Residents wonder why Monticello nuclear plant didn't mention radioactive water leak earlier

a map that shows xcel monticello nuclear plant
Water containing a radioactive form of hydrogen, tritium, leaked out of Xcel Energy's nuclear power plant in Monticello, Minn., in November, state officials said Thursday.
Nicole Johnson | MPR News via Datawrapper

On Wednesday evening, there will be a public meeting in Monticello on whether to extend the license of the nuclear plant in that city. On March 16, state officials said 400,000 gallons of radioactive water had leaked from a nuclear power plant in the city of Monticello back in November 2022.

Officials said there is no danger to the public from the leak. But some are asking why it took so long for state officials and Xcel Energy, which owns the plant, to tell the public about the spill.

The Star Tribune is reporting it's the sixth highest tritium leaks among U.S. plants. MPR News central Minnesota reporter, Kirsti Marohn, has been following this issue. She joined MPR News host Cathy Wurzer to talk about it.

Use the audio player above to listen to the full conversation. 

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Audio transcript

[MUSIC PLAYING] CATHY WURZER: And tonight there's a public meeting in Monticello on whether to extend the license of the nuclear power plant in that city. Last week, state officials said 400,000 gallons of radioactive water had leaked from a nuclear power plant in the city of Monticello back in November. Officials said there is no danger to the public from the leak, but some are asking why it took so long for state officials and Xcel Energy, which owns the plant, to tell the public about the spill.

The Star Tribune is also reporting that it's the sixth highest tritium leaks among US nuclear power plants. Our Central Minnesota reporter Kirsti Marohn has been following this issue, and she joins us right now. Welcome.

KIRSTI MAROHN: Hi, Cathy. Thanks for having me.

CATHY WURZER: Remind us again what happened and also the timeline of events, for people.

KIRSTI MAROHN: Well, last November, a pipe connecting two buildings at the plant broke, and it leaked about 400,000 gallons of water containing this radioactive tritium. Xcel Energy discovered a tritium in one of its monitoring wells that it has at the plant, and Xcel reported the spill to state and federal regulators back on November 22.

But Xcel, they're not exactly sure when the problem began, and they just made it public last week. So Xcel has been pumping the contaminated water and collecting it, and they've also installed additional monitoring wells in the area to track the underground plume of contamination. And so far, Xcel and state officials say that plume has not left the site of the plant.

CATHY WURZER: And for folks who are not sure about this, what exactly is tritium? How dangerous is it?

KIRSTI MAROHN: Sure. Well, it's a radioactive form of hydrogen, and it occurs naturally in the atmosphere. But it's also a byproduct of nuclear power reactors, like the one at Monticello. So it reacts with oxygen to produce radioactive water. And it can be hazardous, but only if it's ingested in large quantities.

So tritium leaks at power plants, they're not common, but they do happen. There actually was one at the Monticello plant back in 2009, although it was much smaller than this one.

CATHY WURZER: So is there a risk to the public?

KIRSTI MAROHN: Well, Xcel and state officials say no. They say the plume hasn't left the plant site, like I mentioned, and it's not moving toward any drinking water wells or the city of Monticello's water supply.

And I talked with Dan Huff. He's an assistant commissioner at the Minnesota Department of Health. Here's what he said.

DANIEL HUFF: Tritium is a very low-energy radioactive chemical or element. If I had a glass on my desk, it's no harm to me because it can't penetrate the skin. The beta particles are too weak. It's only if you ingest it, and you have to ingest a lot to actually increase your radiation exposure.

KIRSTI MAROHN: So Huff said if you drank water contaminated with tritium at that EPA limit over a year, you'd be exposed to just slightly more radiation than if you took a cross-country airplane flight and considerably less than if you got an X-ray.

CATHY WURZER: So do officials know how much tritium was actually released?

KIRSTI MAROHN: Well, quite a bit. Initially, when the release was first detected, it was measured at 5 million picocuries per liter, that's how it's measured, in the groundwater near the plant. The US Environmental Protection Agency's limit for tritium in drinking water is 20,000 picocuries per liter. So it was far above that limit.

Since then, the pumping that they've been doing has reduced that amount to about 2.5 million picocuries per liter right at the plant. And then, the farther you go away from the plant, the amount that shows up in the monitoring wells is less. And again, officials say that plume hasn't left the plant property.

CATHY WURZER: I know you said that officials say that this has not affected nearby wells or Monticello's drinking water supply. But the Monticello plant sits right next to the Mississippi, and that is a drinking water source for a lot of communities downstream, including Minneapolis and Saint Paul. So does anyone know, has the contamination reached the river?

KIRSTI MAROHN: Well, there's no evidence that it has. And the Minnesota Department of Health does routinely test the river water near the plant. And it's important to remember that downstream, the cities that get their water from the river, they also do monitoring and testing of that water.

And also, officials say that there's just a lot of water in the Mississippi River. So even if all of that contamination were to suddenly enter the river, it would be diluted really quickly. But, of course, that is a big concern. So it's something that they will be watching.

CATHY WURZER: Any comment from state officials about the Star Tribune story, about this is one of the largest leaks among US nuclear power plants?

KIRSTI MAROHN: I mean, I did check with the NRC, the Nuclear Regulatory Commission on that. They said, they look at each leak individually. So they don't really compare the two. I think the Star Tribune did that analysis by themselves by looking at some of the reports to the NRC.

So I think it definitely was a large leak. And I'm not sure exactly where it stacks up. But these tritium leaks are not-- like I said, they're not entirely uncommon. But this was a pretty big one.

CATHY WURZER: So, of course, the big question people want to know, why did it take so long for Xcel Energy and the state to tell the public about this? It happened last November.

KIRSTI MAROHN: That's a good question a lot of people have been asking. The NRC did post a notice at the time of the leak, but not very many people read those. And Xcel and state agencies didn't tell the public until last week.

So I spoke with Kurt Koudelka. He's an assistant MPCA commissioner. And I asked him about this yesterday. He said state agencies are committed to protecting human health and the environment, and they just didn't think that this leak, that there was any threat to the public. So here's what he said.

KIRK KOUDELKA: We take our responsibilities very seriously to promptly inform the public when there is a situation that presents any sort of current or imminent risk. I want to again stress that the situation right now does not present that imminent risk to residents' health. It is a plume that is contained on site, underneath the plant right now, and there's not that direct exposure.

KIRSTI MAROHN: And Koudelka said, had there been an immediate threat to human health or the environment, they would have notified residents immediately. But he said it's kind of a balancing act, to make sure that they have enough information to share but not give incomplete information and create unnecessary concern.

CATHY WURZER: So the Monticello plant has been around for a while. Xcel wants to keep it operating. I know its current license is supposed to expire in 2030, and Xcel has asked the federal government for a 20-year extension. Do you think this incident is going to affect that decision at all?

KIRSTI MAROHN: Well, that remains to be seen. One of the issues that antinuclear activists often raise is the concern that aging plants could be more prone to mechanical problems or breakdowns that could cause an issue. I asked state officials if this raises any concerns for them about whether the plant should be relicensed.

They said they'll defer to the Nuclear Regulatory Commission's process, which includes inspecting the plant and getting public input. There's a previously planned meeting tonight in Monticello to get public input about the license renewal. So it will be interesting to see how many people show up and whether anyone raises safety questions about the plant.

CATHY WURZER: I know you'll be following that. Say, speaking of people who have questions and concerns, I know we've gotten some questions from listeners about Monticello. What do folks want to know?

KIRSTI MAROHN: We've gotten lots of questions about whether their water supply is safe. These are people who generally live pretty far from the plant. But they have private wells, and they want to know if the groundwater, if their water supply could be impacted and if they should get their water tested.

The Minnesota Department of Health says that's not necessary. They say the closest private well is about 2/3 of a mile away, and the closest public well is over 2 miles. So it would take several months for the groundwater to travel that far. And it's also in the opposite direction of the groundwater flow.

We've also gotten some questions about the potential impact on wildlife, especially those swans that like to hang out in the Mississippi River, near the plant. Officials say they're not at risk because the contamination hasn't reached the river. And even if it did, like I said, there's a lot of water in the river. So it would be diluted.

But a lot of people have asked that question of why the public wasn't notified of the leak earlier. And state officials told me they recognize that some people aren't happy, and they'll take that feedback into consideration in the future.

CATHY WURZER: Kirsti, thank you so much for the update.

KIRSTI MAROHN: You're welcome, Cathy.

CATHY WURZER: That's Kirsti Marohn. She covers Central Minnesota for MPR News.

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