UCS in Science: The NRC Must Act to Reduce the Dangers of Spent Fuel Pool Fires at Nuclear Plants

May 25, 2017
Ed Lyman
Director, Nuclear Power Safety

In a Policy Forum article published in this week’s Science magazine, I argue, along with my co-authors Frank von Hippel and Michael Schoeppner, that the U.S. Nuclear Regulatory Commission (NRC) needs to take prompt action to reduce the alarmingly high potential for fires in spent fuel pools at U.S. nuclear plants.

The NRC allows nuclear plant owners to pack spent fuel into cooling pools at much higher densities than they were originally designed to handle. This has greatly increased the risk to the public should a large earthquake or terrorist attack breach the liner of a spent fuel pool, causing the pool to rapidly lose its cooling water. In such a scenario the spent fuel could heat up and catch fire within hours, releasing a large fraction of its highly radioactive contents. Since spent fuel pools are not enclosed in high-strength, leak-tight containment buildings, unlike the reactors themselves, much of this radioactive material could be readily discharged into the environment.

The consequences of a fire could be truly disastrous at densely packed pools, which typically contains much more cesium-137—a long-lived, extremely hazardous radioactive isotope—than is present in reactor cores. My Princeton University co-authors have calculated, using sophisticated computer models, that a spent fuel pool fire at the Peach Bottom nuclear plant in Pennsylvania could heavily contaminate over 30,000 square miles with long-lived radioactivity and require the long-term relocation of nearly 20 million people, for average weather conditions. Depending on the wind direction and other factors, the plume could reach anywhere from Maine to Georgia. My co-authors estimate the financial impact on the American economy of such contamination could reach $2 trillion: ten times the estimated $200 billion in damages caused by the release of radioactivity from the damaged Fukushima Daiichi plant.

The danger could be greatly reduced if plant owners thinned out the pools by transferring their older fuel to dry storage casks. But despite the relatively modest cost of this common-sense step—about $50 million per reactor—owners won’t do it voluntarily because they care more about their bottom line.

The NRC could require plant owners to expedite transfer of spent fuel to dry casks. But it refuses to do so, basing its decision on quantitative risk analyses that, as discussed in our Science article, underestimate the benefits of such a transfer by making numerous unrealistic and faulty assumptions. For example, its estimate of the economic damages of a fire in a densely packed spent fuel pool was $125 billion; nearly 20 times lower than the independent estimate of my Princeton co-authors.

In light of our findings, our article calls on the NRC to strengthen the technical basis of its risk analysis methodology by basing it on sound science and sensible policy judgments. We are confident that such an analysis will reveal that the substantial benefits of expedited transfer would more than justify the cost.