ML030840413
| ML030840413 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/14/2003 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| 39670 | |
| Download: ML030840413 (4) | |
Text
U.S. Nuclear Regulatory Commission Operations Center Event Report General Information or Other (PAR)
Event #
39670 Rep Org: WESTINGHOUSE Notification Date /Time: 03/14/2003 15:47 (EST)
Supplier: ABB INC Event Date / Time: 03/14/2003 (EST)
Last Modification: 03/14/2003 Region: 1 Docket #:
City: PITTSBURGH Agreement State: No County:
License #:
State: PA NRC Notified by: HANK SEPP Notifications: DAVID AYRES R2 HO Ops Officer: YAMIR DIAZ MARK SHAFFER R4 Emergency Class: NON EMERGENCY JACK FOSTER NRR 10 CFR Section:
BRIAN MCDERMOTT R1 21.21 UNSPECIFIED PARAGRAPH KENNETH O'BRIEN R3 10 CFR PART 21 REPORT REGARDING FAILURES OF ABB CIRCUIT BREAKERS Circuit breakers manufactured by ABB Inc. and used for Class 1 E applications by Westinghouse were shipped to the Calvert Cliffs Plant with model 5 operating mechanisms installed. Recently, Westinghouse had retrofitted the breakers with model 7 operating mechanisms manufactured by ABB Inc. Westinghouse validated that the original breaker qualifications (for Class 1 E applications) are still applicable with the model 7 operating mechanism installed. Two of these breakers failed to close and latch during testing at Calvert Cliffs. The first breaker failed to close and latch during acceptance testing on January 18, 2003. The second breaker failed to close and latch during its installation acceptance test in the breaker cubicle on January 27, 2001.
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"itu9LJ.LJ OW esting-house Westinghouse Electrlc Campany NudearSevices P.O. Box355 Pittsburgh. Pennsylvanla 15230-035S USA US. Nuclear Regulatory Commission Dlrecttel: (412) 374-5282 Document Control Desk Dire-tfax. (412) 374-4011 Washington, DC 20555-0001 e-mail: Sepplha@westinghouse.com Our ref. LTR-NRC-03-8 March 14,2003.
Subject:
Notification of the Potential Existence of Defects Pursuant to 10CFR21 The following information is provied pursuant to the requirements to 10 CFR 21 to report the potential for the existence of a SUBSTXIAL SAFETY HAZARD. This issue concerns failure of ABt mediuum voltage 4 KV circuit breakers to close and latch. Westiaghousc supplied these breakers for safety-related applications at the Calvert Cliffs Nuclear Power Plant.
Background
Medium voltage (4 KV) 5VHKR/250 Model 80, 1200A circuit breakers were manufactured by ABB Inc.
and commercially dedicated for Class 1E applications by Westinghouse and shippod to the Calvert Clif Nuclear Power Plant with model 5 operating mechanisms installed. Recently, Westinghouse had retrofitted the breakers with model 7 operating mechanisms manufactured by ABB Inc. Westinghouse validated that the original breaker qualifications (for Class 1E applicatioxis) are still applicable with the model 7 operatjing mechanism installed./wo of these breakers f*iled to closo and latch during testing at.
Calvert Cliffs/The first breaker failed to close and latch during acceptance testing on January 18, 2003.
The second breaker failed to close and latch during its instaallation acceptance test in the breaker cubicle on hnumy 27, 2003.
E-valuation It is Westinghouse undcrstaiading fat the direct cause of the failures is the result of out oftolcrance primary and secondary trip latches in the ABB model 7 operating mechanism. The root cause investigation is on-going to determine if manufacturing, inspection and test procedures could have contributed to these failures. WhilUe breakers failed to close and latch on demand, a failure to trip on demand has not been seen during subsequent testing of these breakers.
The e*-tent of the out of tolerance parts has not been determined. ABB Inc. is currently investigating to determine if low voltage circuit breakeis with the model 7 operating mechanism are affected by the out of "tolerance parts.
Westinghouse has performed a seismic re-evaluation that documents that the breakers with The model 7 operating mechanisms installed will remain closed during a seismic event.
A ENFL Group company
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Page 2 of3 OurrctZ: LT~R-NlRC-03-B MavLrch 14, 2003 Failure of the circuit brcaker to close could be detected by observation of the breaker or monitoring lights.
Safety Impact The out oftolerance parts could result in a common mode failure for redundant breakers in safety systems. Based upon testing of the failed breakers, the failure to close and latch condition is intermittent.
In the case of Calvert Cliffs, if both breakers failed to close when containment spray is required, the plant could be in a condition outside the accident analysis. Based upon past testing at ABIB Inc. with the model 7 operating mechanism, breakers that have been perated 300 times or more and have not exhiibitedthe failure to close and latch condition are expected to continue to close and latch as intended.
Corrective Action Tlpon discovery of the breaker out-of-tolerance parts, Calvert Cliffs took corrective actions to remove the breakers that are required to close or re-close to provide a safety function "The extent ofthe out of tolerance parts has not been determined. AD1 Inc. is currently investigating to determine if low voltage circuit breakers with the model 7 operating mechanism are affected by the out of tolerance parts.
Plant Applicability This notification is applicable to Calvert Cliffs. In addition, ABB Inc. is determining which utiliti.es may have purchased or may have the model 7 operating mechanism installed in their circuit breakers.
Communications ABD Inc. and Calvert Cliffs are aware of the out oftolerance primary and secondary trip latches. A Westingbouse Nuclear Saffety Advisory Letter will be sent to all Westinghouse and Combustion Engineering power plants by March 31, 2003.
Very truly yours, Regulatory and Licensing Engineering cc:
G. Shukla A SNFL Group company
03/24/2883 18:32 412-374-4811 W EC-LICENSING PAGE 82 Page 3 of3 Ourrcf LTR-NRC-03-9 March 14, 2003 bcc: H. A. Sepp (ECE 4-7A) IL, IA R. Bastien, (Nivelles, Belgium) 1L, IA L. Ulloa (Madrid, Spain) 1IL, 1A C. Brinkman, IL, IA (Wcstnghouscwectnc Co., 12300 TwinbrookPamicay, Suite330,Rodcvile, MD 20952)
RLE Administrative Aide (FCE 4-7A) IL, IA A BNFL Croup company