ML063620264

Hydraulic Model Study of High Pressure Core Spray Pump Suction to Evaluate the Formation of Air Drawing Vortices and Air Withdrawal

ML063620264
Person / Time
Site:	Clinton
Issue date:	12/31/2006
From:	Cain S, Johansson A, Padmanabhan M Alden Research Lab
To:	Exelon Generation Co, Office of Nuclear Reactor Regulation
References
2006-359_H258C
Download: ML063620264 (67)

Text

HYDRAULIC MODEL STUDY OF HIGH PRESSURE CORE SPRAY PUMP SUCTION TO EVALUATE THE FORMATION OF AIR DRAWING VORTICES AND AIR WITHDRAWAL FOR CLINTON NUCLEAR POWER STATION Prepared by Andrew E. Johansson Mahadevan Padmanabhan, Ph.D.

Stuart A. Cain, Ph.D.

Submitted to EXELON GENERATION COMPANY 2006-3591H258C December 2006

HYDRAULIC MODEL STUDY OF HIGH PRESSURE CORE SPRAY PUMP SUCTION TO EVALUATE THE FORMATION OF AIR DRAWING VORTICES AND AIR WITHDRAWAL FOR CLINTON NUCLEAR POWER STATION Prepared by:

Andrew E. Johansson Reviewed by:

Mahadevan Padmanabhan, Ph.D.

Approved by:

Stuart A. Cain, Ph.D.

Submitted to EXELON GENERATION COMPANY December 2006 ALDEN RESEARCH LABORATORY, INC.

.30 Shrewsbury Street Holden, MA 01520

TABLE OF CONTENTS PAGE ABSTRACT INTRODUCTION 1 MODEL SIMILITUDE 2 MODEL DESCRIPTION 9 INSTRUMENTATION AND MEASURING TECHNIQUES 10 TEST PLAN 11 TEST PROCEDURE 11 RESULTS 12 CONCLUSIONS 14 REFERENCES 15 TABLES FIGURES APPENDIX A - FLOW METER AND PRESSURE CELL CALIBRATION DATA APPENDIX B - TEST PLAN

ABSTRACT At the request of the Clinton Power Station, Clinton, Illinois, a hydraulic model of the Reactor Core Isolation Cooling (RCIC) Tank at the Clinton Nuclear Power Station was constructed and tested at Alden Research Laboratory, Inc. (Alden) to determine the minimum submergences required to avoid air-drawing vortices and/or air entrainment at the High Pressure Core Spray (HPCS) pump suction nozzle for a range of flows and falling water levels.

The model was constructed using a geometric scale of 1:3.051. Testing included transient water level conditions simulating the field conditions for selected flows without return flow to the tank over a desired range of flows (corresponding to prototype flows of 3,000 to 5,500 gpm) and initial water levels giving submergences of 4 ft above the suction nozzles in the model (prototype submergences of 12 ft).

Testing of the original Clinton HPCS suction configuration yielded the following results. No air drawing vortices were observed for any of the flows tested. Air entrainment for all conditions tested was due to a localized draw down of the water level in the vicinity of the suction nozzle as the water level in the tank approached the top of the suction nozzle. At simulated prototype flows of 5,500 gpm, the submergence at the onset of air entrainment ranged from 4.17 to 4.8 inches prototype and the localized draw down could first be observed when the water levels were approximately 0.7 inches (prototype) higher than those at the onset of air entrainment. At simulated prototype flows of 3,000 gpm, the onset of air entrainment ranged from 2.56 to 2.75 inches prototype and the localized draw down could first be observed when the water levels were approximately 0.6 inches (prototype) higher than those at the onset of air entrainment. At a simulated prototype flow of 4,250 gpm, the submergence at the onset of air entrainment was 3.73 inches prototype.

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HYDRAULIC MODEL STUDY OF HIGH PRESSURE CORE SPRAY PUMP SUCTION TO EVALUATE THE FORMATION OF AIR DRAWING VORTICES AND AIR WITHDRAWAL FOR CLINTON NUCLEAR POWER STATION

1.0 INTRODUCTION

At the request of the Clinton Nuclear Power Station, Clinton, Illinois, a hydraulic model of the Reactor Core Isolation Cooling (RCIC) Tank at the Clinton Nuclear Power Station was constructed and tested at Alden Research Laboratory, Inc. (Alden) to determine the minimum submergences required to avoid air-drawing vortices and/or air entrainment at the High Pressure Core Spray (HPCS) pump suction nozzle for a range of flows and falling water levels.

The RCIC tank is a circular tank with an ID of 29' - 11.25". The 16" suction nozzle has an ID of 14.86" and its centerline is 26.75" from the tank floor. The nozzle exits the tank 34.6 degrees from normal to the tank, thus, the nozzle entrance is elliptical in shape. The Clinton Tank and Nozzle geometries are shown in Figures 1 through 5. The suction flows vary depending on the operating cases from 3,000 gpm to 5,500 gpm.

The hydraulic model study allowed evaluation of vortex formation and air withdrawal, if any, over the range of operating water levels.

The Clinton model was constructed using a geometric scale of 1:3.051. The model tank had an I.D. of 9.813 ft and was approximately 6 ft deep. The tank was fitted with a removable floor and had a finished depth of approximately 5.5 ft, which allowed simulation of water levels corresponding to as high as about 16 ft in the plant. However, only lower water levels were tested, as air-entrainment due to air-drawing vortices or other anticipated conditions is likely to occur at lower water levels. Downstream piping geometry just outside the tank is unlikely to influence the flow patterns at the suction nozzle entrance, if a straight pipe of 5 pipe diameters or more is available immediately after the suction pipe exits the tank. In the Clinton plant, about 20 pipe diameters of straight piping is available. Hence, in the model, even though the 16 inch outlet pipe geometry within the tank was fully simulated, outside the tank it was only necessary

to simulate approximately 5 pipe diameters of horizontal straight piping. Additionally, two nozzles internal to the tank (Nozzle K and Nozzle N2) were also modeled due to their close proximity to the suction nozzle which could influence the flow patterns and consequently vortex formation. These nozzles were modeled as obstructions to the flow only. The Clinton test setup is shown in Figures 6 and 7.

Tests were conducted such that air-drawing vortices and/or air entrainment due to outflow through the suction nozzle could be investigated over a desired range of flows and initial water levels and with a desired rate of drop of the water level.

2.0 MODEL SIMILITUDE 2.1 Free Surface Flow Models involving a free surface are constructed and operated using Froude similarity since the flow process is controlled by gravity and inertial forces. The Froude number, representing the ratio of inertial to gravitational forces, can be defined for pump intakes as, where u = average axial velocity at the intake g = gravitational acceleration d = intake diameter (or diameter of a circle having equivalent area to the Elliptical entrance of the nozzle as with the Clinton nozzle)

The model Froude number, Fro, was therefore, made equal to the prototype Froude number Fp to satisfy the required scaling criteria.

Fm = Fp (2)

Where Fm and Fp denote model and prototype Froude numbers. Dividing both sides of equation (2) by Fp gives Fr = 1 (3)

Where Fr denotes the ratio between model and prototype Froude numbers, Substituting Equation (1) into Equation (2) and defining the length ratio by Equation (4), results in the velocity scale ratio given in Equation (5).

Lm / Lp = Lr (4) where Lr is the length scale ratio, Vr = (Lr) 0 5 (5)

The flow ratio, Qr, may be written as Qr= Ar Vr (6)

Where Ar is the area ratio Substituting Equation (5) into Equation (6), and noting that A can be dimensionally expressed as L 2,yields Qr = Lr 5/2 (7)

In modeling of a pump intake to study the formation of vortices, it is important to select a reasonably large geometric scale to achieve large Reynolds numbers so as to minimize viscous scale effects and to reproduce the flow pattern in the vicinity of the intake [Anwar, 1978].

2.2 Similarity of Vortices The fluid motions involving vortex formation in pump intakes have been studied by several investigators. It can be shown by principles of dimensional analysis that the dynamic similarity of fluid motion that could cause vortices at an intake is governed by the following dimensionless parameters:

ud u d ud u 2d FsF ' ' v , and G/p u - Froude number, gd

= Reynolds number, v

of which,

and, Ud - Weber number.

G/p where U = average axial velocity at the intake F = circulation contributing to vortexing

d = diameter of the intake S = submergence at the intake v = kinematic viscosity of water g = acceleration due to gravity C = surface tension of water air interface p = water. density The influence of viscous effects is defined by the Reynolds number, and surface tension effects are indicated by the Weber number. As strong air-core type vortices, if present in the model, would have to be eliminated by a modified design, the main concern for interpretation of model performance involves the similarity of weaker vortices. If the influence of viscous forces and surface tension on vortexing is negligible, dynamic similarity is obtained by equating the parameters ud / F, u / 4,g-d, and d/s in model and prototype. A Froude model satisfies this condition, provided the approach flow pattern in the vicinity of the intake, which governs the circulation, F, is properly simulated.

Alden has conducted considerable research on scaling free surface and submerged vortices.

From a study of horizontal outlets for a depressed sump conducted for containment sumps for Nuclear Power plants [NUREG/CR-2760, 1982 and Padmanabhan and Hecker, 1984], it was determined that no scale effect on vortex strength, frequency, or air withdrawal existed for pipe Reynolds numbers*above 7 x 104.

Daggett and Keulegan [ 1974] indicated that an inlet Reynolds number of 3 x 104 is sufficient to obtain a good model to prototype correlation of vortices. Anwar [1978], using a radial Reynolds number, indicated that viscous forces become negligible at Reynolds numbers of 3 x 104.

Surface tension effects have been shown to be negligible for Weber numbers, W, greater than 120 [Jain et. al., 1978]. The Hydraulic Institute Standards (HI Standards) uses a safety factor of 2 for these values to ensure minimum scale effects for test conditions based on Froude similitude.

Based on the above considerations, the HI Standards recommends that the model scale be chosen such that the model Reynolds and Weber numbers are at least 6 x 104 and 240, respectively.

Considering the recommendations from various studies described above, the model scale for the present study has been chosen so that the Reynolds and Weber numbers for the model with the Froude scaled flows would be well above 7 x 104 and 240, respectively, so that no significant viscous and surface tension scale effects would be present in the model.

2.3 Similitude of Self Aerated Flows Air entrainment is possible due to draw down as the transient water level in the tank approaches the top of the suction nozzle and the flow is at the verge of changing from closed conduit flow in the suction nozzle to free surface flow in the suction nozzle. This phenomenon of air being drawn from the free surface in the tank into the pipe during the draw down falls under the class of flows known as self-aerated flows similar to free surface flows involving air entrainment in drop shafts, hydraulic jumps and free surface vortices. The modeling of self aerated turbulent flows is based on Froude Similitude, as the gravity and inertial forces are the predominant forces, [Characteristics of Self-Aerated Free Surface Flows, by N.S. Rao and H.E. Kobus].

Hence, the Froude similitude that is needed for simulation of vortices is also sufficient for simulation of self-aerated flow resulting from sudden drawdown under transient conditions.

2.4 Model Scale Selection The selected model geometric scale of 1:3.051 for the Clinton HPCS pump suction nozzle provided a model nozzle pipe of 4.875" I.D. The chosen scale allowed the use of commercially available plexiglass pipe. With the proposed geometric scale, both the Reynolds and Weber numbers in the model were high enough to assume that the model (operated based on Froude similitude and with model water temperatures between 51.8°F and 53.67F) is free of any significant viscous and surface tension scale effects throughout the range of flows tested. The minimum Reynolds and Weber numbers in the model throughout the range of flows tested and

water temperatures was 8.6 x 104 and 1,180, respectively.

With the selected model geometric scale mentioned above, the length, velocity, flow, and time scales in the model is as follows:

Scaled Parameter Clinton Model Length Scale Lr = Lm/ Lp 1/3.051 Velocity Scale Vr = V/ Vgp= (Lr) 1 /2 1 / 1.747 Flow Scale Qr= Q/ Qp= (Lr) 5/2 1 / 16.259 2

Time Scale Tr = Tin/Tp = (Lr)1/ 1 / 1.747 2.5 Effect of Other Model Parameters on Vortex Formation 2.5.1 Test Liquid All models used water as the test liquid, as in the prototype. For the flows of interest the prototype Reynolds and Weber numbers are above 7 x 104 and 240, respectively, and hence, as discussed in Section 2.2, any viscous or surface tension effects on vortexing would be negligible.

Hence, the vortexing phenomenon in the prototype would be governed by the Froude number and submergence, which are independent of fluid properties. As discussed in Section 2.3, with the selected model scale, no significant viscous or surface tension effects on vortexing is expected in the model using water as the test liquid. The Froude number and submergence would control vortexing phenomenon in the model as in the prototype.

2.5.2 Acceleration Due to Gravity (g)

The value of g at the model location is 32.16 ft/sec 2 . For calculation purposes, a rounded off.

value of 32.2 ft/sec 2 is used. As all the tests of results are made non-dimensional using the Froude number, the results can be used with the exact value of the Froude number for the prototype calculated with the correct g in the field.

2.5.3 Tank Air Pressure A constant tank air pressure (atmospheric) was used in the model. The prototype tank is vented to atmospheric, hence, a constant tank air pressure (atmospheric) would also occur in the prototype during the transient water level drop. Any slight difference in atmospheric pressure between the model and prototype locations would not affect vortex phenomena, as the submergence at the outlet pipe is actually the difference in pressure between the water surface and the pipe invert, which is independent of the air pressure at the tanks. Submergence and Froude number control the vortexing phenomena.

2.5.4 Water Temperature The kinematic viscosity and surface tension of water change with temperature, and hence, would impact the Reynolds (Re) and Weber (W) numbers, respectively. However, above certain threshold values of Re and W (about 7 x 104 and 240, respectively, as discussed in the similitude section of the report), vortex formation and severity of vortices are not significantly affected by Re and W. The model scale has been chosen such that at the model flows, Re and W are above the threshold values with model water temperatures between 51.8°F and 53.6°F. As the Re and W values in the field (at corresponding water temperatures and flows in the field), are much higher than those in the model, vortex formation and vortex severities predicted by the model are

.applicable in the field for the water temperature ranges anticipated in the field.

3.0 MODEL DESCRIPTION As mentioned previously, the model was designed and constructed using a geometric scale of 1:3.051 to simulate the Clinton RCIC tank from the floor to a height of approximately 16 ft (prototype). The 16 inch outlet pipe geometry within the tank and outside the tank to include approximately 5 pipe diameters of horizontal piping were simulated in the model. Additionally, Nozzle K and Nozzle N2 were also simulated as flow obstructions in the model. Several additional nozzles and obstructions located in the tank were not modeled since their location was sufficiently far away so as not to affect the flow patterns near the suction nozzle of interest.

Photographs of the Clinton model nozzle geometries are shown in Figures 8 and 9.

As shown in Figures 6 and 7, the model was provided with a flow loop. The flow loop included a laboratory sump to draw water from the tank and return piping to return the flow to a laboratory sump. An orifice flow meter calibrated at Alden was used for flow measurements and model flows were set using appropriate valves and a Variable Frequency Drive. Photographs of the model flow loop are shown in Figure 10.

A Tap located on the side wall of the model RCIC tank was used to read water levels in the tank with a differential pressure transducer, one side of which was connected to a known fixed water column. The location of this tap was located approximately 90 degrees from the suction nozzle as in the prototype.

A rectangular acrylic box, enclosing the model outlet pipe, was installed at a selected location to facilitate the viewing and video documentation of air entrainment. This box, when filled with water, allowed compensation for the refraction due to the curvature of the pipe and provided a good viewing and video taping location for air bubble identification. The viewing box is shown in Figure 11.

4.0 INSTRUMENTATION AND MEASURING TECHNIQUES 4.1 Flow All flows were measured with a standard ASME orifice meter installed in the outflow piping downstream of the suction nozzle. The differential head from the orifice meter was measured using a differential pressure cell. A computer data acquisition system using TESTPO1NT software was used to record flows during testing. The orifice meter and differential pressure cells were calibrated at the Alden calibration facility, and the calibration curves are given in Appendix A, including calibration of the pressure cells. DP cells were calibrated in conjunction with the computer data acquisition system. The accuracy of the flow measurement is estimated at +/-2% of the units of measure (GPM). It should be noted that while the calibration report in Appendix A includes calibration for 2, 3 and 6 inch orifice meters, only the 6 inch meter was used for this study.

For Clinton testing, a DP cell with a range of a 0-72 inches (cell # 0697) was used to measure the meter deflection of the 6 inch orifice meter. The 6 inch meter was used to measure target flows of 3,000 to 5,500 gpm prototype (184.5 to 338.3 gpm model) for which the meter deflection range for the target flows was 8.85 to 29.77 inches. The accuracy of the DP cell was +/-0.25% of the DP cell span.

4.2 Free Surface Vortices In order to systematically evaluate the strength of free surface vortices, Alden uses a vortex strength scale of Type 1 to Type 6, as shown in Figure 12, where Type 1 is a surface swirl and Type 6 is an open air-core vortex to the outlet. Vortex types were identified in the model by visual observations with the help of dye tracers. As the tests were under transient conditions and limited time was available to identify vortices, vortex identification was qualitative and limited air-bubble drawing or air core vortices (Types 5 and 6).

4.3 Water Level Water levels were tracked using a DP cell with a range of a 0-72 inches (cell # 0626), stilling well and vernier point gauge, and were measured with an accuracy of +/-0.25% of the DP cell span. The differential pressure cell used to track the water level was also calibrated at the Alden calibration facility and the calibration data are given in Appendix A. Also, as with the flow measurements, a computer data acquisition system using TESTPOINT software was used to record water levels during testing.

5.0 TEST PLAN The test plan included transient water level tests with no return flow in the model. The test matrix for the Clinton HPCS suction nozzle study is shown in Table 1. The test matrix consisted of 7 tests with no return flow to the tank. Tests for Clintoncovered flows ranging from 3,000 to 5,500 gpm (prototype) and the initial water depths tested covered initial submergences corresponding to about 12 ft above the suction nozzle entrance in the plant.

Vortex and air entrainment observations were made under transient conditions (as the water level dropped). For each test, a video recording of any vortices in the tank and air-entrainment in the suction nozzles were obtained. The scope of testing was the same for all tests.

6.0 TEST PROCEDURE Copies of the step by step test procedures for Clinton testing are given in Appendix B of the report. A brief description is given below.

The tank was first filled with water approximately to the desired initial water level using a laboratory fill pump. All differential pressure cells for flow meter differential pressure and water level measurements were purged and checked and the computer data acquisition system was initiated.

Separate video cameras were set up at the tank and at the view box to record the onset of air entraining vortices or air entrainment. The test number and water level were entered and the time clocks in the computer and video system were synchronized.

The pump in the flow loop was started and the pump speed was adjusted until the flow was set to the desired flow, as indicated by the computer (flow meter computer data acquisition), and the return flow was returned to the laboratory sump. The test was now initiated with the computer acquiring and storing data and start the video recording system with the timer on, recording the various flow phenomena of interest.

With continuous video recording, and flow and water level monitoring with the computer, any air bubbles drawn in the suction nozzles were noted.

The test was ended as soon as the flow could no longer be maintained. The pump was shut down and the flow loop was prepared for the next test.

7.0 RESULTS The results discussed below are based on the test data supported by visual observations and video documentation of air drawing free surface vortex types in the tank and air entrainment observations in the outlet pipe (view box location) for the plant configuration.

To represent the data in terms of non-dimensional variables, the following are defined:

Froude number, F = U / (gd)0 5 (8) where u = average model velocity at the suction nozzle entrance g = gravitational acceleration d = suction nozzle entrance diameter (or diameter of a circle having equivalent

area to the elliptical entrance of the nozzle as with the Clinton nozzles.

The test matrix for the Clinton HPCS suction nozzle study is shown in Table 1 and a summary of the test data is shown in Table 2. As mentioned previously, the test matrix consisted of 7 tests with no return flow to the tank. Tests covered specified flows ranging from 3,000 to 5,500 gpm (prototype) and the initial water depths tested covered initial submergences corresponding to about 12 ft (prototype) above the suction nozzle entrance in the plant.

The submergence datum reference is shown on Figure 7. Average model flows were calculated using the recorded flow rates from approximately 1 foot of submergence to the onset of air entrainment. Froude number calculations were made using model velocities calculated from average model flows.

Three tests simulating prototype flows of 5,500 gpm were conducted (Tests 1a through I c). No actual air drawing vortices were observed, however, air was entrained into the suction nozzle due to a localized draw down of the water level in the vicinity of the suction nozzle as the water level in the tank approached the top of the suction nozzle. The submergence at the onset of air entrainment was 4.65, 4.17 and 4.8 inches prototype for test Ia, Ib, and Ic, respectively. For test simulating prototype flows of 5,500 gpm, the localized draw down could first be observed when the water levels were approximately 0.7 inches (prototype) higher than those at the onset of air entrainment.

Three tests (Tests 2a through 2c) were also conducted simulating prototype flows of 3,000 gpm.

As with testing at the higher flows, no actual air drawing vortices were observed. Observed air entrainment in the suction nozzle was due to a localized draw down of the water level in the vicinity of the suction nozzle as the water level in the tank approached the top of the suction nozzle. The submergence at the onset of air entrainment was 2.60, 2.56 and 2.75 inches prototype for test 2a, 2b, and 2c, respectively. For test simulating prototype flows of 3,000 gpm, the localized draw down could first be observed when the water levels were approximately 0.6 inches (prototype) higher than those at the onset of air entrainment.

One test (Test 3) was also conducted at an intermediate flow of 4,250 gpm prototype. Results were similar to previous test in that no actual air drawing vortices were observed. Air entrainment in the suction nozzle was due to a localized draw down of the water level in the vicinity of the suction nozzle as the water level in the tank approached the top of the suction nozzle. The onset of air entrainment occurred at a submergence of 3.73 inches prototype.

8.0 CONCLUSION

S The hydraulic model study of the existing High Pressure Core Spray Suction at the Clinton Nuclear Power Station led to the following conclusions.

1. No air drawing vortices were observed for any of the flows tested.

2. Air entrainment for all conditions tested was due to a localized draw down of the water level in the vicinity of the suction nozzle as the water level in the tank approached the top of the suction nozzle.

3. For the three tests conducted at simulated prototype flows of 5,500 gpm (Tests I a through Ic) the onset of air entrainment occurred at submergences of 4.65, 4.17 and 4.80 inches prototype, respectively. The localized draw down could first be observed when the water levels were approximately 0.7 inches (prototype) higher than those at the onset of air entrainment.

4. For the three tests conducted at simulated prototype flows of 3,000 gpm (Tests 2a through 2c) the onset of air entrainment occurred at submergences of 2.60, 2.56 and 2.70 inches prototype, respectively. The localized draw down could first be observed when the water levels were approximately 0.6 inches (prototype) higher than those at the onset of air entrainment.

5. At the intermediate flow of 4,250 gpm prototype, the onset of air entrainment occurred at a submergence of 3.73 inches prototype.

9.0 REFERENCES

1. Prosser, M.J., "The Hydraulic Design Of Pump Sumps and Intakes," BHRA Report, July, 1977.

2. Padmanabhan, M. and Hecker, G.E., "Scale Effects in Pump Sump Models," ASCE Journal of Hydraulic Engineering, Vol. 110, No. 11, November, 1984.

3. Daggett, L. and Keulegan, G.H., "Similitude in Free-Surface Vortex Formations," Journal of the Hydraulics Division, ASCE, November, 1974.

4. Anwar, H.O., Wellen, J.A., and Amplett, M.B., "Similitude of Free-Surface Vortex at Horizontal Intake," Journal of Hydraulic Research, IAHR, Vol. 16, No. 2, 1978.

5. Jain, A.K., Raju, K.G.R., and Garde, R.J., "Vortex Formation at Vertical Pump Intakes,"

ASCE Journal of Hydraulics Division, Vol. 104, 1978.

6. Hydraulic Institute Standards, American National Standard for Pump Intake Design, ANSI/HI 9.8-1998.

7. Assessment of Scale Effects on Vortexing, Swirl and Inlet Losses in Large Scale Sump Models, NUREG/CR-2760, June 1982.

8. Rao, Nagar S. Lakshmana, and Kobus, Helmut E., "Characteristics of Self-Aerated Free Surface Flows," Water and Waste Water Current Research and Practice, Volume 10, Published by Eric Schmidt Verlag.

TABLES Table 1 Clinton HPCS Suction Test Matrix Scaled Initial Model Tes Ptpe F Model Flow Water Level No. (gpm) (gpm) (in) la 5500 338.3 48 lb 5500 338.3 48 ic 5500 338.3 48 2a 3000 184.5 48 2b. 3000 184.5 48 2c 3000 184.5 48 3 4250 261.4 48 Note: Water level is measured from the top of the suction nozzle.

Table 2 Clinton HPCS Suction Test Summary Prototype Target Target Avg. Initial S, Submergence S, Submergence Model Froude No.

Test No. Prototype Model Model Water at Onset of Air at Onset of Air Froude No. Using Flow Flow Flow Level Entrainment Entrainment Using Avg. Target (gpm) (gpm) (gpm) (Model in) (Model in) (Prototype in) Model Flow Prototype Flow la 5500 338.3 340.8 48 1.52 4.65 1.28 1.27 lb 5500 338.3 340.8 48 1.37 4.17 1.28 1.27 ic 5500 338.3 341.8 48 1.57 4.80 1.28 1.27 2a 3000 184.5 185.4 48 0.85 2.60 0.70 0.69 2b 3000 184.5 186.4 48 0.84 2.56 0.70 0.69 2c 3000 184.5 186.0 48 0.90 2.75 0.70 0.69 3 4250 261.4 262.7 48 1.22 3.73 0.99 0.98 Note: S = Submergence from Top I.D. of Suction Nozzle Pipe

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Figure 5: Clinton Nuclear Power Station RCIC Storage Tank; HPCS Piping ALDEN

RgP LABORATORY NZL , FLOW SUMP

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[202.1]

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[26.75] [18.0]

NOTE: PRIMARY UNITS INMODEL INCHES SECONDARY UNITS INPROTOTYPE INCHES ELEVATION VIEW Figure 7: Clinton HPCS Suction Vortex Study Tank and Suction Nozzle Setup: Elevation ALDEN

Figure 8: Clinton HPCS Suction Vortex Study; Model Nozzle J ALDEN

Figure 9: Clinton HPCS Suction Vortex Study; Model Nozzles N2, K and J ALDEN

Figure 10: Clinton HPCS Suction Vortex Study; Model Flow Loop ALDEN

Figure 11: Air Entrainment Viewing Box ALDEN

VORTEX VORTEX VORTEX VORTEX TYPE TYPE SURFACE SWIRL 2 - SURFACEDIMPLE:

COHERENTSWIRL 3 DYE CORE TO INTAKE: 4 VORTEX PULLING COHERENTSWIRL FLOATING TRASH, THROUGHOUT TRS T BUT NOTAIR WATER COLUMN 5 VORTEXPULLINGAIR 6 FULL AIR CORE BUBBLES TO INTAKE TO INTAKE AIB

~BUBBLES

a. REE4SURFACE VORTICE~S I SWIRL SWDYE CORE SUBUR2 BUBBLES

b. SUBSURFACE VORTICES Figure 12: Alden Vortex Classification ALDEN

APPENDIX A FLOW METER AND PRESSURE CELL CALIBRATION DATA

CALIBRATION OF THREE ORIFICE FLOW SECTIONS ALDEN JOB MCONORTEX AUGUST 2006 REPORT NO. 2006-164/CO CERTIFIED BY James B. Nystrom ALDEN RESEARCH LABORATORY, INC.

30 SHREWSBURY STREET HOLDEN, MASSACHUSETTS 01520

All Client supplied information and calibration results are considered proprietary and confidential to the Client. If a third party is a witness are during calibrations or if the Client requests transmittal of data to a third party, Alden considers that the Client has waived confidentiality for the Witness.

In the event the Client distributes any report issued by Alden outside its own organization, such report shall be used in its entirety, unless Alden approves a summary or abridgment for distribution.

No advertising or publicity containing any reference to Alden or any employee, either directly or by implication, shall be made use of by Client without Alden's written approval.

INTRODUCTION Three Orifice Flow Meters were calibrated at Alden Research Laboratory, Inc. for Alden Job MCO/VORTEX using Alden's standard test procedures, QA-AGF-7-86, Revision 6.1. Flow element performance is presented as discharge coefficient, C, versus Reynolds number, in both tabular and graphical. format.

FLOW ELEMENT INSTALLATION The flow elements were installed in Test Line 4 in the Hooper Facility, which is shown in plan view on Figure 1. A 25 horsepower centrifugal pump, rated at head of 150 ft at a flow of about 2 ft3/s, drew water from the laboratory penstock. The penstock supplies water from the Laboratory Pond at a head of about 18 ft.

Careful attention was given to align the flow element with the test line piping, and to assure no gaskets between flanged sections protruded into the flow. Vents were provided at critical locations of the test line to purge the system of air.

TEST PROCEDURE The test technician verified proper installation of the flow element in the test line prior to introducing water into the system to equalize test line piping and primary element temperature to water temperature. After attaining thermal equilibrium, the test line downstream control valve was then closed and vent valves in the test line were opened to remove air from the system. With the line flow shut off, the flow meter output was checked for zero flow indication. Prior to the test run, the control valve was set to produce the desired flow, while the flow was directed to waste. Sufficient time was allowed to stabilize both the flow and the instrument readings, after which the weigh tank discharge Report Number 2006-164/CO Page I of 15

o Figure 1 z

-tt 40" SUPPLY PENSTOCK SWITCHWAY oo

• 1,000 LB IQ PUMPS WEIGH TANK

// 10,000 LB WEIGH TANK -'

/SCALE-- --

Hooper Low Reynolds Number Facility Test Line 4.

ALDEN

valve was closed and the weigh tank scale indicator and the electric timer were both zeroed. To begin the test. run, flow was diverted into the weigh tank, which automatically started the timer.

At the start of the water collection a computer based data acquisition system was activated to read the meter output, such that the meter output was averaged while the weigh tank was filling. At the end of the run, flow was diverted away from the weigh tank and the timer and data acquisition system were stopped to terminate the test run. The weight of water in the tank, elapsed time, water temperature, and average meter output were recorded on a data sheet. The data were entered into the computer to determine the flow and the results were plotted so that each test run was evaluated before the next run began. The control valve was then adjusted to the next flow and the procedure repeated.

FLOW MEASUREMENT METHOD Flow was measured by the gravimetric method using a tank mounted on scales having a capacity of 10,000 pounds with a resolution of 0.2 lbs. Water passing through the flow element was diverted into the tank with a hydraulically operated knife edge passing through a rectangular jet produced by a diverter head box. A Hewlett-Packard 10 MHz Frequency Counter with a resolution 0.001 sec was started upon flow diversion into the tank by an optical switch, which is positioned at the center of thejet. The timer was stopped upon flow diversion back to waste and the elapsed diversion time was recorded. A thermistor thermometer measured water temperature to allow calculation of water density. Volumetric flow was calculated by Equation (1).

w (1) qa-3 ft where qa = actual flow, -

sec W = mass of water collected, lbm Report Number 2006-164/CO Page 3 of 15

T time, sec

= water density, ibm P" ft3 B: = buoyancy correction, 1 Pa Pw lbm Pa = air density, The buoyancy correction includes air density calculated by perfect gas laws with the standard barometric pressure, a relative humidity of 75%, and measured air temperature. The weigh tank is periodically calibrated to full scale by the step method using 10,000 Ibm of cast iron weights, whose calibration is traceable to NIST. Flow calculations are computerized to assure consistency. Weigh tank calibration data and water density as a function of temperature, are stored on disk file. Data were recorded manually and on disk file for later review and reporting.

DISCHARGE COEFFICIENT CALCULATIONS Discharge coefficient, C, is defined by Equation (2) and plotted versus pipe or throat Reynolds number. The discharge coefficient relates the theoretical flow to the actual flow.

C-q _ qa q FaKmi- (2) where C = discharge coefficient, dimensionless q1 h = theoretical flow, Fa = thermal expansion factor, dimensionless Ah = differential head, ft at line temperature ft2 .5 K, = meter constant, sec Report Number 2006-164/CO Page 4 of 15

The theoretical proportionality constant, Km, between flow and.square root of differential head is a function of the meter throat area, the ratio of throat to pipe diameter, and the local gravitational K t 4* (3)

Km=at K in-f*2g 341 constant, as defined by Equation (3).

2 2 a, throat area, 7rd , f where d = throat diameter, ft ft g = local gravitational constant, 32.1625 at Alden d

ratio of throat to pipe diameter, -, dimensionless D = pipe diameter, ft The effect of fluid properties, viscosity and density, on the discharge coefficient is determined by Reynolds number, the ratio of inertia to viscous forces. Pipe Reynolds number, RD., is determined by Equation (4).

RD = (4) apy D2 where ap pipe area, f2

, tt 2

ft y = kinematic viscosity, sec Report Number 2006-164/CO Page 5 of 15

FLOW METER SIGNAL RECORDING The secondary element, which converts the primary element signal into engineering units, was one of several "Smart" differential pressure transmitters having ranges of 25" W.C.,250" W.C., 1000" W.C. and 100 psid. Each transmitter was calibrated with a pneumatic or a hydraulic dead weight tester having an accuracy of 0.02% of reading. Transmitter signals were recorded by a PC based data acquisition system having a 16 bit A to D board. Transmitter calibrations were conducted with the PC system such that an end to end calibration was achieved. Transmitter output was read simultaneously with the diversion of flow into the weigh tank at a rate of about 34 Hz for each test run (flow) and averaged to obtain a precise differential head. For primary elements with multiple tap sets, individual transmitters were provided for each tap set and all transmitters were read simultaneously. Average transmitter reading was converted to feet of flowing water using a linear regression analysis of the calibration data and line water temperatures to calculate appropriate specific weight.

TEST RESULTS

• The calibration results are presented in individual tables and graphs for each of the three Orifice Flow Sections. The measured values of weight, time and line temperature, which were used to calculate the listed flow, are shown in the tables. The average transmitter reading used to calculate the differential head in feet of water at line temperature is also shown in the tables. Flow meter performance is given as discharge coefficient versus pipe Reynolds number.

Analysis indicates that the flow measurement uncertainty is within 0.25% of the true value for each

.test run. Calibrations of the test instrumentation (temperature, time, weight, and length measurements) are traceable to the National Institute of Standards and Technology (formerly the National Bureau of Standards) and ALDEN's Quality Assurance Program is designed to meet ANSI/NCSL Z540-1-1994 "Calibration Laboratories and Test Equipment-General Requirements" (supercedes MIL-STD-45662A).

Report Number 2006-164/CO Page 6 of 15

THIS PAGE INTENTIONALLY LEFT BLANK Report Number 2006-164/CO Page 7 of IS

ALDEN Purchase Order Number: MCONORTEX CALIBRATION

0 2" ORIFICE METER DATE

June 27, 2006 0D Serial Number: 2" PIPE DIAMETER = 2.0670 z THROAT DIAMETER = 1.1350 C:

C1%

Run Line Air Net Run Output Flow H Line Pipe Coef

1. Temp Temp Weight Duration [see Rey.#

Deg F Deg F lb. secs. note] GPM FT H20 x 10^4 1 69 73 367 298.245 3.110- 8.863 0.287 1.3642 0.6233 2 69 73 754 287.497 7.109- 18.91 1.327 2.9116 0.6190 3 69 73 715 171.653 3.299- 30.04 3.373 4.6247 0.6168 4 69 73 2037 279.607 5.987- 52.53 10.372 8.0977 0.6150 5 69 73 2031 244.486 7.193- 59.92 13.510 9.2360 0.6146 6 69 73 2032 371.910 4.233- 39.40 5.806 6.0727 0.6164 10 to 00 0

- dp transmitter volts The data reported on herein was obtained by measuring equipment the calibration of which is traceable to NIST , following the installation and test procedures referenced in this report, resulting in a flow measurement uncertainty of +/- 0.25% or less.

CALIBRATED BY: PSS, THL CERTIFIED B

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C = Discharge Coefficient ( Dimensionless) ALDEN Ah = Pressure Differential ( Feet of Water at Run Temperature) Purchase Order Number: MCO/VORTEX 2" ORIHCE METER avi2g Klj= Meter Constant = -- 0.0591 Serial Number: 2" June 27, 2006 F = Average Thermal Expansion Factor = 1.0000 a 0 2 a = Throat Area (ft) = 0.0070 2

g = Local Acceleration of Gravity (ft/sec 2 ) 32.1625 6 = Ratio of Throat to Pipe Diameter ( Dimensionless) = 0.5491 Pipe Diameter (Inches) = 2.0670 Throat Diameter ( Inches) - 1.1350 Dimensions By: ALDEN Certified

ALDEN Purchase Order Number: MCONORTEX CALIBRATION 3" ORIFICE METER DATE: June 28, 2006 0 Serial Number: 3" PIPE DIAMETER = 3.0680 THROAT DIAMETER = 1.8750 C') Run Line Air Net Run Output Flow H Line Pipe Coef 07 01 # Temp Temp Weight Duration [see Rey. #

Deg F Deg F lb. secs. note] GPM FT H20 x 1OA5 5 69 72 2051 74.562 9.253- 198.3 18.875 2.0574 0.6137 2 69 72 2046 93.730 6.556- 157.4 11.853 1.6419 0.6147 3 70 72 2043 112.559 5.141- 130.8 8.170 1.3666 0.6154 4 70 72 2035 142.729 3.934- 102.8 5.027 1.0739 0.6165 5 70 72 2035 193.847 3.044- 75.71 2.711 0.7905 0.6180 6 70 72 2030 297.103 6.404- 49.28 1.144 0.5147 0.6194 7 70 72 2028 673.633 2.846- 21.71 0.219 0.2267 0.6240 "o

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-dp transmitter volts The data reported on herein was obtained by measuring equipment the calibration of which is traceable to NIST , following the installation and test procedures referenced in this report, resulting in a flow measurement uncertainty of +/- 0.25% or less.

CALIBRATED BY: PSS

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0.605 0.600 0.0 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 Pipe Reynolds Number (in thousands)

C qa = CFaKM \/Ah qa = Actual Flow (ft3 /sec)

C = Discharge Coefficient (Dimensionless) ALDEN Ah= Pressure Differential (Feet of Water at Run Temperature) Purchase Order Number: MCONORTEX 3" ORIFICE METER a\ 2g KM=f Meter Constant = 0.1658 Serial Number: 3"

\/-1-B June 28, 2006 Fa = Average Thermal Expansion Factor 1.0000 a = Throat Area (ft2) 0.0192 g = Local Acceleration of Gravity (ft/sec2) 2 32.1625 B = Ratio of Throat to Pipe Diameter ( Dimensionless) 0.6111 Pipe Diameter ( Inches) 3.0680 Throat Diameter (Inches) = 1.8750 Dimensions By: ARL Certified

ALDEN Purchase Order Number: MCOIVORTEX CALIBRATION 6" ORIFICE METER DATE: June 28, 2006 Serial Number: 6" PIPE DIAMETER = 6.0650 z THROAT DIAMETER = 4.0000 C) 7-1 Run Line Air Net Run Output Flow H Line Pipe Coef

1. Temp Temp Weight Duration [see Rey. #

Deg F Deg F lb. secs. note] GPM FT H20 x 10^5 1 5 72 8083 90.954 5.461- 641.0 9.003 3.4093 0.6124 2 71 72 8071 107.291 4.476- 542.6 6.440 2.9228 0.6129 3 72 72 8067 129.524 3.696- 449.3 4.409 2.4386 0.6134 4 72 72 8059 165.143 3.039- 352.0 2.697 1.9106 0.6144 5 72 72 6053 171.550 7.414- 254.5 1.407 1.3815 0.6151 6 72 72. 4041 185.239 4.060- 157.3 0.534 0.8530 0.6170 0

- dp transmitter volts The data reported on herein was obtained by measuring equipment the calibration of which is traceable to NIST , following the installation and test procedures referenced in this report, resulting in a flow measurement uncertainty of +/- 0.25% or less.

CALIBRATED BY: PSS CERTIFIEDA Aý\L

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C = Discharge Coefficient ( Dimensionless) ALDEN Ah = Pressure Differential (Feet of Water at Run Temperature) Purchase Order Number: MCONORTEX a' 2g 6" ORIFICE METER KM= Meter Constant = a/ 2g 0.7773 Serial Number: 6" June 28, 2006 Fa = Average Thermal Expansion Factor = 1.0000 a = Throat Area (ft2 ) - 0.0873 g = Local Acceleration of Gravity (ft/sec)2 32.1625 B = Ratio of Throat to Pipe Diameter ( Dimensionless) = 0.6595 Pipe Diameter (Inches) = 6.0650 Throat Diameter (Inches) - 4.0000 Dimensions By: ARL Certified

Thermal Expansion Factor The dimensions of a differential producing flow meter are affected by the operating temperature, requiring a Thermal Expansion Factor (Fa) to be included in the calculations. The calculation requires the temperature at which the meter dimensions were measured be known. If this information is not available, an ambient temperature of 68 0 F is assumed. The Thermal Expansion Factor is calculated according to the American Society of Mechanical Engineers Standard ASME MFC-3M-1989, Equation 17 (pg 11).

Fa =1+ (I-P4) (,PE - m4eas ap)(t- tme) where ratio of throat diameter to pipe diameter, dimensionless aPE thermal expansion factor of primary element, 'F thermal expansion factor of pipe, 'F t temperature of flowing fluid, 'F tmeas temperature of measurements, *F Thermal expansion factors, a, excerpted from MFC-3M-1989, are listed in the Table below for six typically Used materials at three temperatures. Linear interpolation is used to determine the coefficients at flowing temperature.

Thermal Expansion Factors x 10-6 Material -50 0 F7 70°F 200°F Carbon Steel (low chrome) 5.80 6.07 6.38 Intermediate Steel (5 to 9 Cr-Mo) 5.45 5.73 6.04 Austenitic stainless steels 8.90 9.11 9.34 Straight chromium stainless steel 5.00 5.24 5.50 Monel (67Ni-3OCu) 7.15 7.48 7.84 Bronze 9.15 9.57 10.03 Report Number 2006-164/CO Page 14 of 15

WATER DENSITY Temperature Density Temperature Density Temperature Density Fahrenheit lbm /ft3 Fahrenheit lbm / ft 3 Fahrenheit lbm / ft 3 32 62.4179 62 62.3549 92 62.0903 33 62.4201 63 62.3489 93 62.0788 34 62.4220 64 62.3427 94 62.0671 35 62.4235 65 62.3363 95 62.0552 36 62.4246 66 62.3296 96 62.0432 37 62.4255 67 62.3228 97 62.0311 38 62.4260 68 62.3157 98 62.0188 39 62.4262 69 62.3084 99 62.0063 40 62.4261 70 62.3010 100 61.9937 41 62.4257 71 62.2933 101 61.9810 42 62.4250 72 62.2855 102 61.9681 43 62.4240 73 62.2774 103 61.9551 44 62.4227 74 62.2692 104 61.9419 45 62.4211 75 62.2608 105 61.9286 46 62.4193 76 62.2522 106 61.9151 47 62.4171 77 62.2434 107 61.9015 48 62.4147 78 62.2344 108 61.8878 49 62.4121 79 62.2252 109 61.8739 50 62.4092 80 62.2159 110 61.8599 51 62.4060 81 62.2063 111 61.8458 52 62.4025 82. 62.1966 112 61.8315 53 62.3988 83 62.1868 113 61.8172 54 62.3949 84 62.1767 114 61.8027 55 62.3907 85 62.1665 115 61.7880 56 62.3863 86 62.1561 116 61.7733 57 62.3816 87 62.1456 117 61.7584 58 62.3768 88 62.1348 118 61.7434 59 62.3716 89 62.1239 119 61.7284 60 62.3663 90 62.1129 120 61.7132 61 62.3607 91 62.1017 121 61.6978 Report Number 2006-164/CO Page15 of 15

Calibration of Pressure Transmitter Calibrated By: THL Cell No.: 697 Date: 11/14/2006 Temp.: 61 A-D Board No.: 642 Using Pneumatic DWT No.: 550 Weight Id Tester Reading Calculated Percent Approx.

1 2 3 4 5 6 7 8 9 10 11 12 PSI Volts PSI Error inches 1 0.0000 1.9582 2 0.1803 2.5116 0.1801 -0.07% 5.0 31 0.3605 3.0658 0.3607 0.05% 10.0 4 1 0.5408 3.619 0.5409 0.03% 14.9 5 1 1 0.7211 4.1729 0.7214 0.05% 19.9 6 1 1 1 1.0816 5.2795 1.0819 0.03% 29.9 7 1 1 1 1.2618 5.8328 1.2622 0.03% 34.8 8 11 1 1 1.6224 6.9386 1.6224 0.00% 44.8 9 1 1.9829 8.0453 1.9830 0.01% 54.7 10 1 1 2.3434 9.1511 2.3432 -0.01% 64.7 11 1 1 2.3434 9.1508 2.3431 -0.01% 64.7 12 1 1.9829 8.0445 1.9827 -0.01% 54.7 13 1 1 1 1 1.6224 6.9385 1.6224 0.00% 44.8 14 l1 1 1.2618 5.8319 1.2619 0.00% 34.8 15 1 1 1 1.0816 5.2785 1.0816 0.00% 29.9 16 1 1 0.7211 4.1717 0.7210. -0.01% 19.9 17 - 1 0.5408 3.6183 0.5407 -0.02% 14.9 18 1 0.3605 3.0643 0.3602 -0.09% 10.0 19 0.1803 2.5108 0.1799 -0.21% 5.0 20 0.00001 1.9577 -0.0003 Regression Coeffs.

Note: Zeroes not included in regression. Slope: 0.325792 Note: Pressures correct only for temperature Intercept: -0.638112 indicated at top. Std Err of Y Est: 0.0002204 0,05% 1 5

-- I_I_ -- -

I .0..0.%- -

.0.16%

Pa

.029%

0' 0.00 0060 I=0 IM0 2.W LS0 Printed:l 1/14/2*

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Calibration of Pressure Transmitter Calibrated By: THL Cell No.: 626 Date: 1114/2006 Temp.: 61 A-D Board No.: 642 Using Pneumatic DWT No.: 550 Weight Id Tester Reading Calculated Percent Approx.

1 2 314 5 6 7 18 9 11112 0 PSI Volts PSI Error inches 0.0000 1.9971 0.1803 2.5921 0.1803 0.00% 5.0 1 0.3605 3.1871 0.3605 -0.01% 10.0 1 0.5408 3.782 0.5407 -0.02% 14.9 1 1 0.7211 4.3773 0.7210 -0.01% 19.9 1 1 1 1.0816 5.5681 1.0817 0.01% 29.9 1 1 1 1.2618 6.1622 1.2616 -0.02% 34.8 I 1 1 1 1.6224 7.3525 1.6222 -0.01% 44.8 1 1.9829 8.5434 1.9829 0.00% 54.7 1 1 2.3434 9.7339 2.3435 0.00% 64.7 1 1 2.3434 9.7337 2.3434 0.00% 64.7 1 1.9829 8.5436 1.9829 0.00% 54.7 I I 1 1 1.6224 7.3533 1.6224 0.00% 44.8 1 1 1 1.2618 6.1631 1.2619 0.00% 34.8 I I 1 1.0816 5.5682 1.0817 0.01% 29.9 1 I 0.7211 4.3779 0.7212 0.02% 19.9 1 0.5408 3.7823 0.5408 0.00% 14.9 1 0.3605 3.1875 0.3606 0.02% 10.0 0.1803 2.5924 0.1804 0.05% 5.0 0.0000 1.9969 0.0000

..... s~u .'.uc- -* S".

IAegressiuon .,CoIis.

Note: Zeroes not included in regression. Slope: F.302893 Note: Pressures correct only for temperature Intercept: -0.604871 indicated at top. Std Err of Y Est: 0.0001034 0C %

1001%

AM

.0.t3% 1 0.00 0.50 1.00 1.60 2.00 2.5D psi Printed: 11/14/200*

Z:\Jobs\A-E\CNS VORTEXMCALIBRATIONS\DPcell sn 0642 calxls

APPENDIX B TEST PLAN

TEST PLAN CLINTON NUCLEAR POWER STATION HIGH PRESSURE CORE SPRAY PUMP SUCTION VORTEX/AIR ENTRAINMENT STUDY December 5 th 2006 Prepared By Alden Research Laboratory, Inc Holden, MA Prepared by:

fMartin M. Wosnik Reviewed by:

"Andrew E. h MsoTs -' -

Approved by:

Title Document No Revision Pa ge Date Clinton Nuclear Power Station Pump Intake Model 002 1 12/5//2006 CNS/Vortex ALDEN

RECORD OF REVISION Revision Date Description No.

001 12/1/06 Removal of Gas Volume Fraction meter and Pressure Transmitter from Table 1 Measurement Equipment.

001 12/1/06 Change Figure 1 & 2 (Flow Loop).

002 12/5/06 Change item vii under test plan.

002 12/5/06 Change item xii under test plan.

002 12/5/06 Change item xiv under test plan.

002 12/5/06 Change tests under Table 2 Test Matrix.

Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 2 12/5//2006 CNS/Vortex ALDEN

TABLE OF CONTENTS PAGE

1. INTRODUCTION 4

2. SCOPE 4

3. MEASUREMENT EQUIPMENT 4

4. TEST SETUP 5

5. TEST PROCEDURE 5 FIGURES Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 3 12/5//2006 CNS/Vortex ALDEN

1. PURPOSE The purpose of this test is to conduct a physical hydraulic model study of the High Pressure Core Spray (HPCS) tank and suction nozzle of Clinton Nuclear Power Station (CNPS) to evaluate the potential for vortexing/air-entrainment as the tank drains and the water level is lowered to reach specified minimum submergences at specified flow rates.

2. SCOPE The testing will consist of only one phase, which will use the pre-modification design with a horizontal suction nozzle to evaluate vortexing/air-entrainment. 4 tests, covering prototype (plant) flow rates from 3,000 gpm to 5,500 gpm will be performed. All testing will be conducted under transient flow conditions at Froude-scaled flow and submergence.

The flow modeling will be performed at the facilities of Alden Research Laboratory, Inc.

(Alden) in Holden, Massachusetts by Alden personnel. Selected tests will be witnessed by personnel from Clinton Nuclear Power Station.

3. MEASUREMENT EQUIPMENT The measurement equipment required to perform the test program is summarized in Table 1. The accuracy and/or calibration requirements of each piece of equipment are also listed.

Table 1 Measurement Equipment EQUIPMENT PURPOSE ACCURACY ASME Orifice Flow Meter Measure outflow through modeled pump suction +/- 2% of measured nozzles flow Differential Pressure Cell Monitor orifice meter differential head +/- 0.25% of dp cell span Differential Pressure Cell Monitor water level +/- 0.25% of dp cell span Stilling Well Set reference water levels 0.001 ft Thermometer Monitor water temperature +/- 0.5 'F over a 32

'F to 80 °F range Three (3) digital video Monitor and record vortex activity and air N/A cameras with timers entrainment Data Acquisition Computer To record output of differential pressure cells N/A which monitor orifice meter differential head and water level.

Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 4 12/5//2006 CNS/Vortex ALDEN

4. TEST SETUP The test setup will accommodate a hydraulic model of Clinton Nuclear Power Station HPCS Tank and Suction Nozzle, as well as measurement equipment and instrumentation, piping, pump and controller, valves, and a platform for operating and viewing. The geometric scale factor for the hydraulic model will be 1:3.05. Plan and elevation schematics of the test setup for the model are shown in Figures 1 and 2.

5. TEST PROCEDURE The following test procedure has been prepared for the Clinton Nuclear Power Station test program. The procedures may be modified based on preliminary results once the test program begins. Any changes to the test procedure will be communicated to Exelon/AmerGen for approval and will be formally submitted as a revision to the test procedure.

a. Clinton HPCS Tank and Suction Nozzle Test Procedure

i. Fill the tank with water approximately to the initial water level listed in Table 2 using a laboratory fill pump.

ii. Purge all differential pressure cells used to measure flow meter differential pressure and water level so that any air bubbles are removed.,

iii. Ensure Plexiglas view box is filled with water iv. Ensure that the data acquisition system clock and the clocks of the video cameras are synchronized.

v. Open and/or close appropriate valves of physical model flow setup for draining of tank/no return flow.

vi. Start computer data acquisition system. Enter appropriate log data including, but not limited to, date, test number, target flow rate and initial water level in the Alden lab data book. Check that zero flow is indicated with no flow in the loop.

vii. Record the date and test number on the labels of the three videocassettes and load them into the cameras.

viii. Position one video camera to record the water surface in the tank in the vicinity of the outlet pipe entrance where vortex formation is expected.

ix. Position the second video camera to record a side view of air bubbles in the outlet piping at the Plexiglas view box location.

x. Position the third video camera to record a top view of air bubbles in the outlet piping at the Plexiglas view box location.

xi. Read the water level and add/take away water until desired initial water level in the tank is achieved (Table 2).

xii. Start recording data from the data acquisition system and start the video cameras. The start of video recording can be delayed based on engineering judgment.

Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 5 12/5//2006 CNSNortex ALDEN

xiii. Start the pump in the flow loop xiv. Adjust the flow using the variable frequency drive (VFD) and/or control valve until the flow is set to the desired value (given in Table 2) as indicated by the computer (flow meter data acquisition). Flow will be set to within + 2% of the desired flow.

xv. Monitor the tank water surface (to observe onset of air-drawing vorticies) and flow in the outlet pipe to identify at what water level air entrainment begins.

xvi. Stop the test by shutting down the pump, closing the bypass valve, and saving the acquired data.

xvii. Repeat steps i through xvii for the next test series.

Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 6 12/5//2006 CNS/Vortex ALDEN

Table 2 Clinton HPCS Tank and Suction Nozzle Test Matrix Test Prototype Flow Scaled Flow Scaled Flow Flow Initial Water No. [gpm] [gpmj [cfs] Returned to Level*

Tank [in]

[gpm]!

la 5500 338.3 0.754 0 48 lb 5500 338.3 0.754 0 48 Ic 5500 338.3 0.754 0 48 2a 3000 184.5 0.411 0 48 2b 3000 184.5 0.411 0 48 2c 3000 184.5 0.411 0 48 3 4250 261.4 0.582 0 48

• Initial water level from top of suction nozzle.

Additional runs to be determined based on results of tests 1 through 4.

Title Document No Revision Page Date Clinton Nuclear Power Station Pump Intake Model 002 7 12/5//2006 CNS/Vortex ALDEN

NOTEPRUWAY DNW4SON WN MOMWiCMS SECOND IN M DouDmI PLAN VIEW ROTOTs Figure 1: Clinton HPCS Tank and Suction Nozzle Air Entrai8nent/Vortex Study Test Loop Setup: Plan.

Title Document No Revision Pacie Date Clinton Nuclear Power Station Pump Intake Model 002 8 12/5//200 6 CNS/Vortex ALDEN

SUCTION NOZZLE J 66.25

[202.1]

AIR ENTRAINMENT VIEWING BOX 8.77 5.90

[26.75] [18.01 NOTE: PRIMARY UNITS INMODEL INCHES SECONDARY UNITS INPROTOTYPE INCHES ELEVATION VIEW Figure 2: HPCS Tank and Suction Nozzle Air Entrainment/Vortex Study Test Loop Setup: Elevation.

Title Clinton Nuclear Power. Station Pump Intake Model CNS/Vortex Document No ALDEN Revision 002 I Page 9

Date 12/5//2006 I

• MPR ASSOCIATES INCQ E N G I NE ER S December 13, 2006 DRN 0065-0036-01 Mr. Robert Kerestes Clinton Power Station Amergen Energy RR#3 Box 228 Clinton, IL 61727

Subject:

. Independent Third Party Review of Hydraulic Model Study of High Pressure Core Spray Pump Suction

Dear Mr. Kerestes:

Per your request, the purpose of this letter is to perform an independent third party review of the Hydraulic Model Study of the High Pressure Core Spray Pump Suction conducted for Exelon by Alden Research Laboratory (Alden). The scope of this review includes the test plan, scaling calculations, and final test report for the testing performed at Alden on December 5, 2006. Our observations and recommendations are provided below.

MPR reviewed the scaling calculations, model similitude, and test configuration. The geometric scale model used to perform the test was appropriately sized based on the actual configuration at Clinton. The geometric scale of 3.051 appropriately accounted for the velocity, flow, and other parameters for Froude similitude.

The test report states that two nozzles internal to the tank (Nozzle K and Nozzle N2) were also modeled due to their close proximity to the suction nozzle. These nozzles were modeled as obstructions to the flow only. The tank drawing (JND 51749) shows several additional nozzles in the tank.

Recommendation #1: MPR recommends that you confirm that the geometry of these additional nozzles does not impact the flow in the tank. Also, confirm that no other nozzles provide suction or discharge to the tank during the operation of the HPCS pump at Clinton to ensure that the flow field simulated in the test at Alden is representative of actual plant conditions when the pump is running.

The test included the use of several measurement devices which have associated uncertainties (Section 4.0 of the test report). Additionally, multiple runs at the same flow rates were conducted with varying results. The most critical result of the testing is the submergence value (S), documented in the results section and listed in Table 2 of the test report.

320 KING STREET ALEXANDRIA, VA 22314-3230 703-519-0200 FAX: 703-519-0224 http://www.mpr.com

Mr. Robert Kerestes December 13, 2006 Recommendation #2: Analysis will be required to determine using the test data if the air ingested in the piping can reach the pump before recirculation alignment is complete. MPR recommends that Clinton Power Station should perform a statistical analysis of the data recorded in the test before using the submergence values to address the uncertainty in the test results.

The suction flows for the testing varied from 3000 gpm to 5500 gpm (prototype). Three runs were conducted at 3000 gpm (prototype), three runs at 5500 gpm (prototype) and one run at 4250 gpm (prototype). Because multiple runs were performed at the 3000 gpm and 5500 gpm (prototype) flowrates butnot at the 4250 gpm (prototype) flowrate, they provide more assurance of the validity of the results than the 4250 gpm (prototype) run.

Recommendation #3: In addition to the 5500 gpm and 4200 gpm flow rates, a 4200 gpm flow rate was also tested at Alden. The purpose of this run was to ensure that the submergence for this flow was between the measured submergences for the other two flow rates. The test for 4250 gpm was not repeated since only a single run confirmed the expected result. Although, the results of the test were as expected, we recommend that this data point should not be used in analysis unless the test at 4250 gpm is repeated to obtain more readings.

An MPR representative witnessed the testing at Alden on December 5, 2006. The testing was conducted according to the test plan. Conclusions #1 and #2 in Section 8.0 of the test report are consistent with the observations noted by the MPR representative during the testing.

In reviewing the test report, MPR identified two "typos". In Section 2.2, the definition of submergence states: "Bottom of nozzle for McGuire & Catawba, centerline of suction nozzle for Oconee". The fourth sentence of the first paragraph of Section 5.0 states: "Tests for Clinton covered flows from ranging from..."

Recommendation #4: MPR recommends that these typos be corrected.

If you have any questions or comments about our independent third party review of this testing, please do not hesitate to call me or Peter Carlone.

Sincerely, Amol Limaye cc: E. Schweitzer