ML20112D286

Special Rept:On 960421,channel of Vibration & Loose Parts Monitoring Sys Declared Inoperable,Due to Abnormally Low Background Level Being Detected.Cause for Low Output Signal Cannot Be Determined

ML20112D286
Person / Time
Site:	Perry
Issue date:	05/31/1996
From:	Shelton D CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
PY-CEI-NRR-2056, NUDOCS 9606040195
Download: ML20112D286 (2)

Text

..

.* q CENTEREOR ENERGY PERRY NUCLEAR POWER PLANT Mail Address: Donald C. Shelton 10 CENTER ROAD SENIOR VICE PRESIDENT PERRY, OHIO 44081 RR . O 10 44081 NUCLEAR (216) 259-3737 i

May 31,1996 PY-CEI/NRR-2056L United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Perry Nuclear Power Plant Docket No. 50-440 Special Report - Loose-Part Detection System Instrumentation Gentlemen:

In accordance with the provisions of Perry Nuclear Power Plant Technical Specifications Sections 3.3.7.8 and 6.9.2, the enclosed Special Report is being submitted to notify the NRC of an inoperable Loose-Part Detection system instrumentation channel.

If you have questions or require additional information, please contact Mr. James D. Kloosterman, Manager - Regulatory Affairs at (216) 280-5833.

Very truly ours, ,

y h. C. Ske h'~

For Donald C. Shelton 0@U DTG:dtg

Enclosure:

Special Report - Loose-Part Detection System Instrumentation j l

cc: NRC Project Manager  !

NRC Resident Inspector NRC Region III  ;

l 9606040195 960531 l PDR ADOCK 05000440 S pgg ope <corg compon es i crewenwnc nm e n

-m- fg L

• • i Enclosure PY-CE!/NRR-2056L Pye 1.of l SPECIAL REPORT INOPERABLE LOOSE-PART DETECTION SYSTEM INSTRUMENTATION On April 21,1996, one channel of the Vibration and Loose Parts Monitoring System (V&LPMS) was declared inoperable due to an abnormally low background level being detected. In accordance with Technical Specifications (TS) Sections 3.3.7.8 and 6.9.2, a Special Report is required to be submitted to the NRC within 10 days following one or more V&LPMS channels being inoperable for more than 30 days. The inoperable VALPMS channel exceeded the 30 day TS Action time limit on May 21,1996.

The V&LPMS is designed to continuously monitor the reactor vessel for indication ofloose parts.

The V&LPMS has eight channels required by TS which monitor the reactor vessel components by .

accelerometer sensors physically mounted near natural collection areas. Each channel consists of a sensor, pre-amplifier, and signal processing electronics that collectively provide inputs to an nudible speaker, a decibel meter, a control room annunciator, a Loose Parts Events Analysis computer, and a printer.

V&LPMS channel 1 is mounted on an instrumentation line in the upper plenum of the reactor vessel.

On April 21,1996, it was noted that the output signal from the eccelerometer was much lower than expected; therefore, channel I was considered inoperable and removed from service. It was anticipated that the channel would be returned to service within the 30 day allowed outage time.

The problem was originally identified as a faulty channel select switch, and subsequently the part was ordered and replaced. However, after the switch was replaced there was further evidence that either a faulty cable or sensor located in the drywell exists.

A root cause for the low output signal cannot be determined nor can a channel calibration be performed, until a drywell entry can be made. The corrective actions required to return this channel to an operable status include: further troubleshooting of the channel components inside the drywell to determine the cause(s) of the equipment malfunction; repair of the defective component (s); and, subsequent channel calibration. Therefore, the affected channel will remain out-of-service with an unknown root cause(s) until the drywell can be accessed during the next plant shutdown of sufficient duration coincident with a drywell entry and associated inspections.

Although one channel is inoperable, seven of the eight TS required VALPMS channels remain operable. Also, the V&LPMS continues to meet the guidance provided by Regulatory Guide 1.133,

" Loose-Part Detection Program for the Primary System of Light-Water-Cooled Reactors,"

Revision 1, dated May 1981, by maintaining at least two sensors operable at each natural collection region (i.e., reactor vessel upper and lower plenums). Therefore, continued plant operation with channel 1 out-of-service is acceptable.

I i

I