The plant endured more quake movement than it was designed to withstand, according to a preliminary federal analysis:
The North Anna Nuclear Power Station remains "offline"--not working--since nobody knows why the plant shut itself down moments after the earthquake began.Parts of the North Anna Power Station in Mineral, Va., 11 miles from its epicenter, endured jolts equal to 26% of the force of gravity (0.26g) from some of the vibrations unleashed by the quake, said Scott Burnell, spokesman of the Nuclear Regulatory Commission.
An NRC document says the reactors' containment structure was built to withstand 12% of the force of gravity (0.12g.)
Dominion, the plant's operator, says parts of the plant can handle up to 0.18g.
"It's the things inside the buildings that may have been shaken more than the design called for," Burnell said, adding the buildings themselves appear to have been less affected. He said the analysis is based on a seismograph reading taken about 30 miles away by the U.S. Geological Survey.
17 ton storage casks holding spent nuclear material moved up to 4 inches; the public was notified 9 days after the quake.
Nuclear power watchdogs say that leaking tritium from underground pipes may be the biggest threat to Louisa residents and that Dominion should be distributing bottled water indefinitely.
On 9/1/2011, Dominion power affirmed its intention to pursue Reactor #3 at North Anna.
Today (Sept. 8) NYT gives background on the plant and the recent earthquake.