Interactive Map: The Real Seismic Threat to Our Nation's Nuclear Power Plants Interactive Map: The Real Seismic Threat to Our Nation's Nuclear Power Plants
Environment

Interactive Map: The Real Seismic Threat to Our Nation's Nuclear Power Plants

by Ben Jervey

March 27, 2011

When you click on a reactor site, you can see what type of reactor it is, who operates the plant, and, most importantly, the maximum ground acceleration risk. The what what?

During an earthquake, the ground shakes back and forth, and the damage is roughly proportional to the ground’s maximum acceleration (PGA). The map shows the two percent likelihood that the PGA will exceed the shown values in the next 50 years.

In other words, if the map shows that the PGA is 1.0g for a given spot (say, southeast Missouri), that means there is a two percent chance that the peak ground acceleration will be greater than 1.0g at some point in the next 50 years. PGA is measured in “g,” with one g being how quickly an object accelerates in free fall (you can also think about “pulling Gs,” as in a fighter plane).

The PGA risk is what is typically used to set building codes. Most nuclear power plants are designed to operate under 0.2g PGA, and automatically shut off if the PGA exceeds 0.2g. However, they can withstand a PGA many times larger than that.


Here's the full list of nuke plants in the Lower 48 that have that same level of risk:
  • Diablo Canyon, Calif.
  • San Onofre, Calif.
  • Sequoyah, Tenn.
  • H.B. Robinson, SC.
  • Watts Bar, Tenn.
  • Virgil C. Summer, SC.
  • Vogtle, GA.
  • Indian Point, NY.
  • Oconee, SC.
  • Seabrook, NH.

Before you get too alarmed, article author and map-creator David Kroodsma emphasizes:

The bottom line is that a major earthquake would probably not result in a nuclear meltdown at the reactors on the above map, but it could present significant engineering challenges. Quantifying the risks, and minimizing them as much as possible, is a key task for everyone involved in the nuclear energy industry.

You can't help but wonder how seriously the engineers were taking these seismic risks 30-40 years ago when many of these were first built.

+
Join the discussion
Recently on GOOD

Maga-
zines need love too!
Cyberbullying just became a crime in New Zealand. http://t.co/0CFxUgeVm5 http://t.co/zAuupcAM0E
Interactive Map: The Real Seismic Threat to Our Nation's Nuclear Power Plants