05000277/LER-1981-039, Forwards LER 81-039/01T-0.Detailed Event Analysis Encl

Forwards LER 81-039/01T-0.Detailed Event Analysis Encl

ML20031B004
Person / Time
Site:	Peach Bottom
Issue date:	09/11/1981
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20031B005	List: 05000277/LER-1981-039, Forwards LER 81-039/01T-0.Detailed Event Analysis Encl 05000277/LER-1981-039-01, /01T-0:on 810827,C Average Power Range Monitor Found Receiving Only One Low Power Range Monitor (LPRM) Input to C Level.Caused by 810818 LPRM 32-49C Failure & Operator Failure to Recognize Situation
References
NUDOCS 8109280465
Download: ML20031B004 (2)

LER-1981-039, Forwards LER 81-039/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2771981039R00 - NRC Website

text

lllf PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 1881 -1981 PFULADELPHI A. PA.19101

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1215)841 4000 September 11, 981 4,.c

, fil

'A

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.d g/t c,' b Mr.

R.

C. Haynes, Director

',i\\9 (, \\'

Region I ri ",

f s'l Office of Inspection and Enforcement

'i US Nuclear Regulatory Commission

. ' d, 631 Park Avenue King of Prussia, PA 19406 SUBJECT: LICENSEE EVENT REPORT NARRATIVE DESCRIPTION

Dear Mr. Haynes:

The following occurrence was reported to Mr.

R.

Blough, Region I, Office of Inspection and Enforcement on August 27, 1981.

Reference:

Docket No. 50-277 Report No.:

2-81-39/1T-0 Report Date:

September 11, 1981 Occurrence Date:

August 27, 1981 Facility:

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

Technical Specification Table 3.1.1, Note 11, states that, "An APRM will be considered operable if there are at least 2 LPRM inputs per level and ac least 14 LPRM inputs of the normal complement."

Description of the Event:

At 3:25 AM on 8/18/81, LPP.M 32-49C failed up scale resulting in an APRM High Flux Half Scram shile the Unit was shutdown.LPRM 32-49C was bypassed leaving only 1 operable LPRM input to the C

]h6})

level of the C APRM.

From the above time until approximately J

00:05 AM 8/27/81, the C APRM was alternately bypassed and in service.

During those times when the C APRM was in service, the

/ '/

A logic trip system was at times receiving input from only one fully operable APRM becauce APRM

'A' and

'E' were bypassed at times.

8109280465 810911 PDR ADOCK 05000277 g

PDR

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~

Paga 2

. Probable fonsequences of the Occurrence:

Consequences are considered minimal since the C APRM responded to power changes both from rod movement.and flow changes and was capable cf responding to power transients.

The rod block and i

scram functions were operable.

2 Cause of Oecurrence:_

Previous to 8/18/81 two other C level LPRMs were bypassed because of upscale ara drif ting failures.

On 8/18/81 LPRM 32-49C failed l

upscale and was bypassed leaving only 1 operable LPRM input to the C level of APRM C.

Correctiv,e Actiona:

As soon as the situation was recognized, the C APRM was put in bypass and an investigation was made to determine if any LPRM could be returned to service.

At that time LPRM 32-49C was returned to service, restoring two C level inputs to APRM C.

To prevent future occurrences, engraved placards have been installed on the reactor consoles stating that APRMs must have at least two LPRM inputs per level to be operable.

Additionally, the PORC is continuing to review this event to determine if additional action is required.

"ery truly yours,

/Ybht M. J. Cooney S perintendent Generation Division / Nuclear cc:

Director, NRC - Office of Inspection and Enforcement Mr. Nocrian M.

Haller, NRC - Office of Management &

Program Analysis 1

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