[acidburnNSA]

Considering that Reagan reversed this policy by unbanning reprocessing in 1981, this isn't the only reason we don't do it today. Other reasons include that reprocessing is expensive and that we found a lot more uranium ore than originally expected.

https://sgp.fas.org/crs/nuke/RS22542.pdf

[sbierwagen]

The Indian test used weapons-grade plutonium produced in the low power CIRUS research reactor, much like how we were making plutonium in 1945. It's thought that Carter banned civilian reprocessing because a nuclear test in 1962 showed that a weapon could even be made from what the DOE described as "reactor-grade" plutonium: https://permanent.access.gpo.gov/websites/osti.gov/www.osti.... https://npolicy.org/greg-jones-americas-1962-reactor-grade-p...

A bomb with an actively cooled pit probably couldn't be miniaturized enough to be MIRVed but it would be compatible with old school single-warhead ICBMs or air delivery.