用多群蒙特卡罗方法计算快中子核临界K_(eff)和通量密度  

Monte-Carlo calculation of K_(eff) and neutron flux density in fast neutron critical assemblies with multi-group section data

作　　者：徐家云[1] 张一云[1] 林理彬[1] 白立新[1] 范晓强[1] 周厚全[1] 

机构地区：[1]四川大学物理系,四川成都610064

出　　处：《强激光与粒子束》2001年第1期123-128,共6页High Power Laser and Particle Beams

基　　金：中国工程物理研究院院外基金资助课题

摘　　要：用多群蒙特卡罗方法对快中子核裂变系统进行了临界计算。有效增殖因子κｅｆｆ的计算值与实验结果符合。计算所得中子通量密度的空间分布在球形裂变系统中随半径增大单调下降。中子通量密度的能量分布在由高浓缩铀组成的活性区内里单一能量极大值，其对应能量对于裸球核裂变系统和具有反射层裂变系统分别为０．３５ＭｅＶ和０．２５ＭｅＶ，而在由天然铀组成的反射层中在０．１ＭｅＶ附近出现能量双峰。由通量密度所得中子能谱在无反射层球形裂变系统中随半径增加变硬，在有反射层球形裂变系统中随半径增加变软。The fast neutron spherical critical assemblies are analyzed by means of the Monte-Carlo method with multi-group section data. The calculated keff are consistent with the experimental results. The neutron flux density versus energy distribution presents a single maximum in the core made up of high enriched uranium and the distribution presents two maximums in the reflecting layer made up of natural uranium. The neutron spectrum hardens as the radius increases in the bare spherical assembly and softens as radius increases in the assembly with reflecting layer.

关 键 词：有效增殖因子 中子通量密度 中子能谱 多群蒙特卡罗方法 

分 类 号：TL329.2[核科学技术—核技术及应用]