Sunday marks the 25th anniversary of the Three Mile Island nuclear plant accident, and 25 years later the nation’s aging fleet of 103 reactors still face nagging questions about their ability to prevent mishaps.
These concerns, worsened by recent findings of massive corrosion at a nuclear power plant in Ohio, have so far kept utilities away from pursuing new nuclear plants for over two decades despite their potential to replace aging, air-polluting coal units.
In a bid to change that trend, the Bush administration has promoted incentives to build new nuclear plants. But the outlook is uncertain because a Republican-written energy bill with some of the administration’s proposals has long been stalled in the U.S. Senate.
Stepping back into past
On March 28, 1979, Walter Cronkite opened his nightly news broadcast for CBS television, calling the accident at the Pennsylvania plant “the first step in a nuclear nightmare.”
That was the first time that many Americans heard of the mishap, the most serious accident in U.S. nuclear history.
Early that morning, pumps feeding cooling water to the plant’s reactor failed, and 32,000 gallons of radioactive, superheated water spewed from a dodgy valve into the domed concrete reactor housing. Without water to cool them, over half of the reactor’s 36,000 nuclear fuel rods ruptured.
Government scientists said that the 636,000 people living within 20 miles of the plant got only minor radiation doses.
A string of mechanical failures and human errors caused the Three Mile Island accident after operators with Metropolitan Edison Co. switched off crucial equipment that could have lessened the severity of the partial meltdown.
Industry froze
The near-catastrophe at the plant, perched on an island in the Susquehanna River near Harrisburg, Penn., effectively halted any expansion in the U.S. nuclear energy industry, which generates about 20 percent of the nation’s electricity.
The resulting cancellation of dozens of planned nuclear plants forced utilities to rely on decades-old nuclear and coal-burning plants for growing electric power demands.
For the last decade, utilities have looked almost exclusively to natural gas plants to fill the gap, which has exacerbated the nation’s shortage of that clean-burning fuel.
And two years ago, massive corrosion found at an Ohio nuclear plant points to lingering safety questions.
“With plants aging and the number of checks dwindling, this is a troubling trend,” said David Lochbaum, a nuclear safety engineer with the Union of Concerned Scientists.
Activist groups also worry that current security measures cannot prevent a terrorist attack on a U.S. nuclear plant, but the industry counters it has spent millions of dollars to upgrade security since the Sept. 11, 2001, attacks.
Corrosion scare
Safety concerns continue to plague the industry.
Nuclear Regulatory Commission inspectors in early 2002 found massive corrosion at an Ohio nuclear plant owned by FirstEnergy. Leaking boric acid used as a coolant ate a football-sized hole in the steel outer hull protecting the company’s Davis-Besse plant’s reactor core.
No radiation was released, and the NRC allowed FirstEnergy to begin reviving the unit this month after the utility agreed to change its “safety culture.”
NRC Chairman Nils Diaz said the NRC “dropped the ball” by not spotting the corrosion sooner. ”It was no way to do business, either on the part of operators or regulators,” Diaz said.
Nuclear industry officials bristle at any connection between the Three Mile Island and Davis-Besse incidents, and point to advances in operator training and plant design.
“For critics to use (Davis-Besse) as an example to support claims about aging reflects either the fact that they’re ignorant about how that phenomenon played out or they just don’t want to apply it correctly,” said a spokesman for the Nuclear Energy Institute, a lobbying group.
But industry watchdogs say the aging U.S. nuclear utility fleet could be nearing the end of its trouble-free life, with incidents like Davis-Besse foreshadowing mishaps to come.
“We haven’t seen a lot of near-misses in this country since (Three Mile Island),” Lochbaum said. “But the other end of the curve is what we’re approaching, if we’re not there already.”
Bush wants new plant by 2010
The Bush administration, meanwhile, wants to jump-start the U.S. nuclear industry with an energy plan aimed at building at least one new nuclear power plant in the United States by 2010.
One version of the energy bill stalled in the Senate would give tax incentives to build new plants, with a cost of $10 billion. The incentives could be stripped from the bill to appease budget concerns from the administration and others.
Nuclear advocates say such incentives can make nuclear generation competitive with coal and natural gas, and allow utilities to shift from their heavy reliance on fossil fuels.
Utilities have relied on squeezing more megawatts from existing nuclear plants. Capacity factors went from 58 percent in 1980 to 92 percent in 2002, forestalling the need to build new plants, according to the Nuclear Energy Institute.
The industry says that the NRC carefully reviews capacity increases to ensure safety.
Jim Riccio, an anti-nuclear advocate at Greenpeace, doesn't buy that. “After Three Mile Island, the pendulum definitely swung in the direction of safety,” he said. “In the last 25 years, it has swung in the other direction. They’re running these plants to the verge of breakdown.”
400 interviews on Web site
Back at Three Mile Island, the reactor that failed was long ago shut down and defueled, while a sister reactor still runs and is owned by Exelon. Local residents have a new archive to mark the 25th anniversary: Social scientists at nearby Dickinson College have launched a Web site -- -- 400 interviews taken in the accident's aftermath.
Social scientist Lonna Malmsheimer led a few colleagues and about 20 students fanned out into the community to do what social scientists do—field work.
The researchers said they are not trying to pass judgment, just pass along information about what they call a "history-changing event." The point, they say on their Web site, is to make available interviews, some of them audio, "that will enrich our understanding of the emergency and its aftermath."