Study The Influence Of Impurities Seeding Plasma Exposure Deuterium Retention On Tungsten

In the nuclear fusion device,the high parameter plasma operation is bound to exceed the limitation of target.Tungsten has the advantages of proprerty.So it is most likely to be the first wall material for plasma in the future.The impurity gas injection into the fusion plasma can reduce the heat flow of divertor targets effectively,and produce thermal radiation through the ionization of the impurity gas.The energy is dispersed in a wide range to achieve cooling effect.The influence of different impurity gases on fusion plasma is different.However,it is inevitable that the impurities seeding interaction with the plasma facing materials when the impurities gas is injected.The erosion damages of plasma facing material by impurities seeding seriously affect it service behavior.based on this,three kinds of impurities plasma irradiation experiments were carried out to study the influence of impurities seeding exposure on the deuterium retention behavior in tungsten.The main conclusions of this thesis are as follows:1.The linear experimental plasma system?LEPS?is used to simulate the boundary plasma enviroment.The experimental results of low energy nitrogen seeding pre-irradiation show that nitrogen plasma pre-irradiation will increase deuterium retention in tungsten,the main reason is:nitrogen plasma pre-irradiated tungsten samples,A layer of tungsten nitride phase will be formed in the near surface region,which prevents the diffusion and escape of deuterium atoms along the surface direction,thus increasing the deuterium retention in tungsten.The formation of tungsten nitride phase prevents the diffusion and escape of deuterium atoms along the surface direction.2.In the experiment of doped nitrogen seeding in deuterium plasma irradiation tungsten carried out on LEPS,experimental results show that a certain amount of nitrogen seeding doped with deuterium plasma to irradiate tungsten samples will reduce the deuterium retention in tungsten,because the mixing of nitrogen has a certain dilution effect on deuterium plasma,the incident D atom interacts with the N atom on the surface to form compounds such as NH₂D,NHD₂ and ND₃,which makes the flux of D atom enter the material decrease.The deuterium total retention in tungsten decrease by 50%.3.the tungsten irradiated by argon doped deuterium plasma carried out LEPS.The experimental results of argon seeding mixing deuterium plasma show that a certain amount of argon plasma mixing would increase deuterium retention in tungsten due to the etching effect of argon on tungsten in the.The retention of deuterium in tungsten increases by providing more trapping sites for deuterium on the surface of tungsten samples.the deuterium total retention in tungsten increase by40%.