Preparation Of Inorganicfunctional Materials Containing Lead And Boron For Jointly Shielding Of Neutron And Gamma Radiations

With the rapid development of nuclear science and technology,nuclear activities and operations have become increasingly frequent.Effective measures need to be taken to protect the radiation,especially the mixed radiation field containing both neutron and gamma rays to ensure the safety of workers and the normal operation of equipment.In general,light elements(such as H and B)can absorb neutrons;heavy elements can attenuate gamma rays.However,there is no inorganic functional material that can effectively protect neutrons and gamma rays at the same time.For this purpose,it is necessary to combine hydrogen element and heavy element to prepare a new functional material to shield neutron and gamma rays.Firstly,the Pb3B10O16[OH]4 crystals with different shapes and sizes were assembled by the hydrothermal synthesis method to combine the heavy element lead and light elements boron and hydrogen into the function of protecting neutrons and gamma rays Different amount of ammonia is correlative to the degree of supersaturation,which cause more monomer in the reaction The larger the concentration of monomer lead to more nucleates.Thesize of Pb3B10O16[OH]4 crystal can be converted from tens of micrometers to nanometer level.With the increase in the amount of Pb3B10O16[OH]4 crystals,the shielding ability for rays increases.Comparing the absorbability of Pb3B10O16[OH]4 crystals with different scales and morphology,the results show that the sheet material exhibits the best shielding performance.The nanostructured material exhibits better absorption of neutrons and gamma rays.Second,to meet the protection needs of complex radiation environments(such as neutron-dominated).BN/PbWO4 composites andBN@PbWO4 core-shell structure are synthesized,which can control the radiation protection performance of materials by controlling B content in the functional structure.BN/PbWO4 composites can be prepared by hydrothermal method.The morphology and size of the materials are related to the amount of BN added.When the relative mass of BN is 3wt%,the BN-wrapped on rod-like PbWO4 crystal is formed.The sol-gel methods can be used to synthesize BN on the surface of PbWO4 crystal in situ to form a novel BN@PbWO4 core-shell structure material.Neutron and gamma radiations shielding performance of the as-synthesized samples are tested.The shielding ability decreases rapidly with the increasing gamma-radiation energy.Material showed the highest shielding performance at 105.3 keV,shielding rate reached 78.45%.The content of boron element in the material is main reason for the rapid increase in neutron shielding rate,almost 90%of thermal neutrons are absorbed.