Monday, August 29, 2011

Design basis exceeded for North Anna nuclear plant


That's an absolute "For Sure".  When an M5 happened near the Perry nuclear plant, the design basis was exceeded, based on the crappy definition.  The horrible scratch plates went through the roof, as they will be found to have done for this plant.  Had they accelerometers, I'm sure they would have recorded a spike of over 30% g, which is what happened at Perry.

Now they will probably be shut down for quite a few months.  Now, had they decent accelerometers, they could have derived a PGV of a few cm/s and displacements in the mm's.  The old seismic models (lumps on a stick) were probably showing meters of displacement at the design basis.  Of course, normally I would say that any PGV under 10 cm/s must be dismissed as trivial, but that was before Japan....  I don't really know what the 'trivial' level is now.

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