Applications of MHD energy conversion to magnetic fusion reactors

Magnetic Fusion reactors have several characteristics which make them conducive to MHD energy conversion: (1) Large blanket volumes with high magnetic fields (100's of m/sup 3/ at B = 2 - 5 T). (2) Deeply penetrating neutrons and gammas which can heat high temperature pebble-beds behind tritium breeding zones, to produce high temperature heat suitable for MHD conversion (DT reactors) (3) No fission products which would tend to leak out of the high temperature pebbles above 16000K. (4) Production of useful microwave synchrotron radiation from high temperature plasma electrons, which can be used to superheat gas or vapor in-situ, to temperatures much higher than ceramic wall temperatures. (Best for D-3He reactors) For DT reactors, use of an MHD Rankine cycle of Mercury seeded with Potassium yields a higher superheat temperature in a two-zone fusion blanket than possible with helium-cooled blanket in a Brayton cycle. Savings in piping and balance-of-plant is the goal, rather than high efficiency. D-3He can produce the largest ratio of P/sub microwave//P/sub fusion/ of all fusion fuel cycles, yielding highest MHD cycle efficiencies