Monticello nuclear power plant approved to operate through 2040

Xcel Energy’s Monticello Nuclear Generating Plant received approval Thursday to continue operating through 2040. 

The energy company submitted an application to increase storage of spent nuclear fuel at the plant, which was unanimously approved by the Minnesota Public Utilities Commission (PUC)  on Thursday, allowing the site to operate for at least another 10 years, according to the press release.  

The announcement comes after Xcel Energy revealed a leak of approximately 400,000 gallons of water containing radioactive tritium. The leak occurred in November 2022, but the public was not informed until March 2023. A second leak was reported at the end of March. 

While Xcel Energy says the leak is contained, they recently started construction of an underground barrier to keep the radioactive material detected in groundwater from entering the nearby Mississippi. 

"Constructing the barrier wall is another step the company is taking to try and ensure that the small amount of tritium still present in the groundwater remains within the plant boundaries and can be safely recovered, stored and reused on site," Xcel previously said in a statement.

Despite the leak, Xcel Energy said the approval is a "major step toward continuing to provide reliable, carbon-free energy for more than 500,000 customers across the Upper Midwest while meeting the state’s carbon reduction goals."

The energy company has also filed an extension request with the U.S. Nuclear Regulatory Commission, but a decision is not expected until late 2024. 

If Xcel Energy wants to keep operating the plant past 2040, it will need to re-apply for another extension with the PUC for additional spent fuel storage. Without the additional storage, the Monticello Plant would need to close.