ML18152A610

Proposes to Modify Relief Request 1 for Pump Testing in Current Inservice Testing Programs to Include Vibration Velocity Acceptance Criteria.Detailed Description of Proposed Relief Request Encl

ML18152A610
Person / Time
Site:	Surry
Issue date:	12/08/1987
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
86-670B, NUDOCS 8712110295
Download: ML18152A610 (4)

Text

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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 e

W. L. STEWA.JlT December 8, 1987 VXCE PRESXl>ENT NUCLEAR 0PERATXONS United States Nuclear Regulatory Commission Serial No. 86-670B Attention: Document Control Desk NO/JBL:vlh Washington, D.C. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS I AND 2 ASME SECTION XI VIBRATION TESTING CRITERIA The Surry Units 1 and 2 Inservice Testing Programs for Pumps and Valves are in accordance with ASME Boiler and Pressure Vessel Code Section XI, 1980 Edition, Winter 1980 Addenda. Pursuant to 10 CFR 50.55a(g)(5)(iii), we propose to modify Relief Request 1 for pump testing in the current Inservice Testing Programs to include vibration velocity acceptance criteria. The acceptance criteria is based on the ANSI/ASME OM-6 Standard dated July 1987, Draft 11, "In-Service Testing of Pumps."

The proposed vibration acceptance criteria replaces those given in Table IWP-3100-2, "Allowable Ranges of Test Quantities." The enclosed attachment provides a detailed description of the proposed Relief Request.

Should you require additional information, please contact us.

Very truly yours,

~l)~~

W. L. Stewart Attachment cc: U. S. Nuclear Regulatory Commission 101 Marietta Street, N.W.

Suite 2900 Atlanta, GA 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station

ATTACHMENT Page 1 of 3 RELIEF REQUEST 1 Systems: Various Pump(s): IWP Program Pumps. See PUMP INSERVICE TEST TABLE.

ClassSection XI Code Requirements For Which Relief Is Requested Measure pump bearing temperatures and vibration in mils.

Basis For Request Pump vibration and bearing temperature measurements are used to detect changes in the mechanical characteristics of a pump. Regular testing should detect developing problems, thus repairs can be initiated prior to a pump becoming inoperable. The ASME Section XI minimum standards require measurements of the vibration amplitude displacement in mils every three months and bearing temperatures once per year.

Our proposed program is based on vibration readings in velocity units rather than vibration amplitude in mils displacement. This technique is an industry accepted method which is more sensitive to small changes that are indicative of developing mechanical problems and hence more meaningful. Velocity measurements detect not only high amplitude vibrations that indicate a major mechanical problem, but also the equally harmful low amplitude high frequency vibrations due to misalignment, unbalance, or bearing wear that usually go undetected by simple displacement measurements.

In addition, these readings go far beyond the capabilities of a bearing temperature monitoring program. A bearing will be seriously degraded prior to the detection of increased heat at the bearing housing. Quarterly vibration velocity readings should achieve a much higher probability of detecting developing problems than the once per year reading of bearing temperatures.

Bearing temperature tests present problems which include the following:

1. Certain systems have no recirculation test loops and a limited source of water. An enforced thirty minute run time would deplete the source.

2. The lubrication fluid for some pumps is taken from the process water, which can change temperature depending on ambient conditions. Data trending for these cases is not meaningful.

Therefore, the detection of possible bearing failure by a yearly temperature measurement is extremely unlikely. The small probability of detection of a bearing failure by temperature measurement does not justify the additional pump operating time required to obtain the measurements. In addition, it is impractical to measure bearing temperatures on many pumps.

ATTACHMENT Page 2 of 3 RELIEF REQUEST 1 (CONT'D)

Alternate Testing Proposed Pump vibration measurements will be taken in vibration velocity (in/sec). The evaluation of the readings will be per the attached table. The ranges of test parameters given in the attached table were taken from ANSI/ASME OM-6-July 1987, Draft 11, An American National Standard In-Service Testing of Pumps.

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ATTACBMEltff Page 3 of 3 RELIEF REQUEST 1 (can't.)

RANGES OF TEST PARAMETERS (1)

PUMP PUMP TEST ACCEPTABLE ALERT REQUIRED TYPE SPEED PARAMETER RANGE RANGE ACTION RANGE e

Centrifugal (600 rpm vd $2.5 V >2.5V to 6V )6 V r r r r and Vertical Line Shaft but not >10. 5 mils but not > 22 mils 2".600 rpm V $2.5 V )2.5 V to 6V )6 V V r r r r but not >0.325 in/sec but not )0. 70 in/ sec Reciprocating  :;;2.5 V )2.5 V to 6V )6 V r r r r orV V

Note: (1) V is the vibration reference value in the selected units Vr is vibration displacement measured peak-to-peak, unfiltered Vd is vibration velocity measured peak, unfiltered V