Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

Early application of the simple axisymmetric mirror, requiring intermediate performance between a neutron source for materials testing Q=Pfusion/Pinput ~0.05 and pure fusion Q>10, are the hybrid applications. The Axisymmetric Mirror has attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, as well as the typical mirror features of inherently steady-state operation, and natural divertors in the form of end tanks. This level of physics performance has the virtue of being low risk with only modest RD and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 3 keV, for the DT injection energy ~ 80 keV from existing positive ion neutral beams designed for steady state. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 40 m is discussed. Simple circular steady state superconducting coils are based on 15 T technology development of the ITER central solenoid. Three groups of physics issues are presented: axial heat loss, MHD stability, and microstability of sloshing ions. Burning fission reactor wastes by fissioning transuranics in the hybrid will multiply fusion’s neutron energy by a factor of ~10 or more and diminish the Q needed to overcome the cost of recirculating power for good economics to less than 2 and for minor actinides with multiplication over 50 to Q~0.2. Hybrids that obtain revenues from sale of both electricity and production of fissile fuel with fissioning blankets might need Q 4.