TR, what follows is from memory; since you have actual experience in this field please jump in if I am making any totally erroneous
statements.
Admiral Rickover told us that the "waste" should be stored until we knew enough to reuse it, as it still contained a great
deal of power that we simply did not understand how to extract with the then-current state of the art.
Another learned man (at this moment the name escapes me) told us to mix the slurry into a particular type of cement,
form that into bricks, and then stack the bricks in any convenient piece of desert; mixed in that manner there was
no radiation hazard and the nuclear material could be extracted once we learned how to reuse it per Admiral
Rickover.
None of this was done - not because it wasn't possible, but because the political climate in the country at the time
would not support it. Few people understood any of the science but were convinced that any such "waste" was
a clear and present danger no matter how it was handled. Everyone remembered Hiroshima and Nagasaki and knew
that a power plant could turn into a bomb in a split second. Everyone was wrong of course, but that didn't matter.
These fears drove the decisions about nuclear power; in some ways, they still do.