A Continuous Low-Inventory Tritium Fuel Cycle for Fusion

A Continuous Low-Inventory Tritium Fuel Cycle for Fusion DOE Grant No. DE-FG02-98ER86075 Amount: $99,999 Small Business Cryogenic Applications F, Inc. 450 Bacon Springs Lane Clinton, TN 37716-5311 Dr. Christopher A. Foster, Principal Investigator Dr. Christopher A. Foster, Business Official (423) 435-5433 Research Institution Los Alamos National Laboratory MS C334 P.O. Box 1663 Los Alamos, NM 87545 Fusion reactors based on magnetic confinement of plasmas require active pumping and fueling to replenish the deuterium-tritium which escapes the plasma and to remove the helium which is produced during the burn. Cryogenic pumps and frozen pellet injection are the most efficient means of pumping and refueling the tokamak plasma during the burn cycle. However, since tritium is a radioactive gas it is important to limit the total trituim inventory of the reactor to a minimum. A low inventory pumping and fueling system based on a continuous cryopump technology will be assembled and fully tested with tritium at the Los Alamos National Laboratory Tritium System Test Assembly (LANL/TSTA). The continuous cryopump fuel cycle will have reduced inventories since the system removes and directly re-injects 95% of the deuterium-tritium fuel back into the plasma as pellets. The remaining deuterium-tritium and helium will be pumped by a charcoal cryosorption pump developed at LANL/TSTA and processed through the TSTA isotope separation system. Phase I will produce a detailed design and analysis of the combined system. The design will include modifications required to integrate a charcoal cryosorption pump into the existing continuous cryopump, a layout of the system integrated into the TSTA tritium facility, and a detailed analysis of the tritium containment system. The analysis will simulate the performance of the system for design optimization and failure mode prediction. Commercial Applications and Other Benefits as described by the awardee: A practical low inventory tritium fuel cycle should reduce the tritium inventory in a fusion reactor by 50% and reduce the refrigeration requirements by a factor of 28 compared to current cryopump designs. This will dramatically reduce the complexity and cost of the pumping and fueling systems while enhancing reactor safety. The continuous cryopump technology could also be used to improve performance and reduce costs of conventional pumps used in micro-electronic fabrication._