|
|
|
|
|
|
|
|
|
|
|
|
The recent earthquake in Japan and its negative effect on the local nuclear power plant make us all more aware of our own vulnerability to problems at nuclear power plants. Looking at what happened in Japan, a VERY large earthquake (6.8) occurred directly under the nuclear plant, the result was leakage of radioactive water into the ocean, fires and damage to the plant, and the spillage of low-level nuclear waste (which, at this time, cannot be detected outside the building). Thus, it appears that despite the major damage to the plant the immediate proximity of the plant to the fault that generated the earthquake there was, as understood at this time, some contamination but not a deadly nuclear accident. Previous large earthquakes in the region, but not directly under the plant did not cause problems with the plant.
Are South Carolina's nuclear power plants located on or near active faults? Using the map below as a guide we
can locate most of the detectable earthquakes in SC from 1973 to 2000 (from Pradeep Talwani's work at USC;
http://scsn.seis.sc.edu/images/bigeast.gif)
which are shown as stars, the 4 nuclear facilities in South Carolina (from the Dept. of Energy), which are shown with
the standard nuclear symbol, and the major faults in SC as mapped by the USGS. There are two things that the map does
not show. First, the map does not show nuclear sites that tre not power generating sites - Waste or storage sites.
Second, the map does not show are the magnitudes of the earthquakes, all of which are between a magnitude 2 and
5 and it does not include the large earthquakes of Summerville and Union county. According to the map, no nuclear
plants are located where large earthquakes similar to the one that occurred in Japan have been previously noted.
We do see that some of the nuclear plants are located near clusters of earthquakes, particularly the Summer
(Newberry County) and Oconee plants.
However, when we zoom in on these earthquakes and look at the data presented
by the South Carolina Seismic Network operated by Pradeep Talwani from the University of South Carolina, we can see
that the seismicity clusters near both the Summer and Oconee nuclear plants is associated with dams. Dams sometimes
generate earthquakes because they create water pressure below them, which causes the cracks in the rock to slip. Dam
generated earthquakes tend to be small and non destructive, which means that the nuclear plants in the area are
probably not at a significantly higher seismic risk than the other plants in South Carolina.
Thus, we see no evidence for large earthquakes like the recent one in Japan having previously occurred near where today's nuclear plants are located in South Carolina.
Curator: hallcr@cofc.edu
