RECIRCULATION SYSTEM TESTINGSTEAR 8301

BROWNS FERRY NUCLEAR PLANT

CONTENTS

Page

1. Introduction . ~ ~ ~ ~ ~ 1

1.1 Ob]ective .1.2 Background1.3 Reactor Recirculation System Description ~ ~

~ 1

~ 1

2. Test Methodology . ~ ~ 4 ~ ~ ~ ~ ~ 3

2.1 Sensor Locations2.1.1 Accelerometers .2.1.2 Position Transducers .2.1.3 Proximity Probes .2.1.4 Strain Gages .2. 1.5 Thermocouples2.1.6 Moisture Sensors .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ 0 ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ l ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ t ~ ~ ~ ~ ~ ~ ~

~ 3~ 3~ 3~ 3~ 3

44

2.2 Signal Conditioning .2.2.1 Charge Amplifiers2.2.2 Strain Gage Amplifiers .

~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~

2.3 Sensor Calibration/Operability Checks2.3. 1 Acceler ometers .2.3.2 Position Transducers .2.3.3 Proximity Probes2.3.4 Strain Gages .2.3.5 Thermocouples2.3.6 Moisture Sensors .

~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~

5556666

2.4 Data Acquisition System . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 6

2.5 Data Acquisition ~ ~ 4 7

3. Data Processing. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 7

Test Results . ~ ~ ~ ~ ~ ~ ~ ~ 7

4.1 Accelerometers.4.1.1 Noise Condition4.1.2 Shutdown Cooling

~ ~ ~ ~ ~

with RHR~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ t ~ ~ ~ ~ ~ ~ ~ ~ 4 78

~ 9

4.2 Strain Analysis . ~ ~ ~ ~ ~ 9

830823043b 8308li .

PDR ADOCK 05000260P PDR

l t

~rt '

CONTENTS

(Continued)

Page

5. Conclusions ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1 1

6. References ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1 1

Appendixes

A. Test Conditions

List of Tables and Fi r es

Tables

Page

Average Blade Pass (5X) Vibration with Both Recirculation Pumpsoperating near 1,260 rpm . . . . . . . . . . . . . . . . . . 13

2. Piping Displacements

F~lr as

e ~ ~ ~ e ~ s ~ ~ ~ 1

Recirculation System Xsometric2. Loop A Accelerometer Locations3. Loop B Accelerometer Locations

RHR Accelerometer Locations .5. Strain Gage and Position Transducer Locations .6. ARET Spectral Plot/0 to 200 Hz

tt7. ARET Spectral Plot/0 to 800 Hz8. ARET Spectral Plot/0 to 3,200 Hz9. ARET Spectral Plot of Blade Pass Vibration Amplitudes .

10. AECBV Spectral Plot of Blade Pass Vibration Amplitudes11. ARAR Spectral Plot of Blade Pass Vibration Amplitudes .12. ARLBV Spectral Plot During RHR Operation13. ARLBV Spectral Plot During Resonance14. AECBV Spectral Plot During RHR Operation15. AECBV Spectral Plot During Resonance16. Loop B Out-of-Plane Spectral Plot of Displacement and Strain17. Loop B Out-of-Plane Spectral Plot of Acceleration and Strain18. Loop B Out-of-Plane Spectral Plot of Coherence and Phase

15161718

~ 1920

~ 212223242526272829303132

I

List of Abbreviations

rpm - Revolutions per minuteHz - Hertzac - Alternating currentdc - Direct currentdB - decibelV — VoltRCS - Reactor coolant systemmicro in/in - micro inch/inchIRIG - Inter-range instrumentation groupips - inch per secondkHz - kilohertzMWe - MegawattsRHR - Residual heat removalg - Gravitational aoceleration at sea level5X - 5 timesksi —,kilopounds per square inohpsi - pounds per square inchmicro in/in/mil - micro inch per inch per mil

I k

'1

1

,I

1 ' INTRODUCTION

1.1 ~Ob eotXve

The objective of this test was to determine whether indicationsfound on reactor recirculation system risers A2E and A2F at theKR-2-36 (loop B) and KR-2-10 (loop A) sweepolet-to-manifold weldscould have been initiated by system piping vibration duringstartup and operation of the unit 2 reactor.

1.2 ~Bank round

Recirculation system testing conducted in December 1979(BF STEAR 7903) and site observations during star tup of theunit 2 reactor revealed that, during operation of the recit cu-lation pumps in the balanced flow mode at approximately 1260 rpm,a loud, audible noise could be heard in the unit 2 reactor andcontrol areas. Test results indicated that the noise was possi-bly caused by flow-induced vibration which excited a resonance inthe recirculation system piping. Additional testing was sched-uled in March 1980 to further define the source of the excitationand to determine whether corrective action was necessary, but itwas subsequently postponed.

During the cycle 0 refueling outage, TVA examined the sweepolet-to-manifold welds nearest the manifold end caps in response to anNRC region II request. This examination detected a total of fourunacceptable indications in the KR-2-36 and KR-2-14 welds. TVA'smetallurgical analysis (reference 1) of the outside surface ofthe pipe in the vicinity of the indications did not reveal anysign of sensitization; therefore, the indications were believedto be fatigue-induced.. This assumption was supported by thefollowing facts:

1. The subject sweepolet-to-manifold joints would most likelyexperience fatigue problems because of the expected highervibration near the free ends of the recirculation manifold.

2. The indication locations in the sweepolet joints are in ahigher stress area and would be susceptible to fatiguecracking if subjected to vibration-induced cyclic stresses(reference 2).

3. Previous experience would indicate the possibility ofrecirculation system piping vibration during balancedoperation of the recirculation pumps.

1.3 Reactor Recirculation S stem Descri tion

The reactor recirculation system is designed to provide forcedcooling of the core and a variable moderator (coolant) flow tothe reactor core for adjusting reactor power level.

The system consists of the two recirculation pump loops externalto the reactor vessel which provide the driving flow of wate'r tothe reactor vessel )et pumps. Each external loop contains onehigh-capacity, motor-driven recirculation pump and two motor-operated gate valves for pump maintenance. Each pump dischargeline contains a venturi-type flowmeter nozzle. The recirculationloops are a part of the nuclear system process barrier and arelocated inside the drywell containment structure.

Each recirculation pump is a single-stage, variable-speed, ver-tical, centrifugal pump equipped with mechanical shaft sealassemblies. The pump is capable of stable and satisfactoryperformance while operating continuously at any speed corre-sponding to a power supply frequency range of 11.5 to 57.5 Hz.For loop startup, each pump operates at a speed corresponding toa power supply frequency of 11.5 Hz with the main discharge gatevalve closed.

Each recirculation pump motor is a variable-speed, ac electricmotor which can drive the pump over a controlled range of 20 to102 percent of rated pump speed. The motor is designed tooperate continuously at any speed within the power supplyfrequency range of 11.5 Hz to 57.5 Hz. Electrical equipment isdesigned, constructed, and tested in accordance with theapplicable sections of the NEMA Standards. A variable-frequency,ac motor -generator set located outside the dr ywell supplies powerto each recirculation pump motor. The pump motor is electricallyconnected to the generator and is started by engaging thevariable-speed coupling between the generator and the motor.Minimum speed corresponds to a frequency of 11.5 Hz.

The recirculated coolant consists of saturated water from thesteam separators and dryers which has been subcooled by incomingfeedwater. This water passes down the annulus between thereactor vessel wall and the core shroud (see figure 1). A

portion of the coolant exits from the vessel and passes throughthe two external recirculation loops to become the driving flowfor the Jet pumps. The two external recirculation loops eachdischarge high pressure flow into an external manifold from whichindividual recirculation inlet lines are routed to the jet pumprisers within the reactor vessel. The remaining portion of thecoolant mixture in the annulus becomes the driven flow for theget pumps. This flow enters the get pumps at the suction inletand is accelerated by the driving flow. The driving and drivenflows are mixed in the get pump throat section resulting inpar tial pressure recovery. The balance of recovery is obtainedin the get pump diffusing section (reference 3).

2.0 TEST METHODOLOGY

2.1 Sensor Locations

2.1.1 Accelerometers

Endevco model 2273 AM20 high-temperature; radiation-hardened acceler ometer s were used to detect recirculationsystem piping vibration. The accelerometers were attachedat selected locations using special clamps fabricated forthis purpose. The mirror insulation was also modified asrequired to accommodate each accelerometer and itsassociated instrumentation cables. The accelerometerlocations are shown schematically in figures 2, 3, and 4.

2.1.2 Position Transducers

Houston Scientific International, Inc., series 1850position transducers were used to measure the thermalgrowth of the recirculation loop header during heatup andlow frequency piping vibration. Three transducers weremounted triaxially near each of the end cap locations.Special mounting clamps, similar to those fabricated forthe accelerometers, were used in the installation of thetransducers. Also, each position transducer was shieldedwith lead foil to decrease its radiation exposure.

2.1.3 Proximit Probes

A Bently Nevada 7200 series proximity transducer systemwas used to monitor the recirculation pump speeds. Twotransducers, an active and a redundant, were mounted oneach pump for this purpose. Small "L" brackets werefabricated and attached to a water seal bolt so that theproximity probe was aligned with the keyway in the motorshaft.

Ailtech model SG 125 high-temperature, weldable straingages were used to measure the static and dynamic strainsin the recirculation loop piping during the unit heatupand operation. Each gage was individually welded inplace using a low-energy, capacitive discharge weldingtechnique. After installation, the gages were protectedfrom damage by covering them with a fiberglass mat and by

indenting the mirror insulation to prevent surface contactstrains. Figure 5 illustrates the locations wherethe gages were installed.

Type T, copper-constantan thermocouples were secured tothe recirculation loop risers A2E and A2F to measure thesurface temperature of the pipe during testing. Thethermocouples were installed to aid in the evaluation ofthermal-induced pipe growth.

2.1.6 Moisture Sensors

A Techmark model TUM 100 leak detection system wasinstalled on the recirculation system header with themoisture sensors located near each of the four unaccept-able indications. The system was installed as a precau-tionary measure only to detect leaks resulting fromthroughwall crack propagation.

2.2 Si nal Conditionin

2.2.1 Char e Am lifiersThe accelerometers used in this test were thepiezoelectric type. This type of sensor consists of apiezoelectric crystal which develops an electric chargewhen deformed; deformation is a result of vibration sensedby the accelerometers. Preamplifiers or charge converters(Unholtz-Dickie model RCA-2TR) convert the electricalcharge to a voltage signal and allow the signal to betransmitted through long cable runs with little signaldegradation or noise induction. Charge amplifiers(Unholtz-Dickie model D22PMHS) amplify the sensor outputsto usable levels for recording.

2.2.2 Strain Ga e Am lifiersBell and Howell type 1-183 strain gage amplifiers wereused to condition the signals generated by the straingage transducers. The amplifiers provide a wide range of

signal conditioning for transducers in a Wheatstone bridgeconfiguration; the features include adjustable bridgeexcitation, signal amplification from 0.1 to 10,000,variable offset adjustment from -10 to +10 volts, and aninternal, switch selectable, 12 dB per octave, low passfilter. These features afford a wide signal dynamic rangeby reducing dc offset and extraneous noise contamination.

To be compatible with Ailtech model SG 125 strain gagesin a 1/4 arm, self temperature compensated configuration,bridge completion and shunt calibration resistors wereinstalled on the local calibration boards in the 1-183amplifiers. The gain of each amplifier was adjusted for100.

2.3 Sensor Calibration/0 erabilit Checks

2.3.1 Accelerometers

Each accelerometer/charge converter/hardline cable combi-nation was calibrated with a shaker table in the Vibrationand Diagnostic Section's lab; the accelerometers were thenremoved and replaced by an Endevco model 4815A

acceler-'meter

simulator. The simulator sensitivity was adjusteduntil a calibration signal equivalent to that of theshaker-driven accelerometer was obtained. This value wasrecorded for each acceler ometer/hardline cable/chargeconverter combination. As the accelerometers wereinstalled on the recirculation system piping, the simula-tor sensitivity was matched to the previously tabulatedvalue and the charge amplifier sensitivity adjusted,toobtain the proper calibration signal. This procedureensured, with a minimum of personnel exposure, that thehardline cable, charge converter, field-routed cable, andcharge amplifier were operable and calibrated. The simu-lator was then removed and the hardline cable attached tothe installed accelerometer. Each accelerometer wasverified operational by tapping its mounting block lightlywith a small metal object and listening to its response.The calibration data were recorded for future reference.

2.3.2 Position Transducers

Each position transducer was supplied 1-V dc excitationand verified operational by monitoring the transduceroutput while extending and retracting the transducercable.

2.3.3 Proximit Probes

Each proximity probe was supplied minus 24-V dc power.The probe-to-target surface gap was ad)usted duringrecirculation pump operation until stable, twice perrevolution pulses could be obtained; the pulses weregenerated each time the two motor shaft keyways passed theproximity probe. External instrumentation was used tomeasure the time between pulses and display the pump speedin rpm.

'ach

strain gage channel was calibrated after gageinstallation using shunt calibration resistors in theamplifiers to simulate approximately 1,300 micro in/in and2,600 micro in/in compressive loads. The calibration wasreferenced from zero strain at a RCS temperature of 200oF(dictated by unit conditions during the calibration).Thermocouple temperatures and position transducer voltageswere also recorded at this reference point.

Before installation, each thermocouple was verifiedoperational by comparing the indicated drywell airtemperature with the temperature measured by permanentplant instrumentation.

2.3.6 Moisture Sensors

The Techmark TUM 100 system was ad)usted and verified tobe operational by a vendor representative. Daily checksare made by site personnel to ensure leak detection systemoperation and pipe integrity. No leak detection informationwill be submitted in this report.

2.4 Data Ac uisition S stem

All test data were recorded on two Honeywell model 101 frequencymodulated (FM), 14-channel, 1-inch magnetic tape recordersconfigured to IRIG wide band group 1. The data tapes wererecorded at 3-3/4 ips providing an effective signal bandwidthfrom dc to 2.5 kHz.

Channel 8 of each tape recorder was dedicated for servo controland time code signals. The servo control signal provides areference to the servo control system to minimize speedvariations during recording or playback. The time code signalprovides time references for data correlation.

Test signals were recorded on the remaining 13 channels.Selected signals were recor ded on both tape recorders so thatthey could be used for cross correlation during data analysis.

2.5 Data Ac uisition

Test data were recorded on the Browns Ferry unit 2 recirculationsystem starting with the vessel hydro and concluding at a unitgenerator load of 1050 We. During each data set, all relevantparameters were recorded on tape data sheets for futurereference.

3.0 Data Processi

Test signals were reproduced on a Honeywell model 101 instrumentationtape recorder and principally analyzed with a Hewlett-Packi d 5423Astructural dynamics analyzer. The analyzer is a two-channel, fast-Fourier-transform based signal analyzer capable of several time domainand frequency domain measurements. As a part of its broad measurementcapability, the 5423A provides complete facilities for analyzing thevibration characteristics of mechanical devices and displaying animatedmode shapes. Test signals were also examined with a Nicolet Explorer XXdigital oscillosoope and audibly using filters, amplifiers, andspeakers.

4.0 Test Results

4.1 Accelerometers

Vibration information obtained on the unit 2 recirculation systemduring heatup through full power operation revealed the following .

information:

A. The most significant vibration amplitudes occurred during poweroperation at approximately 950 We with both recirculationpumps operating at approximately 'l,260 rpm. Near these pumpspeeds, audible noise characteristic of beating could be heardthroughout the reactor building and in the control areas.

B. During RHR system operation for shutdown cooling with RHR pumpsA and C running, the recirculation system experienced nosignificant vibration amplitudes at any of our instrumentation

-8-

locations. However, the general overall or backgroundvibration was higher during RHR operation. This condition isindicative of flow noise caused by turbulent flow, cavitation,or by both mechanisms.

4.1.1 Noise Condition

Recirculation system vibrations peaked during powerascension at approximately 950 MNe with both recirculationpumps operating near 1,260 rpm. The predominate vibrationfrequency was 5X the recirculation pump speed. This isknown as the blade-pass frequency of the pump. Figures 6,7, and 8 show the difference between the blade-passfrequency amplitude (5X) and other spectral information forbandwidths of 0 to 200 Hz, 0 to 800 Hz, and 0 to 3,200 Hzfull scale respectively, for aocelerometer ARET. Similarinformation was obtained at each accelerometer location.

Data analysis was then concentrated on the blade-passfrequency by altering the 5423A analyzer's center frequencyand bandwidth adjustments to allow for greater data resolu-tion. Plots were generated to illustrate the blade-passfrequency amplitude at seleoted recirculation pump speeds.Samples of these plots are presented in figures 9, 10, and11 for accelerometers ARET, AECBV, and ARAR respectively.Notice that the approximate pump speeds are indicated abovethe blade-pass frequency peaks in each figure. The analysisclearly showed that pump operation near 1,260 rpm excited asystem resonance. During this condition, audible nois'escharacteristic of beating could be heard in the unit 2reactor and control areas. The noises varied in amplitudeas the driving forces (blade-pass) moved in and out ofphase; at one point reinforcing each other and at anothercanceling each other. The beat frequency was verified toincrease as the pump speeds were separated; the beat andnoise disappeared altogether as the pump speeds were movedout of the resonant range. There was no measureablevibration at the beat frequency.

The above observations, and the fact that large pipingsystem fundamental resonances normally occur at frequenciessignifioantly less than 40 Hz, would indicate that theincreased vibration during pump operation at 1,260 rpm iscaused by a hydraulio resonance in the recirculation systempiping. The resonance ocours when pressure waves traverse.the recirculation system piping at the speed of sound andreflect off its boundaries (reference 4).

Average vibration levels for each accelerometer arepresented in table 1. The vibration varied according tothe phase relationship between the driving forces. Themaximum vibration levels occur red on riser E, in thetangential direction (ARET), with both pumps at

approximately 1,260 rpm. The levels occasionally reached1. 1g at 105 Hz (5X) which corresponds to a 0.002 inchdisplacement. All other accelerometer locations experiencedless vibration than acoelerometer ARET.

4.1.2 Shutdown Coolin with RHR

Before the unit 2 heatup, test data were obtained at theinstrumented locations on the recirculation system andselected locations on the RHR system. The RHR was config-ured for shutdown cooling with RHR pumps A and C in opera-tion. In this mode, the RHR pumps draw suction fromrecirculation loop A (shutdown supply line, see figure 2)and discharge through two heat exchangers. Theysubsequently supply cooling water to the reactor throughthe RHR return line which is attached to the recirculationsystem loop B piping (see figure 3). While in this modeof operation, no significant vibration levels were notedat any accelerometer locations. A comparison of spectralplots during the beat condition (figures 13 and 15) andduring RHR operation (figures 12 and 14), clearly show thehigher broad band background noise levels during RHR-

oper ation. The higher broad band vibration levels areindicative of flow noise. Figures 12 and 13 illustratethis point for accelerometer ARLBV. In this case, thedifference is more noticeable because no flow exists inthe RHR system during power operation; however, similarinformation was obtained at other accelerometer locationsas shown in figures 14 and 15.

4.2 Strain Anal sis

Strain gages and position transducers were located, as shown infigure 5, on the A2F (loop A) and A2E (loop B) recirculationsystem risers to measure the thermal and ser vice-induced loadingduring unit operation. In-plane (movement in the two-dimensionalplane of the riser and the header) and out-of-plane (movementorthogonal to in-plane) were selected as the principal orienta-tions of the gages because of the risers'usceptability tofatigue-induced cracking in those directions. Also, the indica-tions found in the manifold were in a region where fatiguecracking could be expected. Position transducers were mountedtriaxially at approximate header azimuths of 140o and 220o.

Data recorded during the testing were analyzed assuming thefollowing.

1. The modulus of elastioity for the header and riser piping was28.5 ksi.

-10-

2. The measured strains were in the linear-elastic range and couldbe evaluated using Hooke's law.

3. The strain gages were temperature compensated for 304SS.

In-plane and tangential measurements were collinear.

5. Out-of-plane and radial measurements were collinear .

6. The referenoe point for all calculations, zero strain and zeropipe displacement, was at a RCS temperature of 200oF.

Based upon the above assumptions, the maximum strain levelsrecorded near the subject indications immediately above thesweepolet-to-riser welds were in the out-of-plane direction onboth risers (see figure 5) during heatup but before loading theunit. Loop A static strains peaked at approximately 570 microin/in (16.2 ksi) while loop B strains in the same condition were450 micro in/in (12.8 ksi). Dynamic strains were negligiblethroughout heatup. Piping displacements, as indicated intable 2, were also at a maximum during heatup with a resultantdefleotion on the A and B loops of 0.90 and 0.78 inchrespectively.

During power ascension, strains deoreased and stabilized atapproximately 530 mioro in/in (15.1 ksi) on the A2F riser and430 micro in/in (12.3 ksi) on the A2E riser. Assuming strainlinearity from ambient to 200oF, these measurements would havepeaked at approximately 750 micro in/in (21.4 ksi) and 610 microin/in (17.4 ksi). Data analysis proved this assumption to beconservative beoause of a decreasing slope (hmicro in/in/ARCStemperature) as the RCS temperature approached 200oF.Alternating strains imposed on the static strains during theresonant condition peaked at 1.2 micro in/in (34.2 psi) and2.4 mioro in/in (68.4 psi) on the A2F and A2E risers. The cyclicstrains were measurable only with both pumps operating atapproximately 1,260 rpm; the frequenoy of the cyclic strains was.105 Hz (the blade-pass frequenoy).

Dynamio strains in the in-plane direction were also at a maximum

during the resonant condition; the highest .level recorded on theA2E riser was 0.86 micro in/in (24.5 psi). Static measurementswere not available at this looation. Position transducer data,however, would indicate that in-plane static strains were less thanstrains in the out-of-plane direction.

As with the strain gages, the deflections measured by the positiontransducers decreased when the unit was loaded and remainedstable throughout power ascension. The resultant A and B loopheader displacements during operation were 0.82 and 0.70 inchrespectively. Vibration amplitudes during all modes of operationwere lower than the resolution of the position transduoers.

Averaged spectra, examples of which are displayed in figures 16,17, and 18, illustrate the similiarities between typicalaccelerometer and strain gage measurements in the same direction.Neglecting 60 oycle noise and its harmonics, figures 16 and 17identify 105 Hz as the predominant mode of vibration while figure18 verifies the coherence of the measurement. Based upon thecollinearity of the transducers and the coherence of the spectralplots generated from each strain gage/accelerometer, an averagesensitivity of 4.1 micro in/in/mil displacement was calculated.This sensitivity was applicable when evaluating dynamic strainsduring all modes of operation. Using this sensitivity along withstrain measurements near the ARER accelerometer, vibrationamplitudes at the ARER location during the noise condition werefound to be less than the ARET accelerometer.

The remaining strain gages, located on the sweepolet-to-manifoldwelds, were only installed to measure the response of the gages ona weld. Since these measurement locations were not consideredappropriate for general testing purposes, data obtained from thesetransducers were not included in the data analysis.

5.0 Conclusions

Vibration and strain levels were measured on the unit 2 reactorreoirculation system piping during startup and operation of the unitfollowing the oycle 4 refueling outage; the measured levels were notconsidered to be of sufficient amplitude to initiate fatigue-inducedcracking in the sweepolet-to-manifold welds. The maximum vibratiorilevels ocourred during power operation with both recirculation pumpspeeds near 1,260 rpm. Vibration amplitudes peaked to 1.1g at 105 Hzon aocelerometer ARET. Similiarly, the statio/dynamic strains for loopsA and B were 530 micro in/in (15.1 ksi)/1.2 micro in/in (34.2 psi) and430 micro in/in (12.3 ksi)/2.4 micro in/in (68.4 psi) respectively.

. Thus, under the present operating conditions, the sub)ect indicationsin the sweepolet-to-manifold welds could not solely be attributed tofatigue.

6.0 References

1. Metallurgical Report, TVA Document No. L29830113934 AnalysisReport, Browns Ferry Nuolear Plant unit 2 Field Metallography onReactor Recirculation System Headers November 10, 1983

2. Battelle Memorial instituteColumbus Laboratories506 King AvenueColumbus, Ohio 43201

Fatigue Evaluation of SweepoletBranch Connections in Carbon Steel Pipe

toBonney Forge and Foundry, Inc.May 15, 1970

3. Browns Ferry FSARVolume 2, section 4.3

4. Formulas for Natural Frequency and Mode Shape, Robert D. Blevins,Ph.D. Van Nostrand Reinhold Company, copyright 1979.

JJS:VD7/22/83

B4174A.KH

-13-

Table 1

Average Blade Pass (5X) Vibration with Both Recirculation PumpsOperating near 1,260 rpm

Sensor Designation1

ARARARAT

ARCVARCRARCT

AECBVAECBRAECBT

A Pump2

(g peak)

o.450.07

o.o60.18o.o4

0.100.180.05

8 Pump2

(g peak)

0.240. 13

0 ~ 200.120.05

o.440.31o.14

ARERARET

ARFR

AECARAECAT

ARHR

ARHT

APAVAPBV

ARLAVARLBVASLAR

o.14

0.26

0.14

0.100 ~ 05

0.07o.o4

0.150.03o.o6

Inoperable

Inoper able

o.74

0.08

o.16

o.14o.o4

0 ~ 110.06

0.020.260.02

The location and orientation of each accelerometer are shown in figures 2,3, and 4.

During the beat condition, the recirculation pump speeds are slightlyunbalanoed causing slight differences in each pumps'lade pass vibrationamplitude component. The 5423A analyzer, by virtue of its enhanced data

'esolution capabilities, accurately identifies both frequency and averageamplitude of both pumps 5X vibration. This is averaged information; theaotual peak vibration levels were higher.

-14-

Table 2

Piping Displacements

RCSPRESS TEHP LORD

LOOP Fl

PECAR PECRT PECRV R

LOOP B

PECBR PECBT PECBV

8 28845 273129 334258 391388 395388 488

. 312 488325 416369 428323 428489 446552 459588 461562 467648 471742 485788 486945 515945 516947 513968 515968 „ 5151888 '545

88

88

88868888888

8888788

8 ~ 88~ 85.28.46.52~ 53~ 55~ 55.58.55.64.78I69~ 72~ 72.75~ 76.83~ 79.85.85.85.78

8. 88-~ 85

-~ 89

—. 15-. 16-

~ 16—

~ 18-. 17-. 18-. 18-. 21—

~ 24~ 22-. 24~ 23

-. 24"~ 24-

~ 26—

~ 27-0 27-. 28—

~ 28—

~ 26

8 ~ 88.86.87.85~ 84.04.64.84.84.84.85.Gi.85.82~ 85.84~ 85.85.84.84.83.82~ 82

8. 88.89~ 23.48.55.56.58.58.61.58.68.74~ 72.76.76.79.88.67.83.89.98.89.82

8. 66.20.28.42.43~ 44.46.46.48.45.53.58.57.58.59 ao62.63..69.69.76.76~ 75.68

8.88-. 81-. 84—.87-. 18-. 18-. 18—.16". 18-. 18-. 13—. 14—.13-. 15-. 14-. 14—.14-.15—.14-. 14".14—.14—.13

8. 88~ 89~ 11.88.88.Gi

-.86.68.06.81.620 ~ 66.83

—.81.83.83.83.83.88.88.88.67.86

8. 88~ 22.31.43.44.46.47.47.49.4?.55.59.59. 68.61.64.64.71.71.78.78~ 77~ 78

R denotes resultant displacement (inch)

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Figure 1

Recirculation System Isometric

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APAVFigure 2

Loop A Accelerometer Locations

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Figure 3

Loop B Accelerometer Locations

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ARLBY

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LOOP A U~~ gAE ZOOP A RETURN CtNEI

ARLAV

Figure 4RHR Accelerometer Locations

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40'C

ICSOVA KloofIKI47IQL IZllAN

gr atsiovy~ir

CL SSO ~

vie.vt

X denotes strain gage locations+ denotes position transducer locations

Ll N N~ L~'~ lfLl004 SHP eCLO >f(IKIAltICte vctT og. e[ sg,

~ ~ C[ (gO s(au Figure 5

Strain Gage and Position Transducer Locations

-20-

h SPEC 1

1. 28888'hc 188 EXPhNO

hRET. 3G. III91. 897. 88. 37. 88

HAG

Figure 6ARET Spectral Plot/0 to 200 Ilz

I

I /-21-

A SPEC 1

1. 2888PAN 188 EXPAND

ABET. 3G. )Hl. 897. 88. 37. 88

5X

HAG

Figure 7ARET Spectral Plot/0 to 800 Hz

h SPEC 1

1. 2888aha 188 EXPANO

ABET, 3G. f191. 897. 88. 37. HH

5X

NAG

Figure 8ARET Spectral Plot/0 to 3200 Hz

A'SPEC 1

1. HHHH

//Ac 28 EXPAND

ABET

SX

HI-RES

HAG

/320

//82

/2Z2+<5

8. 8

98. 888 HZ

Figure 9ARET Spectral Plot of Blade Pass Vibration Amplitudes

-24-

/262

A SPEC 1

588. 88Pha 28 EXPAND

AECBV

/288 5XHI-RES

/2<3

MAC

/320

/345

//82

98. 888 HZ

Figure 10AECBV Spectral Plot of Blade Pass Vibration Amplitudes

-25-

h SPEC 1

588. 88Pha 28 EXPAHO

/262/288

hRAR

SXHI-RES

HhG

/222/320

/345

082

98. 888

Figure 11

ARAR Spectral Plot of, Blade Pass Vibration hmplitude

-2G-

A SPEC 2588. 88

PA) 188 EXPAND

ARLBV. 188G. 813. 873. 11. 24. 88

MAG

Figure 12ARLBV Spectral Plot During RHR Operation

C )I

C n-27-

h SPEC 2588. 88

Phs 188 EXPhNO

hRLBV. 3G, )$89. 896. 23. 57. 88

MAG

Figure 13ARLBV Spectral Plot During Resonance

t > yL

-28-

h SPEC 2288. 88

PA> 188 EXPAND

AECBV. 38G. 812. 873. 18. 47. 88

Figure 14AI,"CBV Spectral Plot During IUIR Operation

-29-

h SPEC ZZHH. 88

Pha 188 EXPAHO

AECBV. 3G, 091, 897. 88. 37. 8

HAG

HZ

Figure 15hECBV Spectrnl Plot During lhesonance

-30-

A SPEC

A SPEC 2Phs 258 EXPAND

Phs 258 EXPAND

28. 888

iii98, 97. 88. 11. 8 ~i-'R

GOAELBR. 18H1L. GREEN

SBRDP6. 18UE. RED/05

/20/80

LGHAGDB

LGHAGDB

t

........ -28. 888

288. 88

Figure 16Loop 8 Out-of-Plane Spectral Plot of Displacement and Strain

-31-

A SPEC 1

A SPEC 295. 888

2liL HM L

Phs 158 EXPAND

PAa 158 EXPAND

L

115. QQ

898. 97. QQ. 11. P4"IAECBH. 1QG, HEO

SBROPG. 1QUE, BLUE

/05

LGHAGOS

LGt<AGOB

j

J

-BH. QHQ)

95. 888 115. QQ

"ZH. HHH

Figure 17Loop B Out-of-Plane Spectral Plot of Acceleration and Strain

~ g t ) '

COHER

TRbl'jS

2. BHHH

95. BQB

O'As 158 EXPAHD

PA) 159 EXPAt j[3

898, 97. 88. 11. )J4-4AECHR-SBROi'6

115. M

..258. 88

! '1

j)sl

~ 1

~al l)~ )

~I

I

tIi tI1 !! I ~

I!

!

l

lqii',

) ~

~ 1

l;l

~

l

lI i,'!

liI)l',;! i,i t, i

'1! ~

I1

PHAGE.

i t"

95. 888

r--115. 88

-258. HB

Figure 18Loop 8 Out-of-Plane Spectral Plot of Coherence and Phase

0l )

0

APPENDIX A

TEST CONDITIONS

Data Set Number Test Conditions

~Ta e No. 1

1 through 6 Vessel hydro/various pressures andrecirculation pump speeds.

7 through 16

17 through 19

~Ta e No. 2

Shutdown cooling/various RHR pumps in service.

Recirculation pump A in operation only, RCStemperature <200oFe

20 through 25

26 through 38

39 through 44

Both recirculation pumps in service atspeeds <500 rpm.

Unit heatup.

Power operation/recirculation speeds C500 rpm.

~Ta e llo.

45 through 49 Power operation/r ecirculat ion speedsapproximately 580 rpm.

50 through 51

52 through 54

Power operation/recirculation speedsapproximately 680 rpm.

Power operation/recirculation speedsapproximately 725 rpm.

55 through 78 Power operation/preconditioning to full power,reoirculation speeds from approximately 740 to1,025 rpm.

Note: Unit 2 removed from service for repairs.

~ .

l'

~Ta s No. 4

79 through 81 Power operation, 990 MWe/recirculation speedsapproximately 1,430 rpm.

Note: Unit 2 generator load reduced to aocommodate system conditions.

82 through 87

88

Power operation, 900 to 960MWe/preconditioning, recirculation speeds fromapproximately 1,160 to 1,265 rpm.

Power operation, 960 MWe/recirculation speeds .

are unbalanced, A = 1,238 rpm; B = 1,265 rpm.

89 through 94 Power operation, 970 MWe to 1,000MWe/preconditioning, recirculation speeds fromapproximately 1,260 to 1,345 rpm.

~Ta s No. 5

95 through 103 Power operation, 1,000 MWe to 1,055MWe/preconditioning, recirculation speeds fromapproximately 1,345 to 1,470 rpm.

~ lfL t

j t "a e

r I