Design And Gama Ray Radiation Shielding Effects Of Materials Incorporated With Bismuth Oxide

Nuclear radiation shielding material is the most important physical guarantee of radiation protection.Researching on radiation shielding material will be beneficial to insuring nuclear science and technology in the cause of sustainable and healthy development.After reviewing recent researches on radiation shielding concretes,we found that there is a tendency to use lightweight-heavyweight aggregate mixing technology in the development of novel radiation shielding concretes.However,additives like lead powder being used either require special crushing processes or pose hygiene hazards like dust and toxicity.Therefore,for this research,we proposed a new idea to develop the Bi₂O₃-loaded concrete mixtures by adding Bi₂O₃ powder in the ordinary concrete mixture as a novel environmentally friendly radiation shielding material.On the other hand,during the pouring and use of the concretes,they may be cracked.And there is always irregular shape of hole in the concrete structure connections.Radiation will leak through the cracks and the hole.In order to solve these problems,we proposed preparing Bi₂O₃/Epoxy composites by adding Bi₂O₃ powder in the epoxy matrix as a novel environmentally friendly radiation shielding and repairing material.Our main research results are as follows:Concretes incorporated with the Bi₂O₃ additives offered better linear attenuation coefficient than those incorporated with the PbO additives at0.36%-1.05%.An increased attenuation of 3.15%,4.20%,5.53%,5.97%,and 6.42%can be observed for Bi₂O₃-loaded concrete specimens with additive rates of 5%,10%,15%,20%,and 25%,respectively.There's a high correlation coefficient of 0.9564 between the experimental values and the theoretical values calculating by XCOM.It can be used to estimate radiation shielding properties of those concretes.The mass attenuation coefficients of 25%Bi₂O₃-loaded concrete and those values of25%PbO-loaded concrete were similar in the majority of energy region expect the energy region around K-absorption edge of Bi and Pb.The Bi₂O₃ addition and PbO addition enhanced the shielding ability against gamma rays for these concrete specimens especially in a certain photon-absorption region ranging from 0.01 MeV to 0.5 Me V according to theoretical analysis.The minimum and maximum Z_eff values of the25%Bi₂O₃-loaded concrete specimens were 9.475-26.071.The ordinary concrete specimen showed significantly lower compressive strength values compared to the 25%Bi₂O₃-loaded concrete specimen.And all the concrete mixtures showed compressive strength values higher than 30MPa.Of all the concrete specimens considered in this study,25%Bi₂O₃-loaded concrete exhibited the best radiation shielding ability and mechanical property among the various mixtures.It can be used in various nuclear facilities where low dimension requirement and high hygienic requirement must be met.And it will be beneficial to reduce the radiation harm and save budget.The mean effective atomic number of Bi₂O₃,25%Bi₂O₃-loaded concrete and epoxy were 67.7420,15.0729 and 5.5552,respectively.For the 137Cs?-ray source of 0.662 keV,an increased attenuation of10.46%,53.17%,122.36%,and 231.26%can be observed for Bi₂O₃/epoxy composites with additive rates of 10%,30%,50%and 70%,respectively.And this trend was similar to that of the PbO/epoxy composites.50%Bi₂O₃/epoxy composites can be used as fillers for 25%Bi₂O₃-loaded concrete'cracks and voids.And this conclusion can be theoretically applied to photon energy in the range of 2.59 keV-0.60 MeV and 10 MeV-100 GeV.All the Bi₂O₃/epoxy showed tensile and flexural strength values higher than 10 MPa,and 30 MPa,respectively.