Sunday, November 11, 2012

WSJ "Quake Tremors Go Farther Than Thought": Implications for US East Coast Nuclear Power Plants Ominous


The Wall Street Journal Nov 7, 2012 A4

"Data from the 2011 earthquake centered in Virginia show East Coast tremors can travel much farther and cause damage over larger areas than previously thought, the US Geological Survey said Tuesday.... Scientists also found the quake that caused more than $200 million in damage triggered landslides at distances four times farther and over an area 20 times larger than research from previous quakes has shown."

The Huffington Post is also reporting scientific findings from the event: East Coast Earthquakes' Speed Is Faster Than Previously Thought, Geologists Say By MICHAEL FELBERBAUM http://www.huffingtonpost.com/2012/11/06/east-coast-earthquakes_n_2084093.html

[Excerpted] Additionally, the landslides from the 2011 tremor occurred in an area of about 12,895 square-miles – about the size of the state of Maryland. Previous studies indicated an area of about 580 square-miles – about the size of Houston – from an earthquake of similar magnitude.

"It's just much more dangerous to have an earthquake at that level back on the East Coast than it would be on the West Coast," said Edwin Harp, a USGS scientist and co-author of the study. "If something big happened, although it's much less frequent, it would tend to damage a lot more buildings because they're probably not quite up to the codes that they are in California."

Majia here: What does this mean for nuclear power plants on the US east coast?

The Virginia earthquake caused damage 4X farther and 20X larger than expected!

The Virginia earthquake, a mere 5.8, shut down a nuclear plant, the North Anna plant
http://www.cnn.com/2011/US/08/23/virginia.quake.nuclear/index.html
 
Majia here: At the time of the quake Reuters noted concerns for nuclear plants given the unexpected size of the earthquake: 
 Quake raises safety concerns as nuclear plant shut http://www.reuters.com/article/2011/08/24/us-quake-usa-nuclear-dominion-idUSTRE77M8C120110824


[Excerpted] The largest earthquake to hit the East Coast of the United States in 67 years raised concerns on Tuesday about the safety of the country's nuclear power plants.

The 5.8 magnitude quake's epicenter was just a few miles from the two-reactor North Anna nuclear power plant operated by Dominion Resources in Mineral, Virginia, 80 miles southwest of Washington. 

The plant lost power and automatically halted operations after the quake. While a Dominion spokesman reported no "major" damage to the facility, three diesel generators were required to kick in and keep the reactors' radioactive cores cool. A fourth diesel unit failed.

Majia Here: The Los Angeles Times noted that the Virginia earthquake "jostled" spent fuel storage casks: : "Virginia earthquake shifted nuclear storage casks" September 1, 2011 http://latimesblogs.latimes.com/nationnow/2011/09/virginia-earthquake-shifted-nuclear-storage-casks.html

Majia here: It seems likely that East Coast nuclear power plants were not built with design specifications adequate for the scale of this relatively minor earthquake given the geological effects in East coast soil and topography:

Virginia quake may have exceeded nuclear plant design By Ayesha Rascoe WASHINGTON | Mon Aug 29, 2011 6:33pm EDT http://www.reuters.com/article/2011/08/29/us-usa-dominion-quake-idUSTRE77S66I20110829


(Reuters) - The historic earthquake that shut Dominion Resources Inc's North Anna nuclear plant in Virginia last week may have shaken the facility more than it was designed to withstand, the U.S. nuclear regulator said on Monday. The Nuclear Regulatory Commission said it had sent a special inspection team to the plant rocked by the 5.8-magnitude quake, after initial reviews from Dominion indicated the ground motion may have exceeded North Anna's design parameters.

Majia here: A report on earthquake design specifications commissioned by the US Congress concluded: 

Nuclear Power Plant Design and Seismic Safety Considerations By Anthony Andrews Specialist in Energy and Defense Policy and Peter Folger Specialist in Energy and Natural Resource http://www.fas.org/sgp/crs/misc/R41805.pdf

[Excerpted from Summary] U.S. nuclear power plants designed in the 1960s and 1970s used a deterministic statistical approach to addressing the risk of damage from shaking caused by a large earthquake (termed Deterministic Seismic Hazard Analysis, or DSHA). Since then, engineers have adopted a more comprehensive approach to design known as Probabilistic Seismic Hazard Analysis (PSHA). PSHA estimates the likelihood that various levels of ground motion will be exceeded at a given location in a given future time period. New nuclear plant designs will apply PSHA....

In 2010, the NRC examined the implications of the updated NSHM for nuclear power plants operating in the CEUS [Central and Eastern US], and concluded that NSHM data suggest that the probability for earthquake ground motions may be above the seismic design basis for some nuclear plants in the CEUS. In late March 2011, NRC announced that it had identified 27 nuclear reactors operating in the CEUS that would receive priority earthquake safety reviews....

Majia here: Sizable earthquakes on the US East Coast are a realistic and imminent threat and US nuclear power plants built in the 1960s and 1970s should be shut down immediately or we risk a Fukushima on US soil.
   





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