ML19350A749

Significant Deficiency Rept 413-414/81-02 Re Cracks Found in Contacts,Initially Reported on 810202.Replacement Parts for All Broken or Cracked Arcing Contacts to Be Provided by Manufacturer

ML19350A749
Person / Time
Site:	Catawba
Issue date:	03/09/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8103160746
Download: ML19350A749 (3)

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Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 .

Re: Catawba Nuclear Station Units 1 and 2 Docket Nos. 50-413 and 50-414

Dear Mr. O'Reilly:

Pursuant to 10CFR 50.55e, please find Sttached Significant Deficiency Report SD 413-414/81-02.

Very truly yours,

.%7hkm p. Af rke.Gb William O. Parker, Jr.

E' RWO:ses Attachment cc: Director NRC Resident Inspector Office of Inspection and Enforcement Catawba Nuclear Station U. S. Nuclear Regulatory Commission Washington, D. C. 20555

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h CATAWBA NUCLEAR STATION REPORT NUMBER: SD 413-414/81-02 REPORT DATE: March 2, 1981 FACILITY: Catawba Nuclear Station, Unit 2 IDENTIFICATION OF DEFICIENCY: Several moving arcing contacts on 600VAC Gould K-20005, K-16005 and K-(005 lord center breakers were found cracked. The cracked material may dislodge and fall into the main contact assembly resulting in operational difficulties that could cause a failure or reduction of qualified life.

INIT!AL REPORT:

On February 2,1981, Mr John Raushe of the NRC, Region 11, Atlanta, Georgia office was notified of the deficiency by Mr W J Foley, Mr B M Rice and Mr W 0 Henry of Duke Power Co. , Charlotte, NC 28242.

SUPPLIER AND/OR COMMENTS:

Brown Boveri Electric, Inc. Springhouse, Pa. manufactured the breakers which are used to supply the 600v auxiliary power to equipment used in various class IE functions.

DESCRIPTION OF DEFICIENCY:

During initial inspection of the breakers it was found that some moving arcing contacts had cracks in them. In one instance a similar stationary arcing contact had not only cracked but came off. The arcing contact ma-terial is made of silver and tungsten which is brazed on the copper contact arm pad.

The manufacturer was consulted; he explained that they had already observed cracked contacts and had already tested them with the conclusion that the cracking itself would not cause a breaker to fail. The manufacturer also added that they had never observed a cracked piece falling off. When we indicated to them that we had a stationary contact that had cracked and had fallen off, their response was they wanted the part returned for further study.

On February 17, Duke received a copy of Brown Boveri's August 30, 1979 re-port of the testing done on a cracked contact. Upon review of this report, it was noted that the contacts survived the mechanical operations required by ANSI C37.16 standards. However, it was noted that the electrical re-quirements were not performed. In all cases of a cracked contact the manu-facturer had recommended replacement, but not immediately, due to the m

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successful tests. The manufacturer also concluded his report by stating that a 100% QA checkpoint of &ll factory stocked contact assemolies would be institutec to eliminate cracked contacts being installed on breakers.

Indications are that Duke breakers were shipped af ter this check was theoretically implemented.

During investigation of the cracked contacts it was also discovered that some secondary control blocks, which are used to electrically operate the breaker, were found broken wnen uncrated.

ANALYSIS OF SAFETY IMPLICATION Arcing contact cracks if the arcing contact deficiency was not corrected and a piece of contact fell into the main contact, the main contact may be damaged in such a manner that the contact surface area may be lessened, resulting in hot spots. This may shorten the quali fied life of the breaker.

Control block breakage Should a breaker be installed with a broken control block, the breaker may fail to operate remotely or operate erratically. If such a breaker was in service feeding a load and a fault occurred, the breaker would maintain the safety related function of interrupting the fault and maintaining proper insulative characteristics.

C,0RRECTIVE ACTION Arcing contact cracks The manufacturer will provide replace ent parts to replace all broken or cracked arcing contacts, as required. Duke will visit the manufacturing facilities to review QA programs and to insure proper procedures and check-lists are initiated to prevent broken parts leaving the factory.

Control block breakage Plans arc being made to specify improved packing methods on breakers of this typse to minimize the potential for possible centrol block breakage during shipment and during field handling of the breakers prior to installation.

All safety related breakers at the site have been inspected and control blocks ,

are being replaced as required.

I JMS/csc