基于MCNP的缓发裂变中子衰减时间谱模拟计算

发布时间：2018-07-08 14:48

本文选题：缓发裂变中子 + 中子衰减时间谱　；参考：《原子能科学技术》2017年02期

【摘要】：基于核裂变反应发生与缓发裂变中子发射这两个物理过程在时间上可相互分离的思想,利用MCNP程序计算得到了含铀地层0~100s范围内的缓发裂变中子衰减时间谱。模拟计算了球体几何模型中235 U与238 U核裂变反应率空间分布;借助SOURCE子程序依次对缓发裂变中子的发射位置、发射方向、发生核裂变反应的核素、缓发裂变中子所在的群组、发射时间及其初始能量等参数进行了抽样。结果表明,计算得到的缓发裂变中子衰减时间谱的时间特征与铀核素的缓发裂变中子群参数相符合。对缓发裂变中子总计数与地层铀含量之间的关系进行了线性拟合,拟合结果的相关系数平方值大于0.998 5,该结果从理论上验证了缓发裂变中子测井铀含量线性模型的正确性。
[Abstract]:Based on the idea that the two physical processes of nuclear fission reaction and slow fission neutron emission can be separated from each other in time, the neutron attenuation time spectrum of delayed fission in uranium-bearing strata is calculated by MCNP program in the range of 0 ~ 100 s. The spatial distribution of the nuclear fission reaction rates of 235U and 238U in the spherical geometry model is simulated and calculated, and the emission position, emission direction, fission reaction nuclide and slow fission neutron group are sequentially determined by the source subroutine. The emission time and initial energy were sampled. The results show that the calculated time characteristics of neutron decay time spectrum are in agreement with the neutron group parameters of uranium nuclide. The relationship between the total number of slow fission neutrons and uranium content in formation is fitted linearly. The correlation coefficient square value of the fitting result is more than 0.998. The result theoretically verifies the correctness of the linear model of uranium content in slow fission neutron logging.
【作者单位】：中国原子能科学研究院核技术应用研究所;
【基金】：中国核工业集团公司核能开发科研项目资助(BA13003104)
【分类号】：O571.5

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