ML12037A057

E-mail from D. Decker to M. Khanna, NRR; Subject: Follow-up Question from Congressional Staffer

ML12037A057
Person / Time
Site:	North Anna
Issue date:	09/16/2011
From:	David Decker Office of Congressional Affairs
To:	Meena Khanna Plant Licensing Branch 1
References
FOIA/PA-2011-0357
Download: ML12037A057 (2)

Text

w' DE FOIA Resource From: Decker, David *(-*

Sent: Friday, September 16, 2011 8:39 AM To: Khanna, Meena Cc: Li, Yong; Manoly, Kamal

Subject:

RE: Follow-Up Question from Congressional Staffer Thanks ,teene - this is helpful. I've heard thatthere are two k'nemetricseismometers atNorth 4nne. but wanted to check to see ifyou knew that was correct Thanks!

-Original MeAfge--

From: Khanna, 744eena Sent.: Thursday September /5. 2011 10:50 PAl To: Decker, Dvid Cc. L4 Yong: Manly,. Kamnal

Subject:

FW. Follow-Up Ouestion from CongressionalStaffer Importance. High David p/s use this response in lieu of what I sentyou earlier..thanks

'nemetriksseismometers are relativey rel/ablebecause they provide groundmotion time historiesand the corresponding response spectrum can be calculated Iowever, EngdahlScratchplates only recordpeak accelerationsand due to unknown reasons.the scratchplatesat the North lAnna plantdidnot registeranygroundmotion from the earthquake at certain frequencies. The response spectra from Engdahl and Ahiemetrics seismometersshowedsign/fcantinconsistency.inboth frequenciesandampl/tudes, eventhough the two seimometers are locatedat the same locateon/elevation. However, it should be noted that both types of recordingsindicatedthe exceedance of OBE and DBE atthe North Anna site.

From: Khanna4. ileen~a Sent: Thursday.September 15, 2011 6.35 PiM To: Decker. David Cc. A4anoly Kamal Lt Yong- Wilson. George

Subject:

FW-.Follow-Up Question from CongressionalStaffer David.here is a response to your quest/on...

Yes. Kinemetricrecordingsare more reliablebecause they provide #me historiesand the correspondingresponsespectra can be calculated EngdahlScratch plates only recordpeak accelerationsand couldmiss accelerationsat certain frequencies thus.

one would be expected to see some inconsistency i reflecting the frequency vs. amplitude of Wbrations. However, It shouldbe noted that both types of recordings indicate the exceedance of OBE andDBE atNorth Anna.

Thanks,

,MAeena from:-Decker, DOv&

To: Munson, Clifford Cc: Wilson, George Sent: Thu Sep 15 09.:55:/.82011 Subject. RE: Follow-Up Question from CongressionalStaffer Thanks CMk. Knowkig that we also have datafrom seismometers (do we know how many there are at the p/ant) is good George - anything more thatwe can say about where we got datato evaluate the eartquakes'impact (other than the scratchplates) would be much appreciated From. Munson. Clford \

Sent: Thursday, September 15. 2011 8,01 AM To: Decker. David Cc. Wilson, George

Subject:

RE: Follow-Up Queston from CongressionalStaffer Bill leith of USGS was referringto the "'cratchplate "readouts. Dominion also hasseismometers which give a complete recordof the earthquakemotions so they aren tjust relying on the scratchplates. which are fair4 crude (1.970s technology).

Maybe George Wilson can ampli4 more on the accuracy of the scratchplatessince he has experience with them.

Cliff From: Decker. David U Sentk Wednesday, September 14. 2011 525 PM To.: Wilson, George.: Munson, Clifford-Croteau,Rick: Jones, Wliam

Subject:

Follow-Up Question from CongressionalStaffer We received the following question from Kathy Dedrick (one of our Senate oversightstaffers who we ve talked with on the phone twice recently). aftershe watched the Task Forcepublic meeting today. Thanks for your help in responding to the question below. -David "Can anyone explain to me what the ramificationsare of the USGS testhmony today which saidthat the measurementsat North Anna were probablynot accurate within 10 or 20 percent Does that mean they are less sensitive and theground motion could have been much more? Or what does that mean? It sounds like those instruments are the only source of information,so Dominion would be basingdecisions on something that isn t very accurate."

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