A HIGH PERFORMANCE HEAT EXCHANGER FOR HIGH HEAT FLUX COMPO- NENTS OF FUSION REACTORS

ACTIVE COOLING IS ESSENTIAL FOR FUSION REACTOR COMPONENTS EXPOSED TO HIGH HEAT FLUX LEVELS OVER LONG PULSE DURATIONS. EXISTING WATER COOLING CONCEPTS FACE A POTENTIAL PROBLEM WITH TRITIUM PERMEATION. HELIUM GAS COOLING CONCEPTS NOW BEING CONSIDERED SUFFER FROM LOW HEAT TRANSFER COEFFICIENTS AND HIGH PRESSURE DROP AND PUMPING POWER. THESE EXISTING TECHNIQUES, THOUGH ACCEPTABLE FOR PRESENT FUSION DEVICES, FALL SHORT OF EXPECTED FUTURE NEEDS. A HIGH PERFORMANCE GASCOOLING CONCEPT CAPABLE OF MEETING PRESENT AND FUTURE HEAT FLUX NEEDS AT LOW PRESSURE DROP IS HIGHLY DESIRABLE. IN THIS PROJECT AN INNOVATIVE HEAT EXCHANGER WILL BE DEVELOPED FOR FIRST WALL COOLING WITH HELIUM GAS COOLANT, HAVING HIGH HEAT FLUX AND HIGH EFFECTIVENESS. THIS CONCEPT WILL ALSO BEAPPLICABLE TO OTHER HIGH HEAT FLUX COMPONENTS SUCH AS LIMITER AND DIVERTER PLATES. THE NOVEL DESIGN PROMISES HIGHHEAT FLUXES AT MODEST PRESSURE DROP IN THE COOLANT, THUS REDUCING PUMPING POWER REQUIREMENTS. IN ADDITION THIS CONCEPT WILL RESULT IN MORE UNIFORM SURFACE TEMPERATURES IN THE FIRST WALL, THUS REDUCING THERMAL STRESSES. HEAT TRANSFER PERFORMANCE LEVELS CONSISTENT WITH PRESENT FUSION DEVICES AND EXPECTED FUTURE NEEDS CAN BE ACHIEVED WITH SINGLE PHASE COOLANTS IN THE PLANNED HEAT EXCHANGER GEOMETRY. IN PHASE I THE HIGH HEAT FLUX CAPABILITY OF THE CONCEPT WILL BE DEMONSTRATED. A PROTOTYPE FIRST WALL MODULE EMPLOYING THE HEAT EXCHANGER WILL BE DESIGNED TO BE BUILT AND TESTED IN PHASE II.