We don't have any nuclear weapons for it to play with. At least, not yet.
What we have is an electronically controlled delivery tube system which handles the fuel rods. I *suppose* if they were to be operated beyond their standard tolerances, the fuel rods might exit the gas-tight fuel-rod ports in the hull of the castle enclosure at rather a high velocity, most likely spinning rapidly as well.
If another vessel were so unfortunate as to be in the path of such a "missile", it would very likely involve casualties.
And if several of these fuel rods happened coincidentally to arrive in the same place, at about the same time, why I think there might possibly be a rather spectacular explosion.
Of course, all this is mere idle speculation. It would take a remarkable series of coincidences to arrange such an "accident."
I was thinking more along the lines of it hacking into the DefCon network and pulling a SkyNet on us.