Xcel officials say their plan to make more power in Monticello would require minor changes, relatively speaking.
The company's Brian Zelenak says the first step would be to rearrange the nuclear fuel rods in the reactor's core to create more heat.
"They are moving fuel rods that have more life left from the core of the reactor to the outsides of the reactor. And by doing that, they have a higher burnup inside the reactor, and because of that they are able to produce more steam," says Zelenak.
More steam would mean the plant could make 70 megawatts of additional power. That's enough for 70,000 homes. The plant already makes 600 megawatts of electricity.
The plan would cost Xcel up to $135 million, but company officials say that's hundreds of millions of dollars less than it woulc cost to build a new plant to make the same amount of power.
It could be a year or more before state and federal regulators make a decision on the plan.
Making more power would also mean that in the next 20 years, the plant would need to store 30 percent more spent radioactive fuel.
That has some environmental groups concerned.
"There are some facets of nuclear power that are very attractive when you're looking at it relative to climate change and global greenhouse gases," says Paul Aasen with the Minnesota Center for Environmental Advocacy. "But there is this big issue with storage of spent fuels that has not been resolved yet."
Xcel Energy is currently building a three-acre facility at its Monticello plant, to store spent fuel in steel containers inside concrete vaults. But the company hopes that in the future, the federal government will take the radioactive waste off their hands.
The long-promised option, a nuclear waste storage facility at Nevada's Yucca Mountain, has been delayed for years. And government officials say it could be nearly a decade before the facility is able to accept nuclear material.