ML14058A083

Email from D. Aird, RES to F. Ferrante, NRR GI-204 Dam Failure Comm. Plan Answer

ML14058A083
Person / Time
Site:	Oconee
Issue date:	01/13/2012
From:	David Aird NRC/RES/DRA
To:	Ferrante F NRC/NRR/DRA
Shared Package
ML14055A421	List: ML090570117 ML090680737 ML091620669 ML092020480 ML092940769 ML100280954 ML101750619 ML101890803 ML102990064 ML103410042 ML12268A404 ML14055A410 ML14055A411 ML14055A474 ML14058A015 ML14058A016 ML14058A017 ML14058A018 ML14058A019 ML14058A020 ML14058A021 ML14058A022 ML14058A023 ML14058A024 ML14058A025 ML14058A026 ML14058A027 ML14058A028 ML14058A029 ML14058A030 ML14058A031 ML14058A032 ML14058A033 ML14058A034 ML14058A035 ML14058A036 ML14058A037 ML14058A038 ML14058A039 ML14058A040 ML14058A042 ML14058A043 ML14058A044 ML14058A045 ML14058A046 ML14058A047 ML14058A048 ML14058A049 ML14058A050 ML14058A051 ... further results
References
FOIA/PA-2012-0325
Download: ML14058A083 (3)

Text

q Ferrante, Fernando From: Sent: To: Cc:

Subject:

Aird, David '[-- j Friday, January 13, 2012 1:25 PM Ferrante, Fernando Perkins, Richard RE: GI-204 Dam Failure Comm. Plan Answer Fernando, Thanks for taking a look at my various responses.

I agree that we are converging on the same answer and now understand why not to take ownership of the IPEEE responses especially considering the questionable numbers assigned to dam failures.-..

naviri Outside of Scope In the Oconee Nuclear Station su mi/icensee estimated the im-pact from flooding due to failure of a large upstream dam but also concluded that it this is a low probability event and, therefore, did not pose a severe accident vulnerability.-

Outside of Scope On Oconee, one of the confusions on what the dam frequency represents is that the licensee parsed failure modes by separating seismic and treating the probability of failure due to overtopping individually (using limited hydrologic data). This approach came from an earlier PRA study effort titled NSAC-60, specific to Oconee. The failure modes which the licensee included were primarily embankment piping and foundation failures with a very narrow focus on dams that met the same characteristics of Jocassee Dam, resulting in a lower value than would generally be obtained by using dam failures from all failure modes and years of operations of the general large dam population (which is how they derived the value listed in the IPEEE, which again was based on NSAC-60 approach).

Outside of Scope Richard, " Thanks, David Aird Reliability and Risk Engineer RES/DRA/PRB (301) 251 -7926 Mailstop:

CSB-4CO7M Location:

04-C25:3