ML20010C709
| ML20010C709 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 07/14/1981 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, IEIN-81-06, IEIN-81-6, PLA-872, NUDOCS 8108200332 | |
| Download: ML20010C709 (4) | |
Text
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PPal O h 't. M
'TWO NORTH NINTH STREET, ALLENTO WN, P A.18101 PHONE: (215) 770 5151 j
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' NORVAN W. CURTIS ' -
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F es deK.Ergineeug & Ccnstraction Nuclear
' July 14, 1981
' Mr. Boyce !!.~ Grier
[\\ 19'/pq Director, Region I s-
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!O 4s U. S. Nuclear Regulatory Commission
[h 631 Park Avenue I
King of Prussia, PA 19406 y]
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Ui SUSQUEHANNA STEAM ELECTRIC STATION g
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' FINAL R1 )RT OF A DEFICIENCY INVOLVING OVERSIZED LUGS IN ITE BREAKERS g
ERs 100450/100508 FILE 821-10 A
PLA-872
Dear.Mr. Grier:
This letter serves to provide the Commission with a final report of a
' deficiency relating to the uce of oversized lugs in internal wiring on ITE circuit breakers. The deficiency was the subject of NRC IE Information Notice #81-06 dated March 11, 1981. NRC Region I (Mr. L. Narrow) was advised by Mr. A. Sabol of PP&L that the subject deficiency was contidared l
potentially reportable under 10 CFR 50.55(e) in a telephone conversation on June 2, 1981. The information contained in this report is arbnttted
. pursuant to the provisions of 10 CFR 50.55(e).
L The attachment to this letter contains a description of the problem, its cause, safety implications and the corrective action taken and planned.
We trust the Commission will find this information to be satisfactory.
Ve r-1 truly yours, t
N. W. Curtis l
Vic2 President-2ngineering & Construction-Nuclear FLW:sab
)I Attachment'.
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P E N N 5Y LV A NI A PO WE R i 6iG H T C O M P AN Y
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8108200332 810714 PDR ADOCK 05000387 V W Ifl PDR t
Mr. Boy;e H. Grier,.
July 14, 1981 cc:
Mr. : Victor Stello (15 copies)
Director-Office of Inspectien & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. G. Mcdonald, Director (1)
Office of Management Information & Program Control U. S. Nuclear Regulatory Commission
-Washington, D.C. 20555 Mr. Gary Rhoads U. S. Nuclear Regulatory Commission P.O. Box 52 Shickshinny, PA 18655 a
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Attachm nt to PLA-872 Subject Oversized termination lugs,in ITE Model K-600 load center breakers Description of Problem Wires in ITE 480V load center breakers have been terminated using terminal lugs designed for larger size wires.
An improper crimp on such terminal lugs can result in the wires ca. ting loose and slipping out of the terminal lugs. This problem was described in IE Information Notice #81-06.
Cause The oversized terminal lugs were installed on the load center breaker wiring during manufacturing by ITE.
ITE has verbally indicated that the cause was due to operator error in lug sized selection.
Analysis of Safety Implications Some of the ITE load center breakers with oversized terminal lugs on internal wiring are used to supply 480V safety related loads. They may also be used in an isolation scheme to minimize degrading effects on the class lE system from electrical faults in the non-class IE system, where non-class lE loads are connected to'the class 1E power system.
The use of oversized lugs may lead to degraded electrical connections and an ind-ility of the breaker to trip and isolate fault conditions when required.
In a class lE system, such a breaker anomaly jeorardizes the design function which is to minimize the effects of faults within the class lE system.
In an.
isolation scheme, such a breaker anomaly may allow non-class lE system faults to degrade the class lE system, thus providing a potential common mode failure mechanism to redundant class lE power systems. The common mode failure could occur from multiple non-clar.s lE faults degrading the redundant power supplies
'through failures of the isolation system.
The condition constitutes a significant deficier.cy in Construction and PP&L Project Engineering has determined that, if the conditions described had gone uncorrected, it c' uld have adversely affected the safe operation of the plant, and therefore, is reportable under the requiremer..s of 10 CFR 50.55(e).
Corrective Action An inspection of all safety related load center breakders on Unit 1 and 2 will be yerfcrmed. All oversizedlugs will be replaced with the proper size lugs.
PP&L electrical maintenance will be responsible for the inspection of all Unit 1 and conson equipment. By direction of Nuclear Plant Engineering, this work will be tracked under Plant Staff work authorizations. Bechtel will be requested to perform the inspection on the Unit 2 equipment, and to track this work under Bechtel NCR 7519 Page 1 of 2
' Attachment to PLA-872 PP&I. has requested that Brown Boveri Electric, Inc., suppliers of the ITE breakers, provide a response identifying the corrective action taken to preclude similar occurrences.
Conclusion Upon completion of the inspection and repair program, all oversized lugs will be replaced thus assuring proper operation of the circuit breakers.
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