Officials in Minnesota are monitoring the cleanup of a massive spill of radioactive water from a nuclear power plant just outside Minneapolis. About 1.5 million litres (400,000 gallons) of nuclear wastewater leaked from the plant back in late November, but the incident wasn’t made public until Thursday.
Xcel Energy, the company that operates the affected nuclear power plant, promises that the spill poses no risk to public safety, as did the Minnesota Pollution Control Agency.
“Xcel Energy took swift action to contain the leak to the plant site, which poses no health and safety risk to the local community or the environment,” the Minneapolis-based utility said in a statement.
Xcel reported the leak at its Monticello power plant to state and federal authorities on Nov. 22, the day after the spill was confirmed. The contaminated water contains tritium, a radioactive isotope of hydrogen that occurs naturally in the environment and is a common by-product of nuclear plant operations, according to the U.S. Nuclear Regulatory Commission (NRC).
The leak was sprung from a pipe that ran between two buildings in the power plant complex, which is 55 kilometres northwest of Minneapolis and about 600 kilometres south of Thunder Bay. State officials said they waited until more information could be gathered before making the spill public.
“We knew there was a presence of tritium in one monitoring well, however, Xcel had not yet identified the source of the leak and its location,” Minnesota Pollution Control Agency spokesman Michael Rafferty said.
“Now that we have all the information about where the leak occurred, how much was released into groundwater, and that contaminated groundwater had moved beyond the original location, we are sharing this information,” he said, adding the water remains contained on Xcel’s property and poses no immediate public health risk.
Since the leak, Xcel has been pumping groundwater and storing and processing the contaminated water. They say they have recovered about 25 per cent of the spilled tritium so far and the levels of tritium in the water are below federal thresholds. The company plans to install a permanent solution this spring.
“Ongoing monitoring from over two dozen on-site monitoring wells confirms that the leaked water is fully contained on-site and has not been detected beyond the facility or in any local drinking water,” the Xcel Energy statement said.
The Minnesota Department of Health confirmed that the contaminants did not reach the Mississippi River, which is right in the power plant’s backyard.
The agency also reiterates that the leak poses no health risk at this time, but added that the “main potential health risk from this event is the possibility of radiation exposure to the public.”
“A conservative assumption in radiation protection is that any radiation exposure could result in an increase in cancer occurrences in the population,” the health department writes on its website.
When asked why the company didn’t release news of the leak sooner, Chris Clark, president of Xcel Energy–Minnesota, North Dakota and South Dakota said: “If at any point there had been concern for the public safety, we would, of course, immediately have provided more information.”
“But we also wanted to make sure we fully understood what was going on before we started raising any concerns with the public around us,” he told CBS Minnesota on Thursday.
In a separate statement, the company said it understands “the importance of quickly informing the communities we serve if a situation poses an immediate threat to health and safety. In this case, there was no such threat.”
Tritium emits a weak form of beta radiation that does not travel very far and cannot penetrate human skin, according to the NRC. A person who drank water from a spill would get only a low dose, the NRC says.
Tritium spills happen from time to time at nuclear plants, the NRC says. When they occurred in the past, the spills typically either remained inside the plant property or involved such low offsite levels that they didn’t affect public health or safety. Xcel reported a small tritium leak at Monticello in 2009.
Xcel Energy is considering building above-ground storage tanks to store the contaminated water it recovers, and is considering options for the treatment, reuse, or final disposal of the collected tritium and water. State regulators will review the options the company selects, the MPCA said.
Japan is preparing to release a massive amount of treated radioactive wastewater into the sea from the triple reactor meltdowns 12 years ago at the Fukushima Daiichi nuclear power plant. The water contains tritium and other radioactive contaminants.
— With files from The Associated Press