29th July 2011 - 03:22 AM
Direct conversion to electricity has been demonstrated from radioisotopes. It has a bad efficiency, better only than thermoelectric converters. Wherever a static converter isn't needed, conversion is made through thermal engines - understand: a turbine and alternator.
Magnetohydrodynamics works only in inventor's wishes and people's science up to now. When you put figures on its efficiency, it's ugly. Until someone comes with better ideas.
Neutrons heat materials (like liquid lead-lithium eutectic) as they lose speed there. Once you get heat, the rest is well-known.
Neutron absorption and heat removal are essentially the same in a Tokamak because neutrons receive most of the fusion energy. These functions are completely linked with tritium regeneration (search keywords) because both need to catch all neutrons.
Alas, tritium regeneration needs to multiply the neutrons, and the only promising method uses lead spallation, which creates huge amounts of radioactivity. As much radioactivity as a uranium reactor of identical power, see my estimates there:http://saposjoint.net/Forum/viewtopic.php?f=66&t=2450#p32310
What a disappointment. And what a deception by people working on tokamaks. Knowing that, I prefer to abandon tokamaks completely and concentrate on other sources.
The wall material is still an open question. People will certainly find materials (steel, graphite) that operate for some time. The material could even survive long enough that it gets replaced at the normal maintenance stops of the plant - if research succeeds. But specialists have admitted that this material will become hugely radioactive; their only (questionable) hope would be to restrict radioactivity from the walls to a few centuries.