SAN ONOFRE, Calif. -- An employee at the San Onofre nuclear power plant in San Diego falsified records for five years to show that hourly fire patrols were made, when in fact they were not, the U.S. Nuclear Regulatory Commission announced Monday.

The finding prompted the NRC to order Southern California Edison, which is the majority owner of the San Onofre Nuclear Generating Station, to make changes, including developing special safety training.

The order requires Rosemead-based SCE to expand its ethics training for managers, supervisors and employees; develop new training to prevent deliberate misconduct; conduct an independent safety culture assessment; and monitor the effectiveness of its corrective actions.

In a statement, SCE said the company agrees with the NRC that the worker's behavior "cannot be tolerated."

"We believe the extensive program we have already begun to implement will help strengthen site worker commitment to Edison's standards of conduct and those of the NRC," the statement says.

According to the NRC's investigation, a fire protection specialist at the San Onofre nuclear plant provided inaccurate information about hourly fire watch rounds the staffer was supposed to make while working the midnight shift at the plant from April 2001 to December 2006.

The NRC said the missed rounds had a "low safety significance" because other fire defense measures were in place.

"The order contains a comprehensive set of actions designed to improve performance at San Onofre by emphasizing the importance of a strong nuclear safety culture," said Elmo E. Collins, NRC's Region IV administrator.

"The NRC has confirmed several instances of willful violations at San Onofre during the past year," Collins said. "The NRC depends on a good-faith effort of nuclear power plant workers to follow regulations. Willful violations by workers cannot be tolerated."

The agency also documented several other instances of "willful violations" at the plant in the past year, according to the NRC.

A radiographer deliberately failed to adhere to the terms of a radiation work permit; a technician failed to control the work activities of an unqualified technician performing work on safety-related equipment; and there were also two documented violations for security-related matters, the NRC concluded.