It’s only useful for dirty bomb style weapons that a terrorist might make. You can’t make weapons grade plutonium from it. All plutonium used in US weapons was made in special purpose reactors at Hanford, WA. We made so much of it and have enough stockpiled to build all the bombs we’d ever need that we shut down the production there in 1987.

It may be a useful resource for other types of nuclear plants though.

Ideally we could bury this really deep (as you propose) and forget about it. Or buy out Nevada’s opposition and reopen Yucca.