Waterford — Dominion Resources has volunteered to do additional testing next month on a key component of the coolant system of the Unit 2 reactor at its Millstone Power Station to determine if the part is defective, Nuclear Regulatory Commission officials told a citizen watchdog panel Wednesday.

Kerri Kavanagh, branch chief of the quality assurance vendor inspection branch of the NRC, told the Connecticut Nuclear Energy Advisory Council that the testing will be done during a scheduled refueling outage at Unit 2. She gave the information during an annual meeting in which NRC officials provide the citizens panel with an assessment of Millstone’s performance for the past year.

Millstone inspectors, she said, will “look for the presence of flaws or cracks” in a pressurizer manufactured by the French company AREVA at its Le Creusot Forge, which has been under scrutiny by French authorities since last year after excess carbon was found in some of the components made at the forge that are used in nuclear plants in that country.

The excess carbon, which can affect the “fracture toughness” of the parts, has been found in large parts that are part of the reactor vessel heads of some plants, said David Rudland, branch chief of the vessels and internals integration branch of the NRC. The discovery of problems at the forge has led an investigation by French authorities and a shutdown of multiple plants there.

“There was a significant deficiency in the safety culture at this forge,” Kavanagh said. “There is a concern.”

She added, however, that none of the Le Creusot parts at Millstone or 16 other U.S. nuclear plants are believed to be the same type as those found in France. But because of the problems at the forge, NRC has obtained documentation from AREVA on all the Le Creusot parts at U.S., including Millstone, to check for flaws. An initial review of the documents has determined that the pressurizer at Millstone Unit 2 received three heat treatments instead of the two required by design specifications, she said. The heat treatments are designed to relieve stress.

“But it still met code, so there are no safety concerns,” she said.

Rudland said the NRC will begin a complete inspection of the AREVA documents next week.

During the portion of the meeting reserved for public comment, Nancy Burton, director of the Connecticut Coalition Against Millstone, pressed the NRC officials about whether they would participate in Dominion’s voluntary inspection of the pressurizer. NRC officials said they could not commit to participating in the inspection until they have a complete description from Dominion about what is planned. Rudland said the company could use ultrasonic or optical methods to test the pressurizer for flaws.

“You cannot tell us with certainty that you will have an inspector at the pressurizer?” Burton asked. “That’s not quite good enough to satisfy the concerns of the public.”

Another member of the public, Tom McCormick of West Hartford, agreed that the NRC needs to commit to taking stronger action in response to the issues at the Le Creusot Forge parts.

“There’s plants in France that are closed because of this issue,” he said. “That’s not a safety culture. That is advocacy of keeping these plants running when you don’t know what you’re dealing with.”

j.benson@theday.com