Th fuel will definitely not become a big deal anytime in the next several decades. I think the surplus Pu covered by a US-Russian treaty was supposed to be blended w Th for this purpose but after spending > $15B of your tax $ building facilities in SC to do the job, the feds canned the project and decided to bury the stuff in NM. Of course, that’s another boondoggle larded w fraud and waste that will cost >> $15B but everybody seems to love playing musical chairs.