COOLING OF PLASMA FACING COMPONENTS USING HELIUM-COOLED POROUS METAL HEAT EXCHANGERS

Helium-cooled porous metal heat exchangers are being investigated for cooling of plasma-facing components such as the International Thermonuclear Experimental Reactor (ITER) divertor. The large surface area of porous metals makes it possible to perform efficient cooling using gas coolants. Two generations of helium-cooled porous metal heat exchangers have recently been developed and tested. The first test article was tested at Sandia National Laboratories in August 1993; a record 16 MW/m 2 absorbed heat flux was demonstrated during these tests and heat transfer coefficients of 5,000 to 7,000 W/m 2 /°C were inferred. Using results of these first tests, optimization studies were initiated to define a more optimum design, based on the helium blower power requirements for an ITER gas divertor system. A second generation test article was built and tested; heat transfer coefficients of 15,000 to 18,000 W/m 2 /°C were demonstrated in these tests using 2.0 MPa (300 psi) helium gas, and high heat flux testing at Sandia National Laboratories is planned. Additional improvements are possible through improved gas channel design and improved fabrication techniques. These results show that the potential of gas cooling to meet the needs of high heat flux applications such as the ITER divertor.