ML20083Q023

Ro:On 840224,during Verification of Moisture Monitoring Sys,Point 7 Failed.Cause Will Be Determined During Next Outage W/Drywell Deinerted.Drywell Sump Collection Sys Will Be Monitored Hourly

ML20083Q023
Person / Time
Site:	Peach Bottom
Issue date:	03/23/1984
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
MM-2-02, MM-2-2, NUDOCS 8404200302
Download: ML20083Q023 (3)

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PHILADELPHIA ELECTRIC COMPANY

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l 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 1215)841-4000 March 23, 1984 Docket No. 50-277 Dr. T. E. Murley, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue Washington, DC 20555

SUBJECT:

Peach Bottom Atomic Power Station - Unit 2 Moisture Monitoring System

Dear Dr. Murley:

This letter is a report of moisture monitoring system inoperability in accordance with Philadelphia Electric Company's commitment to report moisture monitoring system problems and alarms unrelated to actual system leakage as stated in letter, J.

S. Kemper, PECo to Dr. T. E. Murley, USNRC, dated September 15, 1983.

Reference:

Docket No. 50-277 Report Number: MM-2-02 Revision No.: 00 Event Date: February 24, 1984 Report Date: March 23, 1984 Facility: Peach Bottom Atomic Power Station RD #1, Box 208, Delta, PA 17314 ABSTRACT During Unit 2 startup operations, routine surveillance testing indicated a moisture sensor in the recirculation system moisture monitoring system was functioning improperly and the system was declared inoperable. Hourly monitoring of the drywell sump pump-out rates was initiated to determine drywell leakage rates. The hourly monitoring will continue until the sensor can be replaced 7

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o Dr. T. E. Murley, USNRC March 23, 1984 MM-2-02 Page 2 of 3 or repaired during the next outage of sufficient duration to carry out the work.

DESCRIPTION OF THE EVENT:

On February 24, 1984, during Peach Bottom Unit 2 startup while conducting a routine surveillance test, (!EP 13.40 ' Checkout of Moisture Monitoring System') to verify the operability of the moisture monitoring system, Point 7 failed. Point 7 is installed on weld A-AM-4/AHG in the 'A' recirculation loop 22 inch mainfold.

The moisture monitoring system was declared inoperable at 8:00 p.m. on February 24, 1984.

CONSEQUENCES OF THE EVENT After the system was declared inoperable, enhanced surveillance requirements (EME 13.41 ' Hourly Drywell Leak Detection') were initiated and will be continued until an outage of sufficient duration to make the system operable. The purpose of ST 13.41 is to provide early warning of reactor coolant leakage via the drywell sump collection system when the moisture monitoring system is inoperable and reactor temperature is above 212 degrees. These surveillance requirements ensure that drywell leakage rates _do not exceed the limits of Technical Specification 3.6.C.l. Therefore, the safety consequences of this event are considered minimal.

CAUSE OF THE EVENT The cause of the event will~be determined during the next unit outage of sufficient duration with the.drywell deinerted.

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Dr.'T. E. Murley,_USNRC March 23, 1984 MM- 0 2 f Page 3 of 3 CORRECTIVE ACTION'S:

Hourly monitoring of the drywell ' sump collection . system will be performed until the next_ unit-ontage of sufficient duration with the drywell deinerted so~that the system can be made operable.

PREVIOUS SIMILAR_ OCCURRENCES:

LER 2-83-26/31, 3-83-16/35, 3-83-21/3L, 3-83-24/3L and letter: '

W. T. Ullrich, PECo to Dr. 2. E. Murley, USNRC, dated March 5, 1984.

Very truly yours,_

W. T.' U'llrich _,

Superintendent.

Nuclear Generation-Division 4

e cc: Mr. Ac R. Blough, Site Inspector-J. F. Stolz, Operating Reactors. Branch No. 4 e

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