A First Principle Study On Tritium Resistance Mechanism Of Al₂O₃/Ti₂O₃ Composite Interface On The Inner Wall Of Nuclear Fusion Reactor

The tritium permeation barrier is an important part of nuclear fusion reactor,and the choice of its material is one of the key problems in the current research.The good performance of the tritium permeation barrier can prevent the radioactive isotope penetration in the fusion reaction,reduce pollution,and extend the life of the nuclear fusion reactor.At present,alumina coating and titanium matrix composite coating have shown good tritium resistance.In order to improve the performance of the coating,people began to develop composite materials as tritium resistance coating.However,most of the current research focuses on the preparation and technology of materials,and the mechanism of tritium resistance is not deeply explored.In this paper,the behavior of hydrogen atom in the?-Al₂O₃/Ti₂O₃composite interface is simulated and analyzed by using the first principle method.Main research contents include:(1)The Al₂O₃/Ti C composite coating prepared by laser-assisted combustion synthesis has a good tritium resistance capability,and the?-Al₂O₃/Ti₂O₃composite interface formed in the composite coating has an important impact on the performance of the tritium resistance coating.In this paper,molecular modeling of?-Al₂O₃/Ti₂O₃composite interface is carried out,and the reasonable interface model structure is determined by simulation.(2)The adsorption of hydrogen isotopes at the composite interface was analyzed.In the process of hydrogen atom passing through the whole composite coating,the adsorption energy value of the surface is the lowest,indicating that the surface has the strongest adsorption capacity for free hydrogen.When hydrogen atoms invade the surface of?-Al₂O₃,the adsorption energy starts to rise,which indicates that the coating has an obstacle to the penetration of hydrogen atoms.The adsorption energy of the interface bonding part decreased obviously,which indicates that the composite interface can effectively capture hydrogen atoms.(3)The diffusion path of hydrogen atom in?-Al₂O₃/Ti₂O₃composite coating is analyzed.Two paths are calculated.The maximum diffusion barrier is 3.392 e V and4.050 e V,respectively,when the hydrogen atom enters the junction of the composite interface from?-Al₂O₃part;The second is the surface part of?-Al₂O₃,which plays a key role in preventing hydrogen isotopes from entering the coating.The high reaction barrier effectively inhibits the diffusion of hydrogen atoms.Combined with the preparation and experiment of composite coating,the adsorption and diffusion behavior of hydrogen isotopes at the interface of composite coating was analyzed by simulation in this paper.The mechanism of composite coating was studied,and the advantages of composite materials as tritium resistant coatings are proved.It provides a reference for the preparation and optimization of tritium permeation barrier.