ML13056A128
| ML13056A128 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/19/2008 |
| From: | Office of Information Services |
| To: | |
| References | |
| FOIA/PA-2012-0325 | |
| Download: ML13056A128 (6) | |
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e Oconee Flood Protection and the Jocassee Dam Hazard DHS Briefing September 19, 2008 10/4/2012 Official e
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SNRC Overview
- Objective
- Provide background information for issue
- Provide status and path forward
- Success
- Understanding of the regulatory and safety issues
- Understanding of NRC planned actions
- Identify any NRC/DHS issues that need further action 10/4/2012 1 / 2Y
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" Three pressurized water reactors located in Seneca, South Carolina Owned and operated by Duke Energy Corporation Operational in 1973-74 Located down river of lake Keowee (just north of site) and lake Jocassee (11 miles upriver)
" Only nuclear plant in the United States that relies on hyrdo-electric generators as emergency power source (Keowee Hydro Station)
- Plant relies on the Standby Shutdown Facility (SSF) to maintain reactor shutdown in case of fires, floods, or sabotage events.
SSF contains its own electric power source (diesel generators, batteries, etc..), control room.
SSF is a retrofit to the original plant design.
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U.S.NRC Oeffical Use On Sen *e Key Insights from Reactor Oversight Process
" In 2007, NRC concluded that the Jocassee dam failure issue had not been adequately resolved.
- Duke Hydro/FERC Inundation Study completed in early 1990s. Estimated flood heights up to 16.8 ft above SSF grade level.
- Floods in excess of 5 ft lead to three-unit core damage event and ultimate failure of each containment building.
" Staff identified an under-estimate in licensee's dam failure frequency.
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-1U.S.NRC ter form Issuance 50.54(f) Letter
- On August 15, 2008, NRC issued letter to licensee requiring information to determine if NRC should modify, suspend, or revoke the license.
- Letter seeks information to assure protection of public and elevates NRC's regulatory and safety concerns.
- Letter states that Jocassee Dam Failure Inundation Study indicates flood heights up to 16.8 feet above SSF grade.
- Licensee to respond to NRC by September 29, 2008.
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U aI OnWI-Sens e Actions Concurrent with 50.54(f) Letter
- Backfit evaluation: external flooding within licensing basis. Licensee did not address Jocassee dam failure.
" "Adequate Protection" based backfit best approach.
- No defense-in-depth: three unit core damage event with ultimate failure of each containment.
- Regulatory expectations for external flood protection includes dam hazards.
" Cost-benefit estimate of $3 million in modifications.
Modifications on the order of $13 million justified.
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- ve.lyfrt Actions Concurrent with 50.54(f) Letter (continued) o In early September 2008, NRC staff notified Congressional staffers regarding the issue.
" NRC anticipates interaction with Congressional staffers on the issue and NRC resolution.
o Generic issue preliminary assessment completed.
- Twenty five sites have a dependency on dam performance. Seven sites (including Oconee) have dams up river of the site.
- Draft Information Notice has been written.
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!ROfficial USn NRCIDHS Interface o NRC staff is providing this information to DHS should it affect the ranking of the Jocassee Dam from a security oversight standpoint.
o NRC has not determined how or if security issues may affect the NRC's regulatory actions.
o Are there any additional actions that DHS could take, if necessary, to further protect the dam?
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