Friday, October 21, 2011

Virginia Earthquake: Nuclear Plant Still Closed


Poor people, if only they weren't so cheap and had installed decent seismic equipment (Ask Me!), they would have been up and running by now.  All they got now is hand waving.  Are they going to rip apart the core now?  

When you do install accelerometers and seismometers for this reason, you have to let go of all your 40 year old seismic engineering assumptions, since they clash with reality.  The best thing is to go with peak ground velocity (PGV), and correlate  that with seismic experience.  I actually wanted continuous recording so normal events, such as water bumps, could be recorded.  This allows a 'Trivial PGV' to be set, especially if the plant experiences it all the time.  It compares to measuring a live bridge or building load.  Wind, for example, can put on a load greater than seismic, and we won't have a rare earthquake, and rare wind storm at the same time.  For nuclear plants, there are major 'internal earthquakes' that they shake off all the time.

I remember that once they were in a flap about the Candu feeder tubes being damaged in an earthquake.  This was a scam to get more overtime and eventually was killed.  But, actual measurements showed normal PGV's to be over 10 times seismic.  They are not even going to notice an earthquake!


This is more fun than a barrel of bureaucrats!   Given one NRC guy's opinion, the station will never restart because it exceeded design.  Well, kiddies, it never exceeded design in terms of displacement and stress.  Can't wait to see how this plays out.

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