Three Mile Island: Thirty Years On
August 4th, 2009 by William Nuttall, University of CambridgeTwo years ago Britain remembered the fiftieth anniversary of the most important event in the history of the UK nuclear enterprise – the Windscale fire of October 1957. That extremely serious accident arose from the rush to build plutonium producing piles for the bomb and a lack of initial understanding of the fundamental physics of graphite reactors.
The fire itself burned out of control until a decision was implemented to flood the reactor with water and to stop the giant air pumps feeding the fire. Thankfully the improvised plan worked, but all involved appreciated the risks and dangers. Windscale is often said to from one part of a triad of nuclear disasters that reveal the folly of mankind’s attempts to control nuclear energy. Rightly most prominent among the three is the 1986 Chernobyl disaster in the Ukraine. This was unambiguously the world’s worst nuclear accident.
The Windscale disaster was of limited impact in the public and political consciousness at the time, partly as a result of extensive British government control of associated information. In contrast Chernobyl resonated with the world’s media. It was a nuclear catastrophe and a global news story as radioactive isotopes rained across several countries. Even before Chernobyl support for nuclear energy in western countries was fragile and the origin of that weakness was a nuclear accident that occurred thirty years ago this year – the third of the big three accidents: Three Mile Island, or ‘TMI’.
On 28 March 1979 the unit 2 reactor at Three Mile Island nuclear power plant near Harrisburg Pennsylvania USA suffered a partial core meltdown. It started with a relatively minor failure of the secondary cooling system which led to the automatic opening of a safety valve in the primary cooling circuit for the reactor itself. That would not have been problematic, but the valve stayed stuck in the open state un-noticed by the reactor operators. Despite the nuclear fission process being shut down, the reactor remained very hot owing to the radioactive decay heat of the nuclear fuel. With insufficient coolant, parts of the core eventually dried out and finally melted. There was a build up of steam and some radioactive gas was vented to the outside. The radiation exposure to the public was extremely small and it is probable that no-one suffered adverse health effects as a result of the accident. It is certain that no-one was killed promptly. In many ways the design features of the reactor prevented what could have been a far more serious accident. Why then does this accident thirty years ago have a place in the triad of great nuclear disasters? The world had previously seen very serious nuclear accidents including the 1952 partial core melting of the NRX experimental reactor at Chalk River, Ontario, Canada; another partial core melt in 1969 in the Lucens reactor at the Paul Scherrer Institute in northern Switzerland; and the 1961 SL-1 reactor incident at the National Reactor Testing Station in Idaho, USA in which three reactor operators were killed. These three accidents and others like them had caused hardly a ripple of concern outside the nuclear engineering community. TMI would be different.
The global significance of the TMI accident has as much to do with the cultural context of late 1970s America as it does with issues of nuclear engineering. For the nuclear energy community TMI could have been just a very expensive internal issue – a catastrophe narrowly averted from which lessons would have been learned. In fact it became much more than a learning point and in the months and years after the accident nuclear power developments in the United States and parts of Europe ground to a halt in consequence.
By the late 1970s ambitions for nuclear power in the US were already in decline owing to falling fossil fuel prices, but the TMI accident ensured that there would be no US nuclear renaissance in the early 1980s as fossil fuel prices rose again following the Iranian revolution and the Iran-Iraq war.
So what are the issues that gave the TMI accident such socio-political resonance? It is important that the accident occurred in a full-size commercial power plant and not in an obscure and secretive government research facility. The TMI plant was part of the infrastructure of the civilian electricity industry, an industry comprising heavily regulated monopoly utilities seemingly there to serve the public good.
Key to the impact of the TMI accident is its timing and its location. The United States of the late 1970s was arguably a country plagued by self-doubt and cynicism. The return to stoicism inherent in the ‘Reagan Revolution’ was yet to come. By 1979 the US had been shaped by a long tradition of public protest from the Bonus Marchers of 1932 through the civil rights protests of the late 1950s and the 1960s to the Vietnam War protests of the late 1960s and early 1970s. For some Americans nuclear energy, with its associations with authoritarian technocracy and looming danger, represented a natural next target for public protest. What the protesters needed was evidence to support their claims that nuclear energy represented a move away from goodness. TMI would provide that evidence at just the right time.
The general Zeitgeist shifted during the 1970s, partly as a consequence of superpower détente. Gone were pure Cold War anxieties and conflict nationalism to be replaced by more complex fears and concerns including environmentalism. In the late 1970s and early 1980s this new awareness would take a more structured form with the emergence of Green political parties, especially in Europe. These movements tapped into a growing interest in alternative forms of governance and decision making all of which challenged the hierarchical and expert-led basis of nuclear energy development. The mid 1970s German environmental slogan ‘Atomkraft? Nein Danke’ became ‘Nuclear Power? No Thanks’ and was soon translated into numerous other languages around the world.
Any accident at a civil nuclear power plant in the spring of 1979 was always going to be politically sensitive and it is no surprise that President Jimmy Carter paid close attention to developments even visiting the plant on 1st April. What was special, however, was Carter’s high level of personal familiarity with the issues. Carter’s early life had been dominated by his service as a submarine officer in the US Navy. For the Navy he had attended courses in nuclear engineering and perhaps most remarkably he had served as part of the joint Canadian-US military team tasked with cleaning up after the 1952 NRX accident at Chalk River. Carter’s response to the TMI accident was to establish a commission of inquiry under the chairmanship of John G Kemeny, a computer scientist and university president. The Kemeny Commission was unusual for its time in not being an expert committee in the usual sense. Rather it brought together eminent people with diverse backgrounds from, for example, the trade union movement and the National Audubon Society. The composition of the Commission ensured that it was not a creature of the nuclear industry. When it reported it was scathing in its criticism of various key industrial players involved in the accident.
However, all the factors described thus far are perhaps not in themselves sufficient to have caused TMI to resonate as strongly as it did. A crucial component of the story must be the remarkable coincidence that the Hollywood feature film The China Syndrome starring Jane Fonda, Jack Lemmon and Michael Douglas opened in cinemas across the United States only two weeks before the TMI accident. The film deals with a fictional accident at a pressurised water reactor in Southern California and the electricity company’s attempts to cover up problems at the plant. The similarities between the crisis at the fictional power plant portrayed early in the film and the real events of TMI are uncanny. The film presents a physics professor warning that a ‘China Syndrome’ could ‘render an area the size of Pennsylvania permanently uninhabitable’. It is bizarre that the screenplay stressed Pennsylvania the later location of the real life TMI accident. While Columbia pictures attempted to distance their new movie from real life events, the synergy was obvious to everyone. For many people the movie gave a prism through which to try and understand real-life events. For the US nuclear industry this prism was the worst imaginable.
Any examination of the TMI story at any level shows it to have been a most frightening and serious event. While the accident revealed several serious failures of equipment and personnel it also showed the importance of a reactor containment vessel. That aspect of the design served as a crucial backstop in the safety of the plant and averted what could have become a true catastrophe.
TMI was part of a long journey of lessons learned for nuclear engineering. It is perhaps analogous to the role Tacoma Narrows suspension bridge disaster of 7 November 1940 in civil engineering. In the bridge accident a gusting wind built up an oscillatory resonance causing the bridge’s spectacular mechanical failure. From that point forward suspension bridges were re-engineered. Similarly TMI gives the world several important lessons learned beyond the importance of containment to include design additions for the mitigation of potential reactor meltdown.
Those concerned with nuclear renaissance in Europe and North America should note that the TMI accident occurred at the half way point of the history of civil nuclear energy development. Since 1979 engineering has improved (computer aided design and build being just one example), but also the social context has changed. The 1970s trend for dark disaster movies has now been replaced by broader genre including animated cartoons for adults, such as The Simpsons with its bungling, but loveable, nuclear plant operator Homer Simpson. It is hard to imagine Homer Simpson as part of a sinister technocracy. Perhaps after the emergence of AIDS and Islamist terrorism and with the arrival of computer viruses, the threat of bird flu and systemic economic problems nuclear power is finally losing its status as lightning rod for society’s unassigned fears. If so, it would appear that TMI’s importance will fade as time passes.
Dr William J. Nuttall is Senior Lecturer in Technology Policy at Judge Business School, University of Cambridge and he is the author of Nuclear Renaissance (Taylor and Francis, 2005)