AN ARGON-FROST CONTINUOUS CRYOPUMP FOR FUSION APPLICATIONS

FUSION REACTORS BASED ON THE MAGNETIC CONFINEMENT OF PLASMASWILL REQUIRE HIGH SPEED PUMPING OF HELIUM, DEUTERIUM, AND TRITIUM AT HIGH THROUGHPUT WHILE LIMITING THE INVENTORY OF TRITIUM IN THE PUMPS TO A LOW LEVEL. MINIMIZING THE TRITIUMINVENTORY OF A FUSION REACTOR IS VERY DESIRABLE BECAUSE IT IMPROVES THE PASSIVE SAFETY OF THE REACTOR. A COMPOUND CRYOPUMP WAS SELECTED BY THE INTERNAL THERMONUCLEAR EXPERIMENTAL REACTOR (ITER) DESIGN TEAM FOR THE CONCEPTUAL DESIGN OF THE ITER VACUUM PUMPING SYSTEM. UNFORTUNATELY, INEXISTING DESIGNS, THE CRYOPUMP MUST BE REGENERATED FREQUENTLY TO LIMIT THE INVENTORY OF TRITIUM IN THE PUMP. THIS FREQUENT REGENERATION REQUIRES RAPID CYCLING OF MANY LARGE VACUUM AND CRYOGENIC VALVES AND OTHER COMPONENTS, COMPROMISING THE RELIABILITY OF THE SYSTEM AND POSSIBLY LEADING TO A HIGHER TRITIUM INVENTORY THAN DESIRABLE. A CONTINUOUS COMPOUND CRYOPUMP IS BEING DEVELOPED THAT MEETS THE ITER PERFORMANCE REQUIREMENTS WITHOUT CYCLING THE PUMP, WHILE REDUCING THE TRITIUM INVENTORY IN THE PUMPING SYSTEM FROM 400 GRAMS TO LESS THAN 100 GRAMS. THIS COMPOUND CRYOPUMP REQUIRES AN EXTENSION OF THE CRYOPUMP TECHNOLOGY BEING DEVELOPED FOR VARIOUS APPLICATIONS; THE NOVEL UNTESTEDFEATURE IS A CONTINUOUS ARGON-FROST CRYOSORPTION PUMP. THE PHASE I EFFORT SHOULD DEMONSTRATE THE FEASIBILITY OF THIS FEATURE AND PRODUCE A CONCEPTUAL DESIGN FOR A PROTOTYPE PUMP FOR THE ITER. THE PHASE II EFFORT WILL UNDERTAKE TO DESIGN AND CONSTRUCT A PROTOTYPE ITER PUMP SUITABLE FOR TESTING AT A DOE TRITIUM FACILITY.