MINNEAPOLIS (July 20, 2023) – Monitoring systems at Xcel Energy’s Monticello Nuclear Generating Plant have determined that groundwater containing very low levels of tritium may be present near the edge of the Mississippi River. In the river water itself, no tritium has been detected, despite increased water sampling. The closest sample to detect tritium is about 30 feet from the river, and detected about 1,000 picocuries per liter, far below Safe Drinking Water Act standards, or below 20,000 picocuries per liter. Any presence of tritium in the river would be well below the Safe Drinking Water standard and likely at levels indistinguishable from what occurs naturally in the environment.

The low concentrations of tritium continue to pose no risk to public health, safety, or the environment, as confirmed by the Nuclear Regulatory Commission (NRC). Xcel Energy continues to work closely with the NRC, Minnesota Department of Health, and the Minnesota Pollution Control Agency. Members of nearby communities can safely continue to drink from their usual water supply and participate in water-based activities like fishing and swimming.

Xcel Energy has increased the number of monitoring points in the river water as well as the pumping rate and storage capacity for groundwater on-site. The company is adapting its groundwater recovery strategy as conditions change to best retrieve the leaked tritium. The company is investigating further containment measures to prevent as much tritium-impacted water as possible from reaching the river.

In March, Xcel Energy permanently fixed the source of the tritiated water leak at its Monticello plant. The company has expanded its monitoring and groundwater management capabilities to better track and remediate the water. To date, the company has pumped over 2.7 million gallons of groundwater for storage and reuse and has recovered over 75% of the tritium that was released. Most of the remaining tritium remains on-site closer to the plant structures. Activities at the site are being implemented to return all monitoring locations at the plant to Safe Drinking Water Act standards, or below 20,000 picocuries per liter. If at any point Xcel Energy detects tritium above Safe Drinking Water Act standards in river water, the company will notify regulators and the public.

“Since the day we first confirmed a leak of tritiated water was present at the plant, we have worked around the clock to isolate and recover the affected groundwater,” said Chris Clark, president of Xcel Energy–Minnesota, North Dakota and South Dakota. “We take our responsibility for providing safe, reliable and clean energy to the community seriously, and will continue to work closely with state and federal regulators to ensure a thorough cleanup.”

Tritium is commonly created in the operation of nuclear power plants but also occurs naturally in the environment. It emits a low-energy radiation similar to everyday materials people use and foods they eat and is only harmful when ingested in large concentrations.

Learn more about progress to recover and treat water released from the plant.

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About Xcel Energy

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