Updated March 24, 11:50 a.m. | Posted March 23, 9:25 p.m.
Xcel Energy says it will power down its Monticello nuclear power plant after monitoring equipment on Wednesday detected more radioactive tritium was leaking into groundwater.
Crews discovered a container being used to catch the contaminated water as a short-term solution had spilled over, resulting in a new leakage from the same location, Chris Clark, president of Xcel's operations in Minnesota and the Dakotas, told reporters Friday morning in Monticello.
“Unfortunately, in the last couple of days, we realized that the catchment that was catching the water from that leak was no longer catching 100 percent of it, and some of it was spilling over and back into the ground,” Clark said.
The new leak was estimated to be in the hundreds of gallons of water containing tritium. That’s much smaller than the original spill of 400,000 gallons, which was discovered last November. It’s believed the water leaked from a pipe connecting two buildings at the plant.
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Clark said shutting the plant down should eliminate the risk of more water with tritium entering the ground.
“As we cut that pipe out, there's always a chance that some water comes out of the system when we do that,” he said. “But we're talking very minimal compared to what we've been dealing with here.”
Reasons behind pipe failure unclear
Clark said he couldn’t speculate on what caused the initial failure. He said the pipe is likely part of the plant’s original infrastructure built 50 years ago, although Xcel has spent millions of dollars to upgrade the plant since then.
Shutting down the plant will give Xcel a chance to remove the broken pipe, analyze what went wrong and do other inspections, Clark said. The plant will be powered down slowly and allowed to cool over the next couple of days.
“We'll cut that pipe out. We'll send that pipe off to a lab and do a full root-cause analysis on why that pipe failed,” Clark said. “And then we'll determine what sorts of things we need to do for the future of the plant to ensure that we don't have that type of situation again.”
Tritium is a mildly radioactive form of hydrogen that occurs naturally in the environment but also during nuclear power production. It mixes with oxygen to produce radioactive water. State and federal officials say it’s hazardous only if ingested in large quantities.
Clark said crews have recovered more than 30 percent of the tritium released. None has made it into drinking water supplies or the nearby Mississippi River, he added.
The Minnesota Pollution Control Agency and Minnesota Department of Health — informed of the leak on Thursday — said they have “no evidence at this point to indicate a current or imminent risk to the public and will continue to monitor groundwater samples. Should an imminent risk arise, we will inform the public promptly.”
Clark said he’s confident that Xcel will be able to bring the plant back online and operate it safely. The company is currently seeking an extension of the plant’s operating license, which expires in 2030.
The plant was scheduled to shut down in April as part of a regular refueling that occurs every two years. Clark said they’d determine as they inspect the plant whether to start the refueling outage early, or bring the plant back online sooner.
‘They have to do something more’
Clark acknowledged criticism that Xcel should have informed the public sooner about the original leak. The company notified the U.S. Nuclear Regulatory Commission on Nov. 22, but the news wasn’t made public until last week.
“I think one of our lessons here is even though we followed the proper formal notifications, we have an opportunity to do a better job being transparent with our neighbors,” he said. “That's certainly a lesson we take from this.”
Following the news conference, Xcel officials held an open house at Monticello’s community center with company and plant officials on hand to answer questions.
Susan Braun has lived in Monticello for 24 years. Her father helped pour footings for the nuclear plant when it was built in the late 1960s to early 1970s.
Braun said she wants to know what Xcel will be doing to replace aging pipes at the plant.
“They have to do something more,” she said. “I mean, this is obvious now that you can't rely on the same old stuff.”
Braun lives well south of the plant, and said the leak shouldn’t affect the private drinking water well. But she said the fact that the contamination reached the groundwater is “very concerning.”
“They say it's contained, but they lost their credibility,” she said. “And to me, that is not good. Once you lose it, it's going to be hard to get the public trust back.”
Nancy McCaffrey and Phyllis Wuollet, who live in a townhome complex within a mile of the plant, said the delay from the time of the leak and when it was made public is worrisome.
“I think the fact that we didn't get notification about this until four or five months after the fact reduces the credibility of the company, because I believe that's something that should have been made public,” Wuollet said.
McCaffrey said she respects how Xcel is important to the community and the state’s energy production. She said she’s “disappointed” in how the company initially handled the situation but encouraged that officials were available Friday to answer their questions.
The Monticello area has long been supportive of the nuclear plant, which provides jobs and tax revenue. Monticello’s public water system has been unaffected by the Xcel leaks but the city will continue to test the water supply as a precaution, Mayor Lloyd Hilgart said in a statement Friday.
Wuollet and McCaffrey said they don’t think the tritium leak will change that support, but it is a “wake-up call” that local residents should pay attention to what’s happening at the plant.
“You need to be more aware and not just accept that it's there, and all is going to be well,” Wuollet said.