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Category:- No Document Type Applies
MONTHYEARML22112A0062022-04-20020 April 2022
(Public Version) Oconee SLRA - Final RCI 3.5.2.2.2.6-L
ML21323A1152021-11-23023 November 2021
Subsequent License Renewal Environmental Review Requests for Additional and Subsequent Information - Enclosure
ML18060A0282018-02-28028 February 2018
Noncurrence Process - Alternative to Codes and Standards
ML16055A1882016-01-15015 January 2016
FOIA/PA-2016-0071 - Resp 3 - Interim, Continuing to Process Request. Part 2 of 2
ML16055A1872016-01-15015 January 2016
FOIA/PA-2016-0071 - Resp 3 - Interim, Continuing to Process Request. Part 1 of 2
ML15224A7792015-08-0707 August 2015
FOIA/PA-2015-0393 - Resp 2 - Final, Part 1 of 1
ML15162A0842015-06-11011 June 2015
GTCC Disposals at the Barnwell Low-Level Radioactive Waste Facility from 1998 to Present
ML14135A4082014-05-0707 May 2014
FOIA/PA-2013-0213 - Resp 3 - Final, Group Letter D. Part 1 of 1
ML14058A0822014-02-0404 February 2014
Questions and Answers Related to the Oconee External Flooding Issue
ML14058A0522014-02-0404 February 2014
Use of FERC Inundation Calculation Parameters
ML14058A0502014-02-0404 February 2014
Questions and Answers Related to Oconee Flood Barrier
ML14058A0492014-02-0404 February 2014
Site Adequate Protection Backfit Documented Evaluation
ML14058A0212014-02-0404 February 2014
Request for Opinion on the Safe Shutdown Facility Added to the License Basis for the Oconee Units in an SER
ML14058A0202014-02-0404 February 2014
Nancy Ssf Flooding URI Number 1
ML14058A0192014-02-0404 February 2014
TIA, Answers to Questions in Relation to Licensing Basis for Flooding for the Safe Shutdown Facility at Oconee Station
ML14058A0152014-02-0404 February 2014
(Redacted) Oconee Nuclear Site Adequate Protection Backfit Documented Evaluation
ML14049A2872013-08-28028 August 2013
Meeting Feedback Form Meeting No. 20140354
ML16070A2882013-04-24024 April 2013
Jocassee and Keowee Dams, Breach Parameter Review, Dated April 24, 2013 (Redacted)
ML13240A0162013-03-0606 March 2013
Report, Enclosure Oconee Nuclear Station Flooding Hazard Reevaluation Report
ML13052A7852013-02-26026 February 2013
Flood Licensing Basis Evaluation Open Items
ML13052A7802013-02-0606 February 2013
Options for Revising Oconee Flood CAL Due Dates
ML13052A7812013-02-0606 February 2013
Timeline - Summary of Events
ML13052A7832013-02-0606 February 2013
Draft NRC Information Notice on Dam Failure Frequency in Probabilistic Risk Assessments
ML13052A7862013-02-0606 February 2013
Jocassee Dame Failure Frequency Components
ML13052A7872013-02-0606 February 2013
Justification for Continued Operation of Oconee Nuclear Station
ML13056A1002013-02-0606 February 2013
Resolution of Oconee Flooding Issue
ML13056A1052013-02-0606 February 2013
Comparison of Approaches for Calculating a Jocassee Dam Failure Frequency
ML12121A6382012-04-30030 April 2012
Response to Nuclear Regulatory Commission Standard Steam Generator Questions for Oconee Unit 3
ML12056A0522012-03-12012 March 2012
Enclosure 6 - List of Power Reactor Licensees and Holders of Construction Permits in Active or Deferred Status
ML12003A0632011-12-16016 December 2011
Tornado and High Energy Line Break (HELB) Mitigation License Amendment Requests (Lars) - Responses to Request for Additional Information, Part 2 of 6
ML12003A0672011-12-16016 December 2011
Tornado and High Energy Line Break (HELB) Mitigation License Amendment Requests (Lars) - Responses to Request for Additional Information, Part 4 of 6
ML12003A0682011-12-16016 December 2011
Tornado and High Energy Line Break (HELB) Mitigation License Amendment Requests (Lars) - Responses to Request for Additional Information, Part 5 of 6
ML12003A0692011-12-16016 December 2011
Tornado and High Energy Line Break (HELB) Mitigation License Amendment Requests (Lars) - Responses to Request for Additional Information, Part 6 of 6
ML1131406132011-11-0101 November 2011
Enclosure 3 - Regulatory Enforcement Conference - Resubmittal of Supplement
ML11279A2532011-10-0606 October 2011
NRC Pre-submittal Meeting - Proposed Tornado Mitigation Flowchart Revision 6 Oconee Nuclear Station, Units 1, 2, and 3
ML11279A2522011-10-0606 October 2011
NRC Pre-submittal Meeting- Proposed Turbine Building HELB Mitigation Flow Chart Revision 5 Oconee Nuclear Station, Units 1, 2, and 3
ML1101907492011-01-18018 January 2011
Enclosure 3 - List of Attendees
ML1035103792010-12-17017 December 2010
NFPA 805 Transition Pilot Plant FAQ 08-0054, Revision 1
ML1026404582010-09-13013 September 2010
Enclosure 2 - Redacted Version of Request for Additional Information Re the License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Generating Plants (2001 Edition)
ML1023705812010-08-19019 August 2010
NFPA 805 Transition Pilot Plant FAQ 08-0054
ML1035100122010-08-19019 August 2010
NRC Staff Response to NFPA 805 Transition Pilot Plant FAQ 08-0054, Revision 0 (Updated)
ML1019301982010-06-0909 June 2010
Onsite Ground/Surface Water Monitoring Questionnaire for Oconee Nuclear Station
ML14058A0612010-04-13013 April 2010
(Redacted) Draft Oconee Nuclear Site Adequate Protection Backfit Documented Evaluation
ML1019304602010-03-25025 March 2010
List of Historical Leaks and Spills at Us Commercial Nuclear Power Plants
ML1019305442010-02-0808 February 2010
Ground Water Communication Supplemental Information Questions and Answers
ML1100606662009-10-0909 October 2009
Photographs of Ssf Asw Leak and Piping Replacement Project Taken Between August 20, 2009 and October 9, 2009, by Oconee Resident Inspectors. Part 2 of 14
ML0927103442009-09-25025 September 2009
Site Visit Observation on 09/25/2009 by Joel Munday for Oconee
ML1100404352009-09-15015 September 2009
Plant Issue Tracking Application; Plant Status Daily - Oconee Information for 09/15/2009
ML0922300422009-08-11011 August 2009
Plants Transitioning to NFPA 805
ML1100309332009-07-13013 July 2009
Congressional Staff Briefing: Monday July 13, 2009, 3:30 Pm, Room 2108 Rayburn Bldg; Topic: Follow-Up Questions Regarding Chairmans June 17, 2009 Response Regarding a IP2 Buried Pipe Leak
2022-04-20
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This document is a redacted publicly available version. In October 2024, the NRC staff identified information within this document that may be Critical Electric Infrastructure Information (CEII) as defined by the Federal Energy Regulatory Commission (FERC). The original file is non-public, designated as CEII, in ADAMS ML24305A172.
NRC staff actions were taken in accordance with:
The Memorandum of Understanding Between US NRC and FERC Regarding Treatment of Critical Energy/Electric Infrastructure Information found at: https://www.nrc.gov/reading-rm/doc-collections/memo-understanding/2024/index.html.
The FERC definition of CEII found at: https://www.ferc.gov/ceii, and, https://www.ferc.gov/enforcement-legal/ceii/designation-incoming-dam-safety-documents.
Questions and Answers Related to Oconee Flood Barrier
- 1. How much confidence does NRR has about the fact the licensee's estimate of the Flood Frequency in its IPEEE is one order of lower based on operating experience?
We have very high confidence in our calculation. Attached is a spreadsheet comparing our experience data with the Oconee PRA and IPEEE calculations. Their error is the counting of only 2 failures of rockfill dams and then applying them to the population of both rockfill and earthen dams. During the same period (1940 to 2000) earthen dams had 32 failures. Had these 32 failures been properly included, the failure frequency would have been 2E-4 failure per dam year. If rockfill dams had been used alone, they would have gotten about the same result. There is no dam or mixture of dam populations that would get a result less than 1 E-4 failure per dam year. Their result of 1.3E-5 is clearly in error.
References:
National Inventory of Dams http://crunch.tec.army.mil/nid/webpages/nid.cfm National Performance of Dams Program http:/lnpdp.stanford.edu/index.html Oconee IPEEE Rev 2 Section B.4.3, "Frequency of Dam failure"
- 2. Are there other IPEEEs which postulate external floods induced by dam failures? If there are, what are the frequencies, which those licensees used to assess risk?
NUREG-1742 identified only two IPEEEs that addressed dam failure floods quantitatively - Ft Calhoun and Diablo Canyon. Everyone else only addressed probable maximum precipitation and screened out dam failure as low probability. Unfortunately, there were few dam failure data sources around back then, so many plants used the estimate published in NUREG/CR-5042. The data source for the estimate in NUREG/CR-5042 was the Oconee PRA - NSAC/60. The calculation in NSAC/60 was done in error and it propagated throughout the industry.
References:
NUREG/CR-5042, "Evaluation of External Hazards to Nuclear Power Plants in the United States.
NUREG-1742, "Perspectives Gained From the Individual Plant Examination of External Events (IPEEE) Program NSAC/60, "Oconee PRA"
- 3. How much confidence do we have on licensee's predicted flood height (1980s study) that estimate the flood heigjht at
? level?
The licensee indicated that their calculations to support the 1983 study were not retrievable and personnel who performed the work were not available. The staff has attempted to reconstruct what may be the logic for the original flood level estimate as follows:
The benchmark nearest to the SSF shown on the Oconee site plan from the FSAR is at 796.63' elevation.
Lake Keowee is maintained at 800' elevation. The difference is 3.37'. In the absence of any documented analysis, the basis for is a mystery. Both the Oconee PRA and the IPEEE are silent on the height and only mention the height and even that is without explanation. However the plant does claim a probable maximum precipitation of 1.33' which when added to 3.37' would come out to 4.70' but that is speculation. Oconee never claimed it.
The plant is protected from lake Keowee by a 20' or so dike that surrounds the intake area and a similar dike that forms an extension of the Keowee dam. The east side of the site slopes down into the river valley. If the waters of lake Keowee find a path into the west yard, the east side slope may not drain them away fast enough to maintain less than of water in the west yard. If the Keowee dam fails, the valley to the east would quickly fill and put about of water into the west yard. The 1992 FERC flood model of Jocassee dam failure put of water on site following failure of the Keowee dam. The now unavailable 1983 Duke study indicated the Keowee dam would survive and a barrier in the yard was adequate. Duke has not presented the 1992 FERC flood model as a design basis.
