Minnesota regulators knew four months ago that radioactive waste had leaked from the Monticello nuclear power plant — but didn’t make a public announcement about the leak until this week.
The delay in notifying the public about 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 the threshold to require public notification.
“This is something we’re struggling with because there’s a lot of concern about anything nuclear,” said Victoria Mitlyng, a spokeswoman for the Nuclear Regulatory Commission. “The concern is very, very understandable. So I want to further clarify the fact that the public in Minnesota, the people, the community near the plant, were not and are not in danger.”
State officials said that while they knew about the leak in November, they were waiting to get more information before making a public announcement.
“We knew there was tritium present in one monitoring well, however Xcel has 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 has 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 power plant operations. It emits a weak form of beta radiation that does not travel far and cannot penetrate human skin, according to the Nuclear Regulatory Commission.
Edwin Lyman, director of nuclear safety at the Union of Concerned Scientists, said significant health risks could only occur if people consumed fairly large amounts of tritium. That risk is limited if the plume remains at the company’s site, which Xcel Energy and Minnesota officials said is the case.
If regulatory officials are sure it hasn’t moved from the site, people shouldn’t worry about their safety, he said, adding that companies typically take action when on-site monitoring wells detect elevated levels of contaminants like tritium.
Mitlyng said there is no official requirement for nuclear plants to report all tritium leaks to the Nuclear Regulatory Commission. Instead, Xcel Energy 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 notice of the leak on its website on Nov. 23, noting that the plant had reported it to the state a day earlier. The report classified the leak as a non-emergency. The notice states that the source of the tritium is being investigated at the time.
Additionally, there was no widespread notification to the public prior to Thursday.
Rafferty said disclosure requirements fall on the facility, and state agencies would immediately notify residents if there was an imminent threat to health or 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 potential movement of the contamination, steps being taken to control the plume and remediation plans including short-term storage of contaminated water.”
Mitlyng said there is no way for tritium to get into drinking water. The plant has groundwater monitoring wells in concentric circles, and plant employees can track the progress of contaminants by seeing which wells detect higher amounts. Nuclear Regulatory Commission inspectors are also 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 spilled tritium so far, that recovery efforts will continue and that it will install a permanent solution this spring.
Xcel is considering building aboveground 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 consider the options the company chooses, the state pollution control agency said.
The regulatory commission said tritium spills occur from time to time at nuclear power plants, but were either confined to plant properties or involved such low off-site levels that they did not affect public health. Xcel Energy reported a small tritium leak at Monticello in 2009.
The Monticello plant is about 55 kilometers northwest of Minneapolis, upstream from 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 left concerns about contaminated air, soil and groundwater — is worrying about the increasing amount of chemicals into the environment.
“I think it’s quite alarming that they didn’t notify the public right away,” Burma said. “They said it wouldn’t cause any harm, but it’s hard to believe when they waited so long to make it public.”
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Phillis reported from New York, 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.
