PY-CEI-NRR-1061, Special Rept:On 890811,vibration & Loose Parts Monitoring Sys Experienced Spurious Alarms.Caused by Excessive Background Noise.Design Change Request Submitted to Address Hard Line Cable Issue

Special Rept:On 890811,vibration & Loose Parts Monitoring Sys Experienced Spurious Alarms.Caused by Excessive Background Noise.Design Change Request Submitted to Address Hard Line Cable Issue

ML20247Q255
Person / Time
Site:	Perry
Issue date:	09/20/1989
From:	Kaplan A CLEVELAND ELECTRIC ILLUMINATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
PY-CEI-NRR-1061, NUDOCS 8909280148
Download: ML20247Q255 (2)

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g et THE CLEVELAND ELECTRIC ILLUMINATING COMPANY P.O. DOX 97 E PERRY, OHIO 44081 E TELEPHONE (216) 2594737 'E ADDRESS 10 CENTER ROAD FROM CLEVEl.AND: 241 1650 Serving The Best Location in the Nation Al Kaplan PERRY NUCLEAR POWER PLANT VCE PRESOENT NUCLEAR GROUP September 20, 1989 PY-CEI/NRR-1061 L U.S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Perry Nuclear Power Plant Docket No. 50-440 Inoperable Loose-Part Detection System Instrumentation - Special Report

Dear Sir:

Attached is a Special Report concerning inoperable Loose-Part Detection System Instrumentation. This report satisfies the conditions of Perry Technical Specifications 3.3.7.8 and 6.9.2.

If you have any questions, please feel free to call.

Very truly your ,

Al Kaplan Vice President Nuclear Group AK:nje Attachment I

cc: T. Colburn P. Hiland USNRC Region III Director, Office of Resource Management 8909280148 890920

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- . -o Attachment 1

- PY-CEI/NRR-1061 L Page 1 of 1 SPECIAL REPORT - INOPERABLE LOOSE PARTS

. DETECTION SYSTEM INSTRUMENTATION l

On August 11, 1989 the Vibration and Loose Parts Monitoring (V& LPM) System I experienced a series of spurious alarms attributed to excessive background l noise. Channel 8 was declared inoperable and the plant entered Technical Specification action statement 3.3.7.8, requiring a special report if one or more V&LPH channels are inoperable for more than thirty days. The thirty day time limit to restore channel 8 to an operable status was exceeded on September 10, 1989. All aspects of the Technical Specification action statement were met.

This system is designed to continuously monitor the Nuclear Boiler for any indication of loose parts in the Nuclear Boiler System. Ten individual channels monitor the reactor vessel components with sensors physically mounted near natural collection areas. Each channel consists of a detector, pre-amplifier, and signal processing electronics which input to . tepe recorder, audible speaker, a dB meter, control room annunciator, a spectrum analyzer, an x-y plotter, a loose part locator, and a printer. Channel 8 monitors the 'B' recirculation discharge line.

The cause of the spurious alarms was evaluated by the Shift Technical Advisor and the System Engineer to be excessive backgroand noise and not a loose part.

This problem is recurrent. In October 1988, the channel 8 hard line cable was replaced with a new hardline cable with Raychem heat shrink tubing applied to the cable in an effort to eliminate ground loops that develop in tne loose parts sensor hard line cable within the dryvell. This new cable subsequently failed after three months due to degradation of the Raychem. In June 1989, another new channel 8 hard line cable with Raychem and an outer fiberglass sleeve was installed. The status of this cable vill remain unknown until the plant enters mode 4 (cold shutdown) when dryvell entry is permitted. However through the previous troubleshooting, the problem is believed to again be due to the grounding problems previously experienced. A design change request (EDCR 89-187) has been submitted to address the hard line cable issue.

Currently channel 8 is inoperable and disconnected via lifted lead, per PAP-1402, " Control of Lifted Leads, Jumpers, Temporary Electrical Devices, and Mechanical Foreign Items".

The channel vill remain inoperable per Technical Specifications until the root cause of the problem can be resolved and a design change implemented.

Implementation of the approved design change vill be performed during an outage of sufficient duration following engineering approval. Examples of design changes being evaluated include the following: replacement of hard line cable with triaxial cable; utilization of a waveform discriminator / analyzer; filtering out flow induced noise; and moving the accelerometers to adjacent instrument lines.

With channel 8 out of service, the V& LPM system still meets the intent of Regulatory Guide 1.133 by maintaining more than two sensors located at each natural collection region (reactor vessel upper and lower plenums).

NJC/ CODED /2624

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