I have heard of a reactor that uses depleted uranium as a fuel source. It's called a Traveling wave reactor. This would be a good way to get rid of all that DU we have lying around. The down side is that the tech is currently still being researched according to the few pubs I took a look at. As such it is a long tem project which would be a good idea to start now (yes I DO know that we have a buget crises)
or at least get some people to really start looking into it as a viable project instead of having the tech finally come out and having to wait ten more years to impelment it because we weren't ready for it.