Nukes are just big bombs, plus a whole fuckton are going to fail. Imagine launching 1960s rockets tipped with 1960s warheads. Sixty year old rockets. Nuclear deterrence is a bluff, any country deploying them en masse is also going to inevitably dirty bomb the hell out of itself since the failure rate is going to be non-zero. I would assume a nuclear detonation would not occur and it'd just spread uranium everywhere when the rocket exploded.