The Application Of Rare Earth In Nuclear Radiation Protection Technology

For the shielding problem of neutron radiation and X-ray/?-ray radiation,taking into account that traditional boron materials do not have neutron absorption after the absorption of neutrons,splitting into helium,lithium,resulting in reduced shielding performance;and traditional lead materials for photon radiation,there is a weak absorption area.Because rare earth elements have a thermal neutron absorption cross section of several ten times that of boron and a special atomic structure,they can make up for the shortcomings of the above-mentioned conventional materials.In this thesis,a series of rare earth/waterborne acrylic resin radiation protection materials were prepared by physical blending.The microstructure of the material was studied by scanning electron microscopy(SEM)and optical microscopy.The radiation shielding performance of the material was measured using a neutron cruiser,environmental X and gamma dose rate meters,and the EGSnrc computer simulation software based on the Monte Carlo method was used.The photon transport process in the medium was simulated.The effects of different rare earth additions on the radiation shielding performance were studied;the radiation shielding performance of rare earths and traditional materials was compared.The results show that: a)The neutron absorption capacity of rare earths,especially rare earth elements such as lanthanum,cerium,lanthanum,and neodymium,is strong,which is 6-12 times that of boron carbide;b)The amount of rare earths should not be excessive.Large,otherwise causing uneven slurry mixing,internal bubble situation,to 60 ? 75w% of the amount of resin is the best;c),rare earth elements on the shielding of photon rays,experimental results and simulation results show that the energy is less than the range of 200 Ke V,shielding is better than the lead;in the energy range of more than 300 Ke V,the traditional lead,antimony,tungsten and other heavy metals are better.In neutron shielding,the absorption of neutrons releases secondary gamma rays.We propose that in order to protect both neutron and photon radiation at the same time,considering the energy of gamma rays,it is possible to combine rare earth/polymer composite materials with lead and other heavy metals in order to achieve the purpose of nuclear radiation protection.