Waterford - The man charged with running Millstone Power Station led the press on a four-hour tour of the site Wednesday, fielding questions about cooling towers, the impact of Fukushima on U.S. reactors and possible dry-storage expansion.

Skip Jordan, the site vice president for Virginia-based owner Dominion, discussed the mechanics of Unit 3, a reactor shut down temporarily for refueling, and pointed out $600 million in major investments the company has made in the entire station since its purchase from Northeast Utilities for $1.3 billion in 2001.

A second, older reactor, Unit 2, continues to operate, while a third, Unit 1, is permanently shut down. Those reactors were not part of the tour.

Asked about a first-ever tax in Connecticut on electricity generation at Millstone and other utilities, Jordan said that doing business in the state became a "major concern" because of the way Millstone was "singled out" - until the original tax proposal was reduced and more fairly distributed.

"I'm confident no matter what the market is, as long as we're not being singled out, we can compete," he said.

While Dominion has no plans to add new reactors or other utilities on the site's 535 acres, only 50 of which are used for Millstone, the company is studying the feasibility of adding closed-cycle cooling towers that state government could see fit to require as part of Millstone's water discharge permit, which was approved last year.

The study and its recommendations are due by Aug. 15, 2012.

Dominion paid $600 million to erect two cooling towers at its Brayton Point fossil-fuel plant in Salem, Mass., but at Millstone three towers would have to be connected to nuclear reactors, said Kevin Hennessy, Dominion's director of government affairs for New England.

To add the massive towers here, which could each be 525 feet high and 100 yards wide at the base, the entire site would have to be retrofitted, and an underground path for piping would have to be created, a feat Millstone spokesman Ken Holt described as challenging.

Dominion is also exploring whether to expand its dry cask storage facility, where older spent fuel is stored, and whether fuel from Units 1 or 3 could be added. Right now, 14 of the 19 storage modules hold spent fuel from Unit 2. The company has a permit to build up to 49 modules, but ultimately wants to see a national repository built, Jordan said.

Unit 2 was chosen because its spent fuel pool was overcrowded with used fuel rod assemblies.

Millstone put a team together as the Fukushima nuclear meltdown was unfolding after the March earthquake and tsunami, Jordan noted.

The company has since determined that having extra backup equipment for emergencies that is compatible with military hardware would make sense, since the Naval Submarine Base and U.S. Coast Guard are located in the area.

At the start of the tour, senior instructor Chuck Mihalko explained how fission, heating, cooling, and steam generation work at a nuclear power plant, using a see-through model reactor.

As nuclear fission heats water to create steam, the steam turns a turbine that generates electricity. Operators are focused on ensuring that redundant safety barriers protect workers and the public from corrosion, radiation and any breaks or challenges to plant systems, he said.

Media also visited a simulated control room where training occurs.

In the middle of the tour, Jordan took the media up steep metal stairs inside the Unit 3 turbine building to view enormous pieces of equipment like the moisture separator reheaters. He explained that Millstone is one of the only stations in the country in which the designs for three nuclear reactors are all different.

Unit 1 is a boiling water reactor, while Units 2 and 3 are pressurized reactors. Unit 3 is a Westinghouse design, and Unit 2 is a Combustion Engineering design. There are fewer economies of scale as a result, Jordan said.

Nonetheless, Units 2 and 3 together now generate nearly 2,097 megawatts, enough to power 500,000 homes.

Over the past decade, the two reactors have produced more than 16 million megawatts, compared with 15.9 million megawatts generated between 1986 and 1995 by all three reactors, according to data supplied by the company.

p.daddona@theday.com