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News release

March 16, 2023


Mike Rafferty, 651-757-2662,

Minnesota state agencies monitoring cleanup of tritium leak at Xcel Energy Monticello Plant

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Leak has not left facility site or contaminated drinking water sources

The Minnesota Pollution Control Agency (MPCA), in coordination with the Minnesota Department of Health, and the Minnesota Department of Natural Resources, is monitoring Xcel Energy’s efforts to clean up a release of water contaminated with tritium detected at the company’s Monticello nuclear generating plant.

Xcel Energy reported the leak to the Minnesota Duty Officer and the Nuclear Regulatory Commission (NRC) in late November 2022 after finding unusual results during routine groundwater monitoring. The leak has been stopped and has not reached the Mississippi River or contaminated drinking water sources. There is no evidence at this time to indicate a risk to any drinking water wells in the vicinity of the plant.  

Tritium is a naturally occurring radioactive form of hydrogen that is produced in the atmosphere. It is a byproduct of the production of electricity by nuclear power plants.

State agencies are actively reviewing data, including well sampling results provided by Xcel Energy, and overseeing remediation efforts. The company continues to update state agencies about cleanup efforts and share data from ongoing groundwater monitoring.

The company reported about 400,000 gallons of the water containing tritium leaked from a water pipe running between two buildings at its Monticello facility. The leak was stopped and the company is monitoring the groundwater plume through two dozen wells. Xcel Energy is also pumping contaminated groundwater through extraction wells. The pumped water is being stored and some is being reused on site.

“Our top priority is protecting residents and the environment, and the MPCA is working closely with other state agencies to oversee Xcel Energy’s monitoring data and cleanup activities,” said Kirk Koudelka, MPCA assistant commissioner for land and strategic initiatives. “We are working to ensure this cleanup is concluded as thoroughly as possible with minimal or no risk to drinking water supplies.”

Xcel Energy is exploring building aboveground storage tanks or installing a retention pond to store water containing tritium that has been collected during ongoing recovery activities. The company is also considering options for treatment, reuse, or final disposal of the collected tritium and water. Minnesota state agencies will review any options selected by Xcel Energy.

For additional information about tritium go to the U.S. Nuclear Regulatory Commission website.

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