ML102310509

Request for Additional Information Related to Exelon Generation Company'S Request to Incorporate Revised Pressure/Temperature Curves

ML102310509
Person / Time
Site:	LaSalle
Issue date:	08/20/2010
From:	Gratton C Plant Licensing Branch III
To:	Pacilio M Exelon Generation Co, Exelon Nuclear
Gratton C, NRR/DORL/LPL3-2, 415-1055
References
TAC ME3801, TAC ME3802
Download: ML102310509 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 20, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO EXELON GENERATION COMPANY'S REQUEST TO INCORPORATE REVISED PRESSUREITEMPERATURE CURVES (TAC NOS. ME3801 AND ME3802)

Dear Mr. Pacilio:

By letter to the Nuclear Regulatory Commission (NRC) dated April 19, 2010 (Agencywide Documents Access and Management System Accession No. ML101130370), Exelon Generation Company, LLC submitted a request to revise its Technical Specifications 3.4.11, "RCS [reactor coolant system] pressure and temperature (PIT) [or P-T] Limits," to incorporate the revised P-T curves that are valid for up to 32 effective full power years of operation, for the LaSalle County Station (LSCS), Units 1 and 2.

The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on August 19, 2010, it was agreed that a call to clarify the intent of information request was not needed and that you would provide a response 45 days from the date of this letter.

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) 415-1055.

Sincerely,

~Christopher Gratton, Sr. Project Manager Plant Licensing Branch '"-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374

Enclosure:

Request for Additional Information cc w/encl: Distribution via ListServ

REQUEST FOR ADDITIONAL INFORMATION LASALLE COUNTY STATION, UNITS 1 AND 2 EXELON GENERATION COMPANY, LLC DOCKET NOS. 50-373 AND 50-374 In reviewing the Exelon Generation Company's (Exelon's) submittal dated April 19, 2010 (Agencywide Documents Access and Management System Accession No. ML101130370), to revise its Technical Specifications 3.4.11, "RCS [reactor coolant system] pressure and temperature (PfT) [or P-T] Limits," to incorporate the revised P-T curves that are valid for up to 32 effective full power years of operation, for the LaSalle County Station (LSCS), Units 1 and 2, the Nuclear Regulatory Commission (NRC) staff has determined that the following infonnation is needed in order to complete its review:

Provide an evaluation for the small-diameter, possibly drill-hole type instrument nozzles (e.g., water level nozzles) which exist in the LSCS, Unit 1 reactor pressure vessel (RPV) beltline region, as indicated in Figure 4-1 of the GE-NE-0000-0003-5526-02R1 a report, "Pressure Temperature [P-T] Curves For Exelon LaSalle Unit 1," dated May 2004. The stress concentration factor associated with the drill-hole type nozzle in the beltline may make it more limiting than the limiting beltline material that was identified and used in the proposed P-T limits for LSCS, Unit 1.

The NRC staff has verified the proposed P-T limits for LSCS, Units 1 and 2, but found no mention of temperature and pressure instrument uncertainties in the submittals. Explain how temperature and pressure instrument uncertainties are addressed in the P-T limit application.

RAI-3

For LSCS, Units 1 and 2, the upper vessel P-T limits were derived from a generic P versus (T-RT NOT) (nil-ductility transition reference temperature) limits shown on Page 41 of the GE-NE-0000-003-5526-02R1a report, or on Page 40 of the GE-NE-0000-003-5526-01 R1a report, "Pressure-Temperature Curves for Exelon LaSalle Unit 2." Demonstrate that you can apply these generic P versus (T-RT NOT) limits to the LSCS, Units 1 and 2 feedwater nozzles, considering the difference between the plant-specific information, such as the units' nozzle and RPV dimensions, and the generic plant (or analysis) information.

The NRC staff's evaluation revealed that the proposed P-T limits for the bottom head and the upper vessel are based on the generic P versus (T-RT NOT) limits reported in Topical Report, Enclosure

-2 Pressure-Temperature Curves." To avoid unnecessary duplicate review on the very details of the P-T limit methodologies, please confirm that the methodologies for the RPV beltline, the bottom head, and the upper vessel curves in this application are identical to those in the approved NEDC-33178P report, so that this application can be considered as a plant-specific application of the NEDC-33178P report. Point out the deviations of the LSCS P-T limit methodology from the NEDC-33178P methodology.

August 20, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO EXELON GENERATION COMPANY'S REQUEST TO INCORPORATE REVISED PRESSUREfTEMPERATURE CURVES (TAC NOS. ME3801 AND ME3802)

Dear Mr. Pacilio:

By letter to the Nuclear Regulatory Commission (NRC) dated April 19, 2010 (Agencywide Documents Access and Management System Accession No. ML101130370), Exelon Generation Company, LLC submitted a request to revise its Technical Specifications 3.4.11, "RCS [reactor coolant system] pressure and temperature (PfT) [or P-TJ Limits," to incorporate the revised P-T curves that are valid for up to 32 effective full power years of operation, for the LaSalle County Station (LSCS), Units 1 and 2.

The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on August 19, 2010, it was agreed that a call to clarify the intent of information request was not needed and that you would provide a response 45 days from the date of this letter.

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) 415-1055.

Sincerely, IRA!

Christopher Gratton, Sr. Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374

Enclosure:

Request for Additional Information cc w/encl: Distribution via ListServ DISTRIBUTION:

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