ML20214G473

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Responds to RO Bulletin 74-09, Deficiency in GE Model 4 Kv Magne-Blast Circuit Breakers. Breakers on HPCS Diesel Generator Sys Have Different Type of Tripping Bar.Ge Applied Better Torquing Stds & Insp to Current Breakers
ML20214G473
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 11/07/1974
From: Stein J
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20214G467 List:
References
CON-WNP-0050, CON-WNP-50 GO2-74-54, IEB-74-09, IEB-74-9, NUDOCS 8605220184
Download: ML20214G473 (2)


Text

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@ Washington Public Power Supply System A JOINT OPERATING AGENCY P. o. nox ,a mi riptw ave. nicsta n o.wassin cro s ,,352 T ELE PsON E (509194 9M1 November 7, 1974 G02-74-54 9 10 D

Mr. R. H. Engelken, Director (h Directorate of Regulatory Operations ~

H01 ytggl4 U. S. Atomic Energy Commission j _

Region V S,tGOM V m

1990 N. California Blvd. 6 DgCF S Walnut Creek Plaza Suite 202 0? DAW <' -

Walnut Creek, California 94596 @ g

Subject:

W. O. 2808 WPPSS NUCLEAR PROJECT N0. 2 DR0 BULLETIN N0. 74-9

" DEFICIENCY IN THE GENERAL ELECTRIC MODEL 4KV MAGNE-BLAST CIRCUIT BREAKERS"

Reference:

1) DRO Bulletin No. 74-9 Deficiency in the G.E. Model 4KV Magne-Blast Circuit Breakers (Forwarding Letter: Docket No. 50-397, R. H. Engelken, AEC, to J. J. Stein, WPPSS, dated August 6,1974)
2) Letter, J. J. Stein, WPPSS, to R. H. Engelken, AEC, G02-74-40, dated September 23, 1974, same subject

Dear Sir:

Reference 1) transmitted the original DRO Bulletin.

Reference 2) extends the response date from September 30,1974 to November 7, 1974.

The referenced bulletin is directed to General Electric 4KV circuit breakers (called Type "AMH-4.76-250" in Reference-1), used in Type AMH-4.76 switchgear (called "MC 4.76" in Reference-1). General Electric has reported that this model breaker contains a roller trip bar which can cause false tripping and is characteristic of the discontinued horizontal drawout breaker used at Calvert.

The 4KV breakers used on the subject contract in the HPCS Diesel Generator System, are a new type of vertical lift breaker (Type AM 4.16 used in Type M26 switchgear) that have a different type of tripping bar.

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. Mr. R. H. Engelken, Di  : tor Not ber 7, 1974 Page 2 Regarding loose mounting bolts of the Auxiliary Switch Assenblies, General Electric has applied better torquing standards and rigid inspection to current manufactured breakers. While G.E. will use the M26 Switchgear, they do not plan to use the Stationary Auxiliary Contacts in essential circuits, since other auxiliary contacts are available for use.

Very truly yours.

. QT_

J.1J. ITEIN Managing Director JJS:GLC:bf cc: PC Otness - BPA

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