CANDU

>
> [snikt]
> > cost - the simplest reactors still need enriched uranium unless
you
> > want to build a CANDU reactor (very!! big). Enriched uranium is
not
> > cheap. Plutonium is even more expensive.
> >
> What's a CANDU reactor?
>
A CANDU reactor is the only type of reactor that can burn natural
unenriched uranium. I had a tour of one before it was turned on
(Darlington, near Toronto Canada). The Caldera (the part that contains
the uranium) is a cylinder 20 m in diameter and 80 m long. The size is
a requirement to get enough uranium together to reach critical mass.
The key is using heavy water as the moderator not light water.
Unfortunately the minimum size is large.