ML20009H091

Advises That Proposed Mods to Mitigate Effects of Grid Voltage Degradation on safety-related Electrical Equipment Are Unacceptable.Design Must Be Modified or Appropriate Justifying Documentation Presented within 60 Days

ML20009H091
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	07/23/1981
From:	Ippolito T Office of Nuclear Reactor Regulation
To:	Rich Smith VERMONT YANKEE NUCLEAR POWER CORP.
References
NUDOCS 8108060001
Download: ML20009H091 (3)

Text

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Distribution:

• (. Docket. File A. Saeed NRC PDR' M. Srinivasan 1'

Local'PDR Docket No. 50-271 ORB #2 F Jg.

9 JUL 2 3 W8I D. Eisennut T. Ippolito o

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Mr. Robert L. Smith V. Rooney 2/

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i Licensing Engineer OELD Vermont Yankee Nuclear Power I&E (3)

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Corporation NSIC 1671 Worcester Road TERA Qp 4

Framingham, Massachusetts 01701 ACRS(10) 4 gy/

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Dear Mr. Smith:

By letter dated February 6,1981 you proposed modifications to mitigate the effects of grid voltage degradation on safety related electrical equipment.

We have reviewed your design and discusse certain aspects of it with you j

by telephone.on Juni 16, 1981.

We understand that the degraded grid voltage protection design activates an alarm ehen the voltage is degraded below the sepoint of the relay.

1 Disconrwetion of the offsite source will occc when low voltage exists for a certain period of time and an accident signal is also present.

For non-accident conditions, the design in present form will expose permanently connected Class 1E equipment to low voltage conditions indefinitely. We conclude the design is unacceptable unless.iocumentation (manufacturer's i

guarantees, etc.) be provided to assure that the permanently connected Class lE equipment would not be damaged if exposed to low voltage conditions for an indefinite period of time. Another alternative can be to disconnect offsite source automatically once it is determined that undervoltage persists for a predetermined time.

Please modify ycur design or provide appnipriathydocumentation within 60 days of receipt of this letter.

Sincerely, ORIGINAL SIGNED BY Thomas A. Ippolito, Chief Oper: ting Reactors Branch #2 Division of Licensing cc: See next page i

8108060001 810723 PDR ADOCK 05000271 lP PDR i omcc)

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Mr. Robert L. Smith 4

cc:

'Mr. W. F. Conway John R. Stanton, Director I

president. & Chief Operating-Officer Radiation Control Agency a

Vermont Yankee Nuclear Power Corp.

Hazen Drive 411 Western Avenue Concord, New Hampshire 03301 Drawer 2 West Brattleboro, Vermont 05301 John W. Stevens Conservation Society of Southern Vermont i

Mr. Louis-H. Heider, V.P.

P. O. Box 255 Yemont Yankee Nuclear Power

. Townshend, Vemont 05353 Corocration Raymond N. M: Candles's 25 Research Drive Radiation Control Pro ram 0ccupational & Radiolfgical Hlth WestH,, Massachusetts 01581 Administration Building i

Jonn.. Ritscher, Escu1re Montpelier, Vernont 05502 1

Ropes & Gray 226 Franklin Street New England Coalition on Nuclear ~

i Boston, Ma,ssachusetts 02110 Pollution Hill and Dale Fam i

Laurie Burt West Hill - Faraway Road j

Assistant Attorney General Putney, Vemont 05345 Environmental Protection Division 1

Attorney General's Office.

Public Service Board i

One Ashburton Place,19th Floor State of Vermont Boston, Massachusetts 02108 120 State Street Montpelier, Yemont 05502 i

Ronald J. Wilson j

81018th' Street, N. W.

W. P. Murohy, Plant Superintendent Suite 802 Vermont Yankee Nuclear Power Washington, D. C.

20006 Corporation P. O. Box 157 Honorable M. Jerome Diamond Vernon, Yement 05354 i

Attorney General State of Vemont David khite d

109 State Street Co-Director Pavilion Office Building Vemont'Public Interest Montpelier, Vemont 05502 Reserach Group, Inc.

43 State Street Vermont Yankee Decomissioning

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Montpelier, Yemont 05602 Alliance 127 Main Street Vemont Yankee Decomissioning Brattleboro, Vermont 05301 Alliance 5 State Street Mr. E. W. Jackson Box 1117 Manager of Operations Montpelier, Vermont 05602 Vermont Yankee Nuclear Po,wer Corp.

411 Western Avenue Brooks Memorial Library Drawer 2 224 Main Street RaR TArmRRicdrem Vermont 05301 Brattleboron Vem;ot 05301

-, ' Robert L. Smith cc:

Resident Inspector c/o U. S. NRC

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P. O. Box 176 Vernon, Yemont 05453 t

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