Lessons Learned from “Lessons Learned”: The Evolution of Nuclear Power Safety after Accidents and Near-Accidents

Some Key Observations

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Edward D. Blandford and Michael M. May
Global Nuclear Future

What can be taken away from the foregoing retrospective survey of the more serious nuclear accidents and near-accidents, and from the lessons learned—and not learned—from those events? A few observations emerge.

On the record of the past fifty years, nuclear power has an edge over other forms of providing energy both in terms of limiting day-to-day adverse health and environmental effects, including greenhouse gas emissions, and in terms of the frequency and toll of major accidents. Table 1 makes this point clear.

Table 1. Main Sources of Electricity in the World and Their Morbidity and Greenhouse Gas Emissions Per Unit of Electricity Produced

Source (% of world use, 2007) Deaths per terawatt-hour Tons of greenhouse gas emissions per gigawatt-hour (life)
Coal (42%) 161 (U.S. average is 15) 800–1,400
Gas (21%) 4 300–500
Hydro (16%) 0.1 (Europe) Small–100
Wind (<1%) 0.15 Small–50
Nuclear (14%) 0.04 Small–50

Table generated by authors using data from Key World Energy Statistics 2009 (Paris: International Energy Agency, 2009), 24; Peter Burgherr and Stefan Hirschberg, “Comparative Risk Assessment of Severe Accidents in the Energy Sector,” International Disaster and Risk Conference, August 25–29, 2008, Davos, Switzerland; http://www.cna.ca/english/pdf/studies/ceri/CERI-ComparativeLCA.pdf; http://pia.sagepub.com/content/early/2011/10/29/0957650911424699.abstract?rss=1; Benjamin K. Sovacool, “Valuing the Greenhouse Gas Emissions from Nuclear Power: A Critical Survey,” Energy Policy 36 (2008): 2940–2953; Alfred Voß, “Energy and Universal Sustainability–An Outlook,” Institute for Energy Economics and the Rational Use of Energy, International Materials Forum 2006, Bayreuth, Germany; Bert Metz, Ogunlade Davidson, Peter Bosch, Rutu Dave, and Leo Meyer, eds., Climate Change 2007: Mitigation of Climate Change, Intergovernmental Panel on Climate Change (Cambridge: Cambridge University Press, 2007).

The low morbidity is due to several factors, but two stand out:

  • Most casualties and other health and environmental effects stem from the extractive and transportation industries. Because the same amount of electric power can be obtained from about 200 to 300 tons of uranium ore as from 3 to 4 million tons of coal or similarly large quantities of gas or oil, these effects are inherently less severe for nuclear power than for the main hydrocarbon sources of electricity.
  • The nuclear power industry has from the start been aware of the need for a strong and continued emphasis on the safety culture, although in the early years that culture was not sufficiently informed by experience.

Nuclear plants have such low levels of emissions because no combustion is involved in nuclear electricity generation. Emissions are generated only during construction, installation, mining, refining, enrichment, transportation, and decommissioning. In addition, the smaller tonnage to be mined, transported, and processed lowers emissions from nuclear plants. The actual amount of greenhouse gases generated depends on how the energy is obtained for each of the steps listed above; it is also dependent on the techniques used to make the concrete needed for nuclear facilities.

Despite all these advantages, nuclear accidents will always be possible, including major accidents that could have serious consequences and a considerable impact on public opinion. The knowledge of how to improve nuclear safety comes from experience—and sometimes that means the experience of accidents, close calls, and routine problems. The process of learning can be viewed as a continuing investment in both the political and financial future of the nuclear industry. It has to be considered as part of the base levelized cost of power, reaching every part of the process of providing nuclear power, from qualification of materials such as concrete and steel to operations. Fortunately, most of our knowledge has come from research and day-to-day learning, not from major accidents. The process of learning, however, must be ongoing, not only for nuclear power but for all complex engineered systems that have the potential to cause major disasters.

All three of the major nuclear power accidents (TMI, Chernobyl, and Fukushima) as well as several of the lesser-known close calls had precursors in previous incidents, although often not in the same country. The lessons-learned reviews that followed most of these events usually made specific useful points. Some of those points were implemented—the lessons were learned—but often they were not. Not surprisingly, implementation steps that translated into more efficient operations, such as better, more standardized operating procedures, were carried out more often than steps that required immediate expenditures to avoid uncertain disaster, such as better defenses against possible flooding. Further analysis may reveal less obvious correlations.

A regulating agency with appropriate power and strong technical expertise—well staffed, well funded, and independent of its licensees—is a necessary, though not sufficient, requirement for safety; in particular, it would formulate and implement lessons learned. Regulatory capture by licensees through either political or administrative processes has been a problem in several countries. Recent decisions (in India, for example) to remove the regulating agency from the administrative structure of the operating and promoting agency is a step toward greater safety. Beyond an effective regulator, however, a culture of safety must be adopted by all operating entities. For this to occur, the tangible benefits of a safety culture must become clear to operators.

In the United States and some other countries, public fear of radioactivity and the ensuing interventions of often well-informed organizations have been a spur to learning from experience. But in countries where the responsible nuclear organizations, governmental and private, were insulated from criticism, learning has been slower. Learning from experience is never an easy process, especially when it takes place in a very public, very critical arena. Nevertheless, transparency has enhanced that process. Transparency helps learning in all three groups: the owners-operators, the government regulators, and some of the intervening organizations. Transparency must be conditional, however: the early critical give-and-take that leads to improvements in design, materials, and operation will not be done frankly and effectively if not done in private.

INPO, funded and supported by the U.S. nuclear power industry, is an example of a well-balanced combination of transparency and privacy; it provides a forum for the ongoing process of learning lessons related to nuclear operations. Operator ratings at the various plants remain private, but results with regard to operating procedures and consequences are public. INPO was started in the United States as a result of the TMI accident, which, as discussed above, resulted from design deficiencies, lack of understanding of some fundamental phenomena, and errors in operating the reactor. Design features prevented any significant release of radiation, but the financial loss was so significant that the industry and its financial backers were moved to cooperate with regulators in establishing and maintaining much improved operator training, operations standards, and operations staffing. The resulting rating of the operators is kept confidential within the industry so that criticism can be uninhibited and action can be taken in a timely manner without fear of misinterpretation. On the other hand, actual performance results, including all incidents, are made public. Expert management in the owner-operator sector has been essential to establish and maintain quality of operations. In addition, dealing with reactors during abnormal conditions requires well-thought-out procedures, clearly established lines of authority, and on-site personnel who are competent and authorized to make tough decisions.

Because so much of the cost of nuclear power is incurred before the first kilowatt-hour is generated, the financial backers, including private and government insurers and guarantors, in theory have considerable leverage over the industry, as does any entity that can delay construction and operations, such as regulators and interveners. That leverage can be obvious, as when the European Reconstruction Bank refused to put money into older Chernobyl-type reactors and insisted on safer Western-style models; but it must work with a regulating and monitoring institution to preserve the investments. Recognition of the need for a strong, competent, and independent regulator has not come easily to most countries and is not always and everywhere accepted in practice to this day. In particular, independence joined with the resources sufficient to maintain competence faces continuing tensions from operators (and, in democracies, their representatives in government), which need to make a profit or at least stay within budget while maintaining market share, and also from government budgeters, who have to work with limited resources.