WASHINGTON >> At least 34 sailors are being kicked out of the Navy for their roles in a cheating ring that operated undetected for at least seven years at a nuclear power training site, and 10 others are under criminal investigation, the admiral in charge of the Navy’s nuclear reactors program told The Associated Press.

The number of accused and the duration of cheating are greater than was known when the Navy announced in February that it had discovered cheating on qualification exams by an estimated 20 to 30 sailors seeking to be certified as instructors at the nuclear training unit at Charleston, South Carolina. Students there are trained in nuclear reactor operations to prepare for service on any of the Navy’s 83 nuclear-powered submarines and aircraft carriers.

Neither the instructors nor the students are involved in handling nuclear weapons.

After further investigation the Navy determined that 78 enlisted sailors were implicated. Although the cheating is believed to have been confined to a single unit at Charleston and apparently was not known to commanding officers, the misconduct had been happening since at least 2007, according to Adm. John M. Richardson, director of naval reactors. The exact start of the cheating was not pinpointed.

“There was never any question” that the reactors were being operated safely, he said in an AP interview, yet the cheating was a stunning violation of Navy ethics.

Richardson said he was “loaded for bear” at the outset of the investigation, unconvinced the cheating was confined to a single training unit. But he now believes that it had not spread, and that this was one reason that the ring managed to operate so long without being discovered.

In addition to the 34 enlisted sailors who were removed from the nuclear power program and are being administratively discharged from the Navy, two more who were implicated as “minimal” participants had their non-criminal punishment suspended due to their “strong potential for rehabilitation.”

Also, 32 sailors were implicated by investigators but later exonerated by Richardson, and he gave one officer a verbal warning. The officer, whom Richardson declined to identify by name or rank, was not accused of participating in the cheating. He was faulted for “deficiencies” in his oversight of the exam program, but Richardson said this was not severe enough to merit punishment.

The Navy investigation also concluded that commanders were not directly at fault. “It was not the result of ‘wishful blindness,” it said.

The 68 implicated sailors are in addition to the 10 whom Richardson said are believed to have been “at the center” of the cheating ring and remain under investigation by the Naval Criminal Investigative Service.

The scandal rocked the Navy, but details until now had remained under wraps as senior Navy officials sought to determine the scope of the cheating — including whether it was happening elsewhere — as well as the root causes and possible remedies.

Unlike an Air Force exam-cheating scandal that came to light in January at a Montana base that operates land-based nuclear-armed missiles, the sailors involved in the Navy cheating had no responsibility for nuclear weapons.

Navy investigators did, however, find one key link between the two episodes. Their investigation report said “a triggering event” for the unidentified sailor at Charleston who alerted superiors to cheating on Feb. 2 was media reports a few weeks earlier about exam cheating at Malmstrom Air Force Base in Montana.

“This increased his concern enough about being caught to outweigh the group behavior of his peers,” the report said, apparently alluding to peer pressure this unidentified sailor may otherwise have felt not to report the misconduct.

Richardson said he met individually with each of the accused and heard at least two common themes: a belief that there was little risk of getting caught, and a work environment at the nuclear training site that created stresses and pressures on the approximately 300 sailors who serve as instructors.

In an interview in his Navy Yard office Tuesday, Richardson said he is taking steps to ease the pressures and to strengthen ethics training.

Richardson said the accused at Charleston fell into two main categories:

–Sailors who cheated on the tests.

–Sailors who enabled the cheating by providing answers in advance to others taking the test and tipping them off about what test they would be given.

Richardson called the latter group of 10 sailors the ringleaders and said their offenses are considered more serious because they had facilitated the illicit transfer of classified test answers.

An extensive investigation ordered by Richardson and led by Rear Adm. Kenneth M. Perry found that an electronic master file of “engineering watch supervisor” tests and answers was illegally removed from a Navy computer “sometime before 2007.” Investigators failed to identify who took it or exactly when.

The set of test and answer keys became known among the cheaters as the “Pencil Files.”

These files were secretly passed via personal email accounts, compact disks, thumb drives and other non-official electronic systems. Richardson said the Pencil Files contained all 600 answers to questions on five sets of tests.

Also, a “Pencil Number” was passed to sailors to tip them to which of the five exams they would be given.

“The result was a deliberate scheme to cheat …,” the report said. It found no evidence of espionage.

Exam security was weak. For example, investigators found that the five tests were used in a predictably rotating order and the questions had not changed significantly since 2004, even though written rules require they be changed frequently.

NCIS investigators interviewed four people thought to have knowledge of the origin of the Pencil Files. Three of them denied involvement in the scheme and the fourth invoked his right to remain silent and requested an attorney.

“Thus, no further evidence of the origin of the ‘Pencil Files’ was obtained,” the investigation report said.