ML20105C795

Final Deficiency Rept CP-92-015 Re GE Circuit Breaker Mounting Hardware Incorrectly Supplied & Installed.Initially Reported on 920623.Mounting Screws Will Be Replaced by 921018

ML20105C795
Person / Time
Site:	Comanche Peak
Issue date:	09/17/1992
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CP-92-015, CP-92-15, TXX-92419, NUDOCS 9209220450
Download: ML20105C795 (3)

Text

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i L.. ~= d L 2 Log # 'iXX-92419 C-C File # 10110 CP-92-015 7UB ECTRIC Ref. # 10CFR50.55(e)

September 17, 1992

(;<.y r,4, o, .b, U. S. Nuclear Reguletory Commission Attn: Document Control Ded Washington, DC 20555

SUBJECT:

COMAtlCHE PEAK STEAM ELECTRIC STAT 10t4 (CPSES) _

DOCKET N05. 50-445 AND 50-446 GENERAL ELECTRIC CIRCt,'T sprAKERS MOUNTING HARDWARE .c lilCORRECTLY SUPPL:io a ad5TALLED BY THE FACTORY SPAR: C P 015 ( F i fW. nt' PORT ) >:

Gentlemen:

On August 18, 1992, v. s facsimile, 10 Electric notified the NRC of a condition where the ventor (General Electric) supplied Class lE nuclear grade 200A circuit brealers with incorrectly sized mounting bolts. The 3 structural integrity of the circuit breaker mounting may have been inadequate during a seismic event. TV Electric has determined that thi deviation is reportable pursuant to 10CFR50.55(e). 6 Attached is a writtea report which satisfies the reporting requirementt of 10CFR50.55(e). The report has been formatted in a manner that corresponds to the specific information requested by subparts (i) through (viii) of pd rdgraph 10CrR50. 55( e )( 8 ) of the regulation. This is exclusive o,' that portion of subpart (viii) regarding advice that has been or will be given -

to other entitles outside TU Electric. Such advice would be dependent on the entitles' spect'ic use ara operating / maintenance history of the subject components.

Sincerely.

William J. Cahill. dr. ,

e ,. . IA_ 0 JW D. R. Woodlan Docket Licensing Manager JMK/RH5/tg Attachment c - Mr. J. L. Mllboan, Region IV Hr. B. E. Holian, NRR Resident inspectors. CPSES (2) s/

92o9220450 920917 ifdi PDR S

ADOCK 05000445 PDR 4co N. onve street . LB. 8 t Dauas. Tem 75201 v

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, Attachment to TXX 92419 Page 1 of 2 10CFR50,55(e) REPORTABLE CONDITION INVOLVING G.E CIRCUIT BREAKERS HOUNTING HARDWARE -

INCORRECTLY SUPPLIED AND INSTALLED

-BY THE FACTORY-(i) Information ' supplied by: >

Willian,J. Cahill. 1r.

IU Elect _

400 North Olive Street, L. B. 81  :

Dallas, Texas. 75201 iii) The f acility is Comanche Peak Steam Electric Station Units 1 and

? The basic component is General Electric 200A circuit breaker .

bucket assembly for use in 480V, 7300 Series motor control centers (MCCs).

(ill) The circuit sreaker bucket assemblies were supplied _by General Electric, (ivi Twelve circuit breaker bucket assemblies were specified for-procurement as Class IE nuclear grade for stock. item for possible l replacement or naw Class IE applications. The 12 circuit breakers purchased in this lot were premounted with 2 out of 4 mounting bolts undersized. These breakers could have been utilized ~to supply vital Class.1E loeds associated with any safe shutdown systea, if used to mount as individual breaker, this condition would have-been self detecting. While torquing the mounting bolts to the appropriate torque .31ues recommerded by-the vendor.- However, if ,

the replacement of -the entire assembly _with the circuit breaker l was required, the mechanical and electricallintegrity=of circuit breakers during and.after a seismic event may have been

compromised.

(v) This defect was identified and documented on corrective' action )

document on June ?3, 1992.

(vi) 12.presounted circuit breakers,-each with 2 out of 4 incorrectly. .

sized mounting bolts, were received as stock items.

4 (vii) This condition, though considered an isolated case, involved 12-p premounted circuit breakers _ one or more of which ceuld'possibly.-

have been used'to supply redundant 480V loads from MCCs, 2

potentially-causing a loss of safety: function during and/or_after

, a selsnic event.

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. Attachment to TXX-92419 Page 2-of 2 I 1

The mounting bolts shall be replaced by proper. vendor -supp!ied :s

1. 1/4-20 screws on all the circuit breakers in this lot assigned-for Class 1E~applic=tions.

Additionally a sample of 200A General E ectric circuit breakers installed in Unit 2 were inspected with no further discrepancies noted.

Corrective actions will be completed' by Octo! sr 18, 1992.  ;

(viii) Unit I was not informed of the defect found in Unit 2 since the 4

sample inspections performed in the Unit 2 did not discover any additional orcurrences for previously installed 200A circuit breakers. 'Therefore, it was inferred that the defective population was limited to the 12 circuit breaker bucket assemblies .

supplied under a specific Unit 2 pu,chasa order. General Electric alsc.. stated in a correspondence that the occurrence was considered to be ,an isolated case te the specific purchase order, n

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