Well, if we're going to play the game of assumptions, then you're assuming Russians have bothered to maintain their warheads properly. Given the very plausible theory that Nord Stream 1 and 2 were taken out as a result of the Russians trying to clear a methane hydrate plug from their side alone and wound up rupturing both pipelines (which, just so we're clear, they've done before)... I'd be a little skeptical of anything involving Russian nukes and the viability of their warheads.