Preliminary Numerical Simulation Of Pellet Injection Fueling Efficiency And Fueling Particles Deposition In The CFETR Tokamak

The goal of China Fusion Engineering Test Reactor(CFETR)is to achieve the fusion output power from 200 MW to 1 GW and realize tritium self-sustaining.How the fuel replenishment to a H-mode burring plasma is efficiently carried out is very important to achieve this goal.It is difficult to achieve the target of fuel consumption required by the traditional ways such as gas puffing and supersonic molecule beam injection.As a mature way of fueling,the pellet injection has been verified in many large-scale devices,and it has been selected by ITER as the main way of fuel replenishment.Therefore,pellet injection is the most likely technical scheme to achieve effective fueling on CFETR.In this thesis,the ablation,deposition,transport and other physical processes of pellet injection in tokamak are studied by analytical calculations and numerical simulations.Firstly,according to the neutral gas shielding(NGS)model of pellet ablation,the injection depth and charging efficiency of the pellet injection in the tokamak device under different conditions are calculated.Secondly,the injection depths of pellet injection at both the high field side and the low field side are compared and discussed.A two-dimensional transport model of burning plasma is established based on the transport module of BOUT++ package.The fueling process of pellet injection into high temperature plasma was studied.The ablation of the pellet injected into the background plasma and the transport of the resulting fuel particles is simulated by coupling the trans-neut module and the NGS model.The influence of the fueling process on the properties of the background plasma is studied,and the corresponding simulated injection depth is compared with that predicted by the NGS model.This preliminary study provides reasonable suggestions for the feasibility of pellet injection fueling in CFETR and the optimization of device design parameters.