My designs are going for most eu out of each cell used since you don't really get a massive amount of these cells.
Thorium Mark 1 - efficiency:7
http://www.talonfiremage.pwp.blueyonder.co.uk/v3/reactorplan…bv2ughpazsl4ow0
Plutonium Mark 1 - efficiency: 4
http://www.talonfiremage.pwp.blueyonder.co.uk/v3/reactorplan…7ejstxe6ly6ysqo
If you can find any way to improve these feel free to share :P.
Also as a side question I noticed it becomes near impossible to have Mark 1's with more then 600 heat generated are there any good ways to get to 700 or 800 heat?