Regulators in Minnesota knew four months ago that radioactive waste had leaked from a nuclear power plant in Monticello, but they didn’t announce anything about the leak until this week.
The delay in notifying the public of the November leak raised questions about public safety and transparency, but industry experts said Friday there was never a threat to public health. They said Xcel Energy voluntarily notified state agencies and reported the tritium leak to the Nuclear Regulatory Commission shortly after it was confirmed and that the leak of 400,000 gallons (1.5 million liters) of radioactive water never reached a threshold that would have required public notice.
“This is something we struggle with because there is great concern about anything nuclear,” said Victoria Mitlyng, a spokeswoman for the Nuclear Regulatory Commission. “The concern is very, very understandable. So I want to make very clear the fact that the Minnesota public, the people, the community near the plant, were not and are not in danger.”
State officials said that although they knew about the leak in November, they waited for more information before making a public announcement.
“We knew tritium was present in a monitoring well, however Xcel had not yet identified the source of the leak and its location,” Minnesota Pollution Control Agency spokesman Michael Rafferty said Thursday. “Now that we have all the information about where the leak occurred, how much was released into the groundwater, and that the contaminated groundwater had moved beyond the original location, we are sharing this information.”
Tritium is a radioactive isotope of hydrogen that occurs naturally in the environment and is a common byproduct of nuclear plant operations. It emits a weak form of beta radiation that doesn’t travel very far and cannot penetrate human skin, according to the Nuclear Regulatory Commission.
Edwin Lyman, director of nuclear power safety for the Union of Concerned Scientists, said a health risk would only occur if people consumed fairly high amounts of tritium. That risk is contained if the plume remains at the company site, which Xcel Energy and Minnesota officials said is the case.
If regulatory officials are sure it didn’t move off-site, people shouldn’t have to worry about their safety, he said, adding that companies typically take action when on-site monitoring wells detect elevated levels of contaminants such as the tritium.
Mitlyng said there is no official requirement for nuclear plants to report all tritium leaks to the Nuclear Regulatory Commission. Instead, Xcel Energy had previously agreed to report certain tritium leaks to the state. When Xcel Energy shares information with the state, it also shares it with the commission.
The commission posted a notification about the leak on its website on November 23, noting that the plant reported it to the state a day earlier. The report classified the leak as an emergency. The notice said that the source of the tritium was being investigated at the time.
Beyond that, there was no widespread notification to the public before Thursday.
Rafferty said the disclosure requirements fall on the facility, and state agencies would have notified residents immediately if there had been an imminent threat to health and the environment.
Rafferty said the Minnesota Pollution Control Agency decided to share information about its role in overseeing the cleanup now “because we have more details about the location and possible movement of the contamination, the steps that are being taken to control the column and remediation plans, including short-term storage. of polluted water.”
Mitlyng said there is no pathway for tritium to get into drinking water. The facility has groundwater monitoring wells in concentric circles, and plant employees can track the progress of contaminants by looking at which wells detect higher amounts. There are also inspectors from the Nuclear Regulatory Commission on site, monitoring the response.
The company said the leak came from a pipe between two buildings.
Xcel said it has recovered about 25% of the tritium spilled so far, that recovery efforts will continue, and that it will install a permanent solution this spring.
Xcel is considering building aboveground storage tanks for the contaminated water it recovers and is considering options for treatment, reuse or final disposal of the collected tritium and water. State regulators will review the options the company selects, the state Pollution Control Agency said.
The regulatory commission said tritium spills do occur from time to time at nuclear plants, but have been limited to plant properties or have involved levels so low off-site that they did not affect public health. Xcel Energy reported a small tritium leak at Monticello in 2009.
The Monticello plant is about 35 miles (55 kilometers) northwest of Minneapolis, upstream of the city on the Mississippi River.
Shelby Burma, who lives minutes from the spill site, said the news, which comes weeks after a train derailment on the Ohio-Pennsylvania border raised lingering concerns about air, soil and water pollution. underground, makes her concerned about an increasing amount of chemicals in the environment.
“I think it’s quite alarming that they didn’t notify the public right away,” Burma said. “They said it won’t cause any harm, but that’s hard to believe when they waited how long to go public.”
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Phillis reported from New York City, Biraben from Pierre, South Dakota. Associated Press writers Trisha Ahmed and Steve Karnowski in Minneapolis and Margaret Stafford in Kansas City, Missouri contributed to this report.