ML20133J604

Forwards RAI Re Alternate AC Power Source Requirements for Plant,Unit 3.Request Response within 45 Days

ML20133J604
Person / Time
Site:	Millstone
Issue date:	01/13/1997
From:	James Anderson NRC (Affiliation Not Assigned)
To:	Kenyon B NORTHEAST UTILITIES SERVICE CO.
References
TAC-M96054, NUDOCS 9701210073
Download: ML20133J604 (6)

Text

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'E-42^6 4 UNITED STATES l g ,j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2006&4001

\ .m. lt January 13, 1997 l

Mr. B. D. Kenyon President - Nuclear Group Northeast Utilities Service Company c/o Mr. Terry L. Harpster Director - Nuclear Licensing Services P.O. Box 128 Waterford, CT 06385

SUBJECT:

MILLSTONE UNIT 3 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO 3 ALTERNATE AC POWER SOURCE REQUIREMENTS (TAC NO. M96054)

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Dear Mr. Kenyon:

1 During a review of the Millstone Unit 3 station blackout (SB0) systems, the special inspection team (SIT) identified a concern with the design of the 4 alternative ac (AAC) power source, the SB0 diesel generator (SBO-DG), and its dedicated battery. The AAC power source may not be available if SB0 occurs due to a loss of onsite power (emergency diesel generators) after one hour of loss of offsite power (LOOP). The AAC power source at Millstone Unit 3, is 4

controlled and monitored by a computer. The AAC power system design includes two batteries (one 48-volt for the computer and the other 125-volt for DG field flashing, oil pump, and breaker control power). The battery chargers for these batteries are fed from offsite power when the AAC power is not ,

operating. If the LOOP occurs first, these batteries will be depleted due to '

connected loads (computer for 48-volt battery and oil pump for 125-volt  ;

battery). Northeast Nuclear Energy Company (NNECO) determined that if the loss of onsite power occurs after one hour of the LOOP event, the batteries will be drained sufficiently so that the SB0-DG cannot be started,

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l By letter dated March 30, 1990, NNEC0 stated that the AAC power source will meet the criteria specified in Appendix B to NUMARC 87-00. By letter dated '

! August 27, 1996, the NRC staff requested additional information on how Millstone Unit 3 meets the NUMARC 87-00, Appendix B criteria; specifically items B.8(e) and B.8(f). By letter dated October 18, 1996, NNECO agreed that the SB0-DG design and/or operation should be modified to ensure availability of the SB0-DG at any time during the postulated 8-hour LOOP, regardless of the j relative timing of emergency diesel generator failure / unavailability. NNEC0 stated that several options were under consideration to achieve this. NNECO committed to identify to the NRC staff by December 31, 1996, the specific design / operation modification required to be made to ensure the availability j of the SBO-DG at any time during a postulated 8-hour LOOP.

In a letter dated December 20, 1996, NNEC0 stated that it has completed its review of the options available to ensure the availability of the SB0-DG and 4

has determined that the best solution is to modify the design of the SB0

system. The modification may require operator actions within the first hour NRC HLE CMSCSM D0065 9701210073 970113 PDR ADOCK 05000423 P PDR r

l Mr. B. D. Kenyon i

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after a LOOP to power the SBO-DG auxiliaries from either the SB0-DG or from another diesel generator. The staff has several concerns about the proposed modification. Enclosed is a request for additional information. Please provide your response within 45 days from the receipt of this request.

Sincerely, Y

s . ndersen, Project Manager Special Projects Office - Licensing Office of Nuclear Reactor Regulation Docket No. 50-423

Enclosure:

As stated cc w/ encl: See next page i

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. Mr. B. D. Kenyon; January 14, 1997 after a LOOP to power the SB0-DG auxiliaries from either the SBO-DG or from another diesel generator. The staff has several concerns about the proposed modification. Enclosed is a request for additional information. Please provide your response within 45 days from the receipt of this request.

Sincerely, 4 Original signed by:

James W. Andersen, Project Manager Special Projects Office - Licensing Office of Nuclear Reactor Regulation Docket No. 50-423

Enclosure:

As stated cc w/ encl: See next page r

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- l RE0 VEST FOR ADDITIONAL INFORMATION 4

ALTERNATE AC POWER SOURCE REQUIREMENTS i

MILLSTONE UNIT 3 By letter dated December 20, 1996, Northeast Nuclear Energy Company (NNECO) i stated that it has completed its review of the options available to ensure the availability of the station blackout diesel generator (S30-DG) and has i determined that the best solution is to modify the design of the SB0 system.

! The modification may require operator actions within the first hour after a 1

loss of offsite power (LOOP) to power the SBO-DG auxiliaries from either the 1

SBO-DG or from another diesel generator. The staff has several concerns about j the proposed modification and NNECO's responses to the following requests are ,

j needed:

! l j 1. After a LOOP, how soon will the SB0-DG auxiliaries be powered from the I

! SBO-DG or ant,ther diesel generator? Also, which procedure will cover i j this requirememi.i

) 2. If the SBO-DG is used to power the auxiliaries:

j a. How long will the SB0-DG be running and at what load?

l j b. What are the consequences of running the SB0-DG at light load 4 conditions?  !

j c. What is the impact on the SBO-DG fuel supply in view of the fact

that the SBO-DG may be running for an additional 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />?

$ 3. If another diesel generator is used to power the auxiliaries:

a. Provide details of this diesel generator (capacity, connectability, availability, reliability, etc.)

b. Is this a new diesel generator?

c. Provide details on how it will be interfaced with existing switchgear and equipment.

4. Provide details regarding the testing and operator training requirements resulting from this modification.

Enclosure

1 .

! Northeast Utilities Service Company Millstone Nuclear Power Station Unit 3 cc:

Lillian M. Cuoco, Esq. Mr. M. R. Scully, Executive Director Senior Nuclear Counsel Connecticut Municipal Electric 2

Northeast Utilities Service Company Energy Cooperative P.O. Box 270 30 Stott Avenue i Hartford, CT 06141-0270 Norwich, CT 06360 l Mr. Kevin T. A. McCarthy, Director Mr. William D. Meinert Monitoring and Radiation Division Nuclear Engineer Department of Environmental Protection Massachusetts Municipal Wholesale 79 Elm Street Electric Company

{ Hartford, CT 06106-5127 P.O. Box 426 l Ludlow, MA 01056 i Mr. Allan Johanson, Assistant Director Office of Policy and Management Joseph R. Egan, Esq.

4 Policy Development and Planning Division Egan & Associates, P.C.

! 80 Washington Street 2300 N Street, NW j Hartford, CT 06106 Washington, D.C. 20037 i

Regional Administrator Mr. F. C. Rothen i Region I Vice President - Work Services U.S. Nuclear Regulatory Commission Northeast Utilities Service Company 475 Allendale Road P.O. Box 128 i King of Prussia, PA 19406 Waterford, CT 06385 First Selectmen Mr. Ernest C. Hadley, Esq, Town of Waterford 1040 B Main Street Hall of Records P.O. Box 549 200 Boston Post Road West Wareham, MA 02576 Waterford, CT 06385 Mr. John Buckingium Mr. Wayne D. Lanning Department of Public Utility Control Deputy Director for Inspections Electric Unit Millstone Nuclear Power Station 10 Liberty Square c/o U.S. Nuclear Regulatory Commission New Britain, CT 06051 P.O. Box 513 Niantic, CT 06357 Mr. James S. Robinson Manager, Nucler 'nvestments and M. H. Brothers, Nuclear Unit Director Administration Millstone Unit No. 3 New England Power Company Northeast Nuclear Energy Company 25 Research Drive P.O. Box 128 Westborough, MA 01582 Waterford, CT 06385 Mr. T. C. Feigenbaum Burlington Electric Department Executive Vice President c/o Robert E. Fletcher, Esq. and Chief Nuclear Officer 271 South Union Street Northeast Utilities Service Company Burlington, VT 05402 P.O. Box 128 Waterford, CT 06385

Northeast Utilities Service Company Millstone Nuclear Power Station ,

Unit 3 cc:

Mr. D. M. Goebel Vice President - Nuclear Oversight Northeast Utilities Service Company P.O. Box 128 Waterford, CT 06385 Mr. J. P. Cowan Millstone Unit No. 3 Nuclear Recovery Officer Northeast Utilities Service Company P.O. Box 128 Waterford, CT 06385 Mr. J. K. Thayer Recovery Officer, Nuclear Engineering and Support Northeast Utilities Service Company P.O. Box 128 Waterford, CT 06385 1

Deborah Katz, President '

Citizens Awareness Network P.O. Box 83 Shelburne Falls, MA 03170 1

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