ML070460285

Request for Additional Information Regarding Alternate Source Term Application

ML070460285
Person / Time
Site:	Hatch
Issue date:	02/22/2007
From:	Martin R NRC/NRR/ADRO/DORL/LPLII-1
To:	Madison D Southern Nuclear Operating Co
Martin R, NRR/DORL, 415-1493
References
TAC MD2934, TAC MD2935
Download: ML070460285 (4)

Text

February 22, 2007 Mr. Dennis R. Madison Vice President - Hatch Edwin I. Hatch Nuclear Plant 11028 Hatch Parkway North Baxley, GA 31513

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 (HNP) - REQUEST FOR ADDITIONAL INFORMATION REGARDING ALTERNATE SOURCE TERM APPLICATION (TAC NOS. MD2934 AND MD2935)

Dear Mr. Madison:

By letter to the Nuclear Regulatory Commission (NRC) dated August 29, 2006 (the submittal),

Southern Nuclear Operating Company, Inc. (SNC), proposed to revise the Edwin I. Hatch Nuclear Plant, Units 1 and 2 (HNP), licensing and design basis with a full scope implementation of an alternative source term (AST). The AST analysis credited the Unit 1 and Unit 2 turbine building (TB) ventilation exhaust systems with purging the area around the main control room beginning 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> following design basis accidents (DBAs). Section 2.7.3 of Enclosure 1 to the submittal indicates that the TB ventilation system has not previously been designed or constructed as an engineered safety feature (ESF) system.

Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, (RG 1.183), states that credit may be taken for accident mitigation features that are classified as safety-related, are required to be operable by the TSs, are powered by emergency power sources, and are either automatically actuated or, in limited cases, have actuation requirements explicitly addressed in emergency operating procedures.

The TB exhaust ventilation system is not an ESF system, but the submittal proposes to assign it an accident mitigation role. In considering a loss-of-coolant accident (LOCA) concurrent with a loss of offsite power (LOOP), the submittal proposes, in lieu of an emergency power source for the TB exhaust ventilation system, to rely upon the ability to take manual actions to restore offsite power in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Based on the information currently available, the NRC staff does not find that the ability to restore offsite power in this time frame has been adequately established, nor has it been demonstrated to be equivalent to being able to operate the system from the emergency power supply, and, therefore, does not provide reasonable assurance that when the TB exhaust ventilation system is required, power will be available to operate the system.

D. Madison Please provide additional information to justify reliance on the ability to restore offsite power under all conditions and potential causes in the midst of a LOCA or other referenced DBA events or provide information as to how this system can be powered from an emergency power source.

We discussed this issue with your staff on February 22, 2007. Your staff indicated that it plans to submit a response to this issue within sixty (60) days of receipt of this letter.

Sincerely,

/RA/

Robert E. Martin, Senior Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366 cc: See next page

- ML070460285 OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/EEEB/BC NRR/SCVB/BC NRR/AADB/BC NRR/LPL2-1/BC NAME RMartin MOBrien IJung RDennig MKotzalas EMarinos DATE 02/22/07 02/22/07 01/11/07 01/10/07 01/10/07 02/22/07

Edwin I. Hatch Nuclear Plant, Units 1 & 2 cc:

Laurence Bergen Oglethorpe Power Corporation 2100 E. Exchange Place P.O. Box 1349 Tucker, GA 30085-1349 Mr. R. D. Baker Manager - Licensing Southern Nuclear Operating Company, Inc.

P.O. Box 1295 Birmingham, AL 35201-1295 Resident Inspector Plant Hatch 11030 Hatch Parkway N.

Baxley, GA 31531 Harold Reheis, Director Department of Natural Resources 205 Butler Street, SE., Suite 1252 Atlanta, GA 30334 Steven M. Jackson Senior Engineer - Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, GA 30328-4684 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission 244 Washington St., SW Atlanta, GA 30334 Arthur H. Domby, Esq.

Troutman Sanders Nations Bank Plaza 600 Peachtree St, NE, Suite 5200 Atlanta, GA 30308-2216 Chairman Appling County Commissioners County Courthouse Baxley, GA 31513 Mr. Jeffrey T. Gasser Executive Vice President Southern Nuclear Operating Company, Inc.

P.O. Box 1295 Birmingham, AL 35201-1295 General Manager Edwin I. Hatch Nuclear Plant Southern Nuclear Operating Company, Inc.

U.S. Highway 1 North P.O. Box 2010 Baxley, GA 31515 Mr. K. Rosanski Resident Manager Oglethorpe Power Corporation Edwin I. Hatch Nuclear Plant P.O. Box 2010 Baxley, GA 31515