Irradiation Creep Lifetime Analysis On First Wall Structure Materials For CFETR

The first wall of CFETR(China Fusion Engineering Test Reactor,CFETR)service in the environment with high heat flow(0.3MW/m2),high irradiation damage(14MeV)and high speed coolant erosion(300-500 ℃),and CFETR second stage of development has a higher power and service temperature.Besides,the replacement of CFETR first wall is very expensive,time consuming and potentially dangerous as one of the harshest parts of the service environment.So,the fusion project design needs to focus on the service lifetime of first wall because the safety and feasibility of fusion reactor is relate to the service lifetime of first wall.This paper first summarizes the development of domestic and international structural steel of fusion first wall and various types of steel typical materials.In addition,the microscopic mechanism and model of irradiation creep are introduced,including SIPN model and SIPAmodel.Besides,the ANSYS finite element method was used to analyze the helium cold solid blanket of CFETR with fluid-solid coupling method,based on first-wall dual-channel model.The temperature and stress of first wall was calculated with different surface heat flux,different first wall thickness and different coolant inlet temperature.The results show that with the increase of heat flux,thickness and the temperature of coolant,the service temperature and stress are increased in different degrees,and the maximum temperature and maximum stress appear in the corner of U-shaped channel.At the same time,The L-M creep life extrapolation models of given material is obtained through combined with three kinds of structural steel irradiation creep rupture experiment and Larson-Miller model method.Furthermore,this paper analyze the St and Sm of candidate structural materials,the St of ferrite martensitic steel PNC-FMS and ODS steel 9Cr-ODS did not significantly reduce in the irradiation environment,and the irradiation creep Performance is less affected by radiation.While the St of austenitic steel has a large degree of reduction in the irradiation environment.The thermal creep St and irradiation creep St of 15-15Ti steel and PNC 1520 steel are better than that of PNC316 steel.In addition,the results show that the cold working has a certain effect on the thermal creep life,but the post-irradiation creep life of austenitic steels is not improved by cold working due to the greater ductility loss.The paper calculates and analyzes the irradiation creep life of PNC316,PNC1520,DIN1.4970,PNC-FMS and 9Cr-ODS based on CFETR helium cold solid blanket,and explores the effect of design parameters of the first wall on irradiation creep life.The results show that the creep life of CFETR decreases with the increase of heat flux,wall thickness and coolant inlet temperature.Consider the acceptable life,heat flux,wall thickness and coolant inlet temperature have some room for improvement.