橡塑合金辐射防护材料的制备及优化设计

发布时间：2018-08-31 11:35

【摘要】：随着核能与核技术应用的迅猛发展,人们接触辐射的机会大为增加,因此对核辐射防护的需求也日益迫切。目前对辐射的防护都是建立在屏蔽材料的基础之上的,所以对屏蔽材料的研究就显得至关重要。很多传统辐射防护材料已经无法满足便携性和可移动性等防护需求,因此研制开发新型的柔性防护材料成为了研究的重点。本文以性能优异的橡塑合金橡胶材料作为基底,通过掺入碳化硼、氧化钆和氧化钨等功能性粒子,研发制备了一种新型辐射防护材料,研究了复合防护材料的各项性能,并结合遗传算法和MCNP程序对材料中功能粒子的配比进行了最优化设计。本文主要的工作及成果如下:(1)利用MCNP程序对Bi、Pb、Ta、Fe、Cu、W、Sn等元素的γ射线防护性能进行了模拟计算,同时利用WinXCom软件对Ce、Sm、Gd、Er等稀土元素的质量衰减系数进行了理论模拟,重点考察了各元素的K吸收边特性,然后对比了各材料对中子的防护效果。基于上述的模拟结果,进行功能粒子的初步筛选和优化组合。结果表明:Gd和W是较好的γ射线屏蔽组合,而且Gd也是优异的热中子吸收材料,由于橡塑合金橡胶的多种优点,将其作为复合材料的基底材料。(2)根据筛选的结果,制备了Gd2O3/WO3/橡塑合金辐射防护材料,研究了经过不同剂量的电子束照射后样品的性能差异及变化规律,通过对材料力学性能和射线防护性能的测试,考察了不同功能粒子加入量对材料的各项性能的影响,最后对比了B4C和Gd2O3的中子屏蔽效果。通过实验发现,100 kGy的电子束辐射使材料获得了较好的机械性能,随着功能粒子含量的增加,材料的屏蔽性能上升,而力学性能随之下降,且Gd2O3的中子透射率低于B4C。(3)在上述的实验结果的基础上,更加深入地研究了材料中功能粒子的配比对其射线防护性能的影响。通过MATLAB中的遗传算法工具箱进行材料组分的最优化计算,然后将最优化计算结果输入到MCNP程序中,从理论的角度对最优化结果进行模拟验证,结论显示了最优化设计的材料相比于其他三种材料拥有更加综合的射线防护性能,理论上证明了最优化结果的正确性。(4)根据遗传算法得到的最优化结果,制备了B4C/Gd2O3/WO3/橡塑合金辐射防护材料,对其微观结构和辐射防护性能进行了测试分析,通过对材料进行射线屏蔽实验,从实验的角度对最优化结果进行了验证,通过测得的实验数据说明了所制备的最优化防护材料拥有更好的屏蔽性能,从实验上证明了最优化结果的正确性。
[Abstract]:With the rapid development of nuclear energy and nuclear technology applications, people's exposure to radiation is greatly increased, so the need for radiation protection is increasingly urgent. At present, radiation protection is based on shielding materials, so it is very important to study shielding materials. Many traditional radiation protection materials have been unable to meet the requirements of portability and mobility, so the research and development of new flexible protective materials has become the focus of research. In this paper, a new type of radiation protection material was prepared by adding functional particles such as boron carbide, gadolinium oxide and tungsten oxide on rubber materials with excellent properties. The properties of composite protective materials were studied. Genetic algorithm and MCNP program are used to optimize the proportion of functional particles in materials. The main work and achievements of this paper are as follows: (1) the 纬 -ray protection performance of Bi,Pb,Ta,Fe,Cu,W,Sn and other elements is simulated by using MCNP program, and the mass attenuation coefficient of rare earth elements such as Ce,Sm,Gd,Er is simulated by WinXCom software. The K absorption edge characteristics of each element were investigated, and the neutron protection effects of each material were compared. Based on the above simulation results, the primary screening and optimization of functional particles were carried out. The results show that: Gd and W are better gamma-ray shielding combinations, and Gd is also an excellent thermal neutron absorption material. Because of the many advantages of rubber, rubber is used as the substrate material of composite materials. (2) according to the screening results, The radiation protection materials of Gd2O3/WO3/ rubber plastic alloy were prepared. The difference and variation of the properties of the samples after different doses of electron beam irradiation were studied. The mechanical properties and radiation protection properties of the materials were tested. The effects of different amount of functional particles on the properties of the materials were investigated. Finally, the neutron shielding effects of B4C and Gd2O3 were compared. The experimental results show that the electron beam radiation of 100 kGy makes the material obtain better mechanical properties. With the increase of the content of functional particles, the shielding property of the material increases, but the mechanical property decreases. The neutron transmittance of Gd2O3 is lower than that of B _ 4C. (3) on the basis of the above experimental results, the effects of the ratio of functional particles in the material on the radiation protection performance are studied more deeply. The optimization calculation of material components is carried out by genetic algorithm toolbox in MATLAB, and then the optimization results are input into MCNP program, and the optimization results are simulated and verified from a theoretical point of view. The conclusion shows that the optimized materials have more comprehensive radiation protection performance than the other three materials, and theoretically prove the correctness of the optimization results. (4) according to the optimization results obtained by genetic algorithm, The radiation protection materials of B4C/Gd2O3/WO3/ rubber and plastic alloys were prepared. The microstructure and radiation protection properties of the materials were tested and analyzed. The optimized results were verified from the point of view of the experiments. The experimental data show that the optimized protective materials have better shielding performance, and the correctness of the optimized results is proved experimentally.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TL752

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