ML20205D850
| ML20205D850 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/12/1986 |
| From: | Carey J DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 2NRC-6-084, 2NRC-6-84, 86-06, 86-6, NUDOCS 8608180188 | |
| Download: ML20205D850 (3) | |
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2NRC-6-084 Beaver Valley No. 2 Unit Project Organizatinn Telecopy 64 2 Ext.160 S.E.G. Building P.O. Box 328 August 12, 1986 Shippingport. PA 15077 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 480V ITE Circuit Breakers Potentially Significant Deficiency Report 86-06 Gentlemen:
This Potentially Reportable Significant Deficiency Report relating to the failure of an ITE molded case circuit breaker is being submitted pursuant to the requirements of 10CFR 50.55(e). This is an final report.
DUQUESNE LIGHT COMPANY By J. J. Carey Vice President RWF/kam Attachment NRC/DEF/RPT/8606 l
cc:
Mr. P. Tam, Project Manager (w/a)
Mr. J. M. Taylor, Director (3) (w/a)
Mr. L. Prividy NRC Resident Inspector (w/a)
INP0 Records Center (w/a)
NRC Document Control Desk (w/a) 8608180188 860812 PDR ADOCK 05000412 S
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ATTACHMENT BEAVER VALLEY POWER STATION - UNIT 2 DUQUESNE LIGHT COMPANY REPORT ON P0TENTIAL SIGNIFICANT DEFICIENCY 0F 480 V ITE/TELEMECANIQUE MOLDED CASE CIRCUIT BREAKERS 1.
Summary A failure of an ITE/Telemecanique molded case circuit breaker for a motor control center (MCC) to reset after trip was reported by CLC Maintenance Department.
2.
Immediate Action Taken Nonconformance and Disposition Report (N&D) 12325 was written on March 20, 1986 addressing this problem.
On April 1,1986, Tele-mecanique field service engineer visited the site to discuss possible solutions and extent of the deficiency.
3.
Description of the Deficiency The breaker reset mechanisum which is held by a slotted clip (latch cam) had moved laterally and come free, no longer providing tension to the reset mechanism.
This allows the breaker operating arm to move freely and not reset the breaker.
Further research and discus-sions with vendor revealed that this slotted latch cam was only manu-f actured during the period of October 6,1982 through April 1,1983.
After April 1,1983, the vendor changed the slotted clip design to a rectangular piece of metal with a hole in the center, thus eliminating movement and maintaining tension.
(This was the original design before October 6, 1983.)
4.
Analysis of Safety Implications The potentially deficient breakers are installed throughout the plant on the 480 V motor control centers in both Category 1E and non-Category 1E service.
The safety functions of these circuit breakers are to provide power to their respective safety related loads and to protect the equipment and electrical busses from overload conditions.
The inability to reset these breakers following either manual or automatic trip does not affect the performance of these safety functions. Opening of one of these faulted circuit breakers would create a condition similar to a blown fuse that requires replacement to utilize the circuit after correcting the initiating condition.
This concern could not have adversely affected the safety of plant operations.
5.
Corrective Action to Remedy Deficiency N&D 12325 was di: positioned on April 15, 1986 requiring DLC Startup Group to inspect all 165n 480 V ITE/Telemecanique molded case circuit breakers and replace all latch cams having the slotted design with the originally designed part (rectangular with a hole in the center).
This replacement will be accomplished through the prevent-ative maintenance program using vendor supplied parts and instruct-ions.
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6.
Additional Reports This is a final report.
No additional reports are anticipated.