ML18219D986

11/11/1976 Response to Request for Additional Information Operating Experience of Loose-Parts Monitoring Systems

ML18219D986
Person / Time
Site:	Cook
Issue date:	11/11/1976
From:	Hunter R American Electric Power Service Corp
To:	Rusche B Office of Nuclear Reactor Regulation
References
Download: ML18219D986 (12)

Text

U.S. NUCLEAR RFGULATORV C EMISSION DOCKET NUMBER NRC ARM 195 (2 76)

FILE NUMQER NRC DISTRIBUTIAN FoR PART 50 DOCKET MATERIAL "ROM DATE OF DOGUMFNT TO: Mr Rusche American Elec Power Service C ll-lk-76 New York, NY R S Hunter DATE RECEIVF.D ] ] ] 6 76 NLETTER QNOTORI2ED PROP INPUT FORM NUMBER OF COPIES RECEIVED ABORIGINAL KUNCLASSIFIE D C3copv one signed'tr DESCRIPTION ENCLOSURE ~

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PLANT NAME: D C Cook 8'1 ASST' SAFETY FOR ACTION/INFORMATION ASSIGNED AD: JEST/'NED DE BRANCH CHIEF:

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• AMERICAN ELECTRIC POWER Service Corporation 2 Broadway, New York, N. Y. 10004 (212) 422 4800 ROBERT S. HUNTER D(gw(g,pl Vice President-Euclcar Engisemng ll, III'ovember 1976 Donald C. Cook Nuclear Plant Unit, N Docket No. 50-315 Oz nocto<~

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~~> ~ ll'o~i Mr. Benard Rusche, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555

Dear Mr. Rusche:

This letter is in response to Mx'. Dennis L.,Ziemann's letter dated September 30, 1976 which requested information concexning the operating experience of the Donald C. Cook Nuclear Plant Loose-parts Monitoring Systems (LPMS) .

The following numbered responses refer to the four questions in the request:

1. No event has occurred in which a loose-part has been found in any part of the primary system.

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2. (a) The LPMS enables the detection of changes in vibration which may occur in the primary system.

Vibrations are detected by twelve accelerometers, mounted throughout the primary system. Four accelerometers are mounted on the reactor vessel.

Two are positioned on the reactox flange above the vessel head, and the other two are located on the vessel bottom where the hemisphere begins. One accelerometer is positioned on each reactor coolant pump, above the impeller, on the lower flange. An accelerometer is mounted on the outside shell steam generator, near the lower tube sheet.

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Mr. B. C. Rusche November ll, 1976 (See Table 1 and Figure No. 1 for details).

The accelerometer output is 'an electrical signal which is fed into an amplifier. Six amplifiers (two input signals per amplifier),-'are mounted on the Unit 1 control room panels and provide a visual display on a sensitivity meter. Should the signal magnitude exceed a preset limit, both an audible and visual alarm are activated.

2b. The LPMS has been in operation since April 1975.'c.

The LPMS monitors vibrations on a continuous basis and sends signals to the control room throughout the monitoring process. Xn addition, expanded surveillance is conducted every three months utilizing a real-time spectrum analyzer and an XY plotter to trace acceleration versus frequency for the reactor vessel, the reactor coolant pumps and the steam generators. At this time, traces are made from each of the twelve detectors over a frequency range. These traces can then'be evaluated for accuracy against previous data sets available.

3. Operating experience since April 1975 has revealed no significant change in vibration signals. No abnormally large vibration signals have been detected that could not be identified as monitoring system faults. Overall signal magnitudes at all frequencies have increased slightly, with increased power operation.

Of the twelve instrumentation channels sending signals to the six amplifiers, three have failed due to an open circuit. in one channel and a short circuit of two channels.

The loose parts monitoring system appears to be an accurate and sensitive method of collecting and analyzing primary system vibrations. By employing this equipment we have been able to closely monitor variations in vibration since April 1975. The

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Mr. B. C. Rusche N ember 11, 1976 installed cost of the LPMS on Unit 1 is approximately

$ 100,000. The benefit to us is that we have an early warning system to detect a loose part and a diagnostic tool to evaluate its significance.

Very truly yours, R. S. Hunter Vice president-Nuclear Engineering RSH:mam cc: G. Charnoff R.'iXJ. Vollen R. C. Callen P. W. Steketee R. Walsh John Tillinghast R. W. Jurgensen Bridgman 4

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SUBJECT Loose Parts Monitoring Syste~

SHEET NO..

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OF D, C. Cook Nuclear Plant, Un~81 DC Charge Converter Endevco Model d2731B 1

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Power Range Detector Charge Amp Accelerometer Endevco 'Endevco Model 2725 Model <2233E (Low Temp.)

82273A (High Temp.)

'NOTE

1. Honeywell SAI-52B Real Time Spectrum Analyzer/Digital Averager

2. Tektronix 5103N Os i lloscope

3. Hewlett - Packard 035B X-Y Plotter 4.. DC Level Alarm Det ction Panel

5. "Loose Parts System Activated" Alarm

• Input 82 employs built in amplifier charge converter.

FIGURE NO. I

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LOOSE PARTS YiONITORING Table 1 Accel erometer Summar Cable Accelerometer Location Acceler. Sensitivity Design Cable Chg.

No. Desi nation Serial d 1 PC/g PC Temp"F ~Len th Ampl.

Reactor Vessel - Upper West CD 66 2. 91 2. 79 750 600 1 Reactor Vessel - Lower Hest DR 48 64.0 500 580 1 Reactor Vessel - Upper North . CD 65 2.87 750 665 2 Reactor Vessel - Lower North DQ 83 63.6 500 580 2 Reactor Coolant Pump >1 (East) CD 82 2. 87 750 430 3 Reactor Coolant Pump 82 (West) DQ 95 63.3 500 660 3 Reactor Coolant Pump d4 (East) CD 49 2.83 750 650 4 Reactor Coolant Pump 83 (West) DQ 80 61.1 500 555 4 Steam Generator <1 (East) CD 55 2.77 . 750 450 5 10 Steam Generator <2 (West) DQ 71 60.1 500 550 5 Steam Generator ~4 (East) CD 51 2.75 750 560 6 12 Steam Generator 83 (West) DE 70 58.5 500 575 6 Six - 750 F Accel. (>2273) ~ 3'.S. 3075 Cable ~ Chg. Converter RG Coax Cable ~ Cont. Rm.

Six - 5000F Accel. (82233) ~ All Special Cable (>3090 8) ~ Control Room

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