MINNEAPOLIS (December 14, 2023) — A year after detecting a leak of tritiated water from its Monticello Nuclear Generating Station, Xcel Energy has recovered the majority of the tritium released and completed actions to contain the leaked water while remediation continues.

The company has removed about 7 million gallons of water from the ground and lowered groundwater tritium concentrations at the site by more than 90%. The low concentrations continue to pose no risk to public health or the environment, as previously confirmed by the Nuclear Regulatory Commission. Tritium has not been detected in the nearby Mississippi River at any point, despite increased sampling by the company and state regulators.

In addition to permanently fixing the source of the leak during a maintenance outage in March 2023, Xcel Energy has taken numerous actions to contain the tritium to the site and facilitate its removal. The company has built an underground barrier wall as an additional groundwater containment measure, has drilled dozens of new wells to monitor concentrations in different areas of the site, has increased the frequency of its measurements and is finalizing a system of underground pumps to control groundwater flow.

“As part of our charge in providing safe, reliable and clean energy to communities, we are responsible for being good stewards of those communities and the natural environment,” said Chris Clark, president of Xcel Energy–Minnesota, North Dakota and South Dakota. “We have made significant progress over the past year to retrieve the water released from our plant and keep it on-site as we do so. We will continue to work closely with state and federal regulators to ensure a thorough remediation.”

Upon first discovering the leak, Xcel Energy made an initial estimate of the total volume of tritiated water released. The estimate was based on the duration and flow rates of the leak known at the time. The company has since completed a detailed accounting based on more comprehensive information now available, including a higher flow rate of water and signs that the leak may have started a few weeks earlier than previously estimated. This updated and more accurate modeling places the total amount of water leaked between 750,000 and 900,000 gallons, including about 14 curies of tritium.

The revised estimate does not present any concern for health or the environment, nor does it require any new measures as the company continues groundwater recovery. In line with state remediation guidance, Xcel Energy will continue its strategy to pump and store groundwater until all monitoring wells are below the EPA standards. The company continues to coordinate with state and federal regulators as well as local officials. After remediation efforts have finished, groundwater monitoring will continue for the remainder of the plant’s operating life.

Tritium is a compound that is naturally present in the environment and is commonly created in the operation of nuclear power plants. It emits low levels of radiation, similar to everyday materials people use and the food they eat. Tritium is only harmful when consumed in very large quantities. According to the Nuclear Energy Institute, no tritium release from a nuclear power plant has ever posed a public health threat or exceeded EPA regulatory limits in drinking water.

Visit the Monticello groundwater page for more information.

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About Xcel Energy

Xcel Energy (NASDAQ: XEL) provides the energy that powers millions of homes and businesses across eight Western and Midwestern states. Headquartered in Minneapolis, the company is an industry leader in responsibly reducing carbon emissions and producing and delivering clean energy solutions from a variety of renewable sources at competitive prices. For more information, visit xcelenergy.com or follow us on X, formerly known as Twitter, and Facebook.