In 2004, Heather Hoff was working at a clothing store and living with her husband in San Luis Obispo, a small, laid-back city in the Central Coast region of California. A few years earlier, she had earned a B.S. in materials engineering from the nearby California Polytechnic State University. But she’d so far found work only in a series of eclectic entry-level positions—shovelling grapes at a winery, assembling rectal thermometers for cows. She was twenty-four years old and eager to start a career.
One of the county’s major employers was the Diablo Canyon Power Plant, situated on the coastline outside the city. Jobs there were stable and well-paying. But Diablo Canyon is a nuclear facility—it consists of two reactors, each contained inside a giant concrete dome—and Hoff, like many people, was suspicious of nuclear power. Her mother had been pregnant with her in March, 1979, when the meltdown at a nuclear plant on Three Mile Island, in Pennsylvania, transfixed the nation. Hoff grew up in Arizona, in an unconventional family that lived in a trailer with a composting toilet. She considered herself an environmentalist, and took it for granted that environmentalism and nuclear power were at odds.
Nonetheless, Hoff decided to give Diablo Canyon a try. She was hired as a plant operator. The work took her on daily rounds of the facility, checking equipment performance—oil flows, temperatures, vibrations—and hunting for signs of malfunction. Still skeptical, she asked constant questions about the safety of the technology. “When four-thirty on Friday came, my co-workers were, like, ‘Shut up, Heather, we want to go home,’ ” she recalled. “When I finally asked enough questions to understand the details, it wasn’t that scary.”
In the course of years, Hoff grew increasingly comfortable at the plant. She switched roles, working in the control room and then as a procedure writer, and got to know the workforce—mostly older, avuncular men. She began to believe that nuclear power was a safe, potent source of clean energy with numerous advantages over other sources. For instance, nuclear reactors generate huge amounts of energy on a small footprint: Diablo Canyon, which accounts for roughly nine per cent of the electricity produced in California, occupies fewer than six hundred acres. It can generate energy at all hours and, unlike solar and wind power, does not depend on particular weather conditions to operate. Hoff was especially struck by the fact that nuclear-power generation does not emit carbon dioxide or the other air pollutants associated with fossil fuels. Eventually, she began to think that fears of nuclear energy were not just misguided but dangerous. Her job no longer seemed to be in tension with her environmentalist views. Instead, it felt like an expression of her deepest values.
In late 2015, Hoff and her colleagues began to hear reports that worried them. P.G. & E., the utility that owns Diablo Canyon, was in the process of applying to renew its operating licenses—which expire in the mid-twenty-twenties—with the federal Nuclear Regulatory Commission. Because its cooling system takes in and spits out about 2.5 billion gallons of ocean water each day, the plant also needs a lease from the California State Lands Commission in order to operate, and P.G. & E. was applying to renew that as well. Environmental groups had come to the commission with long-standing concerns about the effects of the cooling system on marine life and about the plant’s proximity to several geologic faults. The commission, chaired by Gavin Newsom, then the lieutenant governor, had agreed to take those issues into account. At a meeting that December, Newsom said, “I just don’t see that this plant is going to survive beyond ’24-2025.”
Around this time, Hoff discovered a Web site called Save Diablo Canyon. The site had been launched by a man named Michael Shellenberger, who ran an organization called Environmental Progress, in the Bay Area. Shellenberger was a controversial figure, known for his pugilistic defense of nuclear power and his acerbic criticism of mainstream environmentalists. Hoff had seen “Pandora’s Promise,” a 2013 documentary about nuclear power, in which Shellenberger had been featured. She e-mailed him to ask about getting involved, and he offered to give a talk to plant employees. Hoff publicized the event among her colleagues, and baked about two hundred chocolate-chip cookies for the audience.
On the evening of February 16, 2016, a couple hundred people filed into a conference room at a local Courtyard Marriott hotel. Shellenberger told the audience that Diablo Canyon was essential to meeting California’s climate goals, and that it could operate safely for at least another twenty years. He said that it was at risk of being closed for political reasons, and urged the workers to organize to save their plant, for the sake of their jobs and the planet.
Kristin Zaitz, one of Hoff’s co-workers, was also in attendance. A California native and civil engineer, she had worked at Diablo Canyon since 2001, first conducting structural analyses—including some meant to fortify the plant against earthquakes—and then managing projects. Zaitz, too, came from a background that predisposed her to distrust nuclear power—in her case, an environmentally minded family and a left-leaning social circle. When she first contemplated working at Diablo Canyon, she imagined the rat-infested Springfield Nuclear Power Plant on “The Simpsons,” where green liquid oozes out of tanks. Eventually, like Hoff, she changed her thinking. “What we were doing actually aligned with my environmental values,” she told me. “That was shocking to me.”
Zaitz and Hoff sometimes bumped into each other at state parks, where both volunteered on weekends with their children. After Shellenberger’s talk, they lingered, folding up chairs and talking. Before long, they decided to team up. Using the name of Shellenberger's site Save Diablo Canyon, they organized a series of meetings at a local pipe-fitters’ union hall. They served pizza for dozens of employees and their family members, who wrote letters to the State Lands Commission and other California officials. Other nuclear plants across the country were also at risk of closing, and soon they decided that their mission was bigger than rescuing their own plant. They wanted to correct what they saw as false impressions about nuclear power—impressions that they had once had themselves—and to try to shift public opinion. They would show that “it’s O.K. to be in favor of nuclear,” Zaitz said—that, in fact, if you’re an environmentalist, “you should be out there rooting for it.”
Hoff and Zaitz formed a nonprofit. Like the leaders of many other movements led by women—protests against war, drunk driving, and, of course, nuclear power—they sought to capitalize on their status as mothers. They toyed with a few generic names—Mothers for Climate, Mothers for Sustainability—because they worried that the word “nuclear” would scare some people off. But they ultimately discarded those more innocuous options. “We wanted to be really clear that we think nuclear needs to be part of the solution,” Zaitz said. They now run a small activist organization, Mothers for Nuclear, which argues that nuclear power is an indispensable tool in the quest for a decarbonized society.
On December 8, 1953, President Dwight Eisenhower delivered his “Atoms for Peace” speech at the United Nations General Assembly. He described the dangers of atomic weapons, but also declared that “this greatest of destructive forces can be developed into a great boon, for the benefit of all mankind.” Eisenhower proposed that governments make contributions from their stockpiles of uranium and fissionable materials to an international atomic-energy agency. One purpose of such an agency, he suggested, would be “to provide abundant electrical energy in the power-starved areas of the world.”
The first commercial nuclear power plant in the United States opened four years later, in Beaver County, Pennsylvania. In the following decades, dozens more were constructed. There are currently fifty-six nuclear power plants operating in the U.S. They provide the country with roughly twenty per cent of its electricity supply— more than half of its low-carbon electricity.
The plants were not always presumed to be environmentally unfriendly. At the dawn of the nuclear age, some conservationists, including David Brower, the longtime leader of the Sierra Club, supported nuclear power because it seemed preferable to hydroelectric dams, the construction of which destroyed scenery and wildlife by flooding valleys and other ecosystems. But Brower changed his mind in the late nineteen-sixties and, after a bitter split within the Sierra Club over whether to support the construction of Diablo Canyon, left to found Friends of the Earth, which was vehemently anti-nuclear. As John Wills explains in his 2006 book, “Conservation Fallout,” these disputes coincided with broader philosophical shifts. Conservationism—with its focus on the preservation of charismatic scenery for outdoor adventures—was giving way to the modern environmentalist movement, sparked in part by Rachel Carson’s 1962 book, “Silent Spring.” Carson’s book, which investigated the dangers posed by pesticides, articulated an ecological vision of nature in which everything was connected in a delicate web of life. Nuclear power was associated with radiation, which, like pesticides, could threaten that web.
By 1979, the U.S. had seventy-two commercial reactors. That year proved pivotal in the shaping of public opinion toward nuclear power in America. On March 16th, “The China Syndrome,” starring Jane Fonda, Jack Lemmon, and Michael Douglas, was released; the film portrayed corruption and a meltdown at a fictional nuclear plant. Twelve days later, one of the two reactors at the Three Mile Island Nuclear Generating Station in southeastern Pennsylvania partially melted down. Most epidemiological studies would eventually determine that the accident had no detectable health consequences. But at the time there was no way the public could know this, and the incident added momentum to the anti-nuclear movement. By the time of the Chernobyl catastrophe, in Soviet Ukraine, in 1986—widely considered to be the worst nuclear disaster in history—opposition to nuclear power was widespread. Between 1979 and 1988, sixty-seven planned nuclear-power projects were cancelled. In the mid-eighties, the Department of Energy began research into the “integral fast reactor”—an innovative system designed to be safer and more advanced. In 1994, the Clinton Administration shut the project down.
Today, the looming disruptions of climate change have altered the risk calculus around nuclear energy. James Hansen, the NASA scientist credited with first bringing global warming to public attention, in 1988, has long advocated a vast expansion of nuclear power to replace fossil fuels. Even some environmental groups that have reservations about nuclear energy, such as the Natural Resources Defense Council and the Environmental Defense Fund, have recognized that abruptly closing existing reactors would lead to a spike in emissions. But U.S. plants are aging and grappling with a variety of challenges. In recent years, their economic viability has been threatened by cheap, fracked natural gas. Safety regulations introduced after the meltdowns at Japan’s Fukushima Daiichi nuclear plant, in 2011, have increased costs, and, in states such as California, legislation prioritizes renewables (the costs of which have also fallen steeply). Since 2013, eleven American reactors have been retired; the lost electricity has largely been replaced through the burning of fossil fuels. At least eight more closures, including Diablo Canyon’s, are planned. In a 2018 report, the Union of Concerned Scientists concluded that “closing the at-risk plants early could result in a cumulative 4 to 6 percent increase in US power sector carbon emissions by 2035.”
The past decade has seen the rise of a contingent of strongly pro-nuclear environmentalists. In 2007, Shellenberger and his colleague Ted Nordhaus co-founded the Breakthrough Institute, a Bay Area think tank known for its heterodox, “ecomodernist” approach to environmental problems. The organization, which presents itself as more pragmatic than the mainstream environmental movement, supports nuclear power alongside G.M.O.s and agricultural intensification. Other pro-nuclear groups include Third Way, a center-left think tank, and Good Energy Collective, a policy-research organization. (Shellenberger left the Breakthrough Institute, in 2015, and founded Environmental Progress, partly to focus more on efforts to save existing plants.)
The 2011 Fukushima disaster shifted the landscape of opinion, but not in entirely predictable ways. Immediately after Fukushima, anti-nuclear sentiment surged; Japan began to shutter its nuclear plants, as did Germany. And yet, as Carolyn Kormann has written, studies have found few health risks connected to radiation exposure in Japan in the wake of the accident. (The evacuation itself was associated with more than a thousand deaths, as well as a great deal of economic disruption.) Pro-nuclear advocates now point out that, after retiring some of their nuclear plants, Japan and Germany have become increasingly reliant on coal.
Heather Hoff watched news footage of the Fukushima disaster while at Diablo Canyon. What she saw resembled the scenarios she had learned about in training—situations that she had prepared for but never expected to face. “My heart instantly filled with fear,” she later wrote, on the Mothers for Nuclear Web site. For a time, her confidence in nuclear power was shaken. But, as more information emerged, she came to believe that the accident was not as cataclysmic as it had initially appeared to be. Eventually, Hoff concluded that the incident was an opportunity to learn how to improve nuclear power, not a reason to give up on it. She and Zaitz visited the site in 2018. They saw black plastic bags of contaminated soil heaped on the roadside, and ate the local fish. Afterward, they both blogged about the experience. Zaitz wrote that she understood the fear provoked by radiation, “with its deep roots in the horrendous human impacts caused by the atomic bomb.”
Pro-nuclear environmentalists often tell a conversion story, describing the moment when they began to see nuclear power not as something that could destroy the world but as something that could save it. They argue that much of what we think we know about nuclear energy is wrong. Instead of being the most dangerous energy source, it is one of the safest, linked with far fewer deaths per terawatt-hour than all fossil fuels. We perceive nuclear waste as uniquely hazardous, but, while waste from oil, natural gas, and coal is spewed into the atmosphere as greenhouse gases and as other forms of pollution, spent nuclear-fuel rods, which are solid, are contained in concrete casks or cooling pools, where they are monitored and prevented from causing harm. (The question of long-term storage remains fraught.) Most nuclear enthusiasts believe that renewables have a role to play in the energy system of the future. But they are skeptical of the premise that renewables alone can reliably power modern societies. And—in contrast to an environmental movement that has historically advocated the reduction of energy demand—pro-nuclear groups tend to focus more on the value that abundant nuclear energy could have around the world.