摘要
为了在辐射防护时更加仔细地评估238 Pu产生的中子对工作人员的危害,首先,使用多球中子谱仪对3.4 g的^(238)PuO_(2)粉末样品的中子源强度进行了测量,得到平均中子能量为0.57 MeV。其次,根据平均中子能量,分别按照点源方法和体源方法计算了距该样品不同距离处的中子周围剂量当量率。经过计算发现在距离放射源较近时,体源的计算结果要远小于中子点源的计算结果,在距离放射源比较远时,中子点源和体源的计算结果相同。其次,使用经过计量检定的中子剂量当量率仪对距样品不同距离处的中子周围剂量当量率进行了测量,并与中子体源方法的计算结果进行了对比。最后,使用蒙特卡罗软件Fluka分别模拟了平均中子能量为0.57 MeV以及服从麦克斯韦分布的裂变中子的能量的中子周围剂量当量率结果。研究结果表明:使用中子体源方法的计算结果均在中子剂量当量率仪测量结果的范围内;使用Fluka模拟的中子剂量率结果与中子体源方法计算的结果也非常接近,且均在中子剂量当量率仪测量结果范围内。因此,在^(238)PuO_(2)的辐射防护时,可以使用理论计算的方法替代蒙特卡罗模拟。对于其他自发裂变的核素,按照上述方法,也可以计算其中子剂量率。
To ssess the harm of neutrons generated by 238 Pu to staff during radiation protection more carefully,the neutron energy spectrum of the 3.4 g ^(238)PuO_(2) sample is measured using a multi-sphere neutron spectrometer,and the average neutron energy of 0.57 MeV is obtained.Then the neutron dose rate are calculated using both the point source formula and the volume source formula.After calculation,the distance from the radioactive source is relatively close.The calculation result of the volume source is much smaller than that of the point source.When the radiation source is far away,the calculation results of point source and volume source are the same.In addition,the neutron ambient dose equivalent rate is measured at different distances using a neutron ambient dose equivalent rate meter.Finally,the Monte Carlo software Fluka is used to simulate the neutron dose rate results under two scenarios:one with an average neutron energy of 0.57 MeV,and the other with fission neutrons whose energy follows a Maxwels distribution.The results show that the calculation results using the volume source method are all within the range of the measurements from the neutron dose equivalent rate meter;the neutron dose rate results simulated using the Fluka are very close to those calculated by the volume source method,and both are within the range of measurements from the neutron dose equivalent rate meter.Therefore,in the radiation protection of ^(238)PuO_(2),theoretical calculation methods can be used as an alternative to Monte Carlo simulations.For other nuclides that undergo spontaneous fission,the neutron dose rate can also be calculated using the aforementioned methods.
作者
康梦霄
张贵英
黄翰雄
栗星
KANG Mengxiao;ZHANG Guiying;HUANG Hanxiong;LI Xing(Key Laboratory of Nuclear Data,China Institute of Atomic Energy,Beijing 102413,China;Beijing Prevention and Treatment Hospital of Occupational Disease Chemical Industry,Beijing 100093,China;NBU Health Science Center,Ningbo,Zhejiang Province 315211,China)
出处
《现代应用物理》
2024年第5期38-43,共6页
Modern Applied Physics
基金
国家自然科学基金资助项目(11975318)
稳定支持基础科研计划资助项目(BJ010261223282)。
