A Real-Life Disaster Movie

Three Mile Island soon after the meltdown. Three Mile Island 2 encompasses the two towers in the foreground.

(Library of Congress)

It began almost routinely at four o’clock on the morning of March 28, 1979: A pump failed in the Three Mile Island 2 nuclear power plant, and safety controls automatically shut down the reactor.

The glitch was hardly unusual. The facility had operated at full power for only 40 of the 87 days since it had gone on line the previous December. “The equipment never ran right,” a technician said.

During the 1970s the General Public Utilities Corporation had constructed two electricity generating stations on this chunk of land in the Susquehanna River a few miles from Harrisburg, Pennsylvania’s capital. The incident that was about to unfold at one of them would rivet the nation’s attention in the days to come and would change the energy equation in the United States forever.

Even with its nuclear chain reaction halted, the reactor continued to produce about 7 percent of its full energy output, a result of the decay of radioactive isotopes. This amount of heat was enough to raise the temperature in the reactor core past the melting point of its fuel rods.

Besides wrecking the reactor, a meltdown would create temperatures that could liquefy the thick steel of the reactor vessel itself. As the molten fuel poured out, it would melt everything in its path, in theory plunging through the earth toward China. This “China syndrome” was shorthand for an unthinkable accident. Operators knew that it was absolutely imperative that they maintain a steady flow of cooling water through the reactor vessel.

That March morning they failed to do so. A valve stuck open, draining much of the reactor’s coolant. During the next hour, amid a barrage of squawking alarm horns and frantically blinking lights, the operators misread gauges, misinterpreted data, and made unwise decisions. These factors created a situation of unprecedented peril.

Atomic power had become possible in 1954 when the Atomic Energy Act declassified basic wartime nuclear research. During the 1960s utilities eagerly embraced the technology. In 1973 a record 44 new stations came on line. Optimists foresaw 1,000 plants by the end of the century, the virtual disappearance of fossil fuel, and electricity “too cheap to meter.”

But the 1970s brought recession, a drop in electricity demand, and a growing anti-nuclear movement. Citizens grew concerned about spent-fuel disposal and about radiation leaks. More than anything, they worried about the potential for a catastrophic accident.

On the evening of March 28 the CBS anchorman Walter Cronkite called the ongoing incident at Three Mile Island “the first step in a nuclear nightmare,” but added that it was, “as far was we know at this hour, no worse than that.”

In fact it was much worse. What the teams of engineers and federal regulators at the site didn’t know was that fully half of the reactor’s core had melted soon after the incident began. What they did know was that the situation was serious and getting worse. A large bubble of hydrogen gas was forming in the reactor vessel, raising the possibility of a devastating explosion.

By a bizarre coincidence (or an inspired bit of artistic premonition) the movie The China Syndrome had opened around the country only two weeks earlier. The film, which starred Jack Lemmon and Jane Fonda, dramatized with uncanny accuracy the calamitous combination of mechanical failure and human error now taking place in real life. Even the movie’s heavy-handed portrayal of corporate greed had parallels at Three Mile Island, where the utility had cut corners to get the plant on line before the end of 1978 in order to collect millions in tax benefits.

Technicians struggled to find a way to bring the reactor under control and to safely clear the hydrogen bubble. To keep pressure from mounting in an adjacent utility building, they also began to make controlled releases of radioactivity. On Friday, March 30, Governor Richard L. Thornburg ordered an “advisory” evacuation of pregnant women and children within five miles of the plant. Area residents didn’t hesitate to get out. In all, 144,000 people fled the area. One woman, who went to Ohio with her family, said, “You feel like you’re sitting in the middle of a disaster movie.”

By Sunday, April 1, the crisis was beginning to ease. President Jimmy Carter flew in to tour the plant. Though technicians cautioned that the situation was still volatile, Carter’s visit calmed jittery area residents.

Once things stabilized, the plant’s owners thought they might put the reactor back into operation in three years. But when technicians finally opened the reactor vessel, they found the massive damage to the core. Luckily, the first molten fuel to cascade to bottom of the vessel had hardened into a ceramic coating that prevented the China syndrome. Three Mile Island 2 was permanently mothballed.

After the accident, safe nuclear power struck many as an oxymoron. “What shook the public the most,” said Victor Gilinsky, of the Nuclear Regulatory Commission, “was seeing the men in white coats standing around and scratching their heads.”

Advocates pointed out that the feared catastrophe had not happened, and that numerous studies had turned up no clear evidence of adverse health effects from the radiation release. But nothing could erase from the public consciousness those days of anxiety. The giant cooling towers of Three Mile Island became icons of nuclear menace. That May, 75,000 citizens rallied in a Washington anti-nuclear demonstration.

Not a single nuclear-power reactor has been ordered in the United States since the Three Mile Island accident. Yet higher efficiency has allowed the nation’s 104 operating reactors to continue providing about 20 percent of our electric power even as demand has increased.

President George W. Bush, in his 2006 State of the Union address, called for more “clean, safe nuclear energy.” Our dependence on foreign oil, the proliferation of nuclear weapons, the threat of global warming, and reactors’ vulnerability to terrorist attacks—all these will have to be weighed as we consider our energy options. But it’s certain that over any debate about atomic power will loom the shadow of what happened at Three Mile Island 27 years ago.

—Jack Kelly writes often for American Heritage magazine and is the author of Gunpowder: Alchemy, Bombards, and Pyrotechnics—A History of the Explosive That Changed the World.