Waterford — Millstone Power Station has been cited for three violations of “very low safety significance” after a recent three-month inspection by the Nuclear Regulatory Commission.

A fourth finding of “very low significance” — the lowest of the NRC’s four-tiered violation ranking system — was self-identified to the NRC by plant owner Dominion Resources.

The NRC on Thursday released its report on the inspection that concluded on Dec. 31. The inspection covered fire protection, licensed operator requalification and problem identification and resolution procedures at both operating reactors at the plant.

"Although they are all of very low safety significance, we take any violation seriously," said Ken Holt, spokesman for Millstone. "We're taking steps to ensure similar events don't happen in the future."

In the first violation finding, the NRC determined that Millstone workers failed to do routine engineering evaluations to determine the safety of scaffolding that had been in place for more than 90 days. The issue of potentially unsafe scaffolding at Millstone and other plants around the country prompted the NRC in 2007 to issue a notice alerting all nuclear power plants in the U.S. to take action to avoid similar problems. Neil Sheehan, spokesman for the NRC, said periodic inspections of scaffolding left in place for long periods are needed to ensure that the equipment is not interfering with the functioning of certain components of the plant.

In the second violation, the NRC found that the integrity of examinations for 19 licensed operators had been compromised because the tests were not sufficiently changed from the previous exam cycle.

The third violation pertained to a degraded diode in Unit 3. The NRC found that plant workers failed to take timely corrective actions to replace the degraded diode.

Sheehan said the plant already has corrected the violations with the scaffolding and retested the operators with new exams, and has initiated a corrective action plan for the diode problem.

"We'll be following up in a subsequent inspection," he said. No fines are being considered, he said.

In the fourth finding, plant staff reported to the NRC that they did not take appropriate corrective actions to prevent the failure of a water pump lube water valve, according to the report. The company also has taken steps to correct that issue, Holt said.

— Judy Benson