http://newenergytimes.com/news/2008/123abc.htm#lehn
The guest article suggests extracting helium from liquid lead is a problem. A continuous process centrifuge, like those used to extract cream from milk, should do the job very well.
The real problem with the tokamak I think is the idea is about to be replaced with something much better.
Horace Heffner http://www.mtaonline.net/~hheffner/
