Xcel's plan to store more nuclear waste at Monticello plant gets OK

A large concrete bunker behind a fence.
The Minneapolis-based utility says it needs additional storage to continue operating the 52-year-old nuclear plant until 2040, a decade beyond when its current license expires.
Evan Frost | MPR News 2019

State regulators have given a green light to Xcel Energy to store additional radioactive waste at its nuclear plant in Monticello, Minn.

On Thursday, the Minnesota Public Utilities Commission unanimously approved a certificate of need for the project, which involves installing a new concrete pad and storing about 14 additional casks of spent fuel.

The Minneapolis-based utility says it needs additional storage to continue operating the 52-year-old nuclear plant until 2040, a decade beyond when its current license expires.

Xcel says keeping its two Minnesota nuclear plants operating is key to achieving the state’s goal of carbon-free electricity by 2040

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Minnesota’s nuclear plants at Monticello and Prairie Island provide about 30 percent of the electricity for Xcel customers in the Upper Midwest.

“Nuclear power is crucial to achieving those goals because of its unique combination of reliability, affordability and zero emissions,” said Chris Clark, president of Xcel in Minnesota and the Dakotas, in a news release.

Federal regulators are expected to decide late next year whether to extend the plant’s license another 20 years.

Nuclear power has been gaining popularity as countries around the world look to decarbonize. But some environmental groups have raised concerns about the safety of aging nuclear plants and the problem of what to do with spent nuclear fuel, which remains radioactive for thousands of years.

Despite a prolonged debate, there’s still no federal repository to store spent fuel, so waste is stored in dry casks on-site at the plants.

Commissioner John Tuma said he understands the need to store more waste, but isn’t happy about leaving the problem for future generations.

“I get where we’re going,” he said. “But I’m saying this as an apology to our great-great grandchildren down the road — sorry for leaving you with a mess.”

The Monticello plant has been under increased scrutiny since a leak of water containing radioactive tritium last November. In March, Xcel temporarily shut down the plant to repair the leak, and has been pumping groundwater to recover the tritium.

Tritium is a mildly radioactive form of hydrogen that occurs naturally in the environment, and also during nuclear power production. 

State officials concluded that the environmental review of Xcel’s plan to increase waste storage adequately addressed the possibility of tritiated water contamination.