You could transfer the clean fuel as a powder and pelletize and assemble fuel bundles on-site. Just mix the powder with a bunch of frangible containers of deple

You could transfer the clean fuel as a powder and pelletize and assemble fuel bundles on-site. Just mix the powder with a bunch of frangible containers of depleted uranium powder like glass cylinders and if the need arises or in an emergency situation (crash in transport), you've mixed the mildly enriched reactor grade fuel with enough depleted uranium to make it largely worthless. For an operating reactor it would definitely need to be passively safe. If you went with a molten salt breeder reactor or even just a non-breeder like the MSRE you could dump the fuel salt into your drain tanks mixed with a bunch of some boron compound. You could set off small charges to spray a bunch of dimethylmercury all over the outside of the reactor to kill anyone foolish enough to enter the building. I think that would be banned by the Geneva convention but the point is that there are ways of "salting the earth" within a short amount of time.