ML20087N354

Interim Deficiency Rept Re Inadvertent Closure of Brown Boveri 5-kV Circuit Breakers.Initially Reported on 840210. Close Latch Antishock Springs Added to Unit 1 Breakers,Per Vendor Recommendation.Unit 2 Breakers Mfg After 1977

ML20087N354
Person / Time
Site:	Seabrook
Issue date:	03/09/1984
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
SBN-633, NUDOCS 8404030365
Download: ML20087N354 (3)

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IPUEBLIC SERVICE Companyof New Humpehu o 1671 Worcester Road Frominoham, Massachusetts 01701 (617) 872 - 8100 March 9,1984 SBN 633 T.F. Q2.2.2 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Mr. Richard W. Starostocki, Director Division of Project and Resident Programs

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) Telecon of February 16, 1984, A. L. Legendre (YAEC) to William Borchardt (NRC, Region I)

Subject:

Interim 10CFR50.55(e) Report; Inadvertent Closure of Brown Boveri 5 kV Circuit Breakers

Dear Sir:

On February 10, 1984, a potentially reportable 10CFR50.55(e) item was reported [ Reference (b)] regarding inadvertent closure of Brown Boveri 5 kV circuit breakers. -We have reviewed this problem further and conclude that it is reportable as a 10CFR50.55(e) deficiency. The following is our interim report concerning this subject.

Description of Deficiency During preoperational testing at the Limerick Generating Station, a Brown Boveri 5 kV circuit breaker inadvertently closed on its own following completion of spring charging. The springs are recharged after each breaker trip to provide stored energy for a complete close/ trip cycle. Brown Boveri's evaluation of the problem determined that the close latch slipped because of the shock from release of the springs at the end of the spring closing cycle.

Brown Boveri determined that the problem could occur in breakers manufactured before October 1973 and between June 1975 and June 1977. Unit 1 breakers were manufactured in this time period and therefore, could be susceptible to the problem. Unit 2 breakers were manufactured after June 1977 and therefore, are not susceptible to the problem.

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PDR ADOCK 05000443 S PDR p l{ O

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United States Nucieer Regulatory Commission March 9, 1984 Attention: Mr. Richard W. Starostecki, Director Page 2 Safety Implication The postulated inadvertent closure of a 5 kV breaker could create undesirable emergency diesel generator loading if the diesels were supplying the emergency buses, .Also, inadvertent closure of the diesel generator breaker to the emergency bus could cause diesel generator damage.

Corrective Action t

Brown Boveri recommends that a close latch anti-shock spring be added to the breakers to eliminate the possibility of inadvertent closure. These springs are presently being added to the Unit 1 breakers with completion anticipated by the end of April. The Unit 2 breakers require no corrective action since they were manufactured after June 1977, and had the closing latch anti-shock spring installed by the manufacturer.

This letter is being filed pursuant to the interim reporting provisions of 10CFR50.55(e)(3).

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY

/ ~ 1 John DeVincentis l- Project Manager cc: Atomic Safety and Licensing Board Service List Director, Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 r

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William S. Jordan, III, Esquire Brentwood Board of Selectmen Harmon & Weiss RED Dalton Road 1725 I Street, N.W. Suite 506 Brentwood, New Hampshire 03833 Washington, DC 20006 Roy P. Lessy, Jr., Esquire Office of'the Executive Legal Director Edward F. Meany U.S. Nuclear Regulatory Commission Designated Representative of

Washington, DC 20555 the Town of Rye 155 Washington Road Robert A. Backus. Esquire Rye, NH 03870 116 Lowell Street P.O. Box.516 +

Calvin A. Canney Mancehster, NH 03105 City Manager City Hall Philip Ahrens, Esquire 126 Danial Street Assistant Attorney General Portsmouth, NH 03801 Department of the Attorney General Augusta, ME 04333 Dana Bisbee, Esquire Assistant Attorney General Mr. John B. Tanzer Office of the Attorney General Designated Representative of 208 State House Annex the Town of Hampton Concord, NH 03301 5 Morningside Drive Hampton, NH 03842 Anne Verge, Chairperson Board of Selectmen Roberta C. Pevear Town Hall Designated Representative of South Hampton, NH 03642 the Town of Hampton Falls Drinkwater Road Patrick J. McKeon

.Hampton Falls, NH 03844- Selectmen's Office 10 Central Road Mrs. Sandra Gavutis- Rye, NH 03670 Designated Representative-of the Town of Kensington Carole F. Kagan, Esq.

RFD 1 Atomic Safety and Licensing Board Panel East Kingston, NH 03827 U.S. Nuclear Regulatory Commission

-Jo Ann Shotwell, Esquire Assistant Attorney General Mr. Angie Machiros Environmental Protection Bureau Chairman of the Board of Selectmen Department of the Attorney General Town of Newbury One Ashberton Place, 19th Floor Newbury, MA 01950 Boston, MA 02108 Town Manager's Office Senator Gordon J. Humphrey Town Hall - Friend Street U.S. Senate Amesbury, Ma. 01913 Washington, DC 20510

.(Attn: Tom Burack) Senator Gordon J. Humphrey 1 Pillsbury Street Diana P. Randall Concord, NH 03301 70 Collins Street (Attn: Herb Boynton)

SEabrook, NH 03874 Richard E. Sullivan, Mayor Donald E. Chick City Hall Town Manager Newburyport, MA 01950 Town of Exeter

-10 Front Street.

Exeter, NH 03833

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