Waterford - The Nuclear Regulatory Commission has found three safety and compliance violations of "very low safety significance" during its most recent quarterly inspection of Millstone Power Station.

In a report released Wednesday, the NRC said one of the violations involved Millstone operators failing to promptly notify the NRC that the monitoring equipment on stacks that discharge gaseous effluent stopped working on April 16.

The NRC did not learn about the inoperable monitoring equipment, which measures radiation levels of the releases from the stacks, until inspectors asked Millstone operators about it on April 18. The plant's permit requires that the NRC be notified of monitoring equipment breakdowns within eight hours, and failure to do so was categorized as a "severity level IV" violation - the lowest level.

NRC spokesman Neil Sheehan said the radiation levels from the releases were measured by the plant with other equipment and never exceeded acceptable parameters.

"The question was timing," he said.

The equipment has since been replaced, and Millstone has submitted a corrective action plan to the NRC to prevent a recurrence, Sheehan said. He also referred to a July notice from the NRC that 20 other plants over the last five years have had breakdowns in their effluent radiation monitoring systems. The notice recommended that plant operators be aware of the problems and check their facilities.

The second violation involved installation of equipment without proper design modifications, causing a valve to open and an uncontrolled loss of reactor coolant system inventory, according to the NRC report. Both it and the third violation, involving the failure to follow proper procedure to prevent buildup of hydrogen gas in Unit 3, were labeled "green" findings, for low safety significance.

Millstone spokesman Ken Holt said corrections have been made in all three areas where the violations were found and a corrective action plan submitted to the NRC.

"We take these issues very seriously, as we do with all the issues identified by the NRC," he said.

j.benson@theday.com