Waterford - A federal quarterly inspection report has cited Dominion, the owner of Millstone Power Station, with four violations that the company says have since been corrected.

Three of the issues during the period from April through June occurred at the Unit 2 reactor; one occurred at Unit 3. In two cases at Unit 2 and one at Unit 3, operators failed to address known problematic conditions in a timely way, inspectors said. Dominion reported two of the problems while NRC inspectors found the other two.

The Nuclear Regulatory Commission conducts the quarterly inspections, which cover everything from drill evaluations and surveillance testing to plant modifications and radiation hazard assessments.

The four violations are considered "more than minor" but of "very low safety significance," resulting in baseline oversight, said Donald E. Jackson, chief of the Projects in Branch 5 of the Division of Reactor Projects.

Since the findings did not threaten public health and safety, the violations will be treated as "non-cited," meaning they already have taken or are taking corrective actions that the NRC is confident will be satisfactory, he said.

"Dominion continues to operate the plant in a manner which preserves public health and safety," Jackson said in a phone interview.

One problem in April at Unit 2 involved seals on pipes in the filtration system that could have released radioactive material when they failed to seat properly. No abnormal release occurred, Jackson said. They are now enclosed in reinforced fiberglass fabric called "boots" to better maintain the integrity of the system, Dominion Spokesman Ken Holt said.

Also in April at Unit 2, operators failed to correct conditions that affected the calibration of so-called "inverters," equipment that converts battery power to alternating-current power. Dominion's test of this equipment was too restrictive, and testing continually failed, so testing procedures have been changed, Jackson said.

A June incident at Unit 2 resulted in an operating crew's failure to maintain sufficient suction pressure, which led to an accidental reactor shutdown.

A May incident at Unit 3 resulted in three cooling water valves unassociated with the reactor that were leaking. Operators had been fixing nine other values and didn't get to those three in time, Holt said.

Dominion has since corrected all of the conditions or procedural deficiencies that led to each problem so that they don't reoccur, Holt said.

"That may be true, but we will follow up," Jackson said.

p.daddona@theday.com