Washington - The Navy is investigating 30 or more senior sailors in connection with alleged cheating on written tests designed to qualify them as instructors at a school that trains younger sailors to operate naval nuclear power reactors, officials said on Tuesday.
The reactors at Charleston, South Carolina, are of the kind used in propulsion systems for Navy submarines and aircraft carriers.
The alleged misbehaviour is unrelated to Navy nuclear weapons carried aboard Trident submarines, according to Admiral John Richardson, the director of the Navy's nuclear propulsion programme.
He said it came to light on Monday when a senior enlisted sailor at the Charleston training site reported the cheating to higher authorities. Richardson said the unidentified sailor "recognised that this was wrong" and chose to report it.
Pressed to say how many sailors were implicated in the investigation by the Naval Criminal Investigative Service, Richardson said a "ballpark figure" was something in the neighbourhood of 12 to 20.
But a short time later another Navy official said the number was approximately 30 but could change as the investigation unfolds.
The official spoke on condition of anonymity because the official was not authorised to discuss publicly any details beyond what Richardson and the Navy's top officer, Admiral Jonathan Greenert, disclosed at a Pentagon news conference.
Greenert, the chief of naval operations, said he was upset to learn of the breakdown in discipline at Charleston.
"To say I am disappointed would be an understatement," Greenert said. "We expect more from our sailors - especially our senior sailors."
Neither Greenert nor Richardson identified the rank of the alleged cheaters but described them as senior enlisted members. There are about 150 instructors at the Charleston site.
Richardson said the examinations on which sailors allegedly cheated included classified information. He said he could not discuss possible disciplinary action against those involved because the probe was ongoing.
However, he said that anyone in the naval nuclear power programme - either in a training setting or aboard a ship at sea - who is caught cheating would usually be removed from the programme and "generally" would be kicked out of the Navy.
The decision to have Greenert and Richardson publicly announce the cheating investigation was a sign of how seriously the Navy takes the matter.
The alleged cheating did not involve naval nuclear weapons and thus was not directly comparable to the Air Force's investigation of alleged cheating by officers who operate land-based nuclear missiles.