ML20105C795
| 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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Log
- 'iXX-92419 C
C File # 10110 CP-92-015 7UB ECTRIC Ref.
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 ad5TALLED BY THE FACTORY a
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.
IA_ 0 JW e,..
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 1l!
I PDR ADOCK 05000445 v
S PDR 4co N. onve street. LB. 8 t Dauas. Tem 75201
-.~.___.
- 6 g.
Attachment to TXX 92419 I
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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a' Attachment to TXX-92419 Page 2-of 2 I
1
- The mounting bolts shall be replaced by proper. vendor -supp!ied
- s
- 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 sample inspections performed in the Unit 2 did not discover any 4
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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