I believe the restriction is based on nuclear weapons, not reactors. That is, personnel are not allowed to confirm or deny that a given ship is carrying nuclear weapons. This has gotten the Navy banned from a few ports, particularly in New Zealand where the government requires a ship certify that it is "nuke free" before entering port.

This, of course raises the odd prospect of a ballistic missile sub remaining mute over whether or not it is carrying any missiles.

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"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." - William Thompson, 1st Baron Lord Kelvin

"If it was so, it might be, and if it were so, it would be, but as it isn't, it ain't. That's logic!" - Tweedledee

This isn't right. This isn't even wrong. - Wolfgang Pauli