Research On Radiation Protection Material Based On Rare Earth Used For Nuclear Power Plant Radiation Environment And Medical Radiation Environment

Rare earth element belongs toⅢB family of the periodic table of elements, including a total of 17 elements, such as scandium, yttrium, and lanthanides, etc. Their K-layer absorption edge are in the "weak absorption area of lead", so the rare earth element can replace lead to protect low-energy rays.In this thesis,we have prepared rare-earth oxides (erbium oxide, samarium oxide, cerium oxide) /epoxy resin radiation protection materials via the route of surface treatment, and have prepared polyacrylate /epoxy resin radiation protection materials by means of radiation graft polymerization. This paper studies the micro-structure of the materials by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectrometer; tests and analyzes the mechanical properties of materials; tests and analyzes the radiation protection capacity of materials with multi-channelγspectrometer and GammaVision software, simulates transport process of the radial in the material, discusses the changing amount of injection and dose of the radial through the material by using EGSnrc procedure based on Monte Carlo methods, compares the simulated screening rate with the actual screening rates so as to reveal the factors that affect the screening rate of material. The thesis gives a comparison of the radiation protection performance between polyacrylic acid lead /epoxy resin and polyacrylic acid Sm /epoxy resin composite material, and makes a comprehensive comparison of the microstructure and properties between the oxidation Sm / epoxy resin and polyacrylic acid Sm /epoxy resin composite material which have the same element concentrations of samarium, revealing the advantages and disadvantages of two preparation methods. According to the differences of the K layer absorption edge of metal elements, the research adds different elements in a material simultaneously to explore the protective capability of material against mixed-ray with high and low radiation.The results show that rare earth element distribution in the materials obtained from two methods are relatively uniform and that the mechanical properties of composite materials compared with pure epoxy resin have been improved. The ray-protective results are obvious. The rare earth element content in the material produced by surface treatment is easy to be increased while that in Polyacrylate /epoxy resin is more difficult to be enhanced with more excellent mechanical properties.The irradiation dose in the process of radiation graft polymerization for preparing the composite materials should be appropriately controlled around 50KGy. Adding lead and samarium simultaneously in a material can increase the protective capability of materials against mixed-ray with high and low energy radiation. Protective capacity of rare earth against low-energy radiation is stronger than that of the traditional shielding elements, such as lead. Rare earth-based epoxy resin composite materials'mass absorption coefficient of shielding low-energy photon is higher than that of the pure lead. Thus, in comparison with the lead, it is a lightweight material.