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Power and gas flow models for monoenergetic neutral beam injectors

Description: Large, ignition tokamak reactors (ITR, EPR, and beyond will require supplemental heating to achieve ignition. In the earlier machines, at least, this heating will probably be provided by monoenergetic neutral beams. These beams, with energies approximately greater than 150 keV, will most likely be derived from D/sup +/ or D/sup -/ ions produced by direct extraction ion sources. A positive ion source will be followed by a bending magnet, a neutralizer, and a second bending magnet. The first magnet will remove molecular ions, and the second one atomic ions. Direct convertors will be used to recover energy from unused molecular and atomic ions. The first bending magnet may be omitted if D/sup -/ ion sources are used. Models have been developed for power and gas flow in injectors which employ direct extraction D/sup +/ or D/sup -/ ion sources. The power flow model accounts explicitly for all beam losses in terms of line densities of gas along paths traversed by ions and neutrals and cross sections for dissociation and charge-changing collisions. The gas flow model uses the results of power flow calculations and known gas flows from sources and neutralizers to determine gas loads and pumping requirements in various parts of the injector.
Date: January 1, 1977
Creator: Fasolo, J.A.
Partner: UNT Libraries Government Documents Department

Vacuum for a tokamak experimental fusion power reactor

Description: A preliminary study was made of the vacuum system requirements for a D-T burning TEPR with major radius R = 6.25 m and plasma radius a = 2.1 m. Approximate requirements for the neutral injector vacuum system have been determined as functions of neutral beam power for a one-component, 180 keV D$sup 0$ beam derived from D$sup +$. For the 40 MW reference design D$sup 0$ beam, the total injector gas load varies from approximately 500 to approximately 800 Torr-l/ s as the assumed ion source gas efficiency varies from 40 to 25 percent. The torus or plasma containment vessel has 711 m$sup 3$ of volume and 592 m$sup 2$ of surface area. Material selection for the first wall will affect the total gas load available to be pumped. The toroidal pumping system must be able to reduce the pressure after the burn or fusion cycle from 10$sup -3$ Torr to 10$sup -5$ Torr or less in 10 to 15 s. Furthermore, before each experimental run, or possibly more often, this pumping system must be capable of evacuating the entire volume down to 1 x 10$sup -8$ Torr or less to assure a reasonably contamination free plasma. (auth)
Date: January 1, 1975
Creator: Moenich, J.S.; Fasolo, J.A. & Stevens, H.C.
Partner: UNT Libraries Government Documents Department