Conceptual design study for CFETR divertor target using CLAM steel as structural material

This paper presents a design study of an optimized monoblock to meet the requirements for CFETR operating conditions, which establishes a good basis for engineering design of CFETR. The monoblock uses tungsten as armour and CLAM steel as the structural material, with a copper interlayer. The operating temperature window of CLAM steel was determined by irradiation embrittlement, softening, and other aging effects. Initial design rules for the W/CLAM monoblock were checked; thermal results by finite element analysis (FEA) show that the design concept is able to withstand a heat flux of 10 MW/m2 after examining the temperature for each material and the margin to the wall critical heat flux (WCHF) on the tube. Mechanical results indicate that the CLAM steel meets the ITER SDC-IC elastic rules under potential irradiation level of CFETR, irrespective of residual stress. Also the fatigue criteria were checked for unirradiated conditions with a reasonable life time of 16,000 cycles.