Preparation And Optimization Design Of NBR/PVC Blend Radiation Shielding Material

With the rapid development of nuclear technology,the need for nuclear radiation protection is increasingly urgent because of the increasing opportunities for people's exposure to radiation.At present,the radiation protection is based on the shielding materials,so the research of shielding materials is crucial.Many traditional radiation shielding materials have been unable to meet the protection requirements of portability and mobility,thus,development of new types of flexible shielding materials has become the focus of research.In this paper,rubber-plastic alloy rubber with excellent properties was chosen as the substrate.A new type of radiation shielding material was developed and prepared by blending in the functional particles of boron carbide,gadolinium oxide and tungsten oxide.The performance of the shielding materials was studied,and the optimization of the proportion of each functional particle was figured out with genetic algorithm combined with MCNP program.The main work and results are as follows:(1)The gamma-rays shielding performance of Bi,Pb,Ta,Fe,Cu,W and Sn was simulated using MCNP program,and the mass attenuation coefficients of rare earth elements of Ce,Sm,Gd,Er were also analyzed using Win XCom software.The characteristics of each element's K absorption edge were investigated,and the neutron shielding performance of each material was compared.Based on the above simulation results,the preliminary screening and optimal combination of functional particles were completed.The results showed that the Gd and W were good gamma-rays shielding combination,and Gd was an excellent absorber to thermal neutrons.After comparison to other materials,the rubber-plastic alloy was selected as the substrate due to its varieties of advantages.(2)The shielding composites of Gd2O3/WO3/rubber-plastic alloy were prepared according to the screening results.The performance differences and the characteristics of the shielding materials which changed after different doses of electron beam irradiation were studied.By testing the mechanical properties and radiation protection properties of materials,the effects on the performance of the materials with different functional particle contents were investigated.Eventually,the neutron shielding abilities of B4 C and Gd2O3 were compared.The experiment found that the materials had good mechanical properties when the electron beam radiation was 100 kGy.With the increase of the functional particle content,the shielding performance of the materials increased,but the mechanical properties decreased.And the neutron transmittance of Gd2O3 was lower than that of B4 C.(3)On the basis of the above experimental results,the influence on the shielding performance ofdifferent functional particles' ratios in the material was further studied.The material components was optimized by genetic algorithm toolbox in MATLAB,and then the optimization calculation results was edited into the MCNP input file in order to verify the optimization results from the theoretical point of view.The conclusions discovered that the optimized design materials had more comprehensive radiation shielding performance than other three materials,and the correctness of the optimization results was proved theoretically.(4)The samples of B4C/Gd2O3/WO3/rubber-plastic alloy were prepared according to the optimization results of genetic algorithm.The microstructures and radiation shielding performance of these samples were tested.Through the shielding tests on the materials,the optimization results were verified from the angle of the experiment.The measured experimental data showed that the optimized shielding materials had better shielding performance,and the correctness of the optimization results was proved experimentally.