ML13066A200

Email from J. Mitman, NRR to M. Galloway, NRR on Ofi - Does NRC Correspondence Speak to Failure Modes of the Jocassee Dam

ML13066A200
Person / Time
Site:	Oconee
Issue date:	12/22/2009
From:	Jeffrey Mitman NRC/NRR/DRA
To:	Galloway M Division of License Renewal
References
FOIA/PA-2012-0325
Download: ML13066A200 (1)

Text

Mitman, Jeffrey From: Mitman, Jeffrey /. .

Sent: Tuesday, December 22, 2009 6:35 PM To: Galloway, Melanie I o.(L-Cc: James, Lois; CunningHam, Mark; Ferrante, Fernando

Subject:

OFI - Does NRC Correspondence Speak to Failure Modes of the Jocassee Dam?

The above subject question was asked during our recent discussions. I've reviewed both the August 15, 2008 50.54(f) and April 30, 2009 NRC letters, both are silent as to which failure modes need to be considered.

Duke, however, is not silent on the issue.

In the 50.54(f) response letter, dated September 26,2008, Duke discusses at length Jocassee Dam failure modes. This response discusses a 2004 Potential Failure Modes Analysis (PFMA) conducted at FERC request. This analysis determines that only piping failures met FERC requirements. This analysis specifically determines that for FERC consideration seismic, overtopping from over-pumping are not a concern. The language on overtopping from PMP/PMF is more ambiguous, it appears to rule this out as well.

In the letter of November 30, 2009, Duke reiterates that the failure modes of seismic and overtopping from a PMF are not considered in their updated inundation analysis again referring to the 2004 PFMA.

One further note. The Duke 50.54(f) response letter states: "Flooding (of ONS), due to the potential failure of the Jocassee dam, is not addressed and is not currently considered part of the CLB (current licensing basis).

External flooding due to a postulated Jocassee dam failure has been considered as a beyond design basis event and managed as a risk assessment issue." I bring up this statement because some NRC staff have said that overtopping and seismic issues are outside the license while sunny day failure are within it. According to Duke, this understanding is incorrect, all flooding from all Jocassee Dam failures modes are outside the CLB.

Jeff 1