ML13024A226

Request for Additional Information

ML13024A226
Person / Time
Site:	Vogtle
Issue date:	01/28/2013
From:	Martin R Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Martin R
References
TAC ME7105, TAC ME7106
Download: ML13024A226 (3)

Text

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• • 'Mt Chuck R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION, REVISION OF TECHNICAL SPECIFICATION 3.7.9 "ULTIMATE HEAT SINK," (TAC NOS. ME7105AND ME7106)

Dear Mr. Ajluni:

By letter dated September 1, 2011 (Agencywide Documents Access and Management System Accession No. ML112450171), Southern Nuclear Operating Company (SNC, the licensee),

submitted a license amendment request to change the Technical Specification (TS) for Vogtle Electric Generating Plant, Units 1 and 2. The amendment would revise the TS Limiting Condition for Operation for TS 3.7.9, "Ultimate Heat Sink" regarding Nuclear Service Cooling Water tower three and four fan operation. The U.S. Nuclear Regulatory Commission staff finds that additional information in the balance-of-plant area is needed as set forth in the enclosure.

These requests were discussed with your staff on January 24, 2013.

Please provide the additional information within thirty (30) days of the date of this letter.

Sincerely,

/""\

"~UJ/Il~

£/ Robert E. Martin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425

Enclosure:

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

REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 (VEGP)

SOUTHERN NUCLEAR OPERATING COMPANY (SNC)

Upon reviewing Southern Nuclear Operating Company's (SNC's) December 18, 2012 letter providing responses to several of the staff's requests for additional information in the letter dated January 11, 2012, the following issues need to be addressed:

1. Calculation X4C1202V70, Version 3, uses 97 degrees Fahrenheit (OF) as the design basis temperature for the cooling tower basins. The Updated Final Safety Analysis Report (UFSAR) states that 95°F is the maximum design temperature. Acknowledging the exception on Page 9.2-22 of the UFSAR where basin temperature remains above 95°F for periods of 20 or 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> conSidering only residual heat removal operation, calculation X4C1202V70 Version 3, allows basin temperature to exceed 95°F for up to 54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br />.

a. What are the effects of other loads cooled by nuclear service cooling water if 95°F is exceeded for such a long period of time?

b. Can the diesel generators operate satisfactorily with cooling water above 95°F for that many hours?

c. Does the diesel generator vendor support SNC's answer?

2. Calculation X4C1202V70, Version 3, does not consider the first 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after a loss of offsite power (LOSP). However, when a tornado occurs and causes a LOSP, the fan loss occurs immediately at which time the cooling towers have heat loads from diesel generators of about 17 million British thermal units per hour (M BTU/hr), containment cooling at about 10.5 M BTu/hr and spent fuel pool cooling at about 24 M BTU/hr.

Calculation X4C1202V70, Version 3, does not include the fan loss and heat loads from 0 to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Please explain why SNC did not account for the first 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after LOSP when computing values for the new Figure 3.7.9-1.

ML13024A226

• Via email OFFICE DORULPL2-1/PM ?ORULPL2-1/LA DLR/RERBIIBC* DORULPL2-1J'BC NAME RMartin SFi ueroa GCasto RPascarelii RMartin DATE 01/28/13 01/24/13 01/22/13 01/28/13 01/28/13