Controversy surrounds the expiration of the plant's license in 2030.

The avocado green paneled walls inside the control room of Xcel Energy's Monticello Nuclear Generating Plant may look like a throwback to the 1970s, but officials with the utility say the investments it's made in the plant during its 48-year life mean it could keep operating safely and efficiently at least another two decades.

The central Minnesota plant generates enough electricity to power half a million homes, and has been a fixture in the community, providing jobs and tax revenue.

But the plant's license is set to expire in 2030 — and Xcel wants to keep the plant operating until at least 2040, as part of its public promise to pivot away from coal over the next few decades.

Xcel operates two nuclear plants in Minnesota — one in Monticello and another on Prairie Island. The utility says keeping the plants going is a crucial part of its plan to produce carbon-free electricity by 2050. Xcel's plan includes retiring its two remaining coal plants in the Upper Midwest, and adding more natural gas, solar and wind to its energy mix.

The Monticello plant has seen many changes since it began operating in 1971. Security was tightened after the Sept. 11, 2001, terrorist attacks. A decade later, after the Fukushima nuclear disaster in Japan, the federal government required Xcel and other nuclear plant operators to better prepare their facilities for the possibility of flooding. In 2013, Xcel spent more than $600 million to boost the plant's energy output.

Xcel officials say those investments are part of their ongoing efforts to improve the plant's performance and safety — and have set the plant up to increase its longevity, Minnesota Public Radio News reported.

"This is really isn't a 50-year-old plant, when you think about all of the upgrades and improvements we've made to the equipment," said Pam Gorman, who works on nuclear policy and strategy for the utility. "We're continually refurbishing it and upgrading it."

Some environmental groups say any money Xcel invests in aging nuclear plants would be better spent developing renewable energy sources that don't pose the safety risks of nuclear power, such as the storage of radioactive spent fuel.

"We should be really looking at moving toward renewable energy, toward energy solutions that don't come with so many downsides," said Rebecca Kling, who works with the Sierra Club's Beyond Coal Campaign.

Inside the Monticello nuclear plant

As nuclear plants age, they require more intensive surveillance, monitoring and maintenance, said Edwin Lyman, acting director of the Nuclear Safety Project at the Union of Concerned Scientists, which advocates for nuclear safety.

"The real question is, is the cost of those additional activities going to increase to the extent that it will downgrade the economics of the plant and put additional burden on the utility to keep running it?" Lyman said.

But Chris Clark, president of Xcel in Minnesota and the Dakotas, said the company believes it can keep the Monticello plant operating without more major, expensive renovations.

"We really feel like the Monticello plant is well-positioned to get at least another 10 years of life very cost-effectively for our customers," he said.

Spent fuel storage

Nuclear energy is generated from splitting uranium atoms. During the energy-generation process, a reactor uses nuclear fuel to heat up water, which produces steam and generates electricity without burning fossil fuels. So while nuclear power doesn't generate greenhouse gases, it does generate spent nuclear fuel that stays radioactive for many years.

Despite a prolonged debate over a proposed storage site at Yucca Mountain, Nevada, there's still no federal repository to store that spent fuel, so it's up to individual power plant operators to manage the waste.

At Monticello, spent fuel rods sit in a cooling pool inside the plant for several years. Then they're moved to outside large steel and concrete storage casks.

"We've actually had studies that show they can be hit directly by a freight train or a plane and not be damaged," said plant manager Don Barker. "So they're very robust."

Xcel officials say there's enough room its cooling pool for all of the spent fuel that would be generated until 2030. But eventually, the company would like to ship its spent fuel to a private storage facility in Texas or New Mexico.

Clark said it's also possible that researchers will find an innovative use for the spent fuel.

"I understand why people view it as waste," he said. "But we view it as used, because there is a lot of potential energy still left in it."

The Union of Concerned Scientists' Lyman said he's concerned that, if utilities are allowed to ship spent fuel away from their nuclear plants, it won't just be offsite, it will be "out of mind."

"They don't care where it goes. It's not their problem anymore," he said. "The danger is that you're just transferring the problem from one place to another, and you're not actually solving it."

One of many?

Minnesotans will have the opportunity to weigh in on Xcel's Upper Midwest energy plan — in which the company lays out its goals for the next 15 years — at a series of public meetings. It's required to file these plans with the state Public Utilities Commission on a regular basis.

Extending the life of the Monticello nuclear plant would require approval by state and federal regulators. The Minnesota PUC would need to sign off on storing more spent fuel on the site beyond 2030.

And as the nation looks for ways to slow climate change, Xcel won't be the only utility seeking to extend the life of a nuclear plant. There are 96 nuclear reactors producing electricity in the United States today. Most were built in the 1970s or '80s, and most have already been approved once by the federal government to operate an additional 20 years beyond their original license.

Prema Chandrathil, a spokeswoman for the U.S. Nuclear Regulatory Commission, said her agency is currently reviewing three applications for the relicensing of six reactors, and is expecting to receive an application for two more reactors soon.

Chandrathil said the relicensing period takes about 18 to 22 months and requires a safety evaluation, onsite inspection and environmental review. If state regulators approve Xcel's energy plan, the utility likely would apply for a license extension for the Monticello plant by 2025.

Beyond that, the NRC requires plants seeking to extend their life to 80 years in operation to have a plan for managing aging components, such as reactor parts, cables and piping, she said.

Prepared for the worst

Watching the process closely will be the city of Monticello, where the nuclear plant has been a fixture for almost 50 years. It provides jobs, taxes — and the need to plan for the possibility of a nuclear disaster.

Every two years, local officials and emergency responders from federal, state and local agencies practice as if there were an actual incident at the nuclear plant.

While a major catastrophe might be unlikely — the plant has been operating since 1971 without a major incident — officials still have to plan for it.

Jim King, who has evaluated nuclear drills for the Federal Emergency Management Agency for 30 years, said preparing for a radiological incident is different from preparing for other natural disasters, which are often over relatively quickly. Recovery can take much longer after a nuclear incident, King said.

"It could take years or decades in order for (recovery to bring a city) close to where it used to be," he said.

Most people who live in adjacent Wright and Sherburne counties know this, and they seem to take it in stride.  Residents who live within a 10-mile radius of the Monticello plant get a mailing every year from Xcel Energy, telling them what to do if they're evacuated: Close doors and windows. Pack a few personal items. Bring pets and prescription medications along with you.

Residents within the 10-mile zone also can get potassium iodide pills to have on hand, to protect their thyroid gland if they're exposed to radiation.

Still, local officials said they and other residents generally accept the extra safety planning the plant requires.

"I think we've always felt that it's really the price that we'd gladly accept for the benefits of having a power plant here," said City Administrator Jeff O'Neill.

Local impact

Those benefits are significant: The plant employs about 650 full-time workers — and Xcel pays about 60 percent of the city's total property taxes.

Not long ago, Monticello officials had started to brace for a different future, beyond 2030, when the plant's current license is set to expire. O'Neill said they had been closely watching the nearby central Minnesota city of Becker, as it prepares for the closure of its Sherco Generating Station, a coal-fired power plant that's also run by Xcel.

"We didn't feel there was a guarantee that nuclear power would be part of the mix," O'Neill said. "We thought we were going to be right on the heels of Becker."

Then came the welcome news that Xcel wants to keep operating the Monticello plant at least another 10 years. And now, Monticello leaders hope they'll get a reprieve before they have to think too hard about a future without nuclear.

In the meantime, the city is trying to attract new businesses in manufacturing and retail, to diversify its economy so it's not relying so heavily on the plant.

"Although we liked and really enjoyed the benefits of having the nuclear tax base, we're hoping we're using those resources wisely to prepare for the day when they're not here," O'Neill said.

And then, there are the swans.

The Monticello plant discharges warm water into the Mississippi River, attracting hundreds of trumpeter swans to the ice-free spot every winter. They've become a tourist attraction — and Monticello has embraced them as a part of the city's identity.

"It really is something that you have to see to believe and fully experience," said Rachel Leonard, the city's spokeswoman. She said the swans have become a popular spectacle for winter visitors — and when they come for the swans, they often stay for lunch, or shopping.

City officials say they know someday the nuclear plant will stop operating. When that happens, it's likely the swans — and the business they bring __will move on. And the city too, will need to find new ways to thrive.