ML20041B045

RP 2-81-40/IT:on 810923, Survivability of Rockbestos Type RSS-6-104 & Rss-6-110 Coaxial Cable at Elevated Ambient Temps Not Proven.Caused by Apparent Design Deficiency.Cable to Be Replaced During Mar 1982 Refueling Outage

ML20041B045
Person / Time
Site:	Peach Bottom
Issue date:	02/10/1982
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
CON-NRC IEB-79-01B, IEB-79-1B, RO-2-81-40-IT, NUDOCS 8202230202
Download: ML20041B045 (3)

Text

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l PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHIA PA.19101 12151841 4000 February 10, 1982 9 =

Mr. R. C. Haynes, Director &

Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission g 2

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SUBJECT:

License Event Report Narrative Description

Dear Mr. Haynes:

Thefollowingisafollow-uptoLER2-81-h0/ITwhichwas forwarded to you on October 6, 1981.

Reference:

Docket No. 50-277 Report No: 2-81-h0/3X-1 Report Date: February 10, 1982 Occurrence Date: September 23, 1981 i Facility: Peach Bottom Atomic Fower Station

( RD #1, Delta, PA 17314 I

Technical Specification

Reference:

None t

This LER is reported under the requirements of IE j

Bulletin 79-01B which directs, among other things, that we " Submit a ' License Event Report' for any class IE electrical equipment item which has been determined as not being capable of meeting environmental qualification l requirements for service intended."

l 8202230202 820210 PDR ADOCK 05000277 I6,J.&

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s Mr. R. C. Haynes, Director Page 2 Description of the Event:

Continuing Investigation has been unable to provide sufficient assurance of the survivability for Rockbestos Type RSS-6-104 and RSS-6-110 coaxial cable at elevated ambient temperatures.

Probsble Conseauences of the Occurrence:

The acoustic monitoring system was installed to meet the requirements of NUREG 0578, Section 2.1 34, which specified that a method of indicating safety / relief valve position be provided. An interim system utilizing non-qualified equipment was approved for service until the qualified equipment was procured and installed.

It is believed that the event being reported will have minim 1 impact on the public health and safety due to the purpose of the installed system and the nature of the potential failure mode. The anticipated failure would be caused by environmental conditions, in this case high ambient temperature. It would

be necessary to have a loss of drywell cooling or an accident condition such as a pipe break to obtain the temperatures re-quired to initiate cable failures. The purpose of acoustic monitoring system is to detect a stuck open relief valve (SORV).

While the simultaneous occurror.ce of a SORY and a failure of drywell cooling or a pipe break type of accident is possible, it is highly unlikely, therefore, it is felt that the acoustic monitoring system would be available to perform the task for which it was installed. In addition, a redundant system utilizing theromcouples to detect leakage is installed.

The potential failures are projected to occur several minutes after the cables are subjected to the high ambient temperatures and some of the cables did not fail, during the testing, therefore, the possibility exists for the system to function at least through the early stages of an accident.

Cause of tho Occurrence:

Apparent design deficiency by the manufacturer is the reason i for the potential failures.

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Mr. R. C. Haynes,' Director Page 3 Immediate Corrective Action:

None Future Corrective Actions:

Plans are underway to accommodate the replacement of the cable during the next refueling outage, currently scheduled for March, 1982.

Very truly yours,

[

. J, Cooney.

Sup intendent ration Division - Nuclear I

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