Column: Nuclear plants built to endure an earthquake

  • Posted: Monday, March 10, 2014 12:01 a.m.

Late on Valentine’s night, Will Williams, the dapper head of the local Economic Development Partnership, took to Facebook with an alert for his friends. “I think I just felt the earth move,” he wrote.

He was right. Minutes later, the U. S. Geological Survey (USGS) confirmed that an earthquake measuring 4.1 on the Richter Scale had struck the area. The tremor occurred at 10:23 p.m. and was centered seven miles west-northwest of Edgefield.

The quake came on the heels of a menacing snow and ice storm that left thousands without power in Aiken County and throughout the state.

According to the USGS, a magnitude 4.0 earthquake in the eastern United States typically can be felt as far as 60 miles from where it occurred and infrequently cause damage near its source.

Many are surprised to learn that the United States has averaged more than 3,000 earthquakes per year over the past 20 years. They are mostly in the mild to moderate range (magnitude 2.0 to 5.9).

The USGS reports that South Carolina typically experiences 15 to 20 earthquakes a year. Most are minor, often unfelt, and cause no damage. However, the state was also home base for the largest earthquake ever recorded on the east coast.

The 1886 quake centered in Summerville measured 7.3 on the Richter Scale and caused significant damage throughout the Lowcountry. It was felt over 2 million square miles from Boston to Bermuda.

One of the expected aftershocks of the Edgefield quake was concern about the safety of the region’s operating nuclear power plants, including Southern Company’s Plant Vogtle in Waynesboro, and SCANA’s V.C. Summer Plant near Columbia.

Should be public be shaking in their boots?

Not really. In the recent series of treacherous natural events, the nuclear plants continued to hum along as designed even as power was lost to homes and businesses over a wide area. Highly engineered with redundant safety systems, local nuclear plants were unaffected by snow, ice and earthquakes.

The Nuclear Energy Institute describes these plants as “unyielding structures with multiple layers of safety designed and built into them.” Federal regulations require that they be able to withstand extreme natural events that may occur in the region where they are located, including earthquakes, hurricanes, tornadoes and floods.

But, if these plants are so secure, why did so many lose power in their homes and businesses?

To use a physical analogy, think of the nuclear reactor as the human heart, buried deep inside the chest, surrounded and protected by flesh and bone and operating at a steady temperature of 98.6 degrees. The power lines that deliver the electricity are our extremities – arms, legs, fingers and toes – constantly exposed to the elements, always vulnerable to sunburn, frostbite and other external threats.  

In the recent ice storm and earthquake, even as the heart – the nuclear reactor – continued to pump out the kilowatts unperturbed by the elements, the extremities – miles of power lines exposed to the snow, wind and rain — eventually succumbed to falling trees, sliding vehicles and the weight of the ice that engulfed them.  

The most powerful and well-protected part of the system marched on, doing its job oblivious to earthquakes and ice while the weakest link broke under the stress, plummeting thousands into darkness for days.

The public should be reassured to know that earthquake safety standards are more stringent for nuclear energy facilities than for any other type of infrastructure. And they are constantly under review.

Earthquake safety drew increased attention in 2011 after a tsunami triggered by a powerful earthquake disabled safety systems at the Fukushima Daiichi nuclear power plant in Japan and led to an accident.

Although it was flooding from the tsunami rather than shaking from the earthquake that caused the accident, the Nuclear Regulatory Commission – or NRC – folded its ongoing review of seismic safety into its post-Fukushima recommendations for U.S. reactors.

Earthquake protection for nuclear plants is continually assessed. The U.S. Nuclear Regulatory Commission re-examines seismic safety at nuclear energy facilities as new information becomes available. The NRC has required the companies that operate U.S. nuclear plants to have seismic experts re-evaluate the potential earthquake impact at their sites using the latest data and methodologies.

The first part of the analysis is scheduled for submission to the NRC for sites east of the Rocky Mountains, including our region’s plants, by the end of this month.

Mike Butler has been involved in Department of Energy and nuclear industry issues for more than 40 years. He is also president of Carolina Public Relations Group and can be reached at mbutler@carolinaprgroup.com.

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