.Experimental verification results on the several operating reactors show that the difference between the theoretical and experimental results is less than 3%,which also proves its effectiveness and accuracy.[Conclusions]This method has been applied to the large Chinese Gen-III advanced pressurized water reactor(HPR1000)and is universal.It can be used for the signal analysis of different types of SPNDs,as well as for providing valuable references for core monitoring systems in other reactors,such as the Gen-IV fast reacto

关 键 词：自给能中子探测器 绝缘体 空间电场效应 信号电流 蒙特卡罗方法 

分 类 号：TL99[核科学技术—核技术及应用]