The Nuclear Regulatory Commission is sending a special team to the Millstone Power Station Tuesday to investigate an accidental spike in power that occurred at a reactor there more than a week ago.

On Feb. 12 Dominion operators in the control room at the Unit 2 reactor had reduced power from 100 percent to 88 percent in order to test valves in the turbine, which converts steam energy into electricity through a generator.

When one of the control room operators pushed a control button in the wrong direction, the power began to increase, said Skip Jordan, Millstone site vice president for Dominion, which owns and operates the plant. In a conference call with The Day today, Jordan said that in less than five minutes, the power increased to 96 percent.

"You shouldn't have an unexpected power increase at any time ever," said Jordan. "There should have been other checks and balances in there that would have prevented the power increase that we saw. Controlling reactor power is something we take as a core value, and we did not do that to our expectations."

The situation did not pose any risk to the public because the reactor was at reduced power when it occurred, said Neil Sheehan, a spokesman for the NRC in Region 1. This was the first time that such a lapse occurred at Millstone since Dominion bought the nuclear complex in 2001, Jordan said.

Sending a special NRC investigative team is rare, added Sheehan, but the NRC is doing so because the six-man team in the control room made a number of mistakes after the first one when they could have mitigated the problem. "These operators are expected to follow very prescribed steps, and if that doesn't occur that's worthy of review," he said.

Dominion is investigating the causes and is calling upon other control room operators from the company fleet and two outside power stations to help, said Jordan.