The Minnesota Public Utilities Commission (PUC) has approved Xcel Energy’s request for a certificate of need to expand spent fuel storage at the utility’s Monticello nuclear power plant.

The additional storage, according to the PUC, requires installation of a second concrete support pad and modular concrete storage system designed to hold 14 additional steel canisters.

Xcel had requested increased outdoor storage to accommodate its plan to extend Monticello’s operational life by 10 years, to 2040.

A recurring leak of water containing tritium has led to the temporary shutdown of Xcel Energy's Monticello nuclear power plant, in Minnesota.

“While the leak continues to pose no risk to the public or the environment, we determined the best course of action is to power down the plant and perform the permanent repairs immediately,” said Chris Clark, president of Xcel Energy–Minnesota, North Dakota, and South Dakota, in a March 23 news release. “We are continuing to work with and inform our state, federal, city, and county leaders in the process.”

Powering down the reactor to shutdown condition started last Friday.

An Xcel Energy news release issued last week regarding the leak of some 400,000 gallons of tritium-containing water at Minnesota’s Monticello nuclear power plant in 2022 has sparked a flood of news stories over the past few days—in large part because the general public had previously been unaware of the leak. (A low-level beta emitter, tritium is a common byproduct of nuclear reactor operation.)

The Nuclear Regulatory Commission has accepted for review Northern States Power Company’s subsequent license renewal application for its Monticello nuclear power plant. A notice of the agency’s decision, along with information on requests for a hearing in the matter, was published in the March 3 Federal Register.

Xcel Energy subsidiary Northern States Power Company has submitted to the Nuclear Regulatory Commission a subsequent license renewal application for the utility’s Monticello reactor. Notice of the agency’s receipt of the application was published in the January 31 Federal Register.

NuScale Power has signed a memorandum of understanding with Xcel Energy to explore the feasibility of the utility’s serving as a plant operator at NuScale plants, the Portland, Ore.-based small modular reactor developer announced earlier this week.

Xcel owns and, through subsidiary Northern States Power Company, operates Minnesota’s two nuclear plants, Monticello and Prairie Island. The Monticello facility houses one 671-MWe boiling water reactor, while Prairie Island has twin 550-MWe pressurized water reactors.