05000277/LER-1981-040, Forwards LER 81-040/01T-0.Detailed Event Analysis Encl

Forwards LER 81-040/01T-0.Detailed Event Analysis Encl

ML20031F815
Person / Time
Site:	Peach Bottom
Issue date:	10/06/1981
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20031F816	List: 05000277/LER-1981-040, Forwards LER 81-040/01T-0.Detailed Event Analysis Encl 05000277/LER-1981-040-01, /01T-0:on 810923,review of Rockbestos RSS-6-104 & RSS 6-110 Cables,Used in Safety Relief Valve Acoustic Monitoring Sys,Revealed Potential Failure at Elevated Temps Following LOCA or Pipe Break Accident
References
NUDOCS 8110200452
Download: ML20031F815 (3)

LER-1981-040, Forwards LER 81-040/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2771981040R00 - NRC Website

text

Liz PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 1881 -1981 PHILADELPHI A. PA.19101 (215)841-4000 October 6, 1981 h?q f(? \\f l, 'v's Mr.

R.

C.

Haynes, Director O'

'* U ' ' I [Z

Region I OCT101981 l

Office of Inspection and Enforcement j

u.s,ev aran uoutA m U.S.

Nuclear Regulatory Commission N ' 5*

631 Park Avenue U

,D King of Prussia, PA 19406

/

w

SUBJECT:

License Event Report Narrative Description

Dear Mr. Haynes:

The following occurrence was reported to Region I, Office of Inspection and Enforcement on September 23, 1981.

Reference:

Docket No. 50-277 Report No.:

2-81-40/IT-O Report Date:

October 6, 1981 Occurrence Date:

September 23, 1981 Facility:

Peach Bottom Atomic Power Station RD # 1, Delta, PA 17314 Technical Specification Reference:

None This LER is reported under the requirements of IE Bulletin 79-01B which directs, among other things, that

--( S Y s

/ /

r71102004S2 811006 PDR ADOCK 05000277 s

PDR

Mr.. R.

C. Haynes, Director Page 2 we " Submit a ' License Event Report' for any class lE electrical equipment item which has been determined as not being capable of meeting environmental qualification requirements for service intended."

Description of the Event:

Investigation by the Engineering Department indicates that the Rockbestos Type RSS-6-104 and RSS-6-110 coaxial cable used on the safety relief valve acoustic monitoring system may fail at elevated ambient temperatures.

Specific information provided to us has been less than conclusive at this time, some of the samples tested failed at various temperatures or did not fail at all up to temperatures exceeding the Peach l

Bottom LOCA profile, however, it has been deemed prudent to make this notification.

l l

Probable Consequences 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 minimal 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 required to initiate cable failures.

The purpose of acoustic monitoring system is to detect a stuck open relief valve (SORV).

While the simultaneous occurrence of a SORV 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 t....

Mr.

R.

C.

Haynes, Director Page 3 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 the occurrence:

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

Immediate Corrective Actions

Samples of cable have been sent to the manufacturer for testing.

Future Corrective Actions:

Plans are underway to accommodate the replacement of the cable, if.necessary, during the next refueling outage, currently scheduled for March, 19 82.

Very truly yours,

/

V <*/ M.

J.

Cooney Superintendent Generation Division - Nuclear cc: Resident Inspector Director, NRC - Of fice of Inspection and Enforcement Mr. Norman M. Haller, NRC - Office of Management &

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