ML20054L480

Informs That Design Re Adequacy of Station Electric Distribution Sys Voltages Is Acceptable

ML20054L480
Person / Time
Site:	Beaver Valley
Issue date:	06/21/1982
From:	Varga S Office of Nuclear Reactor Regulation
To:	Carey J DUQUESNE LIGHT CO.
Shared Package
ML20054L481	List: ML20054L480
References
TAC-13110, NUDOCS 8207080161
Download: ML20054L480 (9)

Text

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e DISTRIBUTION Docket

.JUN 21 1982 NRC PDR L PDR NSIC ORR#1 Rdg Docket No. 50-334 DEisenhut 0 ELD IE ACRS-10 Pr. J. J. Carey, Vice President CParrish Duquesne Light Company PTam Nuclear Division RDudley Post Office Box 4 Gray Shippingport, Pennsylvania 15077

SUBJECT:

ADEQUACY OF STATION ELECTRIC DISTRIBilTION SYSTEM VOLTAGES Duquesne Light (DL) was requested by NRC letter dated August 8,1979 to review the subject natter. The review was to consist of:

a) Determining analytically the capacity and capability of the offitte power system and onsite distribution system to automatically start, as well as operate, all required loads within their required voltage ratings in the event of 1) an anticipated transient, or 2) an accident (such as LOCA) without manual shedding of any electric loads.

b)

Determining if there are any events or conditions which could result in the simultaneous or, consequential loss of both required circuits from the offsite network to the onsite electric distribution systen and thus violating the requirements of GDC 17.

DL responded by letters dated October 15, 1979, February 27,1980, June 17, 1000, July 24,1980 December 15,1981, f! arch 11,1982 and May 3,1982.

Ve have requested our contractor, EG8G, to review these submittals.

We concur with the EG&G findings that:

1/ DL has provided verified voltage analysis to demonstrate that after the proposed nodifications are accomplished, Class IE equiment voltages will remain within acceptable operating limits for the worst case analyzed conditions.

2.

The tests used to verify the analysis was valid and showed the analysis to be accurate.

3 DL's reaffirmation of compliance with GDC 17 requirements is acceptable.

8207080161 820621 hDRADOCK 05000334 PDR OFFICE)

SURNAME) onE>

OFFICIAL RECORD COPY useo: an-mm nac ronu sta tio-aoi nacu o24o

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t'r. J. J. Carey We therefore find tha Beaver Valley Power Station, Unit 1 design acceptable with respect to the adequacy of station electric distribution system vol tages.

Sincerely, Original signed by:

S. A. Varga Steven A. Varga, Chief Operating Reactors Branch #1 Division of Licensing

Enclosures:

1.

Safety Evaluation Report l

2 Technical Evaluation Report cc w/ enclosures:

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OFFIClAL RECORD COPY usceo:i

-m. eo NRC FORM 318 (10-80) NRCM 0240

Mr. J. J. Carey Duquesne Light Company cc:

Mr. H. P. Williams Mr. J. D. Sieber, Manager Nuclear Safety and Licensing Station Superintendent Duquesne Light Company Duquesne Light Company Beaver Valley Power Station Nuclear Division Post Office Box 4 Post Office Box 4 Shippingport, Pennsylvania 15077 Shippingport, Pennsylvania 15077 Mr. T. D. Jones, Manager Resident Inspector U. S. Nuclear Regulatory Commission Nuclear Operations Post Office Box 298 Duquesne Light Company Shippingport, Pennsylvania 15077 Post Office Box 4 Shippingport, Pennsylvania 15077 Ronald C. Haynes Regional Administrator - Region I B. F. Jones Memorial Library U. S. Nuclear Regulatory Commission 663 Franklin Avenue Aliauippa, Dennsylvania 15001 631 Park Avenue King of Prussia, Pennsylvania 19406 Gerald Charnoff, Esauire Jay E. Silberg, Esquire Shaw, Dittman, Potts and Trowbridge 1800 M Street, N.W.

Washington, D.C.

20036 Karin Carter, Esquire Special Assistant Attorney General Bureau of Administrative Enforcenent 5th Floor, Executive House Harrisburg, Pennsylvania 17120 Marvin Fein Utility Counsel City of Pittsburah 313 City-County Building Pittsburgh, Pennsylvania 15219 Mr. John A. Levin Public Utility Commission P.O. Box 3265 Harrisburg, Pennsylvania 17120 Irwin A. Dopowsky, Esquire Office of Consuner Advocate 1425 Strawberry Square Harrisburg, Pennsylvania 17120 Charles A. Thomas, Esquire Thomas and Thomas 212 Locust Street Box 999 l ' '

Harrisburg, Pennsylvania

ENCLOSURE 1 SAFETY EVALUATION BEAVER VALLEY PCWER STATION UNIT 1 DOCKET NO. 50-334 ADECUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES INTROCUCTION AND SUS' MARY Duquesne Light (OL) was requested by NRC letter dated August 8,1979 to review the electric power system at Beaver Valley Power Station Unit 1.

The review was to consist of:

a) Determining analytically the capacity and capability of the offsite power system and onsite distribution system to automatically start as well as operate all required loads within their required voltage ratings in the event of 1) an anticipated transient, or 2) an accident (such as LOCA) without manual shedding of any electric loads, b)

Determining if there are any events or conditions which could result in the sir.ultaneous or, consequential loss of both required circuits from the offsite network to the onsite electric distribution system and thus violating the requirements of GDC 17.

The August 8,1979 letter included staff guidelines for performing the required voltage analysis and the licensee was further required to perform a test in Order to verify the valicity of the analytical results.

DL responded by letters dated October 15, 1979, February 27, 1980, June 17, 1980, July 24, 19EC, Cecember 15, 1981, March 11, 1982 and May 3, 1982. A I

' detailed review and technical evaluation of the submittals was performed by EG&G under contract to the NRC, with general supervision by NRC staff.

This work is reported by EG&G in Technical Evaluation Report (TER),

" Adequacy of Station Electric Distribution Systems Voltages, Beaver Valley Power Station Unit No. 1," dated May, 1982 (attached). We have reviewed this report and concur in the conclusions that the offsite power system and the onsite distribution system are capable of providing acceptable voltages for worst case station electric load and grid voltages.

EVALUATION CRITERIA The criteria used by EG&G in this technical evaluation of the analysis includes GDC 5 (" Sharing of Structures, Systems, and Components"), GDC 13

(" Instrumentation and Control"), GDC 17 (" Electric Power Systems") of Appendix A to 10 CFR 50; IEEE Standard 308-1974 (" Class lE Power Systems for Nuclear Power Generating Stations"), ANSI C84.1-1977 (" Voltage Ratings for Electric Power Systems and Equipment - 60 Hz"), and the staff positions and guidelines in NRC letter to DL dated August 8,1979.

ANALYSIS AND TEST FEATURES Duquesne Light (DL) has determined by load flow studies that the maximum 138 kv switchyard voltage is 143.4 kv and the minimum is 133.7 kv.

DL analyzed each offsite power source to the onsite distribution system under extremes of load and offsite voltage conditions to determine the bus voltages available to the Class lE equipment. The worst case Class IE equipment terminal voltages occur under the following conditions:

. (1) The maximum analyzed equipment terminal voltages occur when the grid is at maximum expected value (143.4 kv), each system auxiliary transformer is supplying power to its Class 1E bus, and no unit loads exist.

(2) The minimum analyzed continuous equipment terminal voltages occur when the grid is at its minimum expected value (133.7 kv) and each system auxiliary transformer is supplying all connected auxiliary and Class lE loads.

(3) The minimum analyzed transient equipment terminal voltages occur under the same conditions of 2 above, concurrent with the start of a 6000 hp reactor coolant pump. The voltage will recover fully within the 30 second deadtime of the automatic load trip changer on station service transformers.

The voltage analysis was verified by measuring the grid and bus voltages, actual loading on the buses, and selected equipment while the unit was being restored from a plant shutdown. A computer analysis was then run using the grid voltage for this plant loading. A comparison of the measured and analyzed voltages showed a difference between the two voltage values of less than 0.66% for any Class lE bus during steady l

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state and transient conditions. This close correlation verifies the i

l' accuracy of the analysis submitted.

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CESIGN CHANGES AND DISCUSSION j

The voltage analysis submitted by DL is based on the following design J

changes.

1 1

i (1)

Installation of new station service transformers with automatic tap changers.

1 480/240/120V transformers to provide 2 1/2%

(2) Changing of taps on voltage boost.

(3)

Installation of new self regulating transformers as backup power supply to vital buses.

Installation of the new station service transformers with automatic load changer will maintain the output voltage of each transformer to the tap 4160 volt Class lE buses at 4360 (1 52) volts during all analyzed conditions.

1 of these transformer and comple:icn of modifications (2) and Installation (3) above will insure that acceptable operating voltages are provided to all Class lE equipment during the worst case analyzed conditions.

CC.;CLUSICNS We have reviewed the EG&G technical evaluation report and concur in the findings that:

DL has provided verified voltage analysis to demonstrate that after 1.

the proposed modifications are accompit-ad Class lE equipment I

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voltages will remain within acceptable operating limits for the worst case analyzed conditions [

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2.

The tests used to verify the analysis was valid and showed the analysis to be accurate.

3.

DL's reaffirmation of compliance with GDC 17 requirements is 1

acceptable.

We therefore find the Beaver Valley Power Station, Unit I design acceptable with respect to the adequacy of station electric distribution system voltages.

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