Calling it “a seminal event in the history of nuclear power,” the chairman of the U.S. Nuclear Regulatory Commission told the AAAS Forum on Science and Technology Policy that the tsunami-triggered accident at the Fukushima Daiichi facility in Japan is likely to provide nuclear safety lessons for regulators in this country as well as Japan.
“Every time we’ve had an incident in the nuclear industry, we have learned lessons and I don’t expect this will be any different,” NRC Chairman Gregory B. Jaczko said in a 6 May luncheon talk at the 36th annual Forum. But he added, “At this time, we haven’t seen anything that would tell us there is an immediate change or an immediate safety concern with any of the plants that we operate in this country.”
Jaczko said recent violent storms and tornadoes in the United States are reminders that nuclear plants in this country also can be exposed to significant natural hazards. “By and large those plants have responded the way that they’re designed to,” Jaczko said, “but that will be good information for us to look at as we compare what happened in Japan with what changes we may need to make here in the United States.”
The AAAS Forum on Science and Technology Policy convened in Washington, D.C., with some 475 U.S. and foreign leaders from government, education, and business attending to hear top policy experts talk on critical issues. The Forum’s two-day program, organized by the AAAS R&D Budget and Policy Program, this year had a strong focus on U.S. innovation and the federal investment in science and technology.
Jaczko’s agency has undertaken two studies in the aftermath of the 11 March earthquake and tsunami in Japan—a 90-day review aimed at a quick assessment of any vital safety issues involving U.S. plants, including external events that could lead to a prolonged loss of cooling; and a longer-term study to assess whether any permanent changes are needed in NRC regulations.
The agency, charged by law with providing “reasonable assurance of adequate protection of public health and safety,” must respond to new research and experience, Jaczko said. He traced the evolution of nuclear safety in the United States in response to three other catalytic events: a 1975 fire at the Browns Ferry nuclear plant near Athens, Alabama; the 1979 nuclear accident at the Three Mile Island plant in Pennsylvania; and the September 11 terrorist attacks in 2001.
“All of these events have served to transform in fairly fundamental ways how we understand the nature of nuclear safety and security and what we need to do, ultimately, in order to protect the public,” Jaczko said. And the recent events in Japan suggest “that our understanding of nuclear safety may further evolve,” he said.
In each case, he said, it is important that the methods of science, including an open and questioning attitude, inform public policy. The Browns Ferry incident, which occurred shortly after the NRC was established as an independent regulatory agency, revealed the need for more systematic risk analysis at nuclear plants.
A worker was using a candle to check for air leaks around conduits into the plant’s containment structure. It was a standard procedure in those days?any movement of air near cable conduits would cause the flame to flicker. The flame started a fire in electrical cables that disabled safety systems. Remarkably, up until that time, there had been no urgent concern about the use of open flames near vital cables. For the workers, one of the preferred methods for extinguishing fires in electrical cables was to beat them out with their flashlights, Jaczko said.
“These things seem comical but they were practices at the time because we didn’t appreciate that fire was necessarily something that could have an impact on the safe operation of the facility,” Jaczko said.
A better understanding of the risks and hazards was crucial, including the fact that a fire in a room with cables controlling all of the plant’s major systems represented a single-point vulnerability. The Browns Ferry fire spurred development of more sophisticated quantitative methods for assessing risk.
Similarly, the 1979 accident at Three Mile Island—in which there was a partial meltdown of the reactor core but only small off-site releases of radioactivity?led to an overhaul of emergency management procedures at nuclear plants, more NRC inspectors at facilities, a strengthening of enforcement, and a continued shift toward risk assessment as a tool to identify vulnerabilities at power plants and inform regulatory decisions.
Perhaps most significantly, however, the accident spotlighted the importance of the human-machine interface at nuclear plants, Jaczko said. It became clear that reactor operators were overwhelmed by complex and confusing information that they did not fully understand as the accident progressed.
“Before the Three Mile Island accident,” Jaczko said, “if you asked nuclear power plant operators or regulators the first word that came to mind when they heard phrases like ‘nuclear safety,’ they would have likely responded with words like ‘engineering’ or ‘equipment,’” Jaczko said.
The overwhelming focus of the NRC and the nuclear industry was on the role of hardware in preventing accidents. “The Three Mile Island accident changed that,” he said.
The new world was one in which “people’s attitudes and actions, in the form of operator errors, management deficiencies, and complacencies” posed perhaps the greatest risks to nuclear plant safety, Jaczko said.
The accident led to an increased focus on human performance and revamped training of plant operators. But that new emphasis proved difficult to wrap into a quantitative risk analysis. It is easier to determine the frequency of failure of a particular valve than it is to predict the frequency of failure of a reactor operator faced with a particular warning alarm on a control panel, Jaczko said. There remains an active research program to develop better methods for analyzing the human-machine interface in complex systems, he said.
After the 9/11 terrorist attacks, the NRC was faced with another key variable in nuclear risk analysis. Beyond random acts of nature or accidents—whether through equipment failures or human error—the agency now had to consider intentional acts by terrorists that could compromise the safety at power plants. Once again, there was a dramatic change in thinking about how the NRC must pursue its mission, Jaczko said.
As for Fukushima, the lessons still are emerging and it is important for NRC to “take the time to fully understand the situation in Japan and to identify the full range of questions that we need to answer,” Jaczko said.
In response to one question from a Japanese physicist at the Forum luncheon, Jaczko defended his agency’s safety assessment for American citizens living in Japan. On 16 March, the NRC recommended that U.S. citizens living within 50 miles of the Fukushima plant evacuate their homes. The Japanese government had recommended that those within 20 kilometers (12.4 miles) of the plant should evacuate and those within 30 kilometers (18.6 miles) should shelter in place. The physicist said NRC’s recommendation had created confusion in Japan and mistrust of the government. Jaczko would not address that concern directly, but he said his agency’s recommendation was conservative and based on limited information NRC was getting about the reactors at the time. He said there were some conversations with counterparts in Japan and elsewhere prior to release of the recommendation.
In the aftermath of the Fukushima nuclear plant incident, Jaczko can expect more tough questions as his agency sorts out the lessons from the event. But the constant interplay between science and policy is part of what makes his position at NRC interesting, Jaczko said. A theoretical physicist by training, he first came to Washington as a AAAS Congressional Science & Engineering Fellow. He said it was an opportunity that “really gave me my first taste of this interesting mix of science and public policy that happens so much here in Washington.”
His training as a scientist has given him a perspective on his current role. There are numerous examples in science of “tightly held beliefs that were later discredited and discarded due to new research information and experience,” Jaczko said. He noted that he learned as a young physicist that neutrinos have no mass—a concept now discarded by experimental results showing that the ghostly particles do have mass, albeit a very small one. The same intellectual curiosity that motivated him as a graduate student has kept him engaged with the evolving challenges of nuclear safety and security, Jaczko said.
Watch highlights from Jaczko’s address at the 2011 Forum.
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See the full Forum agenda.