含水二氧化硅介质14 MeV中子慢化长度与中子迁移长度模拟计算  

Simulation of the 14 MeV Neutron Slowing-down and Migration Length in Water-Contained Quartz Medium

作　　者：杨国召 张国光[1] 张帅[1] 赵潇[1] 苏丹[1] 丰树强[1] 

机构地区：[1]中国原子能科学研究院

出　　处：《核电子学与探测技术》2016年第3期338-343,共6页Nuclear Electronics & Detection Technology

基　　金：中国核工业集团公司核能开发科研项目子项目"先进铀矿勘查核探测技术"

摘　　要：基于MCNP程序模拟计算了不同孔隙度二氧化硅介质地层14 Me V中子慢化长度与中子迁移长度。首先,模拟计算了241Am-Be中子源条件下不同孔隙度Si O2介质地层的中子通量空间分布,并利用源距均方值公式计算得到了对应的中子慢化长度LS和中子迁移长度LM。与文献结果对比:中子特征长度LS与LM结果相对误差均值分别为1.20%与-2.60%;该结果验证了源距均方值公式计算中子特征长度的有效性和可行性。同样地,计算得到了不同孔隙度Si O2介质地层14 Me V中子的中子特征长度LS和LM;计算结果表明:14 Me V中子的中子特征长度同样随地层孔隙度的增加而降低;其中水的14Me V中子特征长度为LS=12.73 cm、LM=13.00 cm,Si O2的14 Me V中子特征长度为LS=30.08 cm、LM=34.31 cm;中子慢化长度LS结果与文献结果的相对偏差≤±3.1%。The 14 MeV neutron slowing- down length and neutron migration length in different porosity quartz formation have been calculated by MCNP simulation in this work. Firstly, the neutron fluenee spacing distribu- tion in different porosity quartz formation with point 241 Am - Be neutron source condition was calculated. With these neutron fluenee data and the mean square spacing distance formula, the 241Am - Be neutron characteristic lengths, neutron slowing - down length Ls and neutron migration length LM, in corresponding formation have been calculated. Compared with results in the literature, the average relative error of Lu is - 2.60% and that of Ls is 1.20%. Good agreements between our results and that from references verified the validity and feasibili- ty of this technique, that calculation of the neutron characteristic length with the mean square spacing distance formula. Similarly, the 14 MeV neutron characteristic lengths in different porosity quartz formation were also calculated. The result shows that the neutron characteristic lengths decrease while the porosity increases. The calculated 14 MeV neutron characteristic lengths in water are Ls = 12.73 cm and LM = 13.00 cm and that in quartz are Ls = 30.78 cm and LM = 34.31 era. The result also shows that the relative error of 14 MeV neutron slowing - down length between this work and the references is less than 3.1%.

关 键 词：二氧化硅 源距均方值公式 中子慢化长度 中子迁移长度 

分 类 号：TL816.3[核科学技术—核技术及应用]