Waterford - For the second time since Dominion purchased Millstone Power Station in 2001, the company is considering boosting power at the Unit 3 reactor.

"We are investigating the feasibility of an uprate at Unit 3," Ken Holt, a Dominion spokesman, said Thursday. "We have not made a definitive decision. We are in the study phase right now."

Two years ago, the Nuclear Regulatory Commission approved a 7-percent "stretch power uprate" at Unit 3, the newer of the two operating reactors there. The uprate increased the amount of electricity generated at Unit 3 by 80 megawatts, bumping up overall output from approximately 1,150 to 1,227 megawatts, enough to power about 60,000 additional homes.

An uprate is an increase in the maximum power level at which a commercial nuclear power plant may operate, according to the NRC website. The reactor owner is only allowed to adjust that output if it demonstrates to the NRC that the plant can continue to operate safely with the uprate in place.

Today, Units 2 and Unit 3, combined, produce 2,111 megawatts of electricity, enough to power about 1 million homes.

Dominion started its latest uprate analysis about a year ago, and doesn't believe it will be done with the assessment "anytime soon," Holt said. Dominion will finish the study and make a decision "when we are satisfied our reviews are complete and (we) have done a thorough job evaluating (it)," he said.

The company also went to ISO New England, the manager of the region's electric grid, late last year to find out if there is any availability on the grid to take more electricity from Millstone, he added.

An ISO New England spokeswoman said she cannot confirm the status of any request or proposal from any specific party.

Holt said he could not discuss the amount of any possible increase in megawatts from a second uprate unless and until the company actually applied for it.

The Unit 2 reactor generates about 884 megawatts, according to recent filings with the Connecticut Siting Council, which is in the process of writing its annual forecast on electric loads and resources.

A third reactor at Millstone, Unit 1, is closed.

p.daddona@theday.com