Calculation And Analysis Of Shielding Effectiveness And Radio-toxicity Of Depleted Uranium Applied To Nuclear Power Reactor Protection

Depleted uranium is uranium with a lower content of ²³⁵U than natural uranium and is a by-product of nuclear fuel production.With the application of nuclear energy,nuclear-related countries have accumulated a large amount of depleted uranium,and most of them have been stored and processed.There are no other better disposal and processing methods,but their storage management costs are relatively expensive.Finding possible ways for the treatment and disposal of depleted uranium has become a hot issue of concern in various countries.Depleted uranium has a good shielding effect on both?-rays and X-rays,and is a structural shielding material with excellent performance.It has also been more maturely applied in?-ray protection.The use of shielding materials based on depleted uranium will Significantly reduce the size and weight of storage,transportation and disposal containers.Limited by volume and weight,marine nuclear power plants have high requirements for the performance and lightness of shielding materials,so depleted uranium can be considered as a protective material for marine nuclear power cabins.However,due to the strong neutron radiation field in the nuclear power reactor cabin,it will cause the activation and fission of depleted uranium,cause the generation of secondary gamma rays and increase of radionuclides,which may cause comprehensive shielding of depleted uranium.Changes in performance and radiotoxicity.Therefore,when using depleted uranium as a radiation protection material for marine nuclear power cabins,it is necessary to study and analyze the comprehensive shielding performance and radioactive toxicity of depleted uranium in neutron and?mixed radiation fields over time.In this paper,a pressurized water reactor is used as a reference model for a marine nuclear power reactor,and a Monte Carlo particle transport program?MCNP5?is used to construct a marine nuclear power reactor core and shielding layer layout model.The coupling method considers the effects of secondary?-rays and the changes in the composition of the depleted uranium shielding material after neutron irradiation,and simulates and analyzes the comprehensive shielding of depleted uranium against neutrons and?-rays in a mixed radiation field.Performance,and compared with lead as a shielding material,the results show that when depleted uranium is used as a protective material for marine nuclear power cabins,its comprehensive shielding performance is related to its location;The research and analysis of the comprehensive shielding performance of depleted uranium materials with different thicknesses show that as the thickness increases,the difference in shielding performance between depleted uranium and lead appears to increase first and then decreases,but within the thickness range of 10 cm,Its comprehensive shielding performance is still better than lead,but considering the lightweight requirements of shielding materials,when using depleted uranium as a shielding material,a suitable thickness should be selected;In the research on the shielding performance of depleted uranium against incident neutrons with different energies,it is found that in the resonance region,the difference between the neutron shielding performance of depleted uranium and lead fluctuates greatly,and the shielding performance of depleted uranium will be worse than that of lead.Case.At the same time,the types,masses,and radioactivity of the products produced by depleted uranium materials after 1,20,and 40 years of neutron irradiation were simulated.The limits of the annual intake of depleted uranium before and after irradiation were analyzed.Radioactive toxicity under the definition of ALI.The results show that the added secondary products have little effect on radiotoxicity.