ML20136J082

Forwards Revised PSC of Nh,Seabrook Station Voltage Regulation Study. Changes Include Considered Effects of Generator step-up Transformer Impedance & New 480-volt Unit Substations

ML20136J082
Person / Time
Site:	Seabrook
Issue date:	11/21/1985
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	Knighton G Office of Nuclear Reactor Regulation
Shared Package
ML20136J086	List: ML20136J082 ML20136J101
References
SBN-899, NUDOCS 8511250276
Download: ML20136J082 (4)

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SEABROOK STATION Engineering Office Pub 5c Service of New Hampshko November 21, 1985 Now Hampshire Yankee Division SBN- 899 T.F. B7.1.2 United States Nuclear Regulatory Commission Washington, DC 20555 Attention: Mr. George W. Knighton, Chief Ilcensing Branch No. 3 Division of Licensing

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) PSNH Letter, SBN-289, dated July 2,1982, "FSAR Section 8, Open Item List - Power Systems Branch (Electrical),"

J. DeVincentis to F. J. Miraglia

Subject:

Seabrook Station Voltage Regulation Study

Dear Sir:

In PSNH Letter SBN-289, Reference (b), as a response to RAIs 430.5 and 430.14, we provided the Seabrook Station Voltage Regulation Study. This study provides the voltage analysis required by Position 3 of Branch Technical Position (BTP) PSB-1. ,

The Seabrook Station Voltage Regulation Study has recently been revised in preparation of the planned study verification testing as required by Position 4 of BTP PSB-1. This revision was required to ensure that the study model represents the actual system as accurately as possible. This is necessary to provide optimum correlation between the study and test results.

This revision incorporates a number of changes to reflect the present system design and actual equipment data where applicable. A summary of the major changes incorporated into this revision are as follows:

a. Considered effects of generator step-up transformer impedance.

b. Included actual as-tested transformer impedance data.

c. Included new 480 V unit substations.

d. Revised system model for the 13.8kV and 4.16kV nonsegregated phase bus duct.

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i P.O. Box 300 Seabrook. NH 03874 . Tetophone (603) 474-9521 i

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-United States Nuclear Regulatory Commission

, ~ Attention: Mr. George W. Knighton. Page 2

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e; . Revised. transformer tap settings for optimum voltages.

-f. Included additional system model diagrams.

g. Included all' 4.16kV and 480 V Class 1E buses and 460 V motor control centers.

h. Revised loading assumptions based on Unit Substation Load Study.

Attachment A to this letter is the above mentioned revised Seabrook Station Voltage Regulation Study. This study is being forwarded as a revised response to Position 3 of BTP PSB-1.

Although the voltages in the revised. study differ slightly from the original submittal, the overall conclusions remain the same. Furthermore, we Llike to point out=that as a result of.the revised study, we can now resolve two of the confirmatory items appearing in Section 8.3.1.1.3 of the Seabrook

-SER. :These items are' analyzed below:

Item (3) - A maximum overvoltage condition of 2.9% was identified in our

%- original study submittal. The revised study shows the maximum overvoltage condition to .be 0.8%. While this overvoltage' condition is

. considered to be insignificant, a nominal motor feeder voltage drop of 1.0% should ensure that no overvoltage condition exists at the motor-terminals. We believe that. based on the above data, there should no longer be a need to confirm that there'will in fact be no over voltages-at motor terminals.

Item (4).- In the original study submittal, we identified a level indicator converter which could be subjected to voltages above its design voltage. This particular converter is no longer utilized or supplied power via the nonregulated Class'lE 120 V.ac power distribution panels.

In preparing the revised study, a review was performed to identify any other typical Class lE instrumentation devices which are supplied power from.the nonregulated Class lE 120 V ac System. As a result, another model'1evel indicator converter was identified with a nominal operating-voltage range of 115 + 8% (105.8 to 124.2 V ac). We have received confirmation from the manufacturer ( Attachment B) that a supply voltage up to 130 V ac is acceptable for this instrument. This then resolves the pending confirmation of vendor design certification stated in the SER.

The Seabrook Project would very much appreciate any effort on your staff's part to include the resolution of these confirmatory issues in the next supplement to the Seabrook Station's SER.

Very truly yours, A af A ohn DeVincentis, Director Engineering'and Licensing Attachments-cc: Atomic Safety and Licensing Board Service List t

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William S. Jordan, III Donald E. Chick Diane Curran Town Manager

. Ha rmon, Weiss & Jordan Town of Exeter 20001 S. Street, N.W. 10 Front Street Suite 430 Exeter, NH 03833 Washington, D.C. 20009 Brentwood Board of Selectmen Robert G. Perlis RED Dalton Road Office of the Executive Legal Director Brentwood, NH 03833 U.S. Nuclear Regulatory Commission Washington, DC 20555 Richard E. Sullivan, Mayor City Hall Robert A. Backus, Esquire Newburyport , MA 01950 116 Lowell Street P.O. Box 516 Calvin A. Canney Manc hester, NH 03105 City Manager City Hall Philip Ahrens, Esquire 126 Daniel Street Assistant Attorney General Portsmouth, NH 03801 Augusta, ME 04333 Dana Bisbee, Esquire Mr. John B. Tanzer Assistant Attorney General Designated Representative of Office of the Attorney General the Town of Hampton 208 State House Annex 5 Morningside Drive Concord, NH 02301 Hampton, NH 03842 Anne Verge, Chairperson Roberta C. Pevear Board of Selectmen Designated Representative of Town Hall the Town of Hampton Falls South Hampton, NH 03827 Drinkwater Road Hampton Falls, NH 03844 Patrick J. McKeon Selectmen's Office Mrs. Sandra Gavutis 10 Central Road Designated Representative of Rye, NH 03870 the Town of Kensington RFD 1 Carole F. Kagan, Esquire East Kingston, NH 03827 Atomic Safety and Licensing Board Panel U.S. Nuclear Regulatory Commission Jo Ann Shotwell, Esquire Washington, DC 20555 Assistant Attorney General l

Environmental Protection Bureau Mr. Angi Machiros l Department of the Attorney General Chairman of the Board of Selectmen One Ashburton Place, 19th Floor Town of Newbury l

Boston, MA 02108 Newbury, MA 01950 Senator Gordon J. Humphrey Town Manager's Office U.S. Senate Town Hall - Friend Street l Washington, DC 20510 Amesbury, MA 01913 I (ATTN: Tom Burack)

Senator Gordon J. Humphrey Diana P. Randall 1 Pillsbury Street 70 Collins Street Concord, NH 03301 Seabrook, NH 03874 (ATTN: Herb Boynton)

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ATTACIBENT A f

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