ML13149A111
| ML13149A111 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/17/2013 |
| From: | Boska J P Plant Licensing Branch II |
| To: | Batson S Duke Energy Carolinas |
| Boska J P NRR/DORL/LPL2-1 | |
| References | |
| TAC ME9880, TAC ME9881, TAC ME9882 | |
| Download: ML13149A111 (4) | |
Text
UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 June 17, 2013 Mr. Scott Batson Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752 OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3, REQUEST FOR ADDITIONAL INFORMATION REGARDING AMENDMENT APPLICATION RELATED TO TECHNICAL SPECIFICATIONS FOR THE ONSITE STANDBY POWER SOURCES (TAC NOS. ME9880, ME9881, AND ME9882) Dear Mr. Batson: By letter dated October 30, 2012, Duke Energy Carolinas, LLC (Duke), submitted an application for a proposed amendment for the Oconee Nuclear Station, Units 1, 2, and 3, which would revise the Technical Specifications for the two onsite standby power sources (the Keowee hydro units). The Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). On May 28, 2013, the Duke staff indicated that a response to the RAI would be provided within 30 days of the date of this letter. If you have any questions, please call me at 301-415-2901. Sincerely, Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and Request for Additional cc w/encl: Distribution via REQUEST FOR ADDITIONAL INFORMATION REGARDING TECHNICAL SPECIFICATION CHANGE REQUEST FOR AN INOPERABLE KEOWEE HYDRO UNIT DUKE ENERGY CAROLINAS, LLC OCONEE NUCLEAR STATION, UNITS 1,2, AND 3 DOCKET NOS. 50-269, 50-270 AND 50-287 By letter dated October 30, 2012, Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12307A377, Duke Energy Carolinas, LLC (the licensee), submitted an application for a proposed amendment for the Oconee Nuclear Station, Units 1, 2, and 3, which would revise Technical Specification (TS) 3.8.1 to allow the 45-day Completion Time to be cumulative over three years for the two onsite standby power sources (the Keowee hydro units (KHU>>. Section 4.0, "Risk Insights," of the license amendment request (LAR), states: The justification for the TS Completion Time clarification is based on the deterministic evaluation in section 3.0. Duke Energy reviewed the Probabilistic Risk Assessment (PRA) to gain additional insights concerning the configuration of ONS [Oconee Nuclear Station] with one KHU inoperable for a cumulative 45 days over 3-year time period versus one KHU inoperable for one continuous 45-day time period. The Incremental Conditional Core Damage Probability (ICCDP) and the Incremental Conditional Large Early Release Frequency (ICLERP) risk metrics are the same regardless of whether or not a KHU is inoperable for a continuous 45-day time period or for a cumulative 45 days over any 3-year time period. The insights from the Duke Energy risk analYSis support the deterministic analysis showing that there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner of this license amendment request." The Nuclear Regulatory Commission (NRC) staff is reviewing the submittals and has the following questions. RAI1: Concerning the risk assessment performed to gain insights in Section 4.0 of the Oconee LAR dated October 30, 2012, related to the proposed 45 days cumulative per rolling 3 year period, please discuss the basis for your conclusion(s) on risk insights. RAI2: What duration was used for a single Keowee Hydro Unit (KHU) outage? Were dual KHU outages considered as part of the single KHU outage? Enclosure
-RAI3: When a single KHU outage is entered, how is it ensured that the other KHU will maintain its high reliability to start and run? There may be times when a dual KHU outage is entered, for example to drain the penstock and isolate a single KHU, followed by bringing back one KHU for a period oftime, and then re-entering a dual KHU outage to recover the KHU undergoing maintenance. What steps are taken to ensure that the KHU brought back to service between dual KHU outages does not have degradation in its reliability to start and run? Regarding the Safe Shutdown Facility (SSF) during a dual KHU outage and a single KHU outage, are there differences in the way the SSF is ready to be used if needed (e.g., in the deployment of the SSF)? If so, please discuss the differences. During KHU outages, are there any planned actions in the event of a heightened likelihood of a loss of offsite power (such as tornado warnings)? During KHU outages, are there any planned actions to ensure availability and reliability of the emergency feedwater system? The staff is concerned that using 45 days of outage time for each KHU cumulative over three years could result in a significant increase in the duration of dual KHU outages, which typically occur at the beginning and end of maintenance periods for individual KHUs, due to the shared intake pipe. Dual KHU outages carry more risk than single KHU outages. Please explain how dual KHU outages would be limited to avoid this condition.
June 17, 2013 Mr. Scott Batson Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752 OCONEE NUCLEAR STATION, UNITS 1,2, AND 3, REQUEST FOR ADDITIONAL INFORMATION REGARDING AMENDMENT APPLICATION RELATED TO TECHNICAL SPECIFICATIONS FOR THE ON SITE STANDBY POWER SOURCES (TAC NOS. ME9880, ME9881, AND ME9882) Dear Mr. Batson: By letter dated October 30,2012, Duke Energy Carolinas. LLC (Duke), submitted an application for a proposed amendment for the Oconee Nuclear Station. Units 1. 2. and 3. which would revise the Technical Specifications for the two onsite standby power sources (the Keowee hydro units). The Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). On May 28, 2013, the Duke staff indicated that a response to the RAI would be provided within 30 days of the date of this letter. If you have any questions, please call me at 301-415-2901. Sincerely. IRA! John P. Boska, Senior Project Manager Plant licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287 Enclosure: Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION: PUBLIC RidsAcrsAcnw _MailCtr Resource RidsNrrDorlDpr Resource LPLlI-1 R/F RidsNrrLASFigueroa Resource RidsNrrDorlLp2-1 Resource RidsNrrPMOconee RidsRgn2MailCenter Resource RidsNrrDeEeeb PSahay RMathew GWaig ADAMS Accession No.: ML13149A111 *Via email OFFICE NRRlLPL2-1/PM NRRlLPL2-1/LA NRR/EEEB/BC* N RRiLP L2-1/BC NRRlLPL2-1/PM NAME JBoska SFigueroa MMcConnell (A) RPascarelli ,.I Boska DATE 06/05/13 05/29/13 05/20/13 06/06/13 06/17/13 OFFICIAL RECORD COpy