Yeah, they thought lithium-7 was just junk that was left over because they couldn’t completely do isotope separation yet. Whoopsie daisy, looks like we irradiated a whole shitton of sodium and blew it all over the place along with our fission products from more completely fissioning the uranium tamper.
Incidentally that’s why Russia’s nuclear torpedo was called a radiological weapon. It wasn’t necessarily salted with cobalt, just the seawater is salted enough that when you neutron activate it you get a very nasty short lived gamma emitter that’ll ruin your day if you get sprayed with it just as much as any fission product.
See test Baker from Operation Crossroads, which wasn’t even a damn fusion bomb. They kept the sailors trying to clean the ships with goddamn radioactive water. en.m.wikipedia.org/wiki/Operation_Crossroads#Indu…