ML14058A026

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Status of Oco Flood Issue
ML14058A026
Person / Time
Site: Oconee  Duke Energy icon.png
Issue date: 08/15/2008
From:
Office of Nuclear Reactor Regulation
To:
Shared Package
ML14055A421 List: ... further results
References
FOIA/PA-2012-0325
Download: ML14058A026 (2)


Text

Status of OCO Flood Issue August 15, 2008 - 50.54(f) letter August 15, 2008 - June 2010 - various meetings and correspondence June 10, 2010- Region II completed ICM inspection June 22, 2010 - Issued CAL. CAL directed licensee to:

  • Implement ICMs as documented in the June 3, 2010 letter
  • submit to the NRC by August 2, 2010, all documentation necessary to demonstrate to the NRC that the inundation of the Oconee site resulting from the failure of the Jocassee Dam has been bounded

" submit by November 30, 2010, a list of all modifications necessary to adequately mitigate the inundation

  • make all necessary modifications by November 30, 2011 August 2, 2010 - Oconee provides inundation study (CAL item)

November 29, 2010 - Oconee provides high level, conceptual list of possible modifications.

This was not the detail staff desired. Letter stated they needed to know what Case to use so they knew what flood height to protect against and stated they would provide a final list by April 30, 2011.

January 28, 2011 - Staff issues assessment of inundation study. Letter informed Duke that the staff considered Case 2 to be adequate to bound (Reservoir 1110 full pond, bottom breach el 800 ft, width 425 ft, time-to-failure 2.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />)

April 29, 2011 - Oconee provides list of modifications (intake dike diversion wall, dedicated flood protected offsite power, power block diversion wall, turbine building and yard drain isolation, SFP makeup via re-routed SSF ASW miniflow line). Completion times determined by FERC and NRC (LAR) approvals plus 30 months.

" Licensee made clear in this letter that they still considered this external flood to be a beyond "DBE" as described in their licensing basis which clearly states that DBE's are only those events in Ch 15 of the FSAR.

  • Licensee will not build and treat flood protection features as QAl/safety related August 18, 2011 - NRC sends OCO RAI concerning April 29 2011, letter focused on more details on the flood is a beyond DBE, that natural phenoma are not DBEs, justification for assumptions used to develop mitigation strategies, actions for mitigation strategies, justification for not installing the modifications lAW 50 Appendix B.

October 17, 2011 - Oconee responds to August 18 RAIs

April 29 2011 to present - discussions internally and with the licensee on not building the flood protection features as QAl/safety related. Staff feels that since we have an adequate protection backfit analysis completed we should make the external flood a DBE for OCO and that would require the features to meet QA requirements. On a phonecall with NRR (Kulesa, Stang, Wilson, Rapp, Stamm). I put forth the following 2 options:

1. Make the flood a DBE through an order and drive the modifications to be QA/safety related. This would result in a longer timeline to complete and higher cost.
2. Treat the flood as a "design criteria" as Oconee says and have them make this flood a part of their licensing basis (which they are okay with). Consistent with treatment of other issues such as B.5.b, quicker resolution, and still enforceable.

George Wilson is checking with the Fukishima task force to make sure we handle this consistently with those efforts.