ML13094A431
| ML13094A431 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/12/2013 |
| From: | Boska J Plant Licensing Branch II |
| To: | Gillespie P Duke Energy Carolinas |
| Boska J NRR/DORL/LPL2-1 301-415-2901 | |
| References | |
| TAC ME9021, TAC ME9022, TAC ME9023 | |
| Download: ML13094A431 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 12, 2013 Mr. Preston Gillespie Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752
SUBJECT:
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3, REQUEST FOR ADDITIONAL INFORMATION REGARDING AMENDMENT APPLICATION RELATED TO MAINTENANCE ON THE ON SITE STANDBY POWER SOURCES (TAC NOS. ME9021, ME9022, AND ME9023)
Dear Mr. Gillespie:
By letter dated June 27, 2012, as supplemented on December 14,2012, Duke Energy Carolinas, LLC (Duke), submitted an application for a proposed amendment for the Oconee Nuclear Station, Units 1, 2, and 3, which would allow a one-time extension of the allowed out-of-service time for the two onsite standby power sources (the Keowee hydro units) in order to perform maintenance on the generator field poles.
The Nuclear Regulatory Commission 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 April 4, 2013, the Duke staff indicated that a response to the RAI would be provided within 45 days of the date of this letter.
If you have any questions, please call me at 301-415-2901.
Sincerely,
¥ft 9.~
(J n P. Boska, Senior Project Manager lant 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
REQUEST FOR ADDITIONAL INFORMATION REGARDING TEMPORARY TECHNICAL SPECIFICATION CHANGE REQUEST TO EXTEND THE COMPLETION TIME 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 June 27, 2012, Agencywide Documents Access and Management System (ADAMS) Accession No. ML12181A312, as supplemented on December 14,2012, ADAMS Accession No. ML12359A039, 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 allow a one-time extension of the allowed out-of-service time for the two onsite standby power sources (the Keowee hydro units (KHU>> in order to perform maintenance on the generator field poles. The Nuclear Regulatory Commission (NRC) staff is reviewing the submittals and has the following questions.
EEEB RAI1:
In "Response to staff RAI 2" in its letter dated December 14, 2012, the licensee stated that they do not need to restrict performance of the KHU pole rewind work in the months with higher frequency of tornados because the expected frequency of loss of offsite power (LOOP) events as a result of severe weather is less than the annual average.
Provide the expected frequency of LOOP events for each month of the year. Discuss the protocol and coordination which will be established with the grid operator during the KHU outage.
EEEB RAI2:
In "Response to staff RAI 3" in its letter dated December 14,2012, the licensee stated that they will ensure that pole-rewind work would be scheduled so that there is no impact on or conflict with the protected service water (PSW) related work and that there is no adverse impact on the availability of any safe shutdown systems.
Provide an estimated schedule for the PSW work. Provide the basis for not providing a regulatory commitment in the license amendment request (LAR) to ensure that there would be no impact or conflict between the pole-rewind work and PSW related work, and that there would be no adverse impact on the availability of any safe shutdown systems.
Enclosure
- 2 EEEB RAI3:
In "Response to staff RAI 6," in its letter dated December 14, 2012, the licensee stated that between 2007 through 2012, Lee Combustion Turbine (LCT) 7C failed twice and LCT 8C failed 6 times, and each one resulted in a Maintenance Rule Functional Failure (MRFF).
- 1. Confirm that failures in LCTs are reviewed for common cause if the identical components are used in both LCTs. In particular, discuss whether corrective actions were taken on both LCTs when the LCT 7C (August 19, 2007) failure occurred due to a faulty micro-switch, and the LCT 8C (July 28, 2011) failure occurred due to a faulty servo-control 110 module.
- 2. Are there any repetitive MRFF for the LCT system? Provide a discussion of preventive maintenance and performance or condition monitoring actions taken in accordance with Title 10 of the Code ofFederal Regulations, Section 50.65.
EEEB RAI4 Note 1 for Technical Specification (TS) 3.8.1, Required Action C2.2.5, proposed Completion Time states, "No discretionary maintenance or testing allowed on SSF [Standby Shutdown Facility],
EFW [Emergency Feedwater] and essential AC [alternating current] Power System."
Explain the term "essential AC Power System."
EEEB RAI5 In a presentation dated December 16, 2003 (ADAMS Accession No. ML033520190), for an earlier LAR, dated August 22, 2002, for the KHUs maintenance outage, the licensee discussed the use of temporary diesel generators, during the maintenance period. The use of temporary alternate AC power sources, to enable each unit to reach and maintain cold shutdown, is consistent with NRC Electrical Branch Technical Position 8-8 (ADAMS Accession No. ML113640138) during extended planned outage periods of station emergency power. Given the questionable reliability history of the Lee Combustion Turbines and the susceptibility of the overhead transmission lines to severe weather events, explain why the current proposed one-time 75-day KHU maintenance outage does not include the use of temporary diesel generators.
EEEB RAI6 Provide a summary of all the loads that are required to be connected to the SSF diesel to achieve safe shutdown condition. Explain whether the SSF diesel has adequate capacity to bring all three Oconee units to safe shutdown condition simultaneously.
EEEB RAI7 Provide a discussion of maintaining plant safety and defense in-depth of onsite emergency power system when performing this maintenance work with all three units at power versus all three units in a shutdown condition.
- 3 EEEB RAla The Atomic Energy Commission (AEC) General Design Criterion (GDG) 38 described in the Oconee updated final safety analysis report, Section 3.1, states that:
Criterion 38 - Reliability and Testability of Engineered Safety Features (Category A):
All engineered safety features shall be designed to provide high functional reliability and ready testability. In determining the suitability of a facility for a proposed site, the degree of reliance upon and acceptance of the inherent and engineered safety afforded by the systems, including engineered safety features, will be influenced by the known and the demonstrated performance capability and reliability of the systems, and by the extent to which the operability of such systems can be tested and inspected where appropriate during the life of the plant.
Since the Oconee design basis requires high functional reliability and ready testability, the NRC staff requests that the licensee provide technical and regulatory bases to show that the existing emergency power system design meets AEC GDC 38, considering the TS Completion Time extension requests for KHUs in the last 15 years.
April 12, 2013 Mr. Preston Gillespie Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752 SUB..IECT:
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3, REQUEST FOR ADDITIONAL INFORMATION REGARDING AMENDMENT APPLICATION RELATED TO MAINTENANCE ON THE ONSITE STANDBY POWER SOURCES (TAC NOS. ME9021, ME9022, AND ME9023)
Dear Mr. Gillespie:
By letter dated June 27, 2012, as supplemented on December 14, 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 allow a one-time extension of the allowed out-of-service time for the two onsite standby power sources (the Keowee hydro units) in order to perform maintenance on the generator field poles.
The Nuclear Regulatory Commission 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 April 4, 2013, the Duke staff indicated that a response to the RAI would be provided within 45 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:
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