A nuclear power plant leaked contaminated water in Minnesota. Here’s what we know: NPR

This photo from July 24, 2008 shows the Monticello Nuclear Generating Station in Monticello, MN. In November 2022, the plant confirmed a leak of 400,000 gallons of water containing tritium and reported it to authorities. The leak only became public knowledge on Thursday.

Karen Bleier/AFP via Getty Images

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Karen Bleier/AFP via Getty Images

This photo from July 24, 2008 shows the Monticello Nuclear Generating Station in Monticello, MN. In November 2022, the plant confirmed a leak of 400,000 gallons of water containing tritium and reported it to authorities. The leak only became public knowledge on Thursday.

Karen Bleier/AFP via Getty Images

Minnesota officials are monitoring the cleanup of a 400,000 gallon contaminated water leak from a nuclear power plant in the town of Monticello run by energy giant Xcel Energy. Officials said there was no danger from the leak.

The leak was detected nearly four months ago and reported to state and federal regulators. The Federal Nuclear Regulatory Commission issued a notice publicly at the time, but the company and state agencies did not notify the general public until last week.

“Xcel Energy has taken prompt action to contain the leak to the plant site, which poses no risk to the health and safety of the local community or the environment,” the company said in a statement Thursday. . Continued monitoring confirmed that the leak “is fully contained on site and has not been detected beyond the facility or in local drinking water,” the company said.

Xcel confirmed the tritium-containing water leak in November 2022 and notified authorities the same day, according to the company’s announcement. Officials attributed the leak to a water main connecting two buildings at the plant site. The amount of contaminated water that leaked out is enough to fill an Olympic-sized swimming pool about 60%.

Xcel is based in Minneapolis, Minnesota and operates in eight states in the United States. Its two nuclear power plants are both based in Minnesota. Monticello is about 40 miles northwest of Minneapolis and has a population of about 15,000 people.

Because there was no immediate threat to public health and safety, “we focused on investigating the situation and containing the affected water in concert with our regulatory agencies,” Xcel spokeswoman Lacey Nygard said in an email to NPR when asked why there was an almost four-month delay in notifying the public. “We are now at a place where we can share with the public not only what has already been done, but also what we are going to do next. This timing allows us to provide the most accurate and complete understanding of the situation. .”

In 2009, the same Xcel plant in Monticello had a small tritium leak, which Nygard said was smaller than the 2022 leak and came from a sump rather than a pipe.

“Many operating nuclear power plants have had some level of tritium leakage at some point during their operations,” Nygard said.

Michael Rafferty, spokesman for the Minnesota Pollution Control Agency, told NPR the agency waited for more information before announcing it to the public.

“Minnesota state agencies are deeply committed to our role in protecting human health and the environment and take seriously our responsibility to promptly notify the public when a situation presents a present or imminent risk,” Rafferty said. “The situation at Xcel Energy’s Monticello site has not – and still does not present – ​​an imminent threat to the health of residents.”

Federal Nuclear Regulatory Commission officials did not immediately respond to requests for comment. An NRC spokeswoman, Victoria Mitlyng, told a local news station that the public concern was “very understandable” and stressed that “the Minnesota public, the people, the community near the plant , was not and is not in danger”. “

What is tritium?

Tritium is a naturally occurring form of hydrogen that emits a weak form of radiation, which cannot travel far through air or penetrate skin, according to the NRC.

Tritium is also a byproduct of electricity generation in nuclear power plants, and the dose of tritium from nuclear power plants is far lower than radiation exposures found in the natural environment, according to the NRC. Xcel said tritium levels in the leaking water were below NRC safety limits.

“Everyone is exposed to small amounts of tritium every day because it occurs naturally in the environment and the foods we eat,” according to an NRC fact sheet.

Any exposure to radiation can pose some health risk, including an increased incidence of cancer. Exposure risks are linear, meaning that lower levels of radiation pose less risk.

Eating or drinking food or water containing tritium is the most common way for it to enter the body. It can also be absorbed through the skin. About half leave the body within 10 days of exposure.

Cleanup will take months

Xcel says it has recovered about 25% of the tritium-contaminated water that escaped, and recovery efforts will continue over the next year.

“While this leak does not pose a risk to the public or the environment, we take this very seriously and are working to safely remedy the situation,” said Chris Clark, president of Xcel Energy – Minnesota, Dakota. North and South Dakota, in the company’s statement. “We continue to collect and treat all potentially affected water while regularly monitoring nearby groundwater sources.”

To contain the leak, water is diverted to a treatment system inside the plant, which prevents water from exiting the plant. Xcel said it also inspected all of its piping to ensure this was not happening elsewhere in the facility.

The Minnesota Pollution Control Agency said Xcel is considering building aboveground storage tanks or installing a retention pond to store recovered tritium-containing water, as well as considering treatment, reuse and disposal options. Minnesota regulators will consider any options the company chooses, the MPCA said.

“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 Deputy Commissioner for Land and Policy Initiatives. “We strive to ensure that this cleaning is carried out as thoroughly as possible with minimal or no risk to the drinking water supply.”