ML18153B645
| ML18153B645 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 03/08/1989 |
| From: | Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 89-084A, 89-84A, NUDOCS 8903220399 | |
| Download: ML18153B645 (8) | |
Text
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e VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 W. R. CARTWRIGHT VICE PRESIDENT NUCLEAR March 8, 1989 United States Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D. C.
20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS I AND 2 ASME SECTION XI INSERVICE PUMP TESTING VIBRATION VELOCITY REFERENCE VALUES Serial No.
NO/ETS:vlh Docket Nos.
License Nos.
89-084A 50-280 50-281 DPR-32 DPR-37 In our February 22, 1989 letter (Seri al No.89-084) Vi rgi ni a Electric and Power Company provided a revised relief request for the Inservice Testing Program for Pumps and Valves.
We inadvertently omitted a technical paper that supports our revised relief request.
This letter provides the relief request and the technical paper.
Should you have any questions regarding this relief request, please contact us.
Attachments cc:
U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N. W.
Suite 2900 Atlanta, Georgia 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station
e RELIEF REQUEST P-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 in balance, 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 which can change temperature depending on trending for these cases is not meaningful, from the process water, ambient conditions.
Data 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.
l
e RELIEF REQUEST P-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.
2
PUMP PUMP TEST TYPE SPEED PARAMETER Centrifugal
<600 rp*
vd And Vertical Line Shaft 2:600 rpm V V RELIEF REQUEST P-1 (cont'd)
RANGES OF TEST PARAMETERS (1)
ACCEPTABLE ALERT RANGE RANGE S2. 5 V
)2.5V to 6V r
r r
but not >10.5 mils S2. 5 V (2)
)2.5 V to 6V r
r r
but not )0.325 in/sec
~..
REQUIRED e
ACTION RANGE
)6 V r but not > 22 mils
>6 V r but not >0.70 in/sec Reciprocating
~2.5 V r
>2.5 V to 6V r
r
>6 V r Note:
(1)
(2) orV V V is the vibration referenc*e value in the selected units Vr is vibration displacement measured peak-to-peak. unfiltered v! is vibration velocity measured peak, unfiltered_
Small values for V
will produce small acceptable ranges for pump operation.
Based on a small acceptable range, an idequately and smoothly running pump could be subject to corrective action.
To avoid this situation, a minimum value for V of 0.05 in/sec has been established for velocity r
measurements.
Pumps with a measured reference value below 0.05 in/sec shall have subsequent test results compared to an acceptable range based on 0.05 in/sec.
e PMC/BETA CORPORATION
[ Application Note 803 j DETERMINING VIBRATION WARNING LEVELS This Application Note provides three reference charts, namely: (1) Vibration Warning Level Guide; (2) Vibration Severity Chart; and (3) Vibration Identification Guide. Each is discussed as follows:.
Vibration Warning Level Guide
- 1. The attached Warning Level Guide indicates recommended starting points for vibration warning levels -
defined as levels at which abnormal wear is occurring. Vibration analysis is recommended at this levet Different warning levels are given for different types of machinery.
- 2. These ranges are typical. Each machine will have its own personality, depending on how it is loaded, the particular installation, and the tolerances of the machine itself. Thus, you must make the final judgment for your equipment.
- 3. Trend information is frequently as meaningful as absolute levels. Thus, an alternate method is to determine the existing vibration level (this is easily accomplished using a vibration meter such as the PMC 101 or 201) and setting the trigger between 25% and 50% above this.
- 4. If the existing level is near or above the upper end of the range noted in the Warning Guide, vibration analysis with an instrument such as the PMC 208 should be performed as soon as possible and corrective action taken. (See Vibration Identification Guide below.)
Vibration Severity Chart
- 1. Vibration Severity over the range of 500 RPM to 100,000 RPM is most directly expressed in terms of the vibrational velocity. The attached vibration severity chart shows typical severity levels from smooth to very rough and denotes possible consequences.
- 2. The severity chart is typical for machines with warning levels of.2 to.4 in/sec shown on ttie Warning Level Guide. For types of machines with higher or lower warning levels, the limits shown on the vibration severity chart should be correspondingly increased or decreased.
Vibration Identification Guide An instrument such as the PMC 208 Analyzer enables the user to determine how much of the measured excessive vibration is at the rotating shaft RPM and how much is at other frequencies.
This information is then used to aid in diagnosing the machinery fault as shown on the Identification Guide.
Additional Sources of Information
- 1. International Standards I S02372 and 3945 refer to vibration severity on machines operating in the 600 to 12,000 RPM range. Both specify velocity as the parameter to monitor. Copies may be obtained by writing: ANSI, 1430 Broadway, New York, New York 10018..
- 2. Vibration and Acoustic Handbook, Michael Blake & William Mitchell, Spartan Books, Chapter 12 discusses and gives sample severity Chart expressed in terms of velocity, 4 Tech Circle Natick, Massachusetts 01760 131 Northpoint Drive, Houston, Texas 77060 (6171 237-6920 Telex 94-8435 (713)820-2224 Telex 94-8435
SEVERITY CHART DISPLACEMENT -
MILS (PEAK TO PEAK)
VELOCITY LIMITS VERY ROUGH Danger of oil film breakdown.
(SHUTDOWN)
ROUGH Causes major wear.
FAIR Correct lo save wear.
GOOD Minor faults.
SMOOTH Normal for new equipment.
1-
.8-
.6-
.5-
.4-.
.3-
.2-
.07-
.0I-VERY BAD
'--+---..4-1---+--+4-~........ i..-,.c...-,4-,~~~__,,,q._-4-~13',,-~-+-J.-~~~,L-,,4--~_,,..'+-_,.'l---+......+~~-+4,~~
'-+--.'l-4--+-+-w41-."o-....~~...A----+o-'--+--~-+-4-1.... -i-.,j..........--,."....,.,&;j-,,.._-+,..._-+-_rt---+--+-+-........,~
.,~ BAD
., db
<I'
/
FAIR
/.;,
- Ort,
/*GOOD EXCELLENT o",* e
.os-
~--~~~H-+-H,i,,o'~Y~~-,,"-+?t-H-t-:¥t,-~~:74r-7'"-j'?"---t7...,-H~ti
~
w A. -
u w
(I) a:
w 0..
- u, w
- z:
0 z 0
0
..J w >
.04-.......,. ~~~+-+--,,,~+++hf:A-~~~-74--/--t---rt--+-t--b17'4P"'t:;h~~-xt---::r--r7't-1117'1*-'Kl
.01-.L---__.j,U:L.A~...d:._..1,t:_.J...1:JI..J.I...J.I.d,-----4, ""-'""-~~.A-J.1.1 -1,..... 11....11-1,.... ~---~,--~-~I ~.:-~,--:,-;, -:-, -:,
100 200 500 1000 2000 5000 10,000 20,000 50,000 100,000 R.P.M.
' -~
e PMC/BETA Corpor.on CHART No. 1 VIBRATION IDENTIFICATION GUIDE CAUSE FREQUENCY PtlASE-AMPLITUDE NOTES RELATIVE TO STROBE PICTURE MACHINE RPM Single Study Radial Steady U~nc9 1 X RPM Reference Mn Proportional Common Cause of Vibration To Unbalance DefectiYe Measure Velocity Velocity Largest at Defective Bearing Anti* Friction 10 to 100 X RPM Unstable 0.2 to 1.0 in/sec As Failure Approaches Velocity Signal eeannc Radial Will Increase, Frequency will Decrease Sleewe 1 X RPM Single Reference Not Large Shaft and Bearing Amplitude About Bearing Mark The Same Mlsal9MM"t 2 X RPM Usually 2 Steady High Axial Axial Vibration Can Be Twice Radial.
Coupling cw Sometimes 1 or 3 Reference Marks Use Dial Indicator As Check.
Btwing RPM Sometimes 1 or 3 Bent Shaft 1 or 2 X RPM 1 or 2 High Axial Defective High.
Radial Use Velocity Measurement Gan RPM X Gear Teeth Mechanical 1or2XRPM 1 or 2 Proportional Radial Vibrational Largest Looseness To Looseness In Direction Of Looseness.
Defective Belt RPM X 1 cw :
Erratic Strobe Lite Will Freeze Belt.
Belt Electrical Power Line 1 or 2 Rotating Usually Low Vibration Stops Instantly Frequency X 1 or 2 Marks When Power Is Turned Off.
(3600 or 7200 RPM)
Oil Yttlip Less Then RPM Unstable Radial -
Frequency Maybe As Low As Unsteady Half RPM.
Aerodynamic 1 X RPM<<
May Cause Trouble In Case Number of Blades Of Resonance.
On Fan X RPM Beat 1 X RPM Rotates At V*iable At Caused By Two Machines Running Frequeney S.t Rate But Rate At Close R.P.M.
Resonance Specific Single High
"'9w Will Ctlange With 5pNd. Amplitude Critlcals Reference Mark Will Decrease Above And Below AIIONnr Sc,M. Anonanca Can Be AITTIOVed From Ope,arive Aenga By Stitteni,.._
VELOCITY (IN/SEC) 1.0
.5
.1
.05 0
.2
.05 VIBRATION WARNING LEVEL GUIDE
- MOTOIS/GENEIA TOI SETS:
ELECTRIC DIIVEN
~
LLJ
- GEAI IOXES
- PUMPS:
- HAMMERMILL (UNLOADED) l.2 *5 1 GEAI CENTRIFUGAL
- ELECTIICAL MOTOIS CJ 2
- COMPIESSOIS CENTI I FUGAL rsi
~ LL.J LL_j
- CONVEYORS
- FANS/ILOWEIS
- MACHINE TOOLS (UNLOADED)
- TUIIINES The Warning Level Guide indicates recommended starting points for vibration warning levels -
defined* as levels at which abnormal wear is occurring. Vibration analysis is recommended at this level.
. -~
[ Application Note 803 /
CJ
- l'ACKAGING ~
MACHINERY CJ...
.6
- CIUSHEltS (UNLOADED)
- ENGINES
- ,uM,s=
IECIPIOCATING
- MOTOI/GENEIATOI SETS:
ENGINE DRIVEN
- COMPRESSOIS:
IECIPIOCATING
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