Thermo-structural design of the ARIES-III divertor with organic coolant in subcooled flow boiling

The thermal-hydraulic and structural design of the ARIES-III divertor plate is presented. The divertor plate is made of small-diameter W-3Re tubes laid along the radial direction and coated with 4 mm of plasma-sprayed tungsten on the plasma-facing side to withstand one hard disruption. The plate is contoured to have the constant heat flux of 5.44 MW/m² on the entire surface. The total divertor thermal power of 629 MW is removed by the organic coolant HB-40 with the same inlet/exit temperatures (340°C/425°C) as in the first-wall/shield coolant circuit. The principal mode of heat transfer is by subcooled flow boiling. The inlet pressure is 5.34 MPa and the exit pressure is 4.3 MPa, which, by passing through an orifice, is reduced to 1 MPa, equal to the first-wall/shield exit pressure. The total coolant flow rate is 3.35 m³/s and the circulation power is 18 MWe. The maximum plate temperature is 821°C. The safety factor with respect to the critical heat flux is ⩾2, and it is ~3 with respect to the maximum allowable plate temperature. Maximum equivalent total, thermal, and pressure stresses are also given