SBIR-STTR Award

The development of a fusion reactor-compatible valve should make a significant contribution toward providing vacuum hardware for next-generation tritium-burning devices and should find application in semiconductor manufacturing industries and elsewhere. It is planned to design in Phase I and build and test in Phase II a series of large gate valves up to 1 m diameter that meet the following characteristics: (1) double gate seals that can be differentially pumped; (2) an actuating mechanism that is not required to provide the gate-seal loading; (These two points result in a large weight (hence cost) savings.) (3) a valve body that is not required to react to the gate-seal loading because of radial-directed seal force; (4) scaling that is limited only by the atmospheric loading of the gate plates; (5) a gate shape that is not necessarily round; (6) operability with a minimum number of limited size particulates because of the use of a double gate with differential pumping; (7) a leak rate (undifferentially pumped and barring foreign bodies of too large a size) that becomes asymptotic to a specified level after a number of closure cycles; (8) no organic materials so the valve will be tritium compatible and radiation hardened.Anticipated Results/Potential Commercial Applications as described by the awardee:The results of Phases I and II should be a gate valve that can be used in fusion devices that use tritium and have a radiation environment, in the semiconductor manufacturing industry where high purity and speed of operation steps are important, and in the ion implantation industries. The Phase II work in cooperation with a valve manufacturing company should facilitate putting this valve into production. The planned Compact Ignition Tokamak (CIT) device might be the first use of this valve, should it be developed.

The development of a large ( > 40 cm diameter), innovative, fusion reactor-compatible gate valve should contribute significantly to the vacuum hardware needs of next generation, tritium-burning devices.The two-part program to develop a valve for use in these applications will first verify the concept by designing, building, and testing a 30 cm diameter valve and then, using the experience thus acquired, will design, build, and test a I m diameter valve. The valves will have the following characteristics: (I) double-gate seals that can be differentially pumped; (2) an actuating mechanism that is not required to provide the gate-seal loading. (This point results in a large weight savings and therefore a cost savings); (3) a valve body that is not required to react the gate-seal loading because of radial-directed seal force; (4) scaling that is limited only by the atmospheric loading of the gate plates; (5) ability to be operated with a minimum number of particulates of a limited size through employing a double gate with differential pumping; (6) a leak rate (undifferentially pumped and barring foreign bodies of too large a size) that becomes asymptotic to a specified level after a number of closure cycles; (7) a differential pumping option and low actuator loads that should provide high rcliability; (8) ability to be fitted either with radial pressure seals as a mounting option to enhance remote installation and removal or with more conventional metal seals; and (9) no organic materials so that the valve will be tritium compatible and radiation hardened as well as compatible with toxic gases. Phase I resulted in a feasible preliminary design of the valve. The building and testing of this valve will proceed in Phase II.Anticipated Results/Potential Commercial Applications as described by the awardee: The results of this development should be a gate valve that can be used ( I ) in fusion devices that employ tritium and have a radiation environment, (2) in the semiconductor manufacturing industry where high purity and speedy operation are important, and (3) in the ion-implantation and toxic-waste-handling industries. Work in cooperation with a valve manufacturing company should facilitate putting this valve into commercial production in Phase III. The proposed Compact Ignition Tokamak (CIT) and the Tritium System Test Assembly (TSTA) might be the first uses of this valve. Since the largest commercially available all-metal valve is only 40 cm in diameter, the existing need in the fusion program for a I m diameter valve will greatly aid in the marketability of the valve.Topic 9: Plasma Confinement Systems Technology