As Millstone Nuclear Power Station prepares for a refueling outage, Dominion Energy spokesperson Ken Holt took two Day reporters for a more than three-hour tour Thursday afternoon.

It included the turbine generator building, spent fuel storage, water intake and outtake from Long Island Sound and other parts of the vast facility, which seems to function as a city in itself. Holt noted that security teams, electricians, cafeteria workers, a doctor, nurses and others populate Millstone’s 550-acre campus, in addition to plant operators.

Before the tour, he offered an update on operations at Millstone.

There are currently 800 to 1,000 contractors preparing for the planned fall outage. Dominion Energy has not disclosed exactly when the outage will occur, but Holt said the company likely will send a notice the day before. Millstone's two nuclear reactors are partially refueled every 18 months, and the monthlong process typically requires an influx of hundreds of specialized workers, including electricians, pipefitters and others, who typically travel to plants across the country to execute similar operations.

The federal government had committed to take possession of nuclear waste from facilities but later reneged, meaning Millstone stores its used fuel on site. In addition to spent fuel pools, the plant has dry storage in metal canisters encased in concrete, which can be stored safely for decades. Holt said Thursday that Millstone’s dry cast storage can accommodate the fuel for 60 years.

It’s possible that Millstone could continue operating for 100 years. The federal Nuclear Regulatory Commission is considering expanding license renewal to 100 years of plant operation. Nuclear plants originally were licensed for 40 years, which later was extended another 20 years to 60, and a subsequent renewal brought that number to 80 years.

“If we go for another 20 years with subsequent license renewal, we may need to expand that pad,” Holt said. “We basically build little garages that we put these cylinders of fuel into, and if the federal government takes the fuel — there’s a couple interim locations in Texas and New Mexico that raised their hands and said, ‘Hey, we’d be willing to store fuel here’ — as we empty out the garages where the cylinders are, that leaves them open, and we could then put another cylinder in them.”

The plant has three units but only two of them are operational; Unit 1 was closed down in the late 1990s, before Dominion Energy took ownership of the property. Holt said the plant has worked more efficiently with two units than it did with all three under Northeast Utilities.

Holt said the possibility of license renewal doesn’t necessarily change Millstone’s continuous process of fixing or replacing equipment, and Dominion is always thinking decades down the road. Millstone already replaced its steam generator on Unit 2. In next year’s spring outage, “We’re going to replace the main generator on Unit 3, that’s like a $108 million project.”

“Having our contract with the state enables us to plan for that kind of work and make those kinds of decisions,” Holt said. “We went to the state and said, ‘Look, we don’t want to run this place at a very small margin because that’s when you start to make decisions that affect safety, that’s when you start to cut corners, and Dominion isn’t going to operate this place cutting corners.’ We know one way to operate a plant, and that’s safely, and that requires money and investment.”

After multiple security checks, and a grueling hike up flights of stairs in the 100-plus-degree turbine building while wearing hard hats, masks, earplugs and protective glasses, Holt and the two reporters stepped outside. He said two things are usually associated with nuclear power plants: cooling towers and domes. Millstone does not have a cooling tower because “the waters of Long Island Sound are the cooling tower.” And the domes of the plant are underneath enclosed structures.

Millstone takes water in from the Sound to cool its reactors, then releases the warmed water back into the Sound. This has caused concern among environmentalists, and Millstone has made it clear — as Holt reiterated on Thursday — that the plant would shut down before installing cooling towers, which are expensive structures that can remove heat from the water before releasing it.

Holt said Millstone has minimal environmental impact on the surrounding area. He noted Millstone reduces the flow of water from the Sound during winter flounder spawning season in the spring so not as many eggs and larvae go through the system, which would kill them.

The water used in the reactors is New London city water that has been purified. Water drawn in from Long Island Sound is used as service and circulating water to provide cooling water for the main condenser. Before it is used, water from the Sound is screened so that any fish and lobster that have found their way in can be dumped back into the Sound.

Millstone’s campus has a lab that studies the plant’s environmental impact on Long Island Sound.

The 550 acres also are home to wildlife. Holt said employees have run into turkeys, bobcats and deer. Geese can be seen on the grounds, waddling between the plant's enormous gray structures. Bird nests are situated near high-voltage areas — ospreys, gulls and even a peregrine falcon have made Millstone their home. People often fish near the abandoned rock quarry Millstone empties its outtake water into.

Millstone is the largest power-generating system in New England, carrying 10% to 20% of the region's electricity load. The plant provides roughly half of Connecticut’s energy in a year.

But the plant also depends on electricity to run. Holt said the plant has to pay an electrical bill to Eversource. If the electricity gets cut off, the plant has multiple backups, including a diesel generator.

Dominion spends $60 million to $100 million a year on equipment and implementing new systems, such as digital controls. In just one unit, improvements completed in the last year have rounded up to $91.4 million. Dominion is planning to spend more than $200 million on improvements and replacements starting at the next refueling outage of Unit 2.

Holt said employees rarely go into a reactor when it is operating. When it is shut down, however, a lot of people go in to perform maintenance, being mindful of their time, distance and shielding from the reactor. The plant has gone 1,421 days since its last Occupational Safety and Health Administration reported accident. In 2021, so far there have been five first-aid-related incidents.

Holt said worker radiation exposure has decreased in the last two decades, later pointing to a banner in an office building cafeteria at Millstone spelling out the specific levels of radiation and showing the decline.

“We’ve actually set records for the last 10 years, each outage has been less than the outage before,” he said. “We know how many people should be inside a radiologically controlled area, we have better techniques for having people wait in a low-dose area."

"With radiation there are three things you’re concerned with: Time, distance and shielding," he noted. "If you can decrease time, increase distance from the source or put a shield between you and the source, then you will reduce your exposure.”

At the front desk in a Millstone office building is an “ALARA” suggestion box, or “as low as is reasonably achievable,” where employees can put anonymous suggestions on how to decrease radiation exposure. Holt said Dominion encourages its employees to come to the company, the Nuclear Regulatory Commission or even the news media with safety concerns.

s.spinella@theday.com

j.vazquez@theday.com