Minnesota regulators knew four months ago that radioactive waste had leaked from a nuclear plant in Monticello, but they didn’t disclose 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 that there was never a threat to public health. They said Xcel Energy voluntarily notified government agencies and reported the tritium leak to the Nuclear Regulatory Commission shortly after it was confirmed and that the 400,000 gallon (1.5 million liter) leak of radioactive water never reached a threshold requiring public notice would have been necessary.
“This is something we struggle with because there is so much concern about anything nuclear,” said Victoria Mitlyng, a spokesperson for the Nuclear Regulatory Commission. “The concern is very, very understandable. That’s why I want to make it extra clear that the Minnesota public, the people, the community in the vicinity of the plant was and is not in danger.”
State officials said that while they were aware of the November leak, they were waiting for more information before making a public announcement.
“We knew there was tritium present in one monitoring well, but Xcel had not yet identified the source of the leak and its location,” Michael Rafferty, spokesman for the Minnesota Pollution Control Agency, said Thursday. “Now that we have all the information on where the leak occurred, how much has been released into the groundwater and that any contaminated groundwater has left its original location, we are sharing this information.”
Tritium is a radioactive isotope of hydrogen that occurs naturally in the environment and is a common by-product of nuclear power plants. 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 a health risk would only arise if people consumed fairly large amounts of tritium. That risk is mitigated if the plume remains on the company’s site, which Xcel Energy and Minnesota officials say it does.
If regulatory officials are confident it hasn’t been moved from the site, people won’t have to worry about their safety, he said, adding that companies usually take action when monitoring wells detect elevated levels of contaminants like tritium on site.
Mitlyng said there is no official obligation for nuclear power 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 notice about 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 message stated that the source of the tritium was being investigated at the time.
Beyond that, there was no widespread notice to the public before Thursday.
Rafferty said disclosure requirements apply to the facility and state authorities would have immediately notified residents if there had been an immediate threat to health and the environment.
Rafferty said the Minnesota Pollution Control Agency has decided to now share information about its role overseeing the cleanup “because we have more details about the location and possible movement of the contamination, steps being taken to control the plume and recovery plans, including short-term storage. of contaminated water.”
Mitlyng said there’s no way for the tritium to get into drinking water. The facility has groundwater monitoring wells arranged in concentric circles, and plant workers can monitor the progress of contaminants by observing 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, recovery efforts will continue and will install a permanent fix this spring.
Xcel is considering building above-ground storage tanks for the contaminated water it recovers and 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 committee said tritium releases do occur from time to time at nuclear power plants, but they were either limited to plant properties or had such low external levels that they had no impact on public health. Xcel Energy reported a small tritium leak at Monticello in 2009.
The Monticello factory is about 34 miles northwest of Minneapolis, upriver from the city on the Mississippi River.
Shelby Burma, who lives minutes from the spill site, said the news — coming weeks after a train derailment on the Ohio-Pennsylvania border sparked lingering concerns about contaminated air, soil and groundwater — worries her about an increasing amount of chemicals in the environment.
“I find it quite alarming that they didn’t notify the public right away,” Burma said. “They said it can’t hurt, but that’s hard to believe when they wait how long they come out with it.”
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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.
