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.