Many news reports during this chaotic week have questioned the safety of U.S. nuclear power plants in the wake of the terrible events in Japan. These reports raise questions about the design of reactor containments and spent fuel pools, and of course whether our plants would be able to withstand an earthquake and tsunami like the ones that devastated Japan.
Nuclear power is a complicated, technical subject, and we naturally try to simplify it to make it understandable to the general public. Sometimes, however, simplification leads to misunderstanding, and misunderstanding causes fear.
One example was a so-called “investigative report” on MSNBC.com that ranked nuclear power plants according to their “vulnerability” to major earthquakes. The reporter concluded that the Indian Point plant, 24 miles north of New York City, was “the most vulnerable” in the nation. Instant headlines. You may have heard a local news report that your neighborhood nuclear plant ranked “on the NRC’s Top Ten List” of the plants most likely to tumble in a temblor.
Let’s be clear: The NRC does not rank nuclear power plants according to their vulnerability to earthquakes. This “ranking” was developed by the MSNBC.com reporter using partial information and we believe an even more partial understanding of how we evaluate plants for seismic risk. Each plant is evaluated individually according to the geology of its site, not by a “one-size-fits-all” model – therefore such rankings or comparisons are highly misleading.
We are also frequently asked whether Plant A can withstand a quake of magnitude X. The reporters always want a yes-or-no answer, but again, it’s not that simple. Nuclear plants are designed to withstand a certain level of “ground shaking,” to use a technical term. But the way the ground shakes in an earthquake is a factor of the magnitude and the distance from the epicenter, among other things. So we can’t give a simple answer to such a simple question.
Each plant is built to the circumstances that exist at its location – including earthquakes, floods and tsunamis. For example, at nuclear plants along the Atlantic and Gulf Coasts, the greatest water threat is hurricane storm surge, not a tsunami. Moreover, there is only one fault, near the northwest U.S. coast, that is similar to the subduction fault in Japan, and there are no nuclear plants nearby. The closest coastal plant to that fault is well-protected against tsunami.
Over the last few years, the NRC has reassessed nuclear plants in the central and eastern United States for their vulnerability to earthquakes, using new seismic data developed by geologists. The study’s preliminary work has shown that some plants might have stronger ground motions than originally thought, although still within the plants’ safety margins. These plants will do more research once more detailed analytical models are available later this year.
This is a complex issue that does not always lend itself to simple yes and no answers. Bottom line: the NRC does not rank plants on seismic risk. Plants in this country continue to operate safely and securely.
Public Affairs Director