Orbiting fusion reactors (was: Mirrors versus diffuse reflection)

>>>They do, but it does not affect the fission reaction.
The material degradation is a containment issue, and is handled by
overdesigning the containment vessel to make it damage tolerant.>>>

Actually, neutron embrittlement is a really big problem in fission
reactors. Westinghouse PWR's use a core barrel and neutron panel, in an
effort to try and shield the pressure vessel from the hard neutron flux. In
a fusion reactor you could try something similar (that is, you would coat
the interior of the torus with a thin layer of material with high neutron
cross-section, cadmium? ). The big difference is, that the interior of a
fusion reactor will need to be replaced much more regularly. It will also
be highly radioactive, although most of the radioactive products will
probably have short half-lives.

Tony