Don’t Believe Everything You Read

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 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 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.

Eliot Brenner
Public Affairs Director

Author: Moderator

Public Affairs Officer for the U.S. Nuclear Regulatory Commission

5 thoughts on “Don’t Believe Everything You Read”

  1. Don’t be misled by NRC’s non-denial denial.

    NRC hasn’t said our numbers are wrong. I checked my interpretation with NRC Public Affairs. No challenge from NRC has arrived after publication.

    After all, they’re NRC’s numbers.

    What NRC is saying is that it doesn’t do rankings. That’s right. We did, from NRC’s data. If the NRC was publishing the American League East standings, it would list them alphabetically. (That’s OK with me; the Yankees would be last.)

    You can see for yourself in the NRC report that:

    — NRC says the risk of quakes in the central and eastern states is higher than previously thought.

    — It still thinks plants are safe.

    — but their margin of safety is reduced.

    — and some plants are now near the point where they should be re-examined, and perhaps retrofitted.

    — and the technical staff says this should now move from being a research issue to a regulatory issue.

    — and it has made its best estimates of the frequency (chance, odds) of an earthquake that would cause core damage to a plant, and those are in Appendix D, last column on the right. The links are at the bottom of the article.

  2. Palisades and others have had a significant reduction of the effectiveness of boron inside their fuel racks…40 to 50% reduction of effectiveness…would that make it more complicated in the USA to fight a similar failure of the fuel pool?

  3. Thank you, NRC, for this straightforward response. It is important that you clarify information, or misinformation, that appears in the media.

  4. Good post Eric….I am sick of the sensational journalism as well. I have a feeling that that there are several technical people on this site. If possible, are there links you would be willing to share on rad levels, plant conditions, even pictures etc. Also, I agree with the others posting in other blogs below that you need to give some basic assumptions on the dose calcs in one of your postings. God bless all of you….

  5. “Each plant is built to the circumstances that exist at its location – including earthquakes, floods and tsunamis.” Not True. After the plant at Diablo Canyon was built, an earthquake fault was discovered; therefore that fault was NOT known and NOT considered in the design of Diablo Canyon Plant.

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