重金属-稀土高分子复合材料屏蔽性能的MCNP模拟

MCNP Simulation of heavy metal and composite shielding materials through rare earth doped polymer

本文针对核动力舰船对空间环境的特殊要求,在常用的辐射屏蔽材料基础上设计一种高效、无毒性且兼备优良物理性能的新型二次屏蔽材料。屏蔽结构采用分层设计,内层选用W-Ni合金替代具有毒性的铅,外层采用稀土-高分子复合材料。对其屏蔽性能进行MCNP模拟分析,结果表明:W-Ni合金具有更好屏蔽效果,对于能量高于1.5 MeV的γ射线,其10倍减弱厚度约为铅的一半,适用于空间狭小的区域;加入少量稀土元素能够显著提升高分子材料的屏蔽性能,但其屏蔽性能并非随着稀土含量的增加而增强;稀土对屏蔽性能的提升主要依靠吸收慢化后的热中子。

This article aimed at the special environment of nuclear powered ship designed a new kind of secondary shielding material with high-efficiency, non-toxicity and excellent physical properties. The shielding structure is designed in two layer, the inner layer is constituted with W-Ni alloy and the outer is made up of high polymer material doped with rare earth. The shielding properties of the material were simulated through MCNP. The results show that: the shielding properties of W-Ni alloy is better than lead, the thickness of W-Ni alloy which lead to 10 times less of γray at the energy beyond 1.5 MeV.Means that it’s appropriated for narrow space;The shielding properties are improved significantly by adulteration a few rare earth, but the shielding properties are not enhanced with the increasing of contents of rare earth;The improvement of shielding properties owe to the absorption of thermal neutron by rare earth.