PERFORMANCE EVALUATION OF A

CONTAINMENT SUMP AT FULL SCALE

ST. LUCIE NUCLEAR POWER STATION NO. 2

by

William W. Durgin

Prepared forEbasco Services, Inc.

George E. Hecker, Director

ALDEN RESEARCH LABORATORY

WORCESTER POLYTECHNIC INSTITUTE

HOLDEN, MASSACHUSETTS

September 1982

>>0280? 821006EPDR ADOCK 05000g89 IPDR

Printed at ARL — September 1982

Model tests at full scale were conducted in order to-evaluate the hydraulicperformance of the containment sump (Emergency Safety Feature Sump) of theSt. Lucie Nuclear Power Station, Unit No. 2. A replica of the sump was con-structed within a test basin. The model sump was operated with various com-

binations of water level and two flowrates in each outlet line. Measurements

and observations were made to identify surface vortex types, outlet line,swirl angles, and combined screen/pipe inlet loss coefficients.

By testing at fixed outlet flowrates and at two water levels, various com-

binations of vertical screen blockage (50%), horizontal screen blockage (50%),and approach flow distribution were utilized to arrive at two configurationsfor testing over an appropriate range of surface elevations and flowrates.

The results indicated that the loss coefficients were dependent on submergenceand blockage over the range tested but essentially independent of Reynolds num-ber. The average vortex types observed were between 1 and'2 for all tests, and,therefore, practically insignificant inasmuch as these types do not entrainair or debris. ,Outlet line swirl angles were found to be between 0 and

5.74'nd

depended on blockage but showed no systematic dependence on Reynolds number.

The observed and measured loss coefficients, vortex types, and swirl angleswere compared to similar findings in the literature and found to be consis-tent.

3.3.

ABSTRACT

TABLE OF CONTENTS

TABLE OF CONTENTS

P~aa No.

INTRODUCTION

PROTOTYPE DESCRXPTXON

SIMXLITUDE

MODEL DESCRIPTION

INSTRUMENTATION AND OBSERVATION TECHNIQUES

TEST PROCEDURE

15

20

RESULTS AND DISCUSSION

SUl1l1ARY AND CONCLUSIONS

24

35

REFERENCES

INTRODUCTION

The containment building of the St. Lucie Nuclear Power Station, Unit No. 2,

is equipped with an Emergency Safety Feature (ESF) Sump which must functionsatisfactorily under certain conditions.

Following an accident that would release a significant amount of energy „in-

side containment (eg, Loss of Coolant Accident or Main Steam Line Break) thesubsequent rise in pressure and temperature would trigger the operation ofcertain safety systems. At a predetermined level of containment pressure,operation of the Containment Spray (CS), High Pressure Safety Injection (HPSI),and Low Pressure Safety Injection (LPSI) Pumps would be initiated. Duringthe initial phase of the accident, these six pumps (two of each) draw waterfrom the Refueling Water Tank and deliver it into containment. This estab-lishes a minimum water level inside containment at EL 21.0 ft.

Low tank level would initiate a Recirculation Actuation Signal (RAS) whichwould deactivate both LPSI Pumps and transfer the suctions of the CS and

HPSI Pumps to the ESF Sump. During this mode of operation, total pump flowin each sump outlet pipe will fall within the range 300 gpm to 7300 gpm.

The ESF Sump was designed to provide pump suction in the recirculation mode

for an indefinite period.

The ESF Sump is a collection reservoir located in the annulus between thesecondary shield wall and containment, and functions to provide an adequatesupply of water to the Containment Spray and High Pressure Safety InjectionPumps during the recirculation mode. Two redundant suction lines, each han-dling one CS and HPSI Pump, are located at opposite ends of the sump. Inthis location, the sump is protected from the direct effects of high energyline break, such as jet impingement and pipe whip.

Following an accident, the entire cross-section of the containment would be

filled with water to an elevation within the range EL 21.0 ft and EL 26.0 ft.Water drawn from the sump would be returned to the containment via the con-

tainment spray headers located high in the containment and possibly througha break in the Reactor Coolant System. As such, the majority of the waterwould be returned inside the secondary shield wall and would reach the sump

via shield wall drain openings. These drains are large rectangular openingslocated at various points along the perimeter of the wall. Each opening isequipped with a grating to prevent large debris from reaching the sump.

The ESF Sump is contiguous with the pipe trench around the perimeter of thesecondary shield. Some of the filter screening is, in fact, located withinthe trench. Pipes of various sizes penetrate the screens and a drain collec-tion tank is located within the sump.

A full scale replica of the FSF Sump and nearby features was constructed in a

test facility at the Alden Research Laboratory (ARL) of Worcester PolytechnicInstitute (WPI). A test program was devised in order to investigate free sur-face vortex formation, swirl in the inlet piping, inlet losses, or any otherflow conditions that could adversely affect the performance of the decay heatremoval pumps and the reactor building spray pumps in the recirculation mode.

Operating conditions involving a wide range of possible approach flow dis-tributions, flowrates, water levels, screen blockages, and combinations there-of were tested in the model.

It is of primary importance that Containment Spray Pumps and High PressureSafety Ingestion pumps function properly after a Loss of Coolant Accident orMain Steam Line Break when pump suction is switched to the Emergency SafetyFeature Sump. In particular, it is necessary to evaluate the flow throughthe sump in terms of head loss, air-entrainment, and outlet line swirl. Be-cause the approaches to the sump may be partially blocked by debris, the re-sulting flow patterns can affect these parameters. The head loss through the(partially blocked) sump and outlets can be a principal determinant of avail-able NPSH. The tolerable levels of air content and swirl are dependent on pump

design so that air is not entrained and to minimize swirl so that it has

negligible contribution to pump inlet swirl given the remainder of the,suction

piping.'his

report presents the findings of the study including a description ofthe prototype and the model, and summarizes conditions investigated, simil-itude considerations, test procedures, instrumentation, and interpretation

3

of results.

PROTOTYPE DESCRXPTION

The ESF Sump is located between the shield w'all and containment contiguous

with the pipe trench, Figure 1. The pipe trench is nominally 5 ft wide withthe bottom at EL 12.00 ft. The sump recess is nominally 9 ft wide with bot-tom at EL 7'.58 ft centered about 180 , azimuth. A floor at EL 23.00 ft oc-

cupies the space between the pipe trench/sump recess and containment. There

are three smaller pipe trenches in the floor in the vicinity of the sump.

The shield wall is provided with periodic drain openings nominally 4 ft wide.

Three of these are located in the vicinity of the sump. Two 24 inch outletlines, Figure 2, lead from the lower corners of the sump through containment

at EL 9.00 ft. These lines project into the sump and are provided withsleeves forming re-entrant inlets with exterior steps.

All shield wall drain openings are provided with heavy bar racks to preventingestion of large debris. The sump is completely enclosed by a fine mesh

filter screen. This screen is made up of .047 inch OD stainless steel wirespaced to provide an open area of approximately 90 mils square. Verticalscreen sections are arranged in a sawtooth pattern, forming 60 degree angles,to increase the available surface area. Horizontal sections of the sump

screens are attached to floor gratings at EL 23.00 ft. These gratings are

made of 3/16 inch wide, l-l/4 inch deep rectangular bars spaced 1-3/16 inches

apart with cross members every 4 inches and cover all pipe trenches. Screen,

.however, is only provided on those portions inside the vertical screen panels.A small horizontal grating with screen is provided at EL 11.00 ft between theoutlet pipelines. A flat vertical panel of screen, reinforced with bars, di-vides 'the sump into two, nominally at 180', azimuth, with a small sawtooth

panel protruding into the portal at 180', azimuth.

The reactor drain tank, 12 ft long by 5 ft diameter, is located in the sump,

inside the screens, and between the outlets at EL 12.00 ft. Numerous pipesof various sizes run in the pipe trenches, through the sump, and penetratethe screens and,gratings. Associated with these pipes are pipe supports and

seismic restraints.

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PLATE EL 23'-0"

Q REACTOR

90 MIL SCREEN

EL 22'-2-1/4"

LADDER

BOTTOM OF TRENCHEL 12'-0"

PLATFORMCHKD Q EL 11'-0"

Q REACTOR DR TANK =

EL 12'-0"

BOTTOM OF

TRENCH EL 12'4"

BOTTOM OF SUMP EL 7'-7"

DIVIDER SCREEN

g / 90 MIL~/

/

TRAIN B TRAIN A

FIGURE 2 ESF SUMP SECTION

The sump water temperature can vary between 55 and 225oF, with a surfaceelevation between 2l and 26 ft. The outlet line flow can vary between

300 and 7300 gpm per line and the containment pressure varies between 0

and 44 psig.

The geometry, features, and piping in the sump area were described byEbasco Drawings (l). In addition, a site visit was made and measurements

as well as photographs made of sump details.

SIMILITUDE

The study of dynamically similar fluid motions forms the basis for the

design of models and the interpretation of experimental data. The basic

concept of dynamic similarity may be stated as the requirement that two

systems with geometrically similar boundaries have geometrically similarflow patterns at corresponding instants of time (2). Thus, all individualforces acting on corresponding fluid elements of mass must have the same

ratios in the two systems.

For a situation in which a free surface is present, the Froude number

uF =

MgL

where u and L are a characteristic velocity and length, respectively,should be the same in the model as in the prototype. In the present cases,

the model was constructed the same size as the prototype which gives

,u = u'm p

Thus, velocities, flowrates, and time scales for the model will be the same

as for the prototype.

Scaling considerations then, depend only on secondary non-dimensional groups.In particular, a loss coefficient or Euler number

~b

2pu

where hp is pressure drop and P the fluid density, will depend only weakly

on the Reynolds and Weber numbers

uLR =—

Vu

W =

/o/pz,

where 9 is the kinematic viscosity, and 0 the surface tension. Thus,

E = E(R,W)

with the only variation due to temperature dependence of R and W. Further-more, since only results of very weak vortex activity, were acceptable, theWeber number effect was insignificant. Then,

E = E(R)

and the variation of R over the temperature range should be evaluated. Formodel operation at 68'F (typical) at the lowest flow tested, 4285 gpm 1 line,the pipe Reynolds number becomes

while at 225'FR = 5.7 x 10 , at 68'F5

R = 2.0 x 10 at 225 F6

Since it is known that parameter variation becomes asymptotic at such largeReynolds numbers, the, effect of temperature will be insignificant.

The model, being constructed at full scale, should thus exhibit similar flowpatterns, loss coefficients, vortex formation, and swirl as the prototypeoperating at the same flowrate and water level. In addition, screening ofidentical size and construction was used so that the head losses would alsobe identical under similar operating conditions.

For the prototype operating at maximum flow, 7300 gpm, at maximum temperature,225'F, the Reynolds number for an outlet line would be

R = 3.4 x 106

10

5 6Model tests were conducted at R values of 5.6 x 10 and 1.5 x 10 . Loss

coefficients are usually constant in and above this range and thus should

be the same at the highest prototype Reynolds number. The effect of vary-ing containment pressure with temperature and time does not affect the losscoefficients or inlet pressure loss, but only the NPSH at the pumps.

MODEL DESCRIPTION

The model was constructed at a 1:1 geometric scale within the ExperimentalFacility for,Containment Sump Reliability Studies, Durgin, et al (3), atthe Alden Research Laboratory. This fixed facility includes a large tank(L 70 ft, W 35 ft, D 12 ft) with a flow distribution system capable of sup-

plying 20,000 gpm along three sides. A depressed sump (L 20 ft, W 10 ft,D 10 ft), located in the center, had provision for outlet lines at 15 loca-tions up to 2 ft in diameter. Installed equipment provided for water fil-tration, level control, and flowrate control. Both inlet and outlet lineflow meters were provided as were pressure measurement systems. All dataacquisition and reduction were under control of a mini-computer at the site.

The model was installed in the test basin as shown in Figure 3, primarilyusing plywood panels to generate the fixed boundaries. Three of the shieldwall portals were included through which flow could enter the sump area.In addition, flow could enter over the floor on the east and west ends and

through the pipe trench on the west end. The reactor drain tank was instal-led within the sump as shown in Figure 4 in which the sump divider screenand folded sere'ens can be seen. This screen was identical in size and spac-ing as that of the prototype.

All pipelines of finished diameter greater than 3 inches were installed inthe model as were other objects which might, affect the flow patterns.

h

Figure 5 shows a view looking towards the sump from the west while Figure6 shows a view through the east drain opening. The floor grating and at-tached screen at EL 23.00 can be seen in Figure 7 where a portion of grat-ing has been turned to reveal the sump interior.

z

EAST

180

WEST

FACILITYBOUNDARY

CIC)0)

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C)

O CONTAINMENT

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EL 7.58

EL 1800(TOP EL 22.00)

EL 14.00 (TOP EL 23.001

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EL 15.5

EL 11.00

VERTICALSCREENING

I

<C7~ 00

(TOP EL 22.00)

II(I

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35'0'LOW

DISTRIBUTOR SHIELD WALL

FIGURE 3 MODEL SUMP INSTALLATION

FIGURE 4 SUMP INTERIOR

,/

Hi()j)

)g0

l~~

I

'-hFIGURE 5 WEST PIPE TRENCH, VIEW FROIVI WEST

FIGURE 6 EAST PIPE TRENCH THROUGH SHIELD WALL OPENING

/rp

/

FIGURE 7 HORIZONTAL BAR RACK AND SCREEN, EL 23.00

INSTRUMENTATION AND OBSERVATION TECHNIQUES

Each 24 inch outlet line was equipped with a vortimeter, Figure 8, piezo-meter taps for gradeline measurements, a flow meter, and a regulating valve.The 12 gradeline pressure taps were connected to a scanning valve which

sequentially connected each to a pressure cell. The computer system con-

trolled the scanning valve and measured the voltage output from the pres-sure cell. The differential pressure output from the flow meters was simi-larly measured. Figure 9 shows the outlet piping giving pressure tap loca-tions ~ The various devices used were

flow meters: 24 inch annubars (2)

pressure cell: Sensotec +1 psiD (2)

pressure cell:vortimeter:

Sensotec +7.5 psiD (1)

24 inch ARL

Each test was 30 minutes in duration. The observed vortex type, according tothe ARL scale, Figure 10, was entered to the computer system every 30 seconds

on a hand held computer terminal. The pressure gradelines were fully sampled

every 60 seconds as were the accumulated vortimeter revolutions.

16

FIGURE 8 VORTIMETER

VORTIMETER PRESSURE TAPS GRADELINE PRESSURE TAPS

TRAIN A

VORTIMETER FLOWMETER CONTROL VALVE

TRAIN B

12'6't 22''YP

8'IGURE-9

OUTLET PIPELINES

18

VORTEXTYPE

INCOHERENT SURFACE SWIRL

SURFACE DIMPLE;COHERENT. SWIRL AT SURFACE

DYE CORE TO INTAKE;COHERENT SWIRL THROUGHOUTWATER COLUMN

TnaSH

~l

VORTEX PULLING FLOATINGTRASH, BUT NOT AIR

VORTEX PULLING AIRBUBBLES TO INTAKE

D aiA euseaES

FULL AIR CORETO INTAKE

FIGURE 10 NUMERICAL SCALE FOR VORTEX TYPE CLASSIFICATION

19

The pressure gradeline was extrapolated to the entrance by a linear leastsquares curve fit of the pressure measurements. The area average velocity was

used to calculate the pipe velocity head, which was added to the extrapolatedpressure gradeline. The total head at the pipe inlet was subtracted from thesump water level outside the screens to determine the inlet loss. An entranceloss coefficient was calculated by:

iK =

2

2g

where

K = loss coefficient6H. = inlet head loss, fti

Average swirl in the suction pipes was measured by cross-vane swirl meter.Lee and Durgin (4) have shown that a swivel meter with vane diameter about75% that of the pipe diameter best approximates the solid body rotation ofthe flow. The rate of rotation of the vortimeter was determined by count-ing the number of blades passing a fixed point in two minutes.

An average swirl angle was defined as the arctangent of the maximum tan-gential velocity divided by the axial velocity. 'The maximum tangentialvelocity is the rotational speed times the circumference of the pipe, Tf d N,and the average swirl angle is defined- by:

6 = arctan ( )TdN

U(l4)

where

N = revolutions per second

d = pipe diameter, ftU = mean axial velocity, ft/sec

20

TEST PROCEDURE

Tests were conducted at the available water supply temperature. The model

was filled to the proper level, and all piezometer and manometer lines were

purged of air and the differential pressure cells zeroed. The required flow-rates were then set and allowed to stabilize for 15 minutes. The water levelwas checked and re-adjusted, if necessary. The data acquisition system pro-gram wasram was then started so that all measurements were automatic. The system

signaled the model operator every 30 seconds to request observed vortex typedata. Subsequent to test completion, all data were transferred to'hard diskfiles. An analysis program was then run to determine average vortex type and

standard deviation, swirl angles, and loss coefficients.

The test plan involved systematically varying the water level, flowrates, flowdistribution, blockage of vertical screens, and blockage of the horizontalscreens. To this end, symbolic representation of various parameters was adopt-ed as given in Table 1.

Three water elevations were chosen: 21.00, 23.00, and 25.00 ft.

Flowrates of 0, 4285, and 8785 gpm were specified by Ebasco Services as repre-sentative. These could occur in various combinations in the two outlet lines.

Flow distributions would occur primarily because of blockage of the drainopenings through the shield wall. These were systematically blocked, Figurell, entirely except for the west end which was fed by numerous portals. A

maximum blockage of 1/2 was adopted for this entrance.

Vertically; screen blockage was always 50% of the available screen area butarranged in various patterns. Longitudinally, the screens were divided intosegments, Figure 12, so that any two segments could be blocked. Vertically,the screens were divided in half so that only the top or bottom was blocked.

21

TABLE, 1

TEST PLAN DEFINITIONS

Water Surface Level (ft)

SlS2S3

21. 023.025. 0

Flowrates (gpm)

QlQ2Q3Q4Q5Q6

42854285

0428587858785

42850

4285878542858785

Flow Distribution (see Figure 10)

DO

DlD2D3D4

noneA + BA+B+CD+1/2EC+D+1/2E

Screen Blockage =(vertical; see Figure 11)

VOVlV2V3V4V5U6

noneA + D top to bottomB + C top, to bottomB + D top to bottomA + C top to bottomtop 1/2 allbottom 1/2 all

Screen Blockage (horizontal)

HO

HlH2H3

noneouter 1/2inner 1/2all

22

O.-+- C

FIGURE 11 FLOW DISTRIBUTION DEFINITIONS

/B

Qo

iQo

Qo

- FIGURE 12 SCREEN BLOCKAGE DEFINITIONS

23

Horizontal screen blockage consisted of the outer 1/2, inner 1/2, or allbeing blocked, and was only used for S3 (EL 25.00) tests.

The initial 23 tests concentrated on determining the flow distributions and

screen blockage most conducive to adverse performance. To this end, theflo'ws were fixed at 8785 gpm in each line and only the highest and lowestwater levels used. All vertical screen blockages, *all horizontal screenblockages, and flow distributions were tested independently.

Four combinations of blockage, Cl through C4, were then selected for furtherevaluation. Abridged testing as above, enabled two worst tests, designatedWl and W2, to be selected.

Complete variation of water level and outlet flowrates was then conducted,using Wl and W2, to evaluate the sump performance.

24

RESULTS AND DISCUSSION

The results for all tests are shown in Table 2. It can be seen that theworst vortex type observed was type 2; which was predominant.

For the initial 23 survey tests, the loss coefficients varied from 0.71 to1.09 for Train A and from 0.75 to 1.11 for Train B. The swirl angle ex-tremes were 2.48'o 5.15'or Train A and -1.76 to 0.38'or Train B.

Combination blockage Cl, Figure 13a, was selected by observing that testll had both high swirl and high loss for Train A and that test 17 had thehighest combined swirl for both pipes which was due to horizontal blockage.Thus, it might be expected that vertical blockage V6 combined with horizon-tal blockage Hl, would produce even higher swirl. This was the case because

the Train A swirl increased to 5.74', test 24, but the observed vortex typedecreased and the losses for each line changed only slightly. The swirl inTrain B also remained about the same. Since horizontal blockage could onlybe tested at, elevation S3, a test with H2 'blockage was added but did notproduce interesting results.

Combination blockages C2 and C3, Figures 13b and c, were selected by observ-ing that the D4 flow distribution, tests 16 and 23, respectively, producehigh swirl and above average loss coefficients. This was combined with ver-tical blockage V3 and the antisymmetrical blockage V4 with the thought thatone of them ought to combine with D4 to produce even higher swirl and losscoefficients. This proved to be the. case in test 26, C2, where the Train A

swirl reached 5.28'. The observed surface vortex was type 1 only. A signi-ficantly high loss coefficient was observed for C3 blockage in Train B, test29

'ombination blockage C4, Figure 13d, was selected by observing that the high-est loss coefficient with significant swirl occurred in Train B, test 21, dis-tribution D2.. This was combined with the highest swirl in Train B, test 3,screen blockage V2. The loss coefficients for both Trains A and B reachedtheir highest values in these tests with significantly high swirl angles inTrain A.

TABLE2'est

Results

TestVortex~Ty e

TrainSwirl

eLoss

Coeff.

TrainLoss

Coef f.Swirl

e Blockage

VerticalFlow Screen Horizontal

e Distribution Blockage Blockacle PiowrateSurface

Elevation

1. 2

3

4-5

678

101112

1314151617181920212223

2.02.02.02.01.82.02.02.0.2.02.02.02.0

2.02.01.01.01.01.11.92.02.02.02.0

0.831.090.710.860.860.990.810.940.840.940.810.93

0.820. 820.800.790.790.810.830.941.060.900.91

4.682.484.893.114.413.164.603.614.944.67

4.574.854.465.105.154.544.513.954.423.164.80

0.901.110.860.920.820.860.820.950.810.910.900.99

0. 870. 860.830.860.750.760.851.111.090.910.90

0.00.38

-1.76-1.310.00.0

-l. 54-1.08-0. 94—,0.89-0. 93-0.56

-1.54-1.54-1.54-1.41-1.33-1.23-1.15-0.75-1.15-0.94-1.14

ScreenScreenScreenScreenScreenScreenScreenScreenScreenScreenScreenScreen

Flow distributionFlow distributionFlow distributionFlow distributionHorizontalHorizontalHorizontalFlow distributionFlow distributionFlow distributionFlow distribution

DO

DO

DO

DO

DO

DO

DO

DO

DO

DO

DO

DO

DlD2D3D4DO

DO

DO

DlD2D3D4

VlVlV2V2V3V3V4V4V5V5V6V6

VO

VOVOVO

VOVOVOVO

VO

VOVO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HlH2H3

Q6Q6QG

Q6Q6Q6Q6.Q6

Q6Q6Q6Q6

Q6Q6Q6Q6Q6Q6Q6Q6o6Q6QG

S3SlS3SlS3SjS3SlS3SlS3Sl

S3S3S3S3S3S3S3SlSlSlSl

2425262728293031

1.01.01.02.01.02.0

.2 ~ 02.0

0.880.870.810.970.790.960.921.16

5.745.275.284.243.932.465.322.55

0.790.790. 76

,0.900.861.130.971.29

-1 ~ 131 ~ 23

-0 ~ 96-0.39-1.35-0.50-0,. 97-0. 39

C-1C-1C-2C-2C-3C-3C-4C-4

DO

DO

D4D4D4D4D2 .

D2

V6V6V3V3V4V4.V2V2

HlH2HO

HO

HO

HO

HO

HO

Q6Q6Q6Q6Q6Q6Q6Q6

S3S3S3SlS3SlS3Sl

TABLE 2

Test Results(continued)

VortexTest Type

LossCoeff.

Swirle

Train A Train B

Loss SwirlCoeff. 6

VerticalFlow Screen Horizontal

Blockage Ty e Distribution Blockacle Blockage rlowrateSurface

Elevation

323334353637383940414243444546

1.01.01.01.01.01.01.01.01.01.01.91.01.02.02.0

0.970.93

0.860.861.111.01

l. 391. 01l. 160.97

1.671.07

5.185.10

5.383.953.953.95

4.533.443.353.14

4.382.70

0.96

0.970.840.921.14

0.991.091.471.26

1 ~ 041.101.70

-0. 39

-0. 19-0. 57-0. 57-0. 20

-0.39-0.38-0.39-0.39

0.0-0. 19-0. 58

W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1W-1

D2D2D2D2D2D2D2D2D2D2D2D2D2D2D2

V2V2V2V2V2V2V2V2V2V2V2V2V2V2V2

HO

HO

HO

HO

HO

HO

HO

HO ~

HO

HO

HO

HO

HO

HO

HO

QlQ2

Q3Q4Q5Ql

. Q2Q3Q4

Q5QlQ2Q3Q4

Q5

S3S3S3S3S3S2S2S2S2S2SlSlSlSlSl

474849505152535455565758596061

1.01.01.02.01.01.01.01.0

'.0

1.01.91.01.02.02.0

0.810 '00 F 810.830.890.88

1.060.910.960.91

1. 200.96

1.580.99

2.102.303 '42.56

3.142.10'.60

0.95

0.791.15

0.86

0. 840.970.870.98

0.950.971.151.10

0.961.021.30

0.0

0.0-0.380.00.0

0.0-0. 290.00.0

0.0-0. 380.0

W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2W-2

D4D4D4D4D4D4D4D4D4D4D4D4D4D4D4

V4V4V4V4V4V4V4V4V4V4V4V4V4V4V4

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

HO

QlQ2

Q3Q4

Q5QlQ2Q3Q4Q5QlQ2

Q3Q4

Q5

S3S3S3S3S3S2S2S2S2S2SlSlSlSlSl

27

A) COMBINATION BLOCKAGE C1

c

I

B) COMBINATION BLOCKAGE C2

C) COMBINATION BLOCKAGE C3=W2

D) COMBINATION BLOCKAGE C4=W1

FIGURE 13 COMBINATION BLOCKAGE

28

Since surface vortex activity did not appear significant in any tests through

31, the criterion for selection of combinations Wl and W2 was based on loss co-

efficient. Clearly, combination C4 showed the highest values for both linesand was selected as combination Wl. Of the remaining tests, test 29 showed

the highest. coefficient so that combination C3 was selected as W2.

In both cases, the flow patterns and screen blockages caused significantamounts of flow .to pass through the relatively narrow spaces between thevertical screens and'the corners at the junctions of the pipe trenches and

sump. Typically, surface elevation differences of 2 or 3 inches were ob-served between upstream and downstream flows through these spaces.

For combinations Wl and W2, complete variation of water level and flowrateaccording to Table I was conducted.

The observed surface vortex type, T, for the Wl and W2 series tests (32-61)are plotted against Froude number in Figure 14. Also shown is an envelopedeveloped during full scale generic studies of containment sumps (5). Inthose studies, vortex activity was not observed outside the envelope. Itcan be seen that the observed vortex types for the present study fell wellwithin the envelope and that only types.l and 2 were observed. The consider-able amount of piping within the sump area of this plant apparently served toreduce surface vortex activity to less than might otherwise be expected.

Inlet loss coefficients, K, are plotted against Reynolds number, R, in Figures15 and 16 for all tests with Wl type blockage (30-46) and W2 type blockage (28,29, 47-61). The data are identified with respect to submergence by use of dif-ferent symbols. Furthermore, some tests were run with the flows in the outletlines equal at two values, Ql and Q6, and at two surface elevations, Sl and S3.The corresponding points are connected by solid lines in each figure. Sincethe outlet line flows were equal, these solid lines represent the behavior ofthe coefficient with Reynolds number at fixed flow patterns.

29

0 = W1 BLOCKAGEge W2 BLOCKAGE

~ ENVELOPE FROMGENERIC TESTS (5)

NO OBSERVEDSURFACE VORTEXACTIVITY

lm lm

332Bmm332

28 82

0

0 0.1 0.2

F = uses

0.3 0.4 0.5

FIGURE 14 VORTEX TYPE VS. FROUDE NUMBER

1.8 1.8

1.6

~ 1.4

zO

1.28

1.6

1.4

1.2

S1 SUBMERGENCE

H S2 SUBMERGENCE

Q+ S3 SUBMERGENCE

1.0

Qo

1.0

0.8 0.8Q

5 X 10 106

REYNOLDS NUMBER, R

A) BLOCKAGE W1

0.6

3 X 10 106

REYNOLDS NUMBER, R

8) BLOCKAGE W2

3 X106

FIGURE 15 INLET LOSS COEFFICIENT VS REYNOLDS NUMBER, TRAIN A

1.8 1.8

1.6

I-1.4

O

OO

O-N 1.2

po

1.6

1.4

1.2

4 Sl SUBMERGENCEH S2 SUBMEBGENCE

Q S3 SUBMERGENCE

1.0 1.0

0.8Qi

0.8

0.6

3x10 106REYNOLDS NUMBER, R

A) BLOCKAGE Wl

0.6

Q Q 106

REYNOLDS NUMBER, R

B) BLOCKAGE W2

3 x 106

FIGURE 16 INLET LOSS COEFFICIENT VS. REYNOLDS NUMBER, TRAIN B

32

The data show that the loss coefficient is generally inversely related tosubmergence. Since the measured head losses include screen loss, this de-

crease of coefficient with increasing submergence is likely due to greaterscreen area exposure. For Train A, the data show no variations or slightdecrease of. loss coefficient with Reynolds number. For Train B, the datashow no variation or slight increase of loss coefficient with Reynolds num-

ber. Within measurement uncertainty, it is probable that the coefficientsare constant with Reynolds number as would be expected in this range.

The loss coefficients for blockage combination Wl were generally greater thanfor W2 and it is clear that blockage has significant effect. The largest val-ues recorded were

K = 1.67 for Train A with blockage Wl

(QA = 4285 gpm, QB= 8785 gpm, Sl = 21.0 ft)

K = 1 ~ 70 for Train B with blockage W2

(QA = 8785 gpm, QB= 4285 gpm, Sl = 21.0 ft)

occurring at minimum submergence with the high coefficient associated with theoutlet line carrying the lower flow. Since blockage Wl was selected on thebasis of its corresponding high loss coefficients, these would be the highestvalues expected under the blockage selection scheme.

All measured loss coefficients (all tests) fell within the range 0.71< K < 1 ~ 70.This range corresponds to generic studies (5) of containment sumps where theloss coefficients varied from 0.7< K < 1.6 with an average of K = 1.2.

Swirl angles for Train A are plotted against Reynolds number in Figure 17 forthe type Wl and W2 blockage. A similar plot. for Train B was not made sincethose angles were less than about 1.5'n absolute value. It can be seen that

33

the swirl angle was substantially dependent on the type of blockage butshowed no systematic variation with either submergence or Reynolds num-

ber. The largest swirl angle observed was approximately 5.4'or typeWl blockage with the water surface at EL 23.0 ft at 4285 gpm flow in TrainA and 8785 gpm in Train B (Q4).

For both trains together (all tests), the observed swirl angles variedfrom 0'o 5.74'n magnitude which falls within the 0'o 9'ange foundby Padmanabhan (5) for 24 inch outlets.

bK S1 SUBMERGENCE

H S2 SUBMERGENCE

Q S3 SUBMERGENCE

V)

tUCC ~

U4

O

3

K

g

Qo

Qo

H

3 X 10I

106

REYNOLDS NUMBER, R

A) 'LOCKAGE W1

C) glQ Q

X xFl

106

REYNOLDS NUMBER, R

8) BLOCKAGE W2

3 x 106

FIGURE 17 SWIRL ANGLE VS. REYNOLDS NUMBER, TRAIN A

SUMMARY AND CONCLUSIONS

Loss coefficients were found to depend on submergence and blockage, but tobe essentially independent of Reynolds'umber over the parameter ranges and

blockage configurations- tested. Values between 0.71 and 1.-70 were found and

can be used for system hydraulic calculations, including NPSH.

Swirl angles were found to depend primarily on screen blockage and flow dis-tribution with no systematic variation with either submergence or Reynoldsnumber. The largest value observed was 5.74', which can be compared to pump

manufacturers specifications, taking the length and geometry approach pipinginto consideration.

Free surface vortex activity was found to be type 2, at worst. This reflect-ed the fact that only coherent surface swirls or dimples were observed; debrisor air-ingestion were not observed in any tests.

The proximity of the sump screens to the pipe trench walls at the junctionwith the sump resulted in large amounts of flow passing through the avail-able space under certain types of screen blockage and flow distributions.This did not appear to cause any particular problems, but only resulted inhigher (overall) inlet loss coefficients.

36

REFERENCES

l. Ebasco Drawings

I ESF SUMP COMPOSITE SKETCH

SK-2998-M-710 R6

II GENERAL ARRANGEMENT DRAWINGS

2998-G-065 R2998-G-067 R

III MECHANICAL PIPING DRAWINGS

2998-G-1982998-G-1992998-G-2002998-G-2002998-G-2052998-G"2122998-G-2152998-G-2152998-G-215

R7Sh 2 R6Sh 1 R6Sh 2 R7Sh 1 R5

R4Sh 1 R2Sh 2 R2Sh 7 R2

IV STRUCTURAL DRAWINGS

2998-G-4952998-G-496 Sh2998-G"496 Sh2998-G-5202998-G-5212998-G-797 Sh2998-G-797 Sh2998-G-797 Sh

R51 R42 R3

RlR2

4 R313 R214 R2

Dividing Screen Structural Sketch Rl

SK - 2998-AS-226

V LINE LIST

2998-B-052 Rlo

2. Rouse, H., Handbook of Hydraulics, John Wiley 6 Sons, 1950.

3. Durgin, W.W., M. Padmanabhan, and C.R. Janik, "The Experimental Facilityfor Containment Sump Reliability Studies," ARL Report 120-80/M398, August

1980.

37

4. Lee, H.L., and Durgin, W.W.,'The Performance of Crossed-Vane SwirlMeters," Symposium of Vortex Flows, ASME Winter Annual Meeting, Chicago,1980.

5. Padmanabhan, M. "Containment Reliability Studies," ARL Report No. 49A-82/M398F, August, 1982.