Head of U.S. Nuclear Watchdog Emphasizes Preparing for Unknown
By MATTHEW L. WALD
Published: March 12, 2013
Appealing for a shift in emphasis on nuclear safety, the new head of the Nuclear Regulatory Commission warned a gathering of more than 3,000 industry executives, experts and government regulators on Tuesday against relying too heavily on their ability to predict the future, and suggested that when it comes to commercial reactors, the industry and the government should be ready to deal with the unknown.
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Speaking two years after the Fukushima Daiichi nuclear power plant disaster in Japan, Allison M. Macfarlane, a geologist who became chairwoman of the five-member commission last July, cited aging nuclear reactors, terrorist attacks and natural disasters, saying, “we don’t know everything about how the Earth behaves, and we must factor this into how we approach nuclear safety.'’
In the past few years the commission has employed a safety technique called probabilistic risk assessment, in which engineers assign probability to equipment failure to determine which accidents are the most likely, and thus which systems and components most deserve improvements.
In her talk on Tuesday morning at the agency’s annual Regulatory Information Conference in Bethesda, Md., Dr. Macfarlane used an oft-repeated quote, attributed to the physicist Niels Bohr: “Prediction is very difficult, especially about the future.” Her field, geology, has traditionally concerned itself with understanding history over long periods, although the nuclear industry, with its focus on earthquake risk and its search for areas to bury nuclear waste, has used that science to make predictions.
Her point suggested support for an emerging approach at the commission, preparing for the unknown with stockpiles of equipment that could be used in accidents that are outside the realm of safety problems that the plants were designed to meet. The reactor sites now have portable pumps and generators, hoses and other equipment, and the industry is planning two centralized depots for similar equipment, an approach that to some extent mirrors the oil industry’s preparations for spills, with cooperative regional depots. The commission began focusing on that approach after the Sept. 11 terrorist attacks, and increased its efforts after the Fukushima accident that stemmed from an earthquake and tsunami in March 2011.
But the nuclear industry is moving into the unknown in several ways, Ms. Macfarlane pointed out. By 2017, about half the operating reactors will have exceeded their initial 40-year licenses and will be running on 20-year extensions. The commission is exploring whether some reactors could qualify for a second 20-year extension. But, she said, “there is limited experience to draw from to address life beyond 60 years.”
A handful of new reactors are under construction, with new 40-year licenses, and more plants are shut down and may be mothballed for decades before they are torn down, in a 60-year process. “Both exceed the length of most experts’ professional careers,” she said. “We must ensure that our regulations are sufficiently comprehensive and robust to address issues that will arise long after most of us are retired.”
The current generation of reactors has already outlived the theory of geology that was prevalent when their sites were chosen, she pointed out; they predate wide acceptance of the theory of plate tectonics — the view that the Earth’s crust is made up of plates that rub and slip against one another.
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