As many as 30 senior enlisted sailors at the Navy's Charleston, S.C., nuclear propulsion school are accused of cheating on written tests that qualify them to supervise students learning to operate nuclear reactors used to power Navy vessels.

Chief Naval Officer, Adm. Jonathan Greenert, and the head of the U.S. Navy's nuclear propulsion programs, Adm. John Richardson, briefed Pentagon reporters Tuesday on the emerging scandal, calling it a "disappointment," "contrary to all of our core values."  Both men insisted this was not representative of a broader cultural problem within the Navy.

Yet the accusations closely resemble recent problems within the Air Force, where nearly 100 nuclear missiliers are being investigated for widespread cheating on qualification tests, while others in the same nuclear force are being questioned for drug abuse.

The 30 sailors implicated in the Charleston investigation have been denied access to the training site while the Navy's Criminal Investigation Service (NCIS) evaluates each case separately. Richardson said if the accusations are proven to be true punishment could include dismissal from the Navy.

Richardson said they learned about the allegations from a sailor who came forward to say he was offered the answers to a test so that he could cheat.  Richardson also said the tests on which sailors allegedly cheated included classified information.

"We expect more from our sailors -- especially our senior sailors," Greenert said.