Sailors on the submarine USS Hampton failed to do daily safety checks on the ship's nuclear reactor for a month and falsified records to cover up the omission, a Navy investigation shows.

The revelation is sure to raise new questions about the military's handling of the nation's nuclear assets following an Air Force incident in which a B-52 bomber was accidentally loaded with nuclear-tipped missiles and flown across the country without any one realizing it for more than a day.

In the case of the Hampton, it appears from a preliminary investigation that sailors in Submarine Squadron 11 had skipped the required analysis of the chemical and radiological properties of the submarine's reactor for more than a month, even though a daily check is required.

"Some of the Hampton's operations and records fell short of high Navy standards," said Lt. Cmdr. Ryan Perry, a Navy spokesman at the Pentagon.

"There never was any danger to the crew or the public," he said.

Other members of the squadron discovered the lapse during a routine examination required as part of the redundancy built into the system so that problems are caught, The examination was done as the submarine was nearing the end of a West Pacific deployment, which was completed Sept. 17.

Officials also discovered that logs had been filled out to make it appear that the daily checks of the reactor water had actually been done.

Six nuclear personnel have received an undisclosed nonjudicial punishment after a preliminary investigation, but the probe is continuing, Perry said.

A nuclear powered fast attack submarine, Hampton is the most advanced nuclear attack submarine in the world, carrying a torpedo, cruise missile, and mine-laying arsenal, according to information on its Web site.

The investigation was first reported in Monday editions of Navy Times newspaper, which quoted an unidentified source as saying that failing to measure and maintain the correct water chemistry in the reactor over the long-term could cause corrosion in the system.

"We measure also for general radioactivity levels in the water to make sure the reactor (fuel elements are) intact," said the source, whom the newspaper said had knowledge of the investigation.