ML19327A515

Significant Deficiency Rept SD 413-414/80-09 Re Lack of Radiation Cure on cross-linked Polyethylene Cable Conductor. During Installation of Heat Shrinkable Seals,Insulation on One Conductor Found Melted.Caused by Lack of Radiation Cure

ML19327A515
Person / Time
Site:	Catawba
Issue date:	07/31/1980
From:	Parker W DUKE POWER CO.
To:
References
NUDOCS 8008060300
Download: ML19327A515 (3)

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u DUKE Powen COMPANY Powzu Datomo 422 Sot:Tu Cmtucu STure r. Cn.antortz, N. C. 2em wn va o. a*anca.da- July 31, 1980 VsCf Pattactest T tt t pe= o ns t:Anta704 5'taas Paoouctio 373 4c83 Mr. J. P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303

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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 attached Significant Deficiency Report SD 413-414/80-09.

Very truly yours, a m

} d William O. Parker, Jr.

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• Attachment ec: Director Office of Inspection and Enforcement G. F. Maxwell NRC - Catawba Nuclear Station i

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CATAWBA NUCLEAR STATION Report Number: SD 413-414/80-09

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Report Date: August 1, 1980 Facility: Catawba Nuclear Station, Units 1 & 2 Identification of Deficiency: Lack of radiation cure on cross-linked polyethylene cable conductor.

Initial Report:

On July 3, 1980 Mr. John Rausche of,NRC Region III, Atlanta, Georgia was notified of this deficiency by Mr. W. H. Bradley, Mr. W. J. Foley and Mr. P. M. McBride of Duke Power Company, Charlotte, N. C. 28242 Supplier and/or Component:

The cable conductor found not to have been radiation cured was conductor number 31 of a 16 AWG, 61 conductor control cable with galvanized steel interlocked armor provided by Brand Rex Company of Willimantic, Connecticut, in accordance with Duke Power Company Specification CNS-1354.02-00-0001.

The insulation on-the conductors was to have consisted of 30 mils of cross-linked polyethylene. The insulation on the deficient conductor had not been cross-linked.

Description of Deficiency:

During installation of heat shrinkable seals at cable entrances to cabinets in Catawba Unit 1, it was noticed that the insulation on one of the conductors

(#31) had melted. Since the conductor insulationis supposed to be a thermoset compound, it should not have melted. Subsequent review of manufacturers data and

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tests by the manufacturer on a sample of the cable from the site, indicated that the conductor had not been cured. Curing, in this case, is the exposure of the conductor to a preset dose of electron beam radiation which changes the base thermoplastic polyethylene compound into a thermoset cross-linked polyethylene compound. LA review of the manufacturer's quality control procedures and material processing indicates that there was a breakdown in the manufacturer's QC procedures which were designed to prevent this from occurring.

Analysis of Safety Imolication:

The deficiency was due to the conductor insulation not being radiation cured and thereby not meeting its design or qualification requirements. The effect of this lack of curing is not known since no data exists for the conductor in other than the new condition. In the event of HELB, MSLB, LOCA, or Loss of HVAC, there is a possibility that the conductor insulation may melt, and the conductor short to ground if exposed to moisture.

Cables with this type of insulation are used in safety related circuits inside and outside containment. It cannot be verified through the manufacturer's documentation that all conductors in all cable types provided by the manufacturer i l

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'are properly cured. Therefore, all cables provided by the manufacturer are 1

suspect, until such time that 100% inspection is instituted.

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Corrective Action:

The manufacturer is performing a 100% inspection of all conductors af ter radiation exposure and is maintaining a quality control log on the findings of each inspection. This inspection was instituted in November, 1979, during an upgrading of the manufacturer's quality control program. As of July 21, 1980, the manufacturer will also be performing random sample heat testing

.of conductors prior to and after the conductors are assembled as a cable.

The manufacturer is in the process of identifying all cables furnished to Duke Power Company which were not 100% inspected. This information will be provided with the cables grouped in manufacturing lots. Each' cable within a lot is assembled using the same conddctors,as the other cables within that lot. Duke Power Company will obtain a ca,ble f' rom each lot on the list and have them 100%

inspected for proper curing by Duke Power personnel and the manufacturer's Quality Control Technicians.

All safety-related cables from lots which tests indicate were not properly cured will be replaced with acceptable cable. All reels of cable with deficient conductors will be isolated using Quality Assurance non-conforming item tagging procedures. These actions are expected to be completed by October 1, 1980.

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