电子输运过程的确定论计算方法研究  

Study on Deterministic Calculation Method for Electron Transport Process

作　　者：李晓英 李云召[1] 邵睿智 徐宁 LI Xiaoying;LI Yunzhao;SHAO Ruizhi;XU Ning(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《原子能科学技术》2023年第8期1561-1567,共7页Atomic Energy Science and Technology

摘　　要：电子输运过程是核辐射探测器内形成电流的关键过程之一,相应的数值模拟是先进探测器设计与分析软件急需研发的功能。由于该过程的短平均自由程和高度前向峰等特点,确定论方法比蒙特卡罗方法的计算效率更高。本文采用多群形式的Boltzmann输运方程刻画电子输运过程;从EPICS2017中的电子截面数据EEDL出发,基于核数据处理软件NECP-Atlas编写了相应的电子截面处理模块,制作了多群截面数据库;利用Bamboo-Lattice程序中基于特征线方法的中子输运计算核心,构建了确定论电子输运计算程序。利用单核素均匀问题、化合物均匀问题和化合物非均匀问题等一系列算例,通过与蒙特卡罗程序的计算结果进行详细对比,对该确定论电子输运计算程序进行了定量数值验证与分析。结果表明,该程序可以正确模拟电子输运过程,且计算效率能比蒙特卡罗程序快80倍以上。Electron transport process is a crucial factor in the formulation of the electronic current in nuclear detectors.Accurate calculation of electron transport process is the essential function for advanced nuclear detector design and analysis software.While powerful Monte Carlo codes,such as MCNP and Geant4,can accurately simulate electron transport in various situations,the calculation efficiency of those stochastic simulation methods is relatively low mainly due to the short mean free path and highly forward-peaked nature of the electron transport process.Thus,in this study,the electron transport process was described by using the differential-integral equation in the form of the multigroup Boltzmann transport equation.To obtain the multigroup electron-atomic cross-section,a new module was developed in the nuclear data processing code NECP-Atlas to process the atomic electron cross-section data(EEDL)in EPICS2017.The module considered four important interactions,including ionization,excitation,bremsstrahlung and elastic scattering.Among those,excitation and bremsstrahlung could only change the energy of the free electrons without changing their direction of motion,while elastic scattering could only change the direction of motion without losing energy.Each ionization reaction produced two electrons,including the scattered electron and the recoil electron.During this process,the Auger electrons which may be emitted was neglected due to its low production.Once those multigroup electron-atomic cross-section library applicable to the traditional Boltzmann equation was created,a solver that can solve the Boltzmann transport equation can be employed to carry out the electron transport calculation.Accordingly,a deterministic electron transport calculation program was designed,implemented and constructed using the neutron transport calculation kernel from Bamboo-Lattice which is a lattice calculation code utilized for the pressurized water reactor(PWR)core.In this solver,the method of characteristic(MOC)was employed to sol

关 键 词：电子输运 确定论方法 电子截面数据处理 Bamboo-Lattice NECP-Atlas 

分 类 号：TL32[核科学技术—核技术及应用]