ML103620559
| ML103620559 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/28/2010 |
| From: | Nicholas Difrancesco Plant Licensing Branch III |
| To: | Pacilio M Exelon Nuclear |
| DiFrancesco N, NRR/DORL/LPL3-2, 415-1115 | |
| References | |
| TAC ME1669, TAC ME1670 | |
| Download: ML103620559 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 December 28, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville,IL 60555 BYRON STATION, UNIT NOS. 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION RELATED TO LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK (TAC NOS. ME1669 AND ME1670)
Dear Mr. Pacilio:
By letter to the Nuclear Regulatory Commission (NRC) dated June 30, 2009, as supplemented by letters dated January 25, July 1, and November 8, 2010 (Agencywide Documents Access and Management System Accession Nos. ML091831253, ML100280553, ML101830041, and ML103120556, respectively), Exelon Generation Company, LLC (the licensee), submitted a license amendment request to revise Technical Specification 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect the results of a revised analysis for the UHS. The NRC staff is reviewing your submittals, and has determined that additional information is required to complete its review. The specific information requested is addressed in the enclosed Request for Additional Information (RAI). The RAI was discussed with your staff on December 20, 2010, and they agreed to respond by January 31, 2011. Please note that if you. do not respond to this letter by the agreed-upon date or provide an acceptable alternate date in writing, we may reject your request for approval under the provisions of Title 10 of the Code of Federal Regulations, Section 2.108. The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.
If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1115.
Nicholas J.
Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454 and STN 50-455
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-454 AND 50-455 The Nuclear Regulatory Commission (NRC) staff is reviewing Exelon Generation Company, LLC's (the licensee's) license amendment request (LAR) dated June 30, 2009, as supplemented by letters dated January 25, July 1, and November 8, 2010 (Agencywide Documents Access and Management System Accession Nos. ML091831253, ML100280553, ML101830041, and ML103120556, respectively).
The LAR requests to revise Technical Specification (TS) 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect the results of a revised analysis for the UHS. The NRC staff has determined that the foJ/owing additional information is required to complete its review. The EGC request dated June 30,2009, provided revised TS 3.7.9, "Ultimate Heat Sink," and the revised TS B3.7.9 Bases for a cross tied SX system. The letter dated November 8,2010, includes new proposed TS 3.7.9 for split SX system, but did not include the new TS Bases. Please provide the complete TS B3.7.9 Bases for clarity. Please explain why and how often the SX trains are operated split for one and/or both units. The uprate heat load for the scenarios presented in the letter dated November 8, 2010, for the scenarios where SX is split, show a constant heat load to the UHS for approximately the first 19 minutes after loss-of-coolant accident.
These heat loads differ from the heat loads in the scenarios presented in your letter dated June 30, 2009. The staff recognizes differences in heat loads to the UHS based on one train of SX in the letter dated November 8, 2010, versus two trains of operating SX in your letter dated June 30, 2009. Please explain the reasons for differences in the heat load profiles for your letters dated June 30, 2009, and November 8, 2010. Please explain why the heat load is constant in your November 8, 2010, submittal for the first 19 minutes, whereas the corresponding heat load for the first 19-20 minutes is not constant for the scenarios in the letter dated June 30, 2009.
-2 The proposed TS Limiting Condition for Operation (LCD) 3.7.9 use "SX pump discharge temperature region," to define the LCD. As this temperature varies, the requirements of the LCD change and require operator action. Please explain how the operators will become aware that the "SX pump discharge temperature region," has changed and that operator action is necessary. Indicated SX pump discharge temperature may be different than actual temperature.
How has the temperature instrument and loop uncertainty/inaccuracy been factored into the proposed TS LCD revision?
December 28,2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 BYRON STATION, UNIT NOS. 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION RELATED TO LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK (TAC NOS. ME1669 AND ME1670)
Dear Mr. Pacilio:
By letter to the Nuclear Regulatory Commission (NRC) dated June 30, 2009, as supplemented by letters dated January 25, July 1, and November 8,2010 (Agencywide Documents Access and Management System Accession Nos. ML091831253, ML100280553, ML101830041, and ML103120556, respectively), Exelon Generation Company, LLC (the licensee), submitted a license amendment request to revise Technical Specification 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect the results of a revised analysis for the UHS. The NRC staff is reviewing your submittals, and has determined that additional information is required to complete its review. The specific information requested is addressed in the enclosed Request for Additional Information (RAI). The RAI was discussed with your staff on December 20, 2010, and they agreed to respond by January 31, 2011. Please note that if you do not respond to this letter by the agreed-upon date or provide an acceptable alternate date in writing, we may reject your request for approval under the provisions of Title 10 of the Code of Federal Regulations, Section 2.108. The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.
If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1115.
Sincerely, IRA! Nicholas J. DiFrancesco, Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454 and STN 50-455
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDorlLpl3-2 Resource RidsRgn3MailCenter Resource LPL3-2 rtf RidsNrrLATHarris Resource RidsAcrsAcnw_MailCTR Resource RidsNrrPMByron Resource RidsNrrDorlDpr Resource RidsOgcRp Resource ADAMS Accession No ML103620559 NRR-088 OFFICE LPL3-2/PM LPL3-21LA LPL3-2/BC LPL3-2/PM NAME NDiFrancesco THarris RCarlson(MMahoney for) NDiFrancesco DATE 12/28/10 12/28/10 1228/10 12/28/10 OFFICIAL RECORD COpy