Federal regulators have slapped the troubled San Onofre nuclear power plant in California with a violation for a lapse in plant security.
Operator Southern California Edison reported the problem to the government, and the company said in a statement Thursday it was promptly corrected.
The violation stems from a four-day Nuclear Regulatory Commission inspection in May during which officials reviewed records, observed activities and interviewed personnel.
The agency says the company failed to develop procedures to monitor electronic devices related to security. The NRC withheld most details of the problem.
Edison Senior Vice President Pete Dietrich says changes have been made so "it doesn't happen again."
San Onofre has been closed since January because of excessive wear to tubes that carry radioactive water.
Despite the NRC's disapproval of the procedures, in a report published last month, the commission said the plant's operators handled the leak as best as they could.