ML12037A057
| 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
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 that there are two k'nemetric seismometers at North 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 Congressional Staffer Importance. High David p/s use this response in lieu of what I sent you earlier..thanks
'nemetriks seismometers are relativey rel/able because they provide ground motion time histories and the corresponding response spectrum can be calculated Iowever, Engdahl Scratch plates only record peak accelerations and due to unknown reasons. the scratch plates at the North lAnna plant did not register any ground motion from the earthquake at certain frequencies. The response spectra from Engdahl and Ahiemetrics seismometers showedsign/fcantinconsistency. in both frequencies and ampl/tudes, eventhough the two seimometers are located at the same locateon/elevation. However, it should be noted that both types of recordings indicated the exceedance of OBE and DBE at the 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 Congressional Staffer David. here is a response to your quest/on...
Yes. Kinemetric recordings are more reliable because they provide #me histories and the corresponding response spectra can be calculated Engdahl Scratch plates only record peak accelerations and could miss accelerations at certain frequencies thus.
one would be expected to see some inconsistency i reflecting the frequency vs. amplitude of Wbrations. However, It should be noted that both types of recordings indicate the exceedance of OBE and DBE at North Anna.
- Thanks,
,MAeena from:- Decker, DOv&
To: Munson, Clifford Cc: Wilson, George Sent: Thu Sep 15 09.:55:/.8 2011 Subject. RE: Follow-Up Question from Congressional Staffer Thanks CMk.
Knowkig that we also have data from seismometers (do we know how many there are at the p/ant) is good George - anything more that we can say about where we got data to evaluate the eartquake s' 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 Congressional Staffer Bill leith of USGS was referring to the "'cratch plate "readouts. Dominion also has seismometers which give a complete record of the earthquake motions so they aren tjust relying on the scratch plates. which are fair4 crude (1.970s technology).
Maybe George Wilson can ampli4 more on the accuracy of the scratch plates since 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 Congressional Staffer We received the following question from Kathy Dedrick (one of our Senate oversight staffers who we ve talked with on the phone twice recently). after she watched the Task Force public meeting today. Thanks for your help in responding to the question below. -David "Can anyone explain to me what the ramifications are of the USGS testhmony today which said that the measurements at North Anna were probably not accurate within 10 or 20 percent Does that mean they are less sensitive and the ground 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 basing decisions on something that isn t very accurate."
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