> I don't remember the details, but I do remember there were
> many unanswered technical issues; whether they're solvable is another
> question, but people were impressed enough at the time that nuclear
> might be possible,
> as they'd previously assumed they'd be limited to chemical energy..
It still wouldn't make them possible. To get power out of the reaction you have to be able to capture the radiation produced by the fusion reaction, and convert it into a useful form of energy. To do that you need a barrier of fairly dense matter at least a few inches thick. A nanoscale reactor would simply irradiate the area - there would be no way for the nanobots to capture a significant amount of energy from the reaction.
Billy Brown, MCSE+I