CN-117757172-B - Neutron-gamma composite shielding material and preparation method thereof

CN117757172BCN 117757172 BCN117757172 BCN 117757172BCN-117757172-B

Abstract

The invention discloses a neutron-gamma composite shielding material and a preparation method thereof. The neutron-gamma composite shielding material takes the samarium oxide with the micro-plate structure as a neutron and gamma ray absorber, boron carbide as a neutron absorber and high-density polyethylene as a matrix material, and the samarium oxide with the micro-plate structure has high specific surface area, so that the interaction probability between the samarium oxide with the neutron-gamma ray can be increased, and the neutron-gamma shielding capability of the composite material is improved. In addition, the preparation processes such as high-energy ball milling and banburying are adopted to reduce clusters of the inorganic filler in the matrix and improve interface compatibility between the inorganic filler and the polymer matrix. The neutron-gamma composite shielding material containing the samarium oxide with the micron plate structure disclosed by the invention has higher thermal stability and mechanical property and excellent radiation shielding property, and can be used in the field of high-performance neutron-gamma radiation shielding in medium-low temperature environments, such as nuclear facility radiation protection, nuclear waste preparation, radiation medical radiation protection and the like.

Inventors

HUO ZHIPENG
LU YIDONG
ZHONG GUOQIANG

Assignees

中国科学院合肥物质科学研究院

Dates

Publication Date: 20260508
Application Date: 20231207

Claims (3)

1. The neutron-gamma composite shielding material is characterized in that samarium oxide with a micro-plate structure is used as a neutron and gamma ray absorber, boron carbide is used as a neutron absorber, high-density polyethylene is used as a matrix material, and the mass content of each component of the neutron-gamma composite shielding material is 67-72wt% of high-density polyethylene, 17-22wt% of boron carbide and 8-12wt% of micro-plate structure samarium oxide, wherein the density of the high-density polyethylene is 0.90g/cm 3 ~0.99g/cm 3 ; The particle size of the samarium oxide with the micro-plate structure is 0.1-10 mu m, the specific surface area is 1-100 m 2 /g, the pore volume is 0.01-0.5 cm 3 /g, and the average pore diameter is 1-100 nm; The samarium oxide with the micro-plate structure is prepared by the following method: (1) Weighing samarium nitrate and urea, wherein the molar ratio of the samarium nitrate to the urea is 0.01-10; (2) Dissolving samarium nitrate and urea in ultrapure water, stirring for 1-120 min at room temperature to uniformly mix the solutions, and then reacting the mixed solution at a constant temperature of 60-140 ℃ for 0.1-8 hours to obtain emulsion; (3) Centrifugally separating the emulsion to obtain a precipitate, and cleaning the precipitate; (4) And (3) placing the cleaned precipitate product into an oven, drying for 0.1-24 hours at a constant temperature of 30-120 ℃, and then transferring the precipitate product into a heating furnace, and sintering for 0.1-12 hours at a constant temperature of 300-1900 ℃ to obtain the samarium oxide with the micro-plate structure.
2. A method of preparing the neutron-gamma composite shielding material of claim 1, comprising the steps of: Mixing samarium oxide with a micrometer plate structure, boron carbide and high-density polyethylene, ball milling for 1-60 min to ensure uniform mixing, mixing the mixed powder in an internal mixer at 140-240 ℃ for 1-60 min, then placing the mixed product in a crusher for crushing operation, placing the crushed particles in a hot press die, and performing hot press operation by adopting a hot press under the conditions of firstly preserving heat and maintaining pressure for 1-30 min at 140-400 ℃ and the pressure applied by the hot press to the hot press die at 0-20 MPa, then preserving heat and maintaining pressure for 10-100 min at 180-400 ℃ and the pressure applied by the hot press to the hot press die at 5-90 MPa, finally preserving heat and maintaining pressure for 10-200 min at 190-400 ℃ and the pressure applied by the hot press to the hot press die, and then cooling, releasing pressure and demoulding to obtain the neutron-gamma composite shielding material.
3. The preparation method according to claim 2, wherein the aperture of the crusher screen is 0.5-50 mm.

Description

Neutron-gamma composite shielding material and preparation method thereof Technical Field The invention belongs to the technical field of radiation protection, and particularly relates to a neutron-gamma composite shielding material and a preparation method thereof. Background With the development of aerospace, radiology and civil nuclear power fields, higher requirements are put on nuclear radiation shielding. Various particles and radiation rays, such as alpha particles, beta particles, neutrons with different energies, gamma rays and other charged particles and high-energy rays, can be generated in the nuclear reaction process, and can penetrate the human body due to the strong energy of the high-energy neutrons and gamma rays generated in the nuclear reaction, so that various health problems of the human body, such as nerve injury, reproductive injury, heart disease, leukemia, cancer and the like, are caused, and the development of neutron and gamma radiation shielding materials is particularly necessary. The polyethylene is a typical hydrogen-rich material, has the advantages of light weight, easy processing and strong neutron attenuation capability, and is widely used in the radiation shielding field. The boron carbide material has a higher thermal neutron absorption section, and secondary gamma rays generated by thermal neutron capture reaction have weaker energy, so that the boron carbide material is widely used as a neutron absorber. The high atomic number and high density material has better shielding effect on gamma rays. The rare earth oxide (such as Gd 2O3,Sm2O3 and the like) has the characteristics of high thermal neutron absorption section, high atomic number and environmental friendliness, can be used as a filler of a neutron-gamma composite shielding material, for example, gadolinium has the high thermal neutron absorption section and the high atomic number, but gadolinium usually generates high-energy secondary gamma rays when interacting with thermal neutrons, and limits the use of the gadolinium in a neutron-gamma composite radiation field. Currently, the research of neutron gamma radiation shielding materials is focused on the adjustment and optimization of the types and the component proportions of the filler, and less attention is paid to the research of the microscopic morphology and the size of the filler. Some researches show that functional fillers with high specific surface areas (such as Bi 2WO6, cdO, pbO and the like) can increase the interaction probability of the fillers and radiation particles, and have positive influence on the shielding performance of the composite shielding material. However, the fillers used in these studies are all commercial agents, and their microstructure, particle size and specific surface area are not controllable. In addition, research reports on the relationship between the microscopic morphology of the rare earth-based filler and the radiation shielding performance, the thermal stability and the mechanical property of the composite shielding material are seen. Therefore, the synthesis of rare earth-based fillers with specific morphology and high specific surface area, in particular to Sm 2O3 filler with micro-nano structure, is necessary for the development of neutron-gamma composite shielding materials. Disclosure of Invention In order to solve the defects and shortcomings of the polymer-based composite shielding material, the invention aims to provide a neutron gamma composite shielding material and a preparation method thereof. The neutron-gamma composite shielding material is a neutron-gamma composite shielding material containing samarium oxide filler with a micron plate structure. The neutron-gamma composite shielding material is introduced with two types of fillers of the micron plate structure Sm 2O3 and the micron plate structure Sm 4 C with high specific surface areas, the introduction of the micron plate structure Sm 2O3 with high specific surface areas can increase the interaction probability of the shielding material with neutrons and gamma rays, the neutron-gamma shielding capacity of the composite shielding material is improved, and in addition, the neutron absorption energy ranges of Sm 2O3 and the neutron absorption energy ranges of Sm 4 C can be mutually supplemented. In addition, in order to solve the problem of interfacial compatibility between the polymer and the inorganic filler, the invention uses a series of processes such as high-energy ball milling, banburying and the like to reduce the problem of clusters of the inorganic filler in the matrix, improve the problem of interfacial compatibility between the inorganic filler and the polymer matrix and improve the mechanical property and heat resistance of the composite material. The invention is realized by the following technical scheme: the neutron-gamma composite shielding material takes samarium oxide with a micron plate structure as a neutron and gamma ray absorbent, b