Waterford - The federal Nuclear Regulatory Commission has cited Dominion, the owner of the Millstone Power Station, for three minor violations in last year's quarterly inspection.

All three violations are considered to be "of very low safety significance," according to the inspection report.

In late November, Dominion had an unexpected shutdown of a water pump in the Unit 2 reactor, which triggered an automatic shutdown of the reactor itself.

The reason that happened, said Donald Jackson, NRC chief of projects, branch 5, and the author of the quarterly report, is because the company installed new equipment but failed to update its procedures for cleaning, or backwashing, the reactor's condensers.

Steam that goes through the reactor turbine to generate electricity has to be condensed back into water and heated up again, said Jackson. Water pulled from Long Island Sound helps cool the steam. When operators were cleaning, or backwashing the condenser, they used outdated procedures to shut off the pumps, which couldn't condense the steam, causing an automatic shutdown, he said.

In the second incident, Dominion did not determine the cause and replace parts for an inoperable emergency diesel generator that malfunctioned in July and September of 2009 until February 2010. Its original "corrective action" was incomplete because it failed to examine the cause, and the work required turned out to be more widespread than originally thought, Jackson said.

"We would have expected them to do a better job of analyzing it when it first occurred," he said.

The third violation, which Dominion identified in August, involved a pump that failed a surveillance test on June 30, and was inoperable for about 54 days, which exceeded the time allowed for an outage. As soon as the company learned of the condition, it rectified it, the report states.

Since the inoperable pump remained available to fulfill its safety function, the issue is considered minor, the report states.

Dominion spokesman Ken Holt said the company takes every violation seriously.

"We have already taken corrective actions to ensure these types of events do not happen again," he said.

p.daddona@theday.com