It certainly sounded scary. On March 16, Xcel Energy announced that it was cleaning up a leak of 400,000 gallons of radioactive water at its Monticello nuclear power plant in Minnesota. That’s almost enough water to fill an Olympic swimming pool. Worse, the leak had been detected nearly four months earlier. Though Xcel had notified the Nuclear Regulatory Commission (NRC) and state regulators at the time, the public only learned about it this month.
“While this leak does not pose a risk to the public or the environment, we take this very seriously and are working to safely address the situation,” the company’s president said in a statement that reassured few. News outlets as far away as Europe and India covered the disclosure, and the story quickly went viral. The Left framed the event as yet another indictment of nuclear power’s inescapable risks and lax regulation. “Is this a joke?” asked the ardently pro-renewable, anti-nuclear Stanford professor Mark Z. Jacobson. For the populist Right, the leak joined the recent East Palestine, Ohio, trainwreck as an example of presumed government malfeasance. “Our country is being destroyed,” wrote an “Ultra-MAGA” Twitter personality with 40,000 followers. “Our government is trying to kill us.”
The American public doesn’t respond well to being told “there’s nothing to see here,” and often with good reason. Still, not every worrisome incident is the next Chernobyl, and not every delayed revelation is proof of a conspiratorial coverup. But it is hard for nonexperts to get a balanced picture of events like the Monticello leak for two reasons. First, our news media generally do a poor job covering stories involving scientific questions; even mainstream outlets typically default to alarmism. (The Associated Press, for example, inaccurately described the leak as a form of “radioactive waste.”) Second, in today’s polarized political environment, activists are quicker than ever to seize on events they think will help them advance an agenda. Either way, evenhanded reporting on hot-button scientific issues is rare.
In truth, the Monticello leak is harmless. Here’s why: the source of radiation involved in the incident is tritium, an isotope of hydrogen that poses minimal risks to humans. According to the NRC, “Tritium emits a weak form of radiation, a low-energy beta particle similar to an electron. The tritium radiation does not travel very far in air and cannot penetrate the skin.” Tritium, which is also known as hydrogen-3 or H-3, forms naturally in the atmosphere when cosmic rays interact with nitrogen to create an atom with one proton and two neutrons. Just like normal hydrogen, H-3 easily bonds with oxygen to make H2O. The resulting “tritiated water” falls to the earth where, in minuscule quantities, it mixes with rain, seawater, plants, animals—pretty much everything—becoming part of the low-level background radiation that always surrounds us. Even in concentrated form, tritium is considered safe enough to use in luminescent watch dials, glowing exit signs, and novelty keychains.
In nuclear power plants, tritium sometimes forms—again, in vanishingly low concentrations—via chemical reactions in the water used to cool reactors. This tritiated water is typically stored and reused. (In some cases, it is treated, diluted, and released harmlessly into the environment at concentrations similar to those found in nature.) Nuclear-plant operators are required to keep close tabs on the tritiated water used in their facilities and constantly test for leaks. The Monticello leak was discovered in November, when water from a monitoring well on the plant grounds showed an elevated tritium level. Workers located a broken pipe, made a temporary repair, and then dug additional wells to extract as much of the leaked water as possible. So far, Xcel has recovered about a third of the tritium released.
Activists often focus on the presence of tritium—or occasional leaks or releases of tritiated water—in their arguments against nuclear power. Two New York State lawmakers recently introduced legislation to ban routine releases of slightly tritiated water during the decommissioning process at the closed Indian Point nuclear plant in the Hudson Valley. Overblown tritium concerns have also hampered the cleanup of Japan’s Fukushima plant. In Europe, the prolific anti-nuclear activist Paul Dorfman quickly seized on the Minnesota tritium leak, tweeting, “Normal nuclear pollution. Not green, not clean, too late to help with climate or energy crisis.” Given tritium’s low risk profile—and the tiny quantities involved—nuclear experts find such discussions frustrating.
Coverage of the Monticello incident emphasizes the alarming fact that 400,000 gallons of water leaked. But, as one nuclear advocate noted, “‘Gallons’ is not a measure of radioactivity.” In fact, even the highest level of radiation detected in the Monticello monitoring wells represents no threat to human health. “If you drank nothing but water with that level of tritium in it for an entire year, you would receive more than 10 times less radiation dose than you’d get in a single cross-country flight,” Adam Stein, a nuclear policy analyst with the Breakthrough Institute, told me in an email exchange. Of course, even that level of exposure would be impossible to achieve, he notes. Tests show that the leaked water remains on plant grounds. If any were to migrate beyond site boundaries, it would be massively diluted in the process.
“There simply is no danger to the public from this event,” Stein concludes. “The average person is more likely to be exposed to tritium from a watch face dial or emergency exit sign, which also pose no danger.” Public-health experts often repeat the mantra that “dose matters.” But it is hard for the public to get a realistic sense of risks when the media—and activists—don’t distinguish between meaningful and trivial doses of hazardous materials. By analogy, if a newspaper were to write, “Millions of Americans Exposed to Deadly Chemical” in describing swimming in chlorinated pools, many readers would be skeptical. They know that, while chlorine is highly toxic, the tiny quantities in pool water aren’t generally harmful. But that kind of scientific literacy is much less common—among readers and journalists alike—when it comes to radiation risks. (Indeed, chlorinated pool water represents a significantly greater threat to public health than the low levels of tritium involved in nuclear operations.)
So does this mean that the leak at the Monticello plant is of no concern? Not exactly. Just like ocean-drilling platforms, chemical plants, or commercial aircraft, nuclear plants need to maintain impeccable standards of maintenance and safety compliance. Any mechanical failure that allows 400,000 gallons to leak undetected—even if the spilled water is harmless—needs to be taken seriously. On March 24, Xcel announced that its earlier temporary repair wasn’t fully effective and that a small amount of water continued to leak. Since the reactor was scheduled to shut down for refueling and maintenance later this spring, the company had planned to replace the temporary fix at that time. But now, rather than waiting, “we decided to power down the plant and perform the permanent repairs immediately,” Xcel president Chris Clark said in a statement. Predictably, the disclosure set off a new wave of criticism from anti-nuclear activists.
Should Xcel have made a public announcement back when it first discovered the spill in November? That’s a tricky question. The company did notify the NRC and the Minnesota Pollution Control Agency, and both regulatory bodies opted not to make public statements. “This is something that we struggle with because there is such concern with anything that is nuclear,” NRC spokesperson Victoria Mitlyng told the Associated Press. “The concern is very, very understandable. That is why I want to make extra clear the fact that the public . . . was not and is not in danger.” (The agency did post a “nonemergency” notification about the leak report on its website on November 23.)
In the end, both the NRC and the state Pollution Control Agency waited until they had more complete information before issuing statements to the press. Xcel chose to follow their lead. In retrospect, it might have been wiser to announce the spill immediately. No matter how embarrassing a disclosure might be, a perceived coverup is worse. Then again, the incident highlights the double bind in which nuclear power producers operate. In any other industry, minor breakdowns or accidents don’t make the news. If a chemical plant mishap spills a quart of benzene or releases a momentary puff of chlorine gas, the company might need to alert regulators and document its remediation measures, but no one feels obligated to call reporters. With a nuclear power plant, on the other hand, even minor lapses stoke public fears. If a company reports an incident, it immediately makes headlines. If the company appears to have delayed disclosing the problem, it makes bigger headlines.
On March 22, the NRC held a hearing in Monticello to discuss the spill—and the plant’s future—with local residents. Valerie Myers, a senior health physicist with the agency, reassured the attendees, pointing out that a single hallway exit sign contains three times more tritium than all the leaked water under the plant. The residents appeared attentive but not alarmed by the presentation. Only one person got up to speak. “I think we need cool heads to look at the issues that are facing us and proceed in the manner that needs to be taken to resolve the issues,” he said mildly. This kind of equanimity is quite common among the people who live closest to nuclear power plants. They understand the value of the jobs and the electrical power these plants provide. Perhaps if Xcel Energy had talked to the local community first, it might have avoided making international news over a relatively small problem.
Photo by Renee Jones Schneider/Star Tribune via Getty Images