Wednesday, September 7, 2011

US Earthquake nuclear plant closed 'forever'


I'm using the little kid concept of 'forever'.  I'm sure it will open up some day, but they are caught in the 'Perry Trap', where there is some indication that they 'exceeded design'.  Now, they have exceeded with only one parameter, which is 'Spike PGA', which is the worst indicator of damage potential ever devised.  Still, PGA is important to clueless engineers, and 'exceeding design' sets up a huge cascade of bureaucracy in NRC-land.

After the Perry plant disaster, where spike PGA exceeded design, the industry pet EPRI (consultant think tank) wrote a whole series of reports on proper damage indicators, and what to do with acceleration records.  Perry actually had recordings, where el-cheapo North Anna does not.  They came up with this ludicrous CAV, which is cumulative absolute velocity.  Needless to say, nobody uses it, but their condemnation of PGA is valid, and I promote the use of the much simpler PGV.

I don't know how this nuclear plant is going to extract itself from this sticky mess, since there are no records whatsoever.  If this were Japan (before the disaster), they'd simply hand wave and start up.  But now, all the politicians are looking, and we know how silly that gets.  :)

ps.  it looks like no extra seismometers are on the Virginia site.  I don't see any migration to the lake, so it will most likely settle down and stop all action for a while.  If there is any more action, it will be M5's to expand that zone to produce an M6.5.


Looks like they are saying 26% g for the spike PGA.  Plant design is 12%, with 18% also quoted.

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