NUREG/CR-6902

 LA-UR-05-7631

Effects of Insulation Debris on

Throttle-Valve Flow Performance

A Subtask of GSI-191

Los Alamos National Laboratory

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research

Washington, DC 20555-0001
 

 NUREG/CR-6902

 LA-UR-05-7631 

Effects of Insulation Debris on

Throttle-Valve Flow Performance

A Subtask of GSI-191

Manuscript Completed: March 2006

Date Published: March 2006

Principal Investigators:

C.B. Dale1

, P. Sadasivan1, B.C. Letellier1

Prepared by:

P. Sadasivan1

, C.B. Dale1, A.K. Maji2, K. Howe2 , 

F. Carles2

, C.E. Anderson2 , B.C. Letellier 1

.

1

Los Alamos National Laboratory

Los Alamos, NM 87545

Subcontractors:

2

University of New Mexico

Department of Civil Engineering

Albuquerque, NM 87110

E. Geiger, NRC Project Manager 

Prepared for

Division of Fuel, Engineering and Radiological Research 

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

NRC Job Code Y6871
ii

This page intentionally left blank.
iii 

ABSTRACT 

This document describes a series of tests conducted to assess the potential for loss-of-coolantaccident (LOCA)–generated debris to be trapped in the throttle valve downstream of the sump 

screen. Trapping of debris in the valve has important consequences for emergency-core-coolingsystem (ECCS) operation because it may result in unacceptably high pressure losses in the 

system and consequent degradation of ECCS performance. Tests have been performed using a 

range of loadings and compositions of insulation introduced either as a single batch or as a set of 

successive batches. The tests used a surrogate throttle valve designed to simulate a range of 

representative valve configurations in use within United States pressurized-water reactors. This 

test program was the second in a series of Nuclear-Regulatory-Commission-sponsored tests that 

were conducted to address the effects downstream of the ECCS sump screens. 

The first test program in this series addressed the potential for LOCA-generated debris materials 

to penetrate the sump screen. The current tests addressed the downstream effects of the debris 

that was able to penetrate the sump screen in these earlier tests. The test data provided 

information on the potential blockage of the high-pressure safety-injection throttle valves caused 

by single slugs of unmixed debris, as well as the potential for enhanced blockage caused by 

single or multiple batches of combinations of debris types. The insulation debris that was tested 

included calcium silicate (CalSil) insulation, NUKONTM fiberglass insulation, and reflective 

metallic insulation (RMI); however, many other types of insulation exist in plants. The range of 

debris sizes was based on the results of the screen penetration tests. 

Debris blockage in the valve was gauged using the valve-loss-coefficient K, which was 

calculated using measured data for the pressure drop across the valve, the flow rate through the 

valve, and the temperature of the water. As the effective flow area of the valve decreased 

because of blockage, the loss coefficient increased. The overall approach was first to establish 

baseline loss coefficients for each valve configuration of interest and then to compare loss 

coefficients for various debris flow conditions with the data to get an indication of the extent of 

blockage caused by the debris. In addition, baseline loss coefficients were determined for 

selected known blockages (blockage-area fractions simulated using shims) to determine the 

relationship between K and the blocked-area fraction, as well as the blockage detection threshold 

of the system (~5%–8%). Loss coefficients for debris flow conditions then were compared with 

those for shim blockage data to obtain estimates of the blockage-area fractions. 

Data from tests with single batches of unmixed debris showed that, in general, higher debris 

loadings and larger debris sizes (relative to the throttle-valve opening) resulted in higher 

observed increases in K. The K increases were higher for RMI than for NUKON for equivalent 

mass loadings. However, NUKON is judged to be more likely than RMI or CalSil to cause 

throttle valve blockage because of the propensity for NUKON to transport and penetrate the 

sump screen. 

Tests using CalSil-RMI mixtures were the only two-component combinations that exhibited 

clear increases in K when compared with results from analogous single-debris CalSil and RMI 

tests. The results of tests performed using NUKON-RMI or CalSil-NUKON mixtures did not 

differ significantly from results for analogous separate tests, with one possible exception. One 

mixture test performed using unsieved CalSil with NUKON showed an appreciable increase in 
iv 

valve blockage compared with single-debris NUKON tests. However, it is unclear if this result is 

attributed to clumping within the unsieved CalSil or to retention by NUKON fibers within the 

valve. 

The three-component mixture tests were divided into two types of tests: (1) homogeneous 

mixtures of RMI, CalSil, and NUKON; and (2) sequential additions of each debris type using 

different ordering. Tests using homogeneous mixtures of RMI, CalSil, and NUKON showed an 

increase in valve blockage when compared with analogous single-debris RMI tests. However, no 

particular debris introduction sequence resulted in increases in valve blockage compared with 

results for homogeneous mixtures. Further, in the tests where NUKON was introduced first in 

the debris sequence, the blockage was much less than for homogeneous mixtures. 

Three accumulation tests were performed to investigate the potential for a cumulative increase in 

valve clogging as a result of a stream of debris batches reaching the valve. In these tests, multiple 

batches of debris were introduced at ~15-min intervals over a period of 3 h. Three debris types 

and loadings were tested. The tests with 25 g each of successive additions of NUKON-CalSil 

showed a sustained increase in K over time as more and more debris reached the valve. However, 

consistent with the variability observed in other tests, the increase in K was not observed 

following all additions of debris. Some debris additions did not result in any increase in K, 

suggesting that no net increase in valve blockage occurred at that step. Accumulation tests with 

periodic additions of CalSil alone (after early introduction of NUKON) also showed that some 

CalSil additions triggered increases in K, whereas others did not. Relative to single-debris CalSil 

tests, larger K increases were observed after some CalSil additions, which suggests that the 

potential exists for CalSil to be trapped by NUKON or RMI that may be present in the valve. 

The results for replicated single-debris, multiple-debris, and accumulation tests exhibited 

significant test-to-test variability. This variability is consistent with the inherent randomness 

involved in the process; the propensity for trapping of debris in the valve gap is a function of the 

random orientation of the individual pieces as they enter the valve gap. Further, the bending or 

thrashing of the debris pieces inside the valve also is a random process. This variability makes it 

difficult to quantify trends in these results because only a limited number of replicate tests were 

performed for any single condition. 
v 

FOREWORD

On September 13, 2004, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter 

(GL) 2004-02, “Potential Impact of Blockage on Emergency Recirculation During Design-Basis 

Accidents at Pressurized-Water Reactors (PWRs),” to request that all PWR licensees 

perform an evaluation and ensure acceptable performance of the emergency core cooling 

and containment spray systems during sump recirculation following a loss-of-coolant accident 

(LOCA). This GL addresses technical issues associated with Generic Safety Issue (GSI) 191, 

“Assessment of Debris Accumulation on PWR Sump Performance.” As part of the evaluation, 

the GL requested that licensees consider the effect of debris that is ingested through the sump 

screen on the performance of equipment downstream of the screen (i.e., downstream effects), 

such as the high-pressure safety injection (HPSI) throttle valves, pumps, piping, heat 

exchangers, and reactor vessel internals. 

This report documents the second phase of NRC-sponsored research, conducted at 

the University of New Mexico under the supervision of Los Alamos National Laboratory, to 

address downstream effects. The first research phase (documented in NUREG/CR-6885, 

“Screen Penetration Test Report,” dated October 2005) addressed the potential for debris 

materials to penetrate the sump screen. The primary objective of this second research phase 

was to parametrically assess the potential for ingested debris to be trapped in HPSI throttle 

valves. These tests used a surrogate throttle valve designed to simulate a range of 

representative valve configurations. The debris types that were tested included calcium silicate 

(CalSil) insulation, NUKONTM fiberglass insulation, and reflective metallic insulation (RMI). The 

test program evaluated blockages within the valve caused by (1) single slugs of individual debris 

types, (2) single slugs of various mixed-debris combinations, and (3) repeated loadings (multiple 

slugs) of various mixed-debris combinations to simulate debris accumulation over time. 

Data from tests with single slugs of individual debris types showed that, in general, 

greater debris mass and larger debris sizes (relative to the throttle valve opening) resulted in 

the greatest amount of valve blockage. For equivalent mass loadings, valve blockage was 

greater for RMI than for NUKON debris. However, NUKON is considered more likely to lead to 

throttle valve blockage because it can more easily penetrate the sump screen. Mixtures of larger 

NUKON and RMI debris with smaller CalSil debris appeared to enhance valve blockage 

compared to analogous single-debris tests, presumably because the larger debris more 

effectively traps the smaller debris. Also, repeated loadings of mixed-debris combinations 

demonstrated that valve blockage can increase, albeit nonuniformly, with successive loadings. 

The implication is that blockage accumulation over time is possible. All test results were subject 

to significant test-to-test variability, which is expected given the inherent randomness in the 

accumulation of debris within a flow-restricting valve. 

Consistent with the primary objective of this study, this report provides test data to support 

performance assessments of HPSI and other components downstream of the sump strainer 

screen to determine if they are affected by ingested debris following a postulated LOCA. 

Specifically, NRC staff can use knowledge gained from this study to evaluate licensees’ 

responses to GL 2004-02. 

Carl J. Paperiello, Director 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 
vi 

This page intentionally left blank.
vii 

CONTENTS 

Page 

ABSTRACT...................................................................................................................................iii 

FOREWORD .................................................................................................................................. v 

EXECUTIVE SUMMARY .........................................................................................................xiii 

ABBREVIATIONS .................................................................................................................... xvii 

1 INTRODUCTION .................................................................................................................. 1 

1.1 Background ..................................................................................................................... 1 

1.2 Overall Approach ............................................................................................................ 2 

1.3 Objectives of Test Program............................................................................................. 3 

1.3.1 Baseline................................................................................................................... 4 

1.3.2 Shim Blockage........................................................................................................ 4 

1.3.3 Single-Debris Blockage .......................................................................................... 4 

1.3.4 Debris Combination Blockage................................................................................ 4 

1.3.5 Debris Accumulation Blockage .............................................................................. 5 

1.4 Outline of Report............................................................................................................. 5 

2 TECHNICAL APPROACH.................................................................................................... 7 

2.1 General Approach............................................................................................................ 7 

2.2 Test Facility..................................................................................................................... 7 

2.2.1 Flume ...................................................................................................................... 7 

2.2.2 Flume to Pump........................................................................................................ 9 

2.2.3 Pump Discharge to Throttle Valve ....................................................................... 11 

2.2.4 Throttle Valve ....................................................................................................... 14 

2.2.5 Downstream of Valve ........................................................................................... 16 

2.3 Data ............................................................................................................................... 22 

2.3.1 Data Acquisition ................................................................................................... 22 

2.3.2 Temperature Control............................................................................................. 24 

2.4 Material Preparation...................................................................................................... 24 

2.4.1 RMI....................................................................................................................... 24 

2.4.2 NUKON ................................................................................................................ 25 

2.4.3 CalSil..................................................................................................................... 26 

2.4.4 Mixtures of RMI, NUKON, and CalSil................................................................ 27 

2.5 Test Parameters ............................................................................................................. 27 

2.6 Test Matrix .................................................................................................................... 29 

2.7 Data Analysis ................................................................................................................ 29 

2.7.1 Valve Pressure Loss.............................................................................................. 29 

2.7.2 Using K to Present Results.................................................................................... 33 

3 RESULTS OF BASELINE TESTS...................................................................................... 37 

3.1 Baseline for Unblocked Flow........................................................................................ 37 

3.2 Baseline Data for Known Blockage Area ..................................................................... 39 

4 RESULTS OF SINGLE-DEBRIS TESTS ........................................................................... 47 

4.1 RMI Tests...................................................................................................................... 47 

4.1.1 Tests with a Specified Number of Pieces of RMI................................................. 47 

4.1.2 Tests with Specified Mass of RMI........................................................................ 50 

4.1.3 RMI Repeatability Tests ....................................................................................... 51 

4.1.4 Estimating the Blockage Area .............................................................................. 51 
viii 

4.2 CalSil Tests ................................................................................................................... 59 

4.3 NUKON Tests ............................................................................................................... 61 

4.3.1 Tests with Specified Mass of NUKON................................................................. 61 

4.3.2 NUKON Repeatability Tests ................................................................................ 63 

4.3.3 Estimating Blockage Area .................................................................................... 64 

4.4 Discussion ..................................................................................................................... 65 

5 RESULTS OF MIXED-DEBRIS TESTS............................................................................. 67 

5.1 Mixtures of NUKON and RMI ..................................................................................... 67 

5.2 Mixtures of CalSil and RMI.......................................................................................... 70 

5.3 Mixtures of NUKON and CalSil................................................................................... 70 

5.4 Mixtures of RMI, NUKON, and CalSil ........................................................................ 71 

5.4.1 Homogeneous Combination of RMI, NUKON, and CalSil ................................. 71 

5.4.2 Sequential Addition of RMI, NUKON, and CalSil .............................................. 73 

5.4.3 Estimating Blockage-Area Fractions .................................................................... 73 

5.5 Discussion ..................................................................................................................... 73 

6 ACCUMULATION TESTS ................................................................................................. 79 

6.1 Test A-1......................................................................................................................... 79 

6.2 Test A-2......................................................................................................................... 80 

6.3 Test A-3......................................................................................................................... 83 

6.4 Discussion ..................................................................................................................... 86 

7 CONCLUSIONS................................................................................................................... 89 

8 REFERENCES ..................................................................................................................... 93 

APPENDIX A: TEST PROCEDURE .......................................................................................... 95 

A.1 Baseline Tests................................................................................................................ 97 

A.2 Shim Blockage Tests..................................................................................................... 97 

A.3 Tests with One Batch of Single Debris or Mixed Debris.............................................. 98 

A.4 Accumulation Tests....................................................................................................... 98

APPENDIX B: CALIBRATION................................................................................................ 101 

B.1. Flow-Meter Calibration............................................................................................... 101 

B.2 Pressure Device Calibration ........................................................................................ 102 

B.3. Temperature Device Calibration ................................................................................. 102 

APPENDIX C: STEPS TAKEN TO MINIMIZE DATA FLUCTUATIONS ........................... 105 

C.1 Background ................................................................................................................. 105 

C.2 Frequency Analyses .................................................................................................... 105 

C.3 Mechanical Effects...................................................................................................... 105

C.4 Electrical Effects ......................................................................................................... 105 

APPENDIX D: COMPILATION OF K DATA ......................................................................... 109 

APPENDIX E: COMPILATION OF PLOTS ............................................................................ 113 
ix 

FIGURES 

Page 

Figure 2-1. Schematic of the Throttle Valve Test Loop............................................................ 8 

Figure 2-2. Photograph of the Test Loop (Excluding the Flume) ............................................. 9 

Figure 2-3. Linear Hydraulic Flume........................................................................................ 10 

Figure 2-4. Schematic of Linear Hydraulic Flume (Not to Scale) .......................................... 10 

Figure 2-5. Discharge from Flume .......................................................................................... 12 

Figure 2-6. Detail of Test Loop from Pump to Throttle Valve ............................................... 12 

Figure 2-7. Debris Insertion Manifold..................................................................................... 13 

Figure 2-8. Detail Showing Location of Upstream Pressure Transducer................................ 13 

Figure 2-9. Basic Globe Valve Design with Possible Types of Valve Throat 

Configurations....................................................................................................... 15 

Figure 2-10. Detail of Surrogate Valve Stem and Ring............................................................. 15 

Figure 2-11. Valve Stems Used in the Tests.............................................................................. 16 

Figure 2-12. Key Dimensions of the Valve Stems .................................................................... 17 

Figure 2-13. Valve Seat Rings Used in the Tests ...................................................................... 17 

Figure 2-14. Key Dimensions of Valve Rings........................................................................... 18 

Figure 2-15. Surrogate Throttle Valve....................................................................................... 18 

Figure 2-16. 5L and 5S Valve Stem-Seat Plugs and Seat Rings ............................................... 19 

Figure 2-17. Part of the Test Loop Downstream of the Valve .................................................. 19 

Figure 2-18. Details of the Fluid Return Section of the Test Loop ........................................... 21 

Figure 2-19. Detailed Schematic of the Fluid Return Line (Side Elevation) ............................ 21 

Figure 2-20. Debris Recovery Bucket after a Test Involving a Mixture of RMI and 

NUKON ................................................................................................................ 22 

Figure 2-21. Examples of RMI Samples ................................................................................... 25 

Figure 2-22. NUKON after Processing by Kitchen Blender ..................................................... 26 

Figure 2-23. CalSil Sample........................................................................................................ 27 

Figure 2-24. Transient Variation of Pressure Drop (psi) and Flow Rate (gpm) for 

Test 45LDT4......................................................................................................... 34 

Figure 2-25. Transient Variation of Valve-Loss-Coefficient K for Test 45LDT4 .................... 34 

Figure 2-26. Transient Variation of Pressure Drop and Flow Rate for Test 45LDT6............... 35 

Figure 2-27. Transient Variation of Valve-Loss-Coefficient K for Test 45LDT6 .................... 36 

Figure 3-1. Baseline Data for 45L ........................................................................................... 38 

Figure 3-2. Baseline Data for 5L ............................................................................................. 38

Figure 3-3. Baseline Data for 5S Stem .................................................................................... 39 

Figure 3-4. Detail Showing Placement of a Shim on the Valve Ring ..................................... 40 

Figure 3-5. Transient Variation of K for Different Blockage Conditions ............................... 41 

Figure 3-6. Blockage Test Data for 45L, Valve Opening = 0.159 cm (0.0625 in.)................. 42 

Figure 3-7. Percentage Increase in K as a Result of Blockage [45L, 0.159-cm (0.0625-in.) 

 Opening] ............................................................................................................... 43 

Figure 3-8. Blockage Test Data for 5L, Valve Opening = 0.13 cm (0.05 in.)......................... 43 

Figure 3-9. Percentage Increase in K as a Result of Blockage [5L, 0.13-cm 

(0.05-in.) Opening] ............................................................................................... 44 

Figure 3-10. Comparing Curve Fits for ∆K% vs AB ................................................................. 44 

Figure 3-11. Comparing Shim Blockage to Baseline (45L Stem, Beginning of Test Program, 

 75 gpm) ................................................................................................................. 45 
x 

Figure 3-12. Comparing Shim Blockage to Baseline (5L Stem, Beginning of Test Program, 

75 gpm) ................................................................................................................. 45 

Figure 4-1. Transient Variation of Valve Pressure Drop and Calculated K for 

Test 45LDT1a ....................................................................................................... 49 

Figure 4-2. Transient Variation of Valve Pressure Drop and Calculated K for 

Test 5LDT1c ......................................................................................................... 49 

Figure 4-3. Observed Correlation between the Increase in K and the Number of RMI 

Pieces Recovered in the Valve.............................................................................. 52 

Figure 4-4. Relation between the Increase in K and the Ratio of RMI Size to Gap Size........ 52 

Figure 4-5. Transient Variation of Valve Pressure Drop and Calculated K for Test 5LC4 .... 60 

Figure 4-6. Transient Variation of Valve Pressure Drop, Flow Rate, and Calculated K for 

Test 5sc9 ............................................................................................................... 60 

Figure 4-7. Transient Variation of Valve Pressure Drop and Calculated K for NUKON 

Test 45LN1 ........................................................................................................... 61 

Figure 4-8. Transient Variation of Valve Pressure Drop and Calculated K for NUKON 

Test 5LN2 ............................................................................................................. 62 

Figure 4-9. Transient Variation of Valve Pressure Drop and Calculated K for NUKON 

Test 45LN3 ........................................................................................................... 62 

Figure 4-10. Observed Correlation between Mass of NUKON Introduced and the 

Increase in K. ........................................................................................................ 64 

Figure 4-11. Transient Variation of K for NUKON Repeatability Tests .................................. 65 

Figure 5-1. Comparison of RMI-NUKON Mixed Debris to RMI Alone................................ 70 

Figure 5-2. Transient Variation of Pressure Drop and K for Test D-19c_45L........................ 71 

Figure 5-3. Comparison of RMI-NUKON-CalSil Mixed Debris to RMI Alone .................... 74 

Figure 6-1. Transient Variation of K for Debris Accumulation Test A-1 ............................... 81 

Figure 6-2. Transient Data for RMI Addition, Followed by First Addition of 

NUKON-CalSil..................................................................................................... 82 

Figure 6-3. Transient Data for Three Additions of NUKON-CalSil Mixture ......................... 82 

Figure 6-4. Temperature Data for Test A-1............................................................................. 83 

Figure 6-5. Transient Data for Test A-2 .................................................................................. 84 

Figure 6-6. Early Transient Data for Test A-2 ........................................................................ 85 

Figure 6-7. Temperature Data for Test A-2............................................................................. 85 

Figure 6-8. Transient Data for Test A-3 .................................................................................. 87 

Figure 6-9. Early Stage of Test A-3......................................................................................... 88 

Figure A–1. Valve Identification Numbers Used in the Procedures......................................... 95 

Figure A–2. Debris Found in the Valve Body Following an RMI Single-Debris Test............. 96 

Figure A–3. Debris Found in the Valve Body Following a NUKON Single-Debris Test........ 96 

Figure B–1. Measured Flow vs Flow-Meter Reading............................................................. 101 
xi 

TABLES 

Page 

Table 2-1. Single Debris Test Matrix..................................................................................... 30 

Table 2-2. Mixed-Debris Test Matrix .................................................................................... 31 

Table 2-3. Debris Accumulation Test Matrix ........................................................................ 32 

Table 3-1. Throttle Valve Flow Area Conversions ................................................................ 39 

Table 4-1. Results of Tests with Specified Number of Pieces of RMI Introduced................ 48 

Table 4-2. Results of Tests with Specified Mass of RMI Introduced .................................... 53 

Table 4-3. Results of Repeatability Tests............................................................................... 56 

Table 4-4. Estimates of Blockage-Area Fraction for RMI Tests ........................................... 58 

Table 4-5. Results of CalSil Tests.......................................................................................... 59 

Table 4-6. Results of NUKON Tests...................................................................................... 63 

Table 4-7. Results of NUKON Repeatability Test................................................................. 64 

Table 4-8. Estimates of Blocked Area Fraction for NUKON Tests....................................... 65 

Table 5-1. Results of Tests with NUKON-RMI Mixtures ..................................................... 68 

Table 5-2. Results of Repeatability Test with NUKON RMI Mixtures................................. 68 

Table 5-3. Estimates of Blocked Area Fraction for Tests with NUKON-RMI Mixtures ...... 68 

Table 5-4. Comparing NUKON-RMI Mixture Test Data with Baseline Single-Debris 

Test Data ............................................................................................................... 69 

Table 5-5. Comparing CalSil-RMI Mixture Test Data with Baseline Single-Debris 

Test Data ............................................................................................................... 72 

Table 5-6. Comparing NUKON-CalSil Mixture Test Data with Baseline Single-Debris 

Test Data ............................................................................................................... 72 

Table 5-7. Results of Tests with Homogeneous RMI-NUKON-CalSil Mixtures.................. 75 

Table 5-8. Results of Tests with Sequential Addition of RMI-NUKON-CalSil Mixtures .... 76 

Table 5-9. Comparing RMI-NUKON-CalSil Mixture Test Data with Baseline 1- and 2- 

 Component Debris Test Data................................................................................ 77 

Table 5-10. Estimates of Blockage-Area Fractions for RMI-NUKON-CalSil Mixtures......... 78 

Table B-1. Waterbath Thermocouple Calibration..................................................................102 

Table B-2. In Situ Thermocouple Calibration ......................................................................103 

Table D-1. Summary of K Data .............................................................................................109 
xii 

This page intentionally left blank.
xiii 

EXECUTIVE SUMMARY 

A series of scoping tests has been performed to investigate potential effects of debris streams 

composed of reflective metallic insulation (RMI), NUKONTM fiberglass insulation, and calcium 

silicate (CalSil) insulation on the throttle valves used in the high-pressure safety-injection (HPSI) 

systems of pressurized water reactors (PWRs). The tests were performed under the direction of 

Los Alamos National Laboratory in test facilities located at the University of New Mexico Civil 

Engineering Laboratory. This test program was the second in a series, following a previous test 

program (summarized in NUREG/CR-6885) that studied the propensity for debris to penetrate 

the sump screen. The current tests addressed the downstream effects of the debris that was able 

to penetrate the sump screen in these earlier tests. The test data provided information on the 

potential blockage of the throttle valves caused by single slugs of unmixed debris, as well as the 

potential for enhanced blockage caused by single or multiple batches of combinations of debris 

types. 

The test program employed representative debris compositions and sizes. The debris types that 

were tested included CalSil, NUKON, and RMI. These insulation materials commonly are used 

in United States (U.S.) PWRs. The size range of each debris type tested was based on the results 

of the screen penetration tests. A surrogate valve capable of multiple configurations, rather than a 

specific plant valve, was used so that parametric studies readily could be performed. The 

surrogate valve was designed to be reasonably representative of the types of valve configurations 

used in U.S. PWRs. 

The main geometric features of the valve that influenced the potential for clogging by debris 

were the perpendicular distance between the plug and seat and the angular orientation and length 

of the mating surfaces of the seat and plug. A range of gaps between 0.13 cm (0.05 in.) and 

0.63 cm (0.25 in.) that spans typical PWR plant configurations was used in the tests. Stem angles 

of 5o and 45o were used in the tests. For the 5o stem angle, two stems of different diameters were 

used. The stem angles, angular orientation, and length of mating surfaces of the surrogate valve 

were determined through an informal survey of U.S. PWR plants and qualified vendors. 

The goal for the selection of the pump (and subsequently the flow rate) for this testing was to 

obtain a pump of similar design to the HPSI pumps typically used in U.S. PWRs. The total HPSI 

flow required for the small-break loss-of-coolant accident of interest is on the order of 12.62–

18.93 l/s (200–300 gpm). For HPSI systems having four injection paths, each path has an 

anticipated flow rate of 3.15–4.73 l/s (50–75 gpm) over a pressure drop (∆P) of ~1.38 MPa 

(200 psi). The pump for this test program was chosen to achieve this performance and had a 

rated flow rate of 6.31 l/s (100 gpm). Because the pump was operated at 4.73 l/s (75 gpm) during 

testing, additional head was available to possibly purge debris from the valve in the event of 

clogging. 

Debris blockage in the valve was gauged using the valve-loss-coefficient K, which was 

calculated using measured data for the pressure drop across the valve, the flow rate through the 

valve, and the temperature of the water. As the effective flow area of the valve decreased 

because of blockage, the loss coefficient increased. The overall approach first was to establish 

baseline loss coefficients for each valve configuration of interest and then compare loss 
xiv 

coefficients for various debris flow conditions with the baseline data to get an indication of the 

extent of blockage caused by the debris. In addition, loss coefficients were determined for 

selected known blockage areas (blockage-area fractions simulated using shims) to determine the 

relationship between K and the blocked-area fraction, as well as the blockage detection threshold 

of the system (~5%–8%). Loss coefficients for debris flow conditions then were compared with 

those for shim blockage data to obtain estimates of the blockage-area fractions. 

Data from tests with single batches of unmixed debris showed that, in general, higher debris 

loadings and larger debris sizes (relative to the throttle-valve opening) resulted in higher 

increases in K. In single-debris tests with RMI, the highest observed increase in K was ~50%. 

Based on the results of the screen penetration tests performed previously, <20% of the RMI 

pieces of a given size penetrated the screen with the same opening size. When the RMI debris 

pieces had dimensions smaller than the screen size, a larger fraction of the pieces penetrated the 

screen; however, the current results show that these pieces were also able to clear the throttle 

valve—at least for the range of valve openings tested. The screen penetration tests showed that a 

significant fraction of CalSil passed through the screen, regardless of the screen-opening size. 

The current results show that the same result occurred in the valve, as well—practically all of the 

CalSil passed through the valve without causing appreciable blockage. The screen penetration 

tests showed that as much as 80% of the blender-processed NUKON debris penetrated the 

screen. The current results show that K increased by as much as 220% when the valve 

encountered a stream of blender-processed NUKON. This result translated to 45% blockage in 

the valve-opening flow area. Based on these results, NUKON is judged to be more likely than 

RMI or CalSil to cause throttle valve blockage. A large fraction of blender-processed NUKON 

was able to penetrate the test screen; much of it, in turn, could get trapped in the valve, thus 

resulting in significant increases in valve pressure loss. 

Tests using CalSil-RMI mixtures were the only two-component combination that exhibited clear 

increases in K when compared with results from analogous single-debris CalSil and RMI tests. 

The results of tests performed using NUKON-RMI or CalSil-NUKON mixtures did not differ 

significantly from results for analogous separate tests for each debris component, with one 

possible exception. One mixture test performed using unsieved CalSil with NUKON showed an 

appreciable increase in valve blockage compared with single-debris NUKON tests. However, it 

is unclear if this result is attributed to clumping within the unsieved CalSil or to retention by 

NUKON fibers within the valve. 

The three-component mixture tests were divided into two types of tests: (1) homogeneous 

mixtures of RMI, CalSil, and NUKON; and (2) sequential additions of each debris type using 

different ordering. Tests using homogeneous mixtures of RMI, CalSil, and NUKON showed an 

increase in valve blockage when compared with analogous single-debris RMI tests. However, no 

particular debris introduction sequence resulted in increases in valve blockage compared with 

results for homogeneous mixtures. Further, in the tests where NUKON was introduced first in 

the debris sequence, the blockage was much less than for homogeneous mixtures. 

Three accumulation tests were performed to investigate the potential for a cumulative increase in 

valve clogging as a result of a sustained stream of debris batches reaching the valve. In these 

tests, multiple batches of debris were introduced at ~15-min intervals over a period of 3 h. Two 

of these tests were continued for an additional hour following the last debris addition to examine 
xv 

the potential for erosion of debris trapped in the valve. Three debris types and loadings were 

tested. The tests with 25 g each of successive additions of NUKON-CalSil showed a sustained 

increase in K over time as more and more debris reached the valve. However, consistent with the 

variability observed in other tests, the increase in K was not observed following all additions of 

debris. Some debris additions did not result in any increase in K, suggesting that no net increase 

in valve blockage occurred at that step. When the loading at each step was reduced to 13 g each, 

the net increase in K over time was substantially less. This observation was consistent with 

single-debris results, which indicated relatively small blockage effects for lower debris loadings. 

Accumulation tests with periodic additions of CalSil alone (after early introduction of NUKON) 

also showed that some debris addition events triggered increases in K, whereas others did not. 

Relative to single-debris CalSil tests, larger K increases were observed for some debris addition 

events, suggesting some potential for CalSil to be trapped in the valve by NUKON or RMI that 

may already have existed there. When one test was continued for 1 h following the final addition 

of debris, the valve-loss coefficient decreased precipitously at one point, suggesting erosion of 

the previously trapped debris. 

The results for replicated single-debris, multiple-debris, and accumulation tests exhibited 

significant test-to-test variability. This variability is consistent with the inherent randomness 

involved in the process; the propensity for trapping of debris in the valve gap is a function of the 

random orientation of the individual pieces as they enter the valve gap. Further, the bending or 

thrashing of the debris pieces inside the valve also is a random process. This variability makes it 

difficult to quantify trends in these results because only a limited number of replicate tests were 

performed for any single condition. 
xvi 

This page intentionally left blank.
xvii 

ABBREVIATIONS 

ASTM American Society for Testing and Materials 

CalSil Calcium Silicate 

ECCS Emergency-Core-Cooling System 

GSI Generic Safety Issue 

HPSI High-Pressure Safety Injection 

LANL Los Alamos National Laboratory 

LOCA Loss-of-Coolant Accident 

NRC Nuclear Regulatory Commission 

PVC Polyvinyl Chloride 

PWR Pressurized-Water Reactor 

RMI Reflective Metallic Insulation 

U.S. United States 

UNM University of New Mexico 
xviii 

This page intentionally left blank.
1 

1 INTRODUCTION 

The purpose of the Generic Safety Issue (GSI-191) research program was to determine if the 

transport and accumulation of debris in a containment following a loss-of-coolant accident 

(LOCA) would impede the operation of the emergency-core-cooling system (ECCS) in 

pressurized-water reactors (PWRs). In the event of a LOCA within a PWR containment, thermal 

insulation and other materials (e.g., coatings and concrete) in the vicinity of the break would be 

damaged and dislodged. A fraction of this material would be transported to the recirculation (or 

emergency) sump. The subject of debris transport fraction has been studied previously, as 

documented in Refs. 1 and 2. Part of the debris reaching the sump screen will accumulate on it, 

whereas the remainder will pass through the screen. The debris that accumulates on the screen 

can form a bed that acts as a filter, thus increasing the head loss across the screen. Excessive 

head loss may prevent or impede the flow of water to the ECCS or the containment-spray 

system, potentially degrading system performance or causing pump damage. The subject of 

debris penetration through the sump screen has been addressed in Ref. 3. Debris that passes 

through the screen first encounters the high-pressure safety-injection (HPSI) pumps, followed by 

the HPSI throttle valves. This study addresses the potential clogging of the throttle valves due to 

debris that can penetrate the screen. 

1.1 Background 

The HPSI throttle valves control the injection flow rates, balance the flow among multiple 

injection paths, and prevent pump runout conditions. The potential for clogging of the throttle 

valves has major implications on the operability of the HPSI system. As debris accumulates in a 

valve, flow resistance increases, resulting in an increased pressure drop across the valve. The 

increase in the system head could cause a flow reduction in the affected line and total flow as 

well; continued buildup of debris could completely shut off the flow in one or more lines. 

Therefore, it is important to gain an understanding of the conditions under which debris can clog 

the throttle valve; this understanding is the focus of the current testing program. 

United States (U.S.) PWRs employ a variety of types of insulation and modes of encapsulation, 

ranging from nonencapsulated fiberglass to fully encapsulated stainless-steel reflective metallic 

insulation (RMI). Many PWRs have fiberglass and calcium silicate (CalSil) insulations in the 

containment, either on primary piping or on supporting systems.The types of fibrous insulation 

vary significantly, but much of it is found in the form of common low-density fiberglass 

(NUKONTM*

) and mineral wool. Some plants may have installed “high-performance” fiberglass 

on their primary systems for the higher insulation value, whereas other plants may have installed 

RMI for the low transportability. In general, the smaller pipes and steam generators are more 

likely to be insulated with fiberglass and CalSil than the reactor pressure vessel or the hot and 

cold leg piping. 

The characteristics of the debris stream that reaches the throttle valve depend on the size 

distribution and composition of debris generated as a result of the LOCA, as well as the fraction 

of the debris that penetrates the sump screen. The composition of the debris stream reaching the 

throttle valve depends on the PWR in question. Some plants use fibrous insulation for essentially 

 

*

 NUKONTM is a trademark of Owens Corning. 
2

all of the piping, whereas others may use a combination of CalSil and fibrous insulation such as 

NUKON. As discussed in Ref. 2, the composition of the debris stream is also highly dependent 

on the location of the initiating LOCA. Preferential application of fiber insulation to smaller 

pipes and auxiliary pipes is more common, whereas RMI is used primarily on large components 

such as the reactor vessel and steam generators. This spatial dependency of the insulation 

application means that the debris source term will depend on the break location. This inherent 

lack of homogeneity in the debris stream implies that investigation of throttle valve clogging 

must consider the separate effects of different types of debris, as well as the effects of 

combinations of debris. The test matrix for the test program was developed accordingly. 

Screen penetration testing (Ref. 3) provided data on the size of debris that would be likely to 

reach the throttle valve. For any given debris composition, the fraction of debris that penetrated 

the screen depended on the debris size relative to the screen-opening size, the flow velocity at the 

screen, and whether the debris reached the screen along the floor or in the flow. 

The amount of CalSil passing through the screen was found to depend largely on how much of 

the CalSil was present in the form of clumps and how much of it was broken up by the 

momentum of the initiating LOCA jet or by the momentum of the recirculating flow. A 

significant amount of fine CalSil insulation could pass through screens of any mesh size. The 

fraction of NUKON that penetrated the screen also depended on the nature of aggregation. 

NUKON processed in a blender almost resulted in a suspension, and a significant fraction of it 

passed through screens of any mesh size, whereas NUKON processed in a leaf shredder resulted 

in agglomerated clumps that were almost entirely blocked by the screen. 

The amount of RMI passing through the screen was found to depend on the size of the pieces 

relative to the mesh size of the screen and, to a lesser extent, on the flow velocity. In the screen 

penetration tests, when the size of the RMI pieces was approximately the same as the screen 

mesh, only a small fraction passed through the screen, regardless of the flow velocity. When the 

size of the RMI pieces was somewhat smaller than the screen mesh, a significant fraction (up to 

75%) passed through the screen. The foregoing results of the screen penetration tests were used 

to guide the development of the test matrix for the throttle valve testing program. 

1.2 Overall Approach 

Debris blockage in the valve was gauged using the valve-loss-coefficient K, calculated using 

measured data for pressure drop across the valve, flow rate through the valve, and temperature of 

the water. As the flow area through the valve decreased as a result of blockage, the loss 

coefficient increased. The overall approach was first to establish baseline loss coefficients for 

each valve configuration of interest and then compare loss coefficients for various debris flow 

conditions with the baseline data to get an indication of the extent of blockage caused by the 

debris. In addition, loss coefficients were determined for selected known blockage conditions 

(blockage-area fractions simulated using shims). Loss coefficients for debris flow conditions 

then were compared with those for shim blockage data to obtain estimates of the blockage-area 

fractions. 

The test program employed representative compositions and sizes for the debris stream. The 

valve configurations used in the tests were designed to span typical U.S. PWR plant 
3

configurations. A surrogate valve capable of multiple configurations, rather than actual valves 

used in plants, was used so that parametric studies could be readily performed for multiple valve 

configurations. Types of debris, representative of insulation used in PWRs, were used in the 

tests, either singly or in combination. The debris types that were tested included CalSil, 

NUKON, and RMI. The range of sizes of the debris forms tested was based on the results of the 

screen penetration tests. 

As discussed in the previous section, more RMI debris penetrated the screen when the 

characteristic dimensions were less than the screen size. Penetration behavior of CalSil and 

NUKON was determined more by the nature of aggregation of the debris rather than 

characteristic size. The screen mesh size varies considerably in U.S. PWR plants. However, a 

majority of the plants currently have screen mesh sizes between 0.317 cm (0.125 in.) and 

0.63 cm (0.25 in.) (Ref. 2), although these mesh sizes may change as a result of planned sump 

screen modifications. 

The quantity of debris that could reach the throttle valves post-LOCA could vary greatly, 

depending on the location and size of the break. Therefore, the amount of debris was examined 

parametrically in this test program and was not necessarily representative of what actual plant 

debris loading may be. In the case of RMI, the debris loading has been specified either as a 

number of pieces or as a mass in grams. For NUKON and CalSil, the debris loading has been 

specified as a mass in grams. 

For traditional throttle valve designs, the gap between the plug and valve seat is the primary 

location that is susceptible to debris-related blockage. The main geometric features of this 

location that influence the potential for clogging by debris are the perpendicular distance 

between the plug and seat and the angular orientation and length of the mating surfaces of the 

seat and plug. To cover the range of gap sizes in throttle valves used in PWR plants, a range of 

gaps between 0.13 cm (0.05 in.) and 0.63 cm (0.25 in.) were used in the tests. Stem angles of 5o 

and 45o were used in the tests. For the 5o stem angle, two stems of different diameters were used. 

The stem angles, angular orientation, and length of mating surfaces of the surrogate valve were 

based on an informal survey of U.S. PWR plants and qualified vendors. 

1.3 Objectives of Test Program 

The overall objective of the test program was to assess the potential for debris to clog a HPSI 

throttle valve. This assessment required gathering the following types of data: 

1. Baseline: valve characteristics for normal operating conditions. Data obtained from these 

tests were used to compare with data obtained from debris flow tests (#2–5) to estimate 

the increase in the loss coefficient resulting from debris blockage. 

2. Shim blockage: valve characteristics for known blockage conditions. Loss-coefficient 

results determined from data obtained from these tests were used to gauge the detection 

threshold for the test system and as a basis for comparison with corresponding data 

obtained from debris flow tests listed in items 3–5 to estimate the extent of debris 

blockage. 

3. Single-debris blockage: the extent of valve blockage that resulted when the valve was 

exposed to a single batch of any one type of debris. 
4

4. Debris combination blockage: the valve blockage that resulted when the valve was 

exposed to a single batch of mixtures of debris, either as a homogeneous mixture or 

added successively. 

5. Debris accumulation blockage: the cumulative effect of multiple batches of debris added 

sequentially to examine the potential for progressive buildup of debris in the valve. 

1.3.1 Baseline 

This element of the test program generated baseline data on the valve configurations of interest. 

Baseline tests included a determination of the valve-loss-coefficient K for different valvestem/ring combinations for normal flow conditions with a range of valve openings. Baseline data 

for normal conditions was taken after each set of debris tests described in Sections 1.3.3–1.3.5 to 

keep track of potential changes in the baseline that occurred during testing. 

1.3.2 Shim Blockage 

Shim blockage tests also included a determination of the loss coefficient for selected valve 

stem/ring combinations for known blockage conditions. Blockage was simulated using shims of 

known areas, to establish the relationship between K and the percent area blockage as well as the 

detection threshold for blockage in the valve. The variation in loss coefficient as a function of 

blockage area also was determined. 

1.3.3 Single-Debris Blockage 

This component of the test program, designated as Test Series 1, addressed the issue of valve 

blockage caused by the retention of a single type of debris when the debris was added in a single 

batch. The specific objectives of the first phase of the test program were to generate data on 

clogging of the surrogate throttle valve configurations by single-debris types for a range of valve 

throat gaps and angles. The debris types included 

1. RMI debris with characteristic dimensions between 0.317 cm (0.125 in.) and 0.63 cm 

(0.25 in.). This debris included square pieces with sides 0.317 cm (0.125 in.) and 0.63 cm 

(0.25 in.) or rectangular pieces with sides 0.317 cm (0.125 in.) and 1.27 cm (0.5 in.) (4:1 

aspect ratio). 

2. NUKON debris mixed in water. 

3. CalSil debris. 

1.3.4 Debris Combination Blockage 

This part of the test program, designated as Test Series 2, addressed the issue of valve blockage 

caused by combinations of debris types. Each test involved the introduction of two or more types 

of debris. Specific combinations of debris composition, size, and/or mass were used. The debris 

combination was added in a single step. This series of tests addressed the potential for one type 

of debris to act as a nucleation source for retention of other debris types. The debris types used 

included 

1. NUKON combined with RMI of different sizes; 

2. CalSil combined with RMI of different sizes; 

3. homogeneous mixtures of CalSil, NUKON, and RMI; and 

4. combinations of CalSil, NUKON, and RMI introduced separately in a sequence. 
5

1.3.5 Debris Accumulation Blockage 

This component of the test program, designated as Test Series 3, examined the progressive 

clogging of the valve due to a slow buildup of debris. Multiple batches of debris were introduced 

at specified intervals for a period of several hours to determine the increase in blockage over 

time as a result of accumulation of debris in the valve. 

1.4 Outline of Report 

Section 2 provides a detailed description of the technical approach used for the test program. 

This approach included the methodology used in the experiments, the test facility used, the test 

matrix for the different series of tests, the test procedure used, and the data analysis 

methodology. 

Section 3 provides the results of the baseline tests. Section 4 presents the single debris test 

results. The results of combinations of multiple debris types are summarized in Section 5, 

whereas Section 6 provides the debris accumulation results. In these sections, test results are 

typically presented in the form of valve-loss-coefficient K. Additional details of the data are 

provided in appendices. The conclusions drawn from the results of the test program are discussed 

in Section 7. 
6 

This page intentionally left blank.
7

2 TECHNICAL APPROACH 

2.1 General Approach 

The overall approach was to simulate appropriate PWR debris flow conditions through a throttle 

valve using a flow loop. The test apparatus had the flexibility to control local flow conditions, as 

well as debris quantity and debris types, consistent with the objectives in Section 1. The facility 

also was able to take applicable measurements and visual observations to characterize the debris 

blockage in the valve. A surrogate valve was used in all of the testing described in this report. 

This surrogate valve permitted the simulation of multiple valve configurations by using 

interchangeable valve plugs with the same valve body. Also, the surrogate valve was designed to 

facilitate easy assembly and disassembly, thus enabling inspection of the debris in the valve after 

each test. 

2.2 Test Facility 

The testing was conducted in the open channel hydraulics laboratory in the Ferris Engineering 

Building at the University of New Mexico (UNM). The tests used existing equipment in the 

laboratory and new equipment provided specifically for the throttle valve tests. The throttle valve 

was tested by using a constant speed pump to convey water or water mixed with debris through 

the valve. Water was supplied by an upstream flume, pumped through the throttle valve, and 

discharged back to the flume. Debris was added through a manifold located downstream of the 

pump and upstream of the throttle valve. The performance of the throttle valve was monitored 

with pressure transducers, flow meters, and thermocouples installed upstream and downstream of 

the throttle valve. The overall layout of the test loop is shown schematically in Figure 2-1, and a 

photograph of the flow loop excluding the flume is shown in Figure 2-2. The hydraulic system 

for the throttle valve test from the upstream flume, through the throttle valve is more thoroughly 

described in the following sections. 

2.2.1 Flume 

Water was provided to the suction side of the pump through the “linear hydraulic flume.” The 

flume consisted of an open box 5.94 m (19.5 ft) long, 0.91 m (3 ft) wide, and 1.22 m (4 ft) high, 

with Plexiglas® side panels (Figure 2-3). A schematic of the flume is shown in Figure 2-4. Water 

was added to the flume using a variable-speed centrifugal pump capable of supplying water at 

18.93-138.80 l/s (300-2200 gpm). Water was pumped from an underground reservoir through 

overhead piping that allowed the flume to be filled to the desired level. The water entered the 

flume through a 30.48-cm (12-in.)-diameter pipe at the upstream end of the flume. Water exited 

the flume through a 30.48-cm (12-in.)-diameter drain pipe located in the floor at the downstream 

end of the flume. During the throttle valve tests, water normally was maintained in the flume at a 

depth of 55.88-60.96 cm (22-24 in.). Water was added to the flume before testing, and except for 

tests lasting several hours, water was not added during the testing period. A U.S. Standard #100 

screen was used at the downstream end of the 0.3-m (1-ft)-wide confined flow area to reduce the 

potential for damage to the flow meter and the pump. 
8 

Flow meter 

Pump 

Flume (see Figure 2-3) 

Throttle valve (see Figure 2-10)

Orifice plate 

Pressure measurem

locatio

Flow control valve 

DebrmaniFigur

Thermocouple 

Thermocouple 

Valve 

Debris trap 

Figure 2-1. Schematic of the Throttle Valve Test Loop 
9 

Figure 2-2. Photograph of the Test Loop (Excluding the Flume) 

2.2.2 Flume to Pump 

Downstream of the flume drain pipe was a 30.48-cm (12-in.) butterfly valve, a 90o elbow, 

reducing sections to a 15.24-cm (6-in.)-diameter Schedule-40 poly-vinyl chloride (PVC) pipe, 

and a 15.24-com (6-in. × 6-in.) tee. Figure 2-5 shows the detail of this area. The 90o leg of the tee 

section was controlled by a sliding gate valve, which allowed water to be conveyed out of the 

throttle valve system to a water storage sump or to a surface drain. Except for tests lasting 

several hours, the sliding gate valve was closed during throttle valve testing. 

The upstream flow meter was located 0.91 m (3 ft) downstream of the 15.24-cm × 15.24-cm 

(6-in. × 6-in.) tee. A fine-mesh screen was installed upstream of the flow meter to protect the 

flow meter from damage due to debris ingestion. Between the tee and the flow meter, a reducer 

fitting created a transition to a 7.62-cm (3-in.)-diameter Schedule-40 PVC pipe. The upstream 

turbine- 
10

Figure 2-3. Linear Hydraulic Flume 

 2 ft 2 ft

8 ft 8 ft 39.5 in.

TOP VIEW

ELEVATION

4 ft

2 ft

1 ft 27 in. 3 ft

Water Inlet

from Reservoir

Flowmeter

Valve

Direction of Flow

PUMP

Figure 2-4. Schematic of Linear Hydraulic Flume (Not to Scale) 
11

type flow meter used a meter-mounted display (Great Plains Industries Model A200) with 

5.08-cm (2-in.)-diameter fittings. PVC fittings were used to transition between the 7.62-cm 

(3-in.)-diameter connecting pipe and the 5.08-cm (2-in.) fittings. A remotely mounted transmitter 

(Great Plains Industries Remote 4–20mA) allowed flow rate information to be transmitted to a 

datalogger as a 4-20-mA current signal or as a 0-5-V signal. The equipment was wired to provide 

a 0-5-V signal for the throttle valve tests. The remotely mounted transmitter had a response time 

of 0.7 s. The flow meter had a measurement range of 1.26-12.62 (20-200 gpm), with a relative 

accuracy of 1% of the reading. The maximum rated system pressure of the flow meter was 

2.07 MPa (300 psi). The flow meter and transmitter were obtained as a prepackaged assembly 

from Cole-Palmer (Part number EW-05608-37). 

Located 2.13 m (7 ft) downstream of the flow meter was an eight-stage constant speed pump 

[Flowserve Model WDE8, 3550 rpm, with a 14.50-cm (5.71-in.)-diameter open impeller and a 

rated flow capacity of 0-7.57 l/s (0-120 gpm)]. The pump was driven by a 30-kw (40-hp), threephase, 208-230/460-V continuous-duty motor. At a flow rate of 6.31 l/s (100 gpm), the pump 

had a rated head of 246.28 m (808 ft); at a flow of 3.22 l/s (51 gpm), the pump had a design head 

of 328.27 m (1077 ft). The pump case had a 7.62-cm (3-in.)-diameter horizontal inlet fitting and 

a 0.61-cm (2-in.)-diameter vertical outlet fitting. Flexible vibration fittings were installed at the 

pump inlet and outlet to isolate the pump mechanically from the other portions of the apparatus. 

The goal for the selection of the pump for this testing was to obtain a pump of similar design to 

the HPSI pumps commonly used in U.S. PWRs. The total HPSI flow required for the smallbreak LOCA of interest is on the order of 12.62–18.93 l/s (200–300 gpm). For HPSI systems 

having four injection paths, each path has an anticipated flow rate of 3.15–4.73 l/s (50–75 gpm) 

over a ∆P of ~~1.38 MPa (200 psi). The pump for this test program was chosen to achieve this 

performance and had a rated flow rate of 6.31 l/s (100 gpm). Because the pump was operated at 

4.73 l/s (75 gpm) during testing, additional head was available to possibly purge debris from the 

valve in the event of clogging. Actual HPSI pumps would push up to the rated system pressure 

[15.5 MPa (2250 psi)] in an attempt to overcome actual valve blockage. Some tests were also 

performed at 6.12 l/s (97 gpm), near the rated flow of the pump, to provide a wider range of 

testing for parametric studies. 

2.2.3 Pump Discharge to Throttle Valve 

The section of the test loop from the discharge of the pump to the throttle valve is shown in 

Figure 2-6. The debris insertion manifold shown enlarged in Figure 2-7 was located 0.91 m (3 ft) 

downstream of the pump discharge. Use of the debris insertion manifold allowed debris to be 

inserted into the flow stream without disrupting the flow of water through the throttle valve. The 

debris insertion manifold used 5.08-cm (2-in.)-diameter galvanized steel piping. Two flow paths 

were provided by the debris insertion manifold: (1) a straight path with no debris and (2) a debris 

injection path that was connected to a 5.08-cm (2-in.)-diameter debris insertion port. It was also 

possible to have water simultaneously flowing through both the straight path and the debris 

injection path. Flow in the debris insertion manifold was controlled by four 5.08-cm (2-in.) ball 

valves (Hammond Model 8901 GLP 02-06). The piping diameter, 5.08 cm (2 in.), was chosen 

because it was the most common HPSI injection line size based on informal plant and vendor 

surveys. 
12

Figure 2-5. Discharge from Flume 

Figure 2-6. Detail of Test Loop from Pump to Throttle Valve 

Pump and motor 

Debris insertion 

manifold Throttle valve 

Butterfly valve 

Tee 

To pump 

From flume 

Bottom of flume 

Gate valve 
13

Figure 2-7. Debris Insertion Manifold 

The upstream pressure transducer and pressure gauge were located 15.24 cm (6 in.) downstream 

of the debris insertion manifold (see Figure 2-8). The pressure transducer used was a ColePalmer Model 68070-08 [0-3.45 MPa (0-500 psi), output 4-20 mA]. Installation information 

included with the pressure transducer indicated that it was identical to a Sentra Systems, Inc., 

Model 256. The transducer could send only current signals (in milliamperes) to a datalogger. The 

transducer had an accuracy of ±0.13% of full scale [4.48 kPa at 3.45 MPa (0.65 psi at 500 psi) 

full scale] and a response time of 1-5 ms. A dial pressure gauge having a scale from 0-4.14 MPa 

(0-600 psi) also was placed at the location of the pressure transducer. 

Figure 2-8. Detail Showing Location of Upstream Pressure Transducer 

Debris insertion 

port 
14

2.2.4 Throttle Valve 

The surrogate throttle valve was located 15.24 cm (6 in.) downstream of the upstream pressure 

transducer (Figure 2-8). This valve was the primary focus of the test program described in this 

report, and all of the other equipment in the test facility was used to determine the flow 

conditions through the throttle valve. The valve used was a surrogate for throttle valves that are 

found in PWRs. Because a comprehensive database for U.S. PWR HPSI system parameters was 

lacking, informal surveys of plants and vendors were used to establish HPSI throttle valve 

parameters in the industry. Although a wide range of valve brands and types are used as HPSI 

throttle valves, anecdotal information from qualified valve vendors indicated that the most 

common valve used for this application is a globe valve The sizes employed are relatively small, 

typically in the range of 2.54-10.16 cm (1-4 in.) in diameter. The most common size is thought to 

be ~5.08 cm (2 in.). 

Figure 2-9 illustrates the key features of globe valves. The basic plug-type globe valve has a 

stem-actuated plug that moves parallel to the bulk flow stream passing through the valve port 

opening. The plug position can be adjusted to either restrict or allow flow. Figure 2-9 shows two 

different types of globe valve plug and seat arrangements. 

Because of the wide variety of HPSI throttle valves, no attempt was made to replicate or endorse 

a particular throttle valve design for the current study. The primary goal for the surrogate valve 

design was to be reasonably representative of the actual throttle valves in service by maintaining 

the flow complexity exhibited in common globe valve designs. With that in mind, ranges of 

appropriate valve clearances, angular orientations, inlet and exit diameters, and constriction 

lengths were determined from a qualified vendor supply catalog. 

To maximize debris clogging, the valve gaps should be near the lower end of the service range 

and the angle and length of the flow path should be near the upper end of the service range. The 

surrogate valve was designed based on this conservative configuration and should maximize the 

blockage observed in these tests. 

The surrogate valve was designed by ARES Corporation under contract to Los Alamos National 

Laboratory (LANL). A cross-section drawing of the valve is shown in Figure 2-10.The valve was 

constructed of stainless steel and had 5.08-cm (2-in.)-diameter inlet and outlet flanges. The valve 

was constructed so that the top or the bottom of the valve easily could be opened and inspected. 

The valve had a threaded valve stem that allowed precise adjustment of the space or gap between 

the seat plug and the seat ring. The gap, as measured perpendicular to the face of the seat plug, is 

the valve-opening distance that is referenced throughout this document. The valve stem 

movement was perpendicular to the plane of the seat ring. The seat plug was a truncated 

perpendicular cone such that the valve opening was always symmetrical. The top of the valve 

had a caliper block located near the threaded stem to enable the measurement of the vertical 

distance between the top of the caliper block and the top of the threaded valve stem. This 

distance changed as the valve was opened or closed. To obtain a specific valve opening, the 

manufacturer of the valve provided a table that showed the relationship between the caliper block 

measurements and valve seal gap. The procedure to set a specified valve opening was provided 

by the valve designer. The valve construction and gap setting procedure are described in Ref. 4. 
15

Plug and Seat Ring 

Plug and Cage

Figure 2-9. Basic Globe Valve Design with Possible Types of Valve Throat Configurations 

stem 

ring 

Figure 2-10. Detail of Surrogate Valve Stem and Ring 

Detail of stem and seat (shown 

in the fully closed position) 
16

The valve was supplied with three interchangeable valve stem-seat plug and seat ring assemblies. 

The details of the assemblies are shown in Figure 2-11 through Figure 2-14. The external view of 

the throttle valve body is shown in Figure 2-15 and a photograph of the 5S and 5L stems is 

shown in Figure 2-16. The details are described as follows: 

1. 5S: The seat plug was tapered at an angle of 5o from the axis of the valve stem so that the 

convergence angle of the seat plug sides was 10o (A in Figure 2-12). The maximum valve 

opening with this valve stem-seat plug was 0.2766 cm (0.1089 in.). 

2. 5L: The seat plug was tapered at an angle of 5o from the axis of the valve stem so that the 

convergence angle of the seat plug sides was 10o. The maximum valve opening with this 

valve stem-seat plug was 0.127 cm (0.0501 in.). 

3. 45L: The seat plug was tapered at an angle of 45o from the axis of the valve stem so that 

the convergence angle of the seat plug sides was 90o. The maximum valve opening with 

this valve stem-seat plug was 0.1033 cm (0.4066 in.). 

 

 

 

(a) Stem 45L (b) Stem 5L (c) Stem 5S 

Figure 2-11. Valve Stems Used in the Tests 

2.2.5 Downstream of Valve 

The details of the test loop downstream of the valve are shown in Figure 2-17. 

The downstream pressure transducer and pressure gauge were located 15.24 cm (6 in.) 

downstream of the throttle valve discharge flange. A Cole Palmer applications engineer indicated 

that turbulence had no impact on the accuracy of the pressure transducer reading as long as the 

pipe was filled; therefore, there was no straight run requirement for locating the pressure 

transducers. The pressure transducer and dial gauge were identical to the upstream pressure 

transducer and gauge. By measuring the pressures at each of the gauge locations, it was possible 
17

to determine the pressure differential across the throttle valve. Pressure differential was one of 

the primary measurements used to establish performance of the throttle valve. 

The flow control valve was located 15.24 cm (6 in.) downstream of the downstream pressure 

transducer. This 5.08-cm (2-in.)-diameter forged-steel globe valve had a pressure rating of 

13.10 MPa (1900 psi) and provided the primary mechanism by which flow through the throttle 

valve was adjusted. Although the flow control valve could be opened fully to allow maximum 

system flow, the flow control valve was closed partially for most tests so that a specified flow 

rate [i.e., 4.73 l/s (75 gpm)] could be maintained. For each throttle valve test, the flow control 

valve was adjusted to an initial setting that was not changed until the test was completed. 

Stem 

Designation 

Full-Angle 

A (deg) 

Dimension B 

[cm (in.)] 

Dimension 

C [cm (in.)] 

45L 90 5.71 (2.25) 0.89 (0.35) 

5L 10 5.71 (2.25) 2.54 (1.00) 

5S 10 3.81 (1.50) 2.54 (1.00) 

Figure 2-12. Key Dimensions of the Valve Stems 

(a) Ring 45L (b) Ring 5L (c) Ring 5S 

Figure 2-13. Valve Seat Rings Used in the Tests 
18

Stem 

Designation 

Full-Angle 

A (deg) 

Dimension B 

[cm (in.)] 

Dimension 

C [cm (in.)] 

45L 90 5.71 (2.25) 4.762 (1.875) 

5L 10 5.71 (2.25) n/a 

5S 10 3.81 (1.50) n/a 

Figure 2-14. Key Dimensions of Valve Rings 

Figure 2-15. Surrogate Throttle Valve 
19

Figure 2-16. 5L and 5S Valve Stem-Seat Plugs and Seat Rings 

. 

Figure 2-17. Part of the Test Loop Downstream of the Valve 

Three orifice plates were initially located downstream of the flow control valve. The orifice 

plates were located 20.32 cm (8 in.) apart and the first orifice plate was located 15.24 cm (6 in.) 

downstream of the flow control valve. The orifice plates were placed to reduce the high pressure 

in the throttle valve to an acceptable pressure for discharge to the flume through PVC Schedule40 pipe. The orifice plates also provided flow control when other valves were fully open. The 

orifice plates were 1.90-cm (0.75-in.) flat steel plates placed between flanged fittings with a 

1.587-cm (0.625-in.)-diameter hole drilled in the center of the plate. The orifice plates restricted 

the flow on the adjoining 5.08-cm (2-in.)-diameter pipe. 

The three orifice plates were used for Test Series 1 (Test series designations were defined in 

Sections 1.3.3–1.3.5. At the end of those tests, it was determined that a single orifice plate likely 

would serve the desired function and reduce the potential for debris trapping. Two of the orifice 

Downstream 

pressure transducer 

Flow control valve 

Orifice plates 

Pressure gauge 

and air relief 

valve 
20

plates were replaced with plates with 5.08-cm (2-in.)-diameter holes so that only one plate had a 

1.587-cm (0.625-in.)-diameter flow restriction. The maximum system flow rate increased 

slightly with this modification, but the downstream pressure remained at an acceptable level. 

Test Series 2 and 3 were performed using a single orifice plate. 

A dial pressure gauge and a manual air-bleed fitting were located 10.16 cm (4 in.) downstream of 

the downstream orifice plate. The gauge served to verify that the pressure below the orifice plate 

was sufficiently small that flows could be conveyed in Schedule-40 PVC pipe. The manual airbleed valve was used to remove any air that might be trapped downstream of the orifice plates. 

A low-pressure globe valve was placed 15.24 cm (6 in.) downstream of the dial pressure gauge. 

This valve was open during throttle valve testing but was closed to prevent backflow when the 

throttle valve was opened for inspection. Upstream of the low-pressure gate valve, galvanized 

steel pipe is used. Downstream of the valve, Schedule-40 PVC pipe was used. 

The downstream flow meter was located 4.57 m (15 ft) downstream of the low-pressure gate 

valve. This flow meter was identical in model to the upstream flow meter. The downstream flow 

meter was in place during initial system testing and during throttle valve testing that used only 

RMI debris. Because this was a turbine-type gauge, it was found that RMI would become 

trapped in the gauge mechanism and that the downstream flow measurements would become 

erratic. Frequent removal of the meter for cleaning was required, and the downstream flow meter 

could not reliably measure flow when debris was added. The flow-meter manufacturer did not 

recommend this device for flow with debris. A concern was raised that use of fibrous debris such 

as NUKON would produce additional measurement problems; therefore, the flow meter was 

removed from the test apparatus for all subsequent tests. 

Downstream of the downstream flow meter, 4.57 m (15 ft) of Schedule-40 PVC pipe was used to 

convey the flow back to the upstream end of the linear hydraulic flume. Within this length, a 

1.22-m (4-ft) section of vertical pipe allowed the water to be conveyed above the high-water 

level in the flume, as shown in Figure 2-18a and b. 

Immediately upstream of the vertical pipe section, two 5.08-cm (2-in.) ball valves (Hammond 

Model 8901 GLP 02-06) and a 5.08-cm × 5.08-cm (2-in. × 2-in.) PVC tee were used to create a 

vertical drain. This section of piping is shown schematically in Figure 2-19. During pumping, the 

drain valve could be opened and the main pipe valve closed to flush the discharge line of debris. 

The vertical pipe section also could be back-flushed to the open drain. 

The discharge pipe to the linear hydraulic flume had a short section of vertical pipe that directed 

discharge water vertically downward to the water surface in the flume (Figure 2-18b). At this 

location, a screen collector was placed to capture larger debris particles before they entered the 

flume. Several screen collectors were manufactured from 5-gal. plastic buckets. The bottoms of 

the buckets were removed and replaced with 40- or 100-mesh stainless-steel screens. During 

testing with debris, the buckets were in place to capture debris. A screen collector also was used 

to collect debris that was flushed through the vertical drain valve. The detail of the debris 

recovery bucket is shown in Figure 2-20; this photograph was taken after a test using a NUKONRMI mixture. Both types of debris are visible. The debris recovered from the bucket was dried in 
21

an oven and then weighed to determine the mass of debris recovered (see definition of parameter 

W2 in Section 2.5). 

This section describes the valves, pumps, gauges, transducers, and fittings used in the hydraulic 

system for testing the throttle valve. The other essential element was the data acquisition system, 

which is described in Section 2.3.1. 

 

(a) downstream of orifice plates (b) return to flume 

Figure 2-18. Details of the Fluid Return Section of the Test Loop 

Figure 2-19. Detailed Schematic of the Fluid Return Line (Side Elevation) 

Discharge 

Valves

Debris trap 

and drain Hydraulic flume 
22

Figure 2-20. Debris Recovery Bucket after a Test Involving a Mixture of RMI and NUKON 

2.3 Data 

2.3.1 Data Acquisition 

Data from flow meters and pressure transducers were sent to a National Instruments Field Point 

Network Module (Model FP-1601) and a National Instruments Field Point Analog Input Module 

(Model FP-AI-100). The network module communicated with a computer used to store measured 

data, and the Analog Input Module communicated with instruments that measured electrical 

voltage or current. The network module was connected to the analog input module so that analog 

signals from the instrumentation were sent as digital signals to a data collection computer. The 

collection and processing of analog data was controlled by the National Instruments Lab View 

computer program. For the throttle valve tests, Lab View, Version 7.1 was used with a computer 

running Microsoft Windows XP. The Lab View program contained modules that defined the 

kind of analog signal (range of voltage or current) that the analog input module could receive and 

the frequency and type of data that would be stored on the data collection computer. The 

National Instruments Field Point Network Module and Analog Input Module were powered by a 

24-V power supply that was included with the Field Point equipment. 

When electrical power was supplied to the upstream and downstream pressure transducers, the 

transducers produced an electrical current signal (in milliamperes) that varied with the magnitude 

of the pressure measurement. This signal was processed through the Field Point equipment by 

the Lab View program to obtain measured pressure data. Similarly, when electrical power was 

supplied to the upstream and downstream flow meters, the remotely mounted transmitters 

produced a voltage signal (0-5 V) that varied with the magnitude of the flow. Both the current 

and the voltage signals had to be calibrated to the instrument measurements so that the measured 
23

reading at the pressure transducer or flow meter was in agreement with the value recorded by the 

computer. A calibration equation within the Lab View program performed this task. 

Power (24 V) had to be supplied to the pressure transducer and the flow-meter transmitter for the 

instruments to function. During initial throttle valve testing, four separate power supplies were 

used to supply power to each of the four monitoring devices (two pressure transducers and two 

flow meters). Subsequent review of recommended wiring diagrams for the analog input module 

indicated that a single power supply could be used to supply power to the analog input module 

and that this single power source could be used to provide power to all four monitoring devices. 

It was found that this single power source slightly reduced measurement variability and 

improved the quality of the recorded data. A further discussion of measurement variability is 

found in Sections 4, 5, and 6. 

The choice of a data collection computer was found to impact the precision of the data that could 

be collected. Initial data collection used a collection interval of 100 ms, and a laptop computer 

with a 1.0-GHz or faster processor could collect data at this frequency. Because the testing of the 

throttle valve was measuring flow rate and pressure fluctuations that often lasted <1 s, it was 

desirable to reduce the data collection interval. A 2.0-GHz computer was used to collect data at 

an interval of 6 ms. To obtain this frequency, the Lab View program needed to be revised to 

minimize the graphical display of collected data and the computer had to be temporarily set up to 

minimize parallel processes, such as battery monitors and virus protection. A 1.0-GHz computer 

could not be used with a 6-ms data collection interval. 

During the process of reprogramming Lab View for the 6-ms data collection interval, it was 

noted that the existing programming was not directly recording the measured data but was 

recording the average of the measurement plus the four previous measurements. This 

programming apparently derived from previous use of the program code in an application that 

did not have rapid changes in data values. For the throttle valve tests, the five-point averaging 

was not desirable and all subsequent testing was conducted with single-point data collection. 

These tests included the last two Cv baseline tests for the 45L and 5L stems; the June blockage 

tests; and throttle valve tests N-1 to N-9, D-1 to D-19, and A-1 to A-3. In general, the singlepoint sampling used data collection intervals of 0.006 s, but some long-term testing used 

intervals of 0.1 s. The use of single-point measurements in place of five-point averaging created 

an increase in the data measurement variability; however, the concurrent improvements in the 

electrical wiring more than compensated for this effect. 

After completion of some of the early tests, it was observed that the recorded pressure readings 

had fluctuations that were considerably larger than could be attributed to the inherent 

measurement uncertainty of the pressure transducers. The measurements were fluctuating at 

±13.79 kPa (±2 psi) from a general trend line. The recorded flow rates varied by ±0.0126 l/s 

(±0.2 gpm) from the general trend line at a flow rate of 4.73 l/s (75 gpm). A concern was raised 

that the level of data fluctuation could obscure important physical conditions that needed to be 

measured with the throttle valve tests. Many diagnostic studies were done to address this issue. 

Of the various diagnostics that were done, grounding of the various instruments and the data 

cable conduits produced the most improvement in data quality. The details are included in 

Appendix C. 
24

2.3.2 Temperature Control 

One other important property that affects throttle valve performance is the temperature of the 

water and the resulting changes in viscosity and density. Because the temperature of the water 

was not expected to have a large change during any single throttle valve test, it was not deemed 

necessary to have continuous temperature recording. Instead, manual collection of water 

temperature was used for the throttle valve tests. In general, the water temperature was measured 

at one time for tests lasting <10 min. Multiple measurements were used for longer-duration tests. 

Type-K thermocouples were installed in the PVC pipe sections upstream and downstream of the 

pump and throttle valve. One thermocouple was installed 0.61 m (2 ft) downstream of the 

upstream flow meter. The second thermocouple was installed 0.91 m (3 ft) downstream of the 

downstream orifice plate. In both the upstream and down stream locations, the thermocouples 

were reading fluid centerline temperature. Temperature measurements were obtained using a 

handheld meter (Omegaette HH308) designed to read type-K thermocouples. 

When temperature data were obtained during throttle valve tests, it quickly was found that the 

temperature measurements of the upstream and the downstream thermocouples were not the 

same and that the downstream thermocouple consistently had a higher temperature than the 

upstream thermocouple. It was found that the temperature difference was related inversely to the 

pumping flow rate. At a flow of 4.73 l/s (75 gpm) [nominally 2.90 MPa (420 psi) at the upstream 

pressure tap], the temperature difference was ~1.28°C (2.3°F). This temperature change 

primarily was attributed to the energy supplied to the water by the pump. For short-duration 

tests, the volume of water in the flume was sufficient to limit the amount of temperature gain; 

however, for longer-duration tests, the heating of the water caused the system temperature to 

increase significantly. 

2.4 Material Preparation 

As noted earlier, the debris used in the tests consisted of RMI, NUKON, and CalSil. The debris 

types chosen for these tests were not intended to include everything that could be ingested in an 

ECCS (see Ref. 5 for a more comprehensive list of insulation and coating materials). The 

quantities of RMI, NUKON, and CalSil that were used in this study were based on the quantity 

needed to cause measurable blockage rather than being specifically linked to anticipated plant 

debris loadings. Specifications of the material used and the methods used to prepare them for the 

tests are discussed in this section. 

2.4.1 RMI 

The RMI debris was made of type-304 stainless-steel foils having a thickness of 0.005 cm 

(0.002 in.). The material was purchased in 0.61-m × 1.22-m (2-ft × 4-ft) sheets from Transco 

Products Inc. (Chicago, Illinois) and was prototypical of the foil that Transco uses to fabricate 

RMI cassettes. These sheets were cut by hand to the required dimensions. Three sizes of RMI 

debris were cut: 0.63-cm × 0.63-cm (1/4-in. × 1/4-in.) squares, 0.32-cm × 0.32-cm (1/8-in. × 1/8-

in.) squares, and 0.32-cm × 1.27-cm (1/8-in. × 1/2-in.) rectangles. The sizes for the debris were 

determined by measuring with an ordinary graduated ruler and marking the RMI with a pencil. 

The debris then was cut to size with hand scissors and a paper cutter. For tests conducted after 

February 1, 2005, the RMI came from material that had been used previously in the tests 
25

described in Ref. 1. The RMI material from that test had been cut into 5.08-cm × 5.08-cm (2-in. 

× 2-in.) (approximate) squares and crumpled by hand before testing. For the throttle valve tests, 

these RMI pieces were first flattened using the end of a flat wooden ruler; then the RMI was 

marked with a pencil and cut to size. With this process, some wrinkles remained on the flattened 

squares. Severely crumpled RMI squares were discarded. Figure 2-21 shows photographs of 

three sizes of RMI samples used in the experiments. Each photograph includes pieces before the 

tests, as well as pieces recovered after the tests, which show the bending and twisting that may 

occur as the RMI pieces pass through the test system. 

Based on measurements of 25 cut debris pieces, the 0.63-cm × 0.63-cm (1/4-in. × 1/4-in.) debris 

had a mean weight of 0.0169 g, with a standard deviation of 0.0013 g; the 0.32-cm × 0.32-cm 

(1/8-in. × 1/8-in.) debris had a mean weight of 0.0038 g, with a standard deviation of 0.0007 g. 

Based on measurements of 10 cut debris particles, the 0.63-cm × 0.63-cm (1/4-in. × 1/4-in.) RMI 

samples had a mean dimension of 0.6642 cm (0.2615 in.), with a standard deviation of 0.315 cm 

(0.0124 in.); the 0.32-cm × 0.32-cm (1/8-in. × 1/8-in.) samples had a mean dimension of 

0.3172 cm (0.1249 in.), with a standard deviation of 0.03 cm (0.010 in.). 

The RMI was added to the tests in measured batches. The measurements were obtained by 

placing the debris in a small plastic container, with the material weighed using a 0.01-g balance. 

Except when combined with other debris types, the RMI was added to the debris insertion 

manifold in dry form. In all cases, the manifold was filled with water before debris was 

introduced to eliminate air pockets. 

 

 (a) 0.32 cm × 0.32 cm (b) 0.63 cm × 0.63 cm (c) 0.32 cm × 1.27 cm 

 (1/8 in. × 1/8 in.) (1/4 in. × 1/4 in.) (1/8 in. × 1/2 in.) 

Figure 2-21. Examples of RMI Samples 

2.4.2 NUKON 

NUKON, manufactured by Owens Corning (Toledo, Ohio), is a continuous-filament fiberglassinsulating material with a specific gravity of 2.6. Before use in these tests, the batts of NUKON 

were stored outdoors and exposed to atmospheric conditions. For use during testing, small 

quantities of the NUKON batts were removed and weighed using a 0.01-g balance. Then the 

NUKON was placed in boiling tap water for 5 min; this process made the fiberglass particles 

more flexible. The wet NUKON was removed from boiling water and immediately placed in a 

Untested Untested Untested

Post test Post test Post test 
26

kitchen blender (Black and Decker, Model BL6000). Cold tap water was added in sufficient 

quantity to cover the NUKON fiber. The NUKON and water first were mixed at low speed for 

2 min. Then the blender was turned off, and any NUKON fiber was flushed from the sides of the 

blender chamber. Then the NUKON and water was mixed at medium speed for 3 min. This 

process produced a slurry mix of NUKON and water, as shown in Figure 2-22. The NUKON and 

water slurry then was placed in a separate container before testing. All of the NUKON on the 

blender was flushed from the blender with water. The NUKON quickly settled to the bottom of 

the container. The NUKON slurry may have sat for several hours or days before being used in a 

test. When the NUKON slurry was to be placed in the debris insertion manifold, it was first 

mixed using a metal spoon. Some of the water that was in the manifold had to be removed to 

provide space for the NUKON slurry. This process was accomplished by draining the manifold 

before testing or by using a portable wet-dry vacuum. When the NUKON slurry was added to the 

debris insertion manifold, any space remaining was filled with tap water so that large air pockets 

were not created in the manifold. On several tests, the volume of the NUKON slurry exceeded 

the volume available in the manifold. With these tests, any excess NUKON slurry was ovendried so that the weight of the excess could be subtracted from the original weight of the 

NUKON. 

Figure 2-22. NUKON after Processing by Kitchen Blender 

2.4.3 CalSil 

CalSil is a high-temperature calcium silicate insulation manufactured by RATH Performance 

Fibers, Inc. (Wilmington, Delaware). CalSil contains >90% synthetic calcium silicate, >1% 

aluminum silicate, >1% inorganic fiber, >1% cellulose, and >0.1% crystalline silica. The 

material normally is found as a yellow or white solid block or solid pipe insulation. 

A sample of CalSil that consisted of broken pieces and fine powdery debris was available in the 

UNM laboratory (Figure 2-23). For the throttle valve tests, the CalSil was processed further by 
27

passing the material through a #4 [4.75-mm (0.19 in.)] or #8 [2.36-mm (0.09-in.)] sieve; the 

material that passed through the sieve was retained for testing. The material remaining on the 

sieve was removed, further crushed with a rubber-tipped pestle, and returned to the sieve. After 

several passes of crushing and sieving, any material remaining on the sieve was discarded. 

Except for one test, all of the CalSil used in the throttle valve test had passed a #4 or #8 sieve. 

For one test (test 5sc9) unsieved CalSil from the initial broken sample was tested. Most of the 

CalSil that had passed through the sieves was much finer than the sieve size, and little visual 

difference was observed between the CalSil that had passed the #4 sieve and the CalSil that had 

passed the #8 sieve. Before testing in the throttle valve apparatus, the appropriate quantity of dry 

CalSil was obtained with a 0.01-g balance. Then tap water was added in a sufficient quantity and 

mixed with the CalSil to form a slurry. Water in the debris insertion manifold was removed to 

provide space for the CalSil slurry using the same procedure as with the NUKON insulation. 

Figure 2-23. CalSil Sample 

2.4.4 Mixtures of RMI, NUKON, and CalSil 

Some tests called for a mixture of RMI and CalSil, RMI and NUKON, NUKON and CalSil, or a 

mixture of all three debris types. In all of these tests, the debris was prepared first as described 

for each of the three single debris types. Then the debris types were mixed together by hand. The 

combined debris was added to the debris insertion manifold in a manner similar to that described 

with the NUKON testing. For mixtures of all three debris types, different insertion sequences 

were specified for different tests. 

2.5 Test Parameters 

The test procedure is described in detail in Appendix A. The types of data recorded during each 

test, as well as the nomenclature used to refer to them in subsequent sections, are described in 

this section. 
28

Stem: The valve-stem/ring combination used (one of three possibilities: 45L, 5L, or 

5S). This combination was noted before the start of each test. 

Gap: The valve opening (in inches) specified for each test in the test matrix. The 

gap was measured perpendicular to the face of the seat plug. The range of 

valve-opening sizes for the 5L and 5S configurations was significantly lower 

than that for 45L. This disparity was the result of differences in the design of 

the configurations and the need to maintain similar flow over the range of 

valve openings for a given stem configuration.

N1: The number of RMI pieces introduced in the system (for tests where a 

specified number of pieces of RMI was introduced in the system). 

W1: The mass of RMI introduced in the system, in grams, for tests where a 

specified mass of RMI was introduced. 

WN: The mass of NUKON introduced in the system (grams). 

WC: The mass of CalSil introduced in the system (grams). 

Sieve #: The mesh size of the screen used to sieve the CalSil. The two sieves used were 

#4 and #8. 

RMI size: The size of the RMI pieces introduced (uniform for any given single-debris 

test and possibly a combination of two sizes in the mixed-debris tests). 

Examples of square and rectangular pieces of RMI are shown in Figure 2-21. 

K: Valve loss coefficient. 

K before: The average K before introduction of debris. Typically, the averaging was 

done over a time window between ~500 ms after the start of data acquisition 

and ~0.1 s before the introduction of debris. Averages also were calculated for 

intermediate time windows within this interval and generally were found to be 

within the margin of error for the tests; thus, only the result for the full pre-test 

time interval as described previously was presented. 

K after: The average K after introduction of debris. Typically, the averaging was done 

over a time window between ~30 s after debris insertion and the end of data 

acquisition. Averages also were calculated for intermediate time windows 

within this interval and generally were found to be within the margin of error 

for the tests; thus, only the result for the full post-test time interval as 

described previously was presented. 

∆K%: The percent increase in average K after debris insertion. Only values >5% 

were included. Values less than this value were considered to be within the 

range of uncertainty in the calculation of K and thus were not considered to be 

meaningful (these are indicated by “<5” in the tables). 
29

W2: The mass of debris recovered in the recovery bucket during the test and after 

post-test flushing. The recovery bucket was located inside the flume at the 

outlet of the vertical segment of pipe shown in Figure 2-18b. The debris 

recovered following an example test is shown in Figure 2-20. The procedure 

is described in Section 2.2.5. 

Wf: The mass of debris not recovered during the test and after post-test flushing. 

This measurement was taken as the difference between the initial debris mass 

and the mass of debris recovered in the bucket. The mass of the RMI 

contained within the valve after the test is included in this measurement. 

NR: The number of RMI pieces recovered from the throttle valve after a test. This 

RMI mass is included in Wf. 

2.6 Test Matrix 

The test matrix for debris testing is divided into three tables, representing the three phases of 

testing, single debris, mixed debris, and debris accumulation. Baseline tests were performed 

before each phase of testing and at the end of the test program. Baseline data for known blockage 

conditions were obtained for selected valve configurations at the start of the test program and at 

the end of testing. 

The test matrix for the single-debris tests, Table 2-1, provides the test conditions established for 

the first test series. The key test conditions that were established were the gap size, mass (and 

size for RMI) of debris, type of debris, and stem configuration (45L, 5L, or 5S). The RMI test 

conditions are provided first, followed by NUKON and CalSil. Similarly, the test matrix for the 

mixed-debris tests, Table 2-2, provides the conditions established for the second test series. The 

gap, debris mass, debris type, and debris sizes are provided for the different debris combinations 

and stem configurations tested. The addition sequence is also provided for the sequentially mixed 

debris. The test matrix for the debris accumulation tests, Table 2-3, established the test 

conditions for the third test series. A complete test matrix listing every test along with the 

observed increase in K is provided in Appendix D. 

2.7 Data Analysis 

The approach used to analyze the data and present the results is outlined in this section. 

2.7.1 Valve Pressure Loss 

The valve pressure drop is the indicator of flow resistance in the valve. When debris gets trapped 

in the valve, the flow resistance increases. If the flow rate through the valve remains the same, 

this translates to a higher pressure drop across the valve. The flow resistance of the valve can be 

expressed as either a valve-loss coefficient, K, or equivalently a valve-flow coefficient, Cv. 
30

Table 2-1. Single Debris Test Matrix 

1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces

1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces

-- -- 10 g -- -- -- -- -- -- -- 10 g --

1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces

1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces

1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces 1 g 5 g 10 g 10 pieces

RMI Tests, Stem # 45L

RMI Tests, Stem # 5L

Gap 0.317 cm (0.125 in.)

 RMI Type [cm × cm (in. × in.)]

Gap 0.13 cm (0.050 in.)

 RMI Type [cm × cm (in. × in.)]

0.317 × 1.27 (1/8 × 1/2)

0.317 × 1.27 (1/8 × 1/2)

Gap 0.63 cm (0.25 in.)

Gap 0.159 cm (0.0625 in.)

 RMI Type [cm × cm (in. × in.)]

0.63 × 0.63 (1/4 × 1/4)

RMI Tests, Stem # 5S

 RMI Type [cm × cm (in. × in.)]

0.63 × 0.63 (1/4 × 1/4)

0.317 × 0.317 (1/8 × 1/8) 0.63 × 0.63 (1/4 × 1/4)

 RMI Type [cm × cm (in. × in.)]

0.63 × 0.63 (1/4 × 1/4) 0.317 × 1.27 (1/8 × 1/2)

Gap 0.25 cm (0.10 in.)

0.317 × 0.317 (1/8 × 1/8)

0.317 × 1.27 (1/8 × 1/2)

Gap 0.159 cm (0.0625 in.)

 RMI Type [cm × cm (in. × in.)]

0.317 × 0.317 (1/8 × 1/8) 0.63 × 0.63 (1/4 × 1/4)

0.317 × 0.317 (1/8 × 1/8) 0.63 × 0.63 (1/4 × 1/4)

0.317 × 0.317 (1/8 × 1/8) 0.63 × 0.63 (1/4 × 1/4)

0.317 × 0.317 (1/8 × 1/8) 0.63 × 0.63 (1/4 × 1/4)
31

Table 2-1. Single-Debris Test Matrix (cont) 

Gap Mass (g) Gap Mass (g)

50 50

100 100

50

100

50 (Unsieved)

Gap Mass (g) Gap Mass (g)

25 50

50 100

100

Gap Mass (g)

NUKON Tests, Stem # 5L

0.13 cm 

(0.050 in.) 0.159 cm 

(0.0625 in.)

0.25 cm 

(0.10 in.) 50

0.25 cm 

(0.10 in.)

NUKON Tests, Stem # 45L

0.13 cm 

(0.050 in.)

CalSil Tests, Stem # 5L CalSil Tests, Stem # 5S

0.159 cm 

(0.0625 in.)

0.317 cm 

(0.125 in.) 50

NUKON Tests, Stem # 5S

0.25 cm 

(0.10 in.) 100

0.159 cm 

(0.0625 in.) 50

Table 2-2. Mixed-Debris Test Matrix 

Gap CalSil NUKON RMI RMI Type

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

5 0.317 × 1.27 (1/8 × 1/2)

5 0.63 × 0.63 (1/4 × 1/4)

45L 0.63 (0.25) -- 50 10 0.317 × 1.27 (1/8 × 1/2)

45L 0.317 (0.125) -- 50 10 0.317 × 1.27 (1/8 × 1/2)

45L 0.159 (0.0625) -- 25 5 0.63 × 0.63 (1/4 × 1/4)

5L 0.13 (0.05) -- 50 10 0.317 × 0.317 (1/8 × 1/8)

45L 0.317 (0.125) 25 25 -- --

45L 0.159 (0.0625) 25 25 -- --

CalSil-RMI Mixture 45L 0.159 (0.0625) 50 -- 5 0.63 × 0.63 (1/4 × 1/4)

45L 0.63 (0.25) 25 25 5 0.317 × 1.27 (1/8 × 1/2)

45L 0.317 (0.125) 25 25 10 0.317 × 1.27 (1/8 × 1/2)

45L 0.159 (0.0625) 25 25 5 0.63 × 0.63 (1/4 × 1/4)

45L 0.159 (0.0625) 25 25 10 0.317 × 1.27 (1/8 × 1/2)

5 0.317 × 0.317 (1/8 × 1/8)

5 0.317 × 1.27 (1/8 × 1/2)

45L 0.159 (0.0625) 25 (3rd) 25 (2nd) 5 (1st) 0.63 × 0.63 (1/4 × 1/4)

45L 0.159 (0.0625) 25 (3rd) 25 (1st) 5 (2nd) 0.63 × 0.63 (1/4 × 1/4)

45L 0.159 (0.0625) 25 (3rd) 25 (1st) 10 (2nd) 0.317 × 1.27 (1/8 × 1/2)

CalSil-NUKONRMI Mixture 

(Sequential)

Stem

RMI Mixture

NUKON-RMI 

Mixture

CalSil-NUKON 

Mixture

CalSil-NUKONRMI Mixture 

(Homogeneous)

5L 0.13 (0.05) 25 25

45L 0.63 (0.25) -- --

 
32

Table 2-3. Debris Accumulation Test Matrix 

Test Stem Gap CalSil NUKON RMI RMI Type

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

A-1 45L 0.159 (0.0625) 25 g every 15 min 25 g every 15 min 10 g at t = 0 0.317 × 1.27 (1/8 × 1/2)

A-2 45L 0.159 (0.0625) 12 g every 15 min 13 g every 15 min 10 g at t = 0 0.317 × 1.27 (1/8 × 1/2)

A-3 45L 0.159 (0.0625) 25 g every 15 min 25 g once (t=3 min) 10 g at t = 0 0.317 × 1.27 (1/8 × 1/2)

The energy equation (Ref. 6) applied between the upstream and downstream pressure 

measurement points (denoted by suffixes 1 and 2, respectively) of the throttle valve can be 

written as 

D

2 LV

2

V

2

V P

2

V P

1

2 2

1 1

2 2

2

2 2

1 1 2

2

1 1

1

ρ

ρ ρ ρ ρ ρ f + + gz = + + gz + K + , (2-1) 

where the fourth term on the right-hand side denotes the pressure loss in the valve and the fifth 

term denotes the frictional loss between points 1 and 2. Because the pipe diameters upstream and 

downstream of the valve were the same and the temperature rise in the valve was negligible, the 

fluid density and flow velocity upstream and downstream of the valve were nearly equal. The 

difference in elevation was negligible [~0.62 kPa (0.09 psi), which translates to ~0.09 m (0.3 ft) 

of head], and the friction pressure drop in the piping was also negligible [~0.90 kPa (0.13 psi), 

which translates to ~0.06 m (0.2 ft) of head]. The pressure drop between the measurement 

locations was composed almost entirely of the pressure loss that occurred as the fluid flowed 

through the valve itself [~448 kPa (65 psi), which translates to ~45.7 m (150 ft) of head]. 

Therefore, Equation 2-1 is simplified as 

2

V P P P

2

1 1

1 2

ρ ∆ = − = K , (2-2) 

and the valve-loss coefficient for the valve, K, is described by 

2 V

P 2

ρ

∆ K = . (2-3) 

For a pipe diameter of 5.08 m (2 in.), using a water density of 995.8 kg/m3

 (62.17 lbm/ft3), the 

above equation can be rewritten in terms of the measurement quantities (pressure drop ∆P in 

pounds per square inch and flow rate Q in gallons per minute) as 

2

gpm

psi

Q

P

14269.2

∆

K = . (2-4) 

In the remainder of the report, K calculated using the above equation was used to present the test 

data. 
33

The valve flow coefficient (Ref. 7) is described by the equation 

psi

2

gpm

0 ∆P = Q Cv C , (2-5) 

where C0 is a constant that depends on the density of the fluid. Comparing Eqs. (2-4) and (2-5), it 

is noted that 

2

1

Cv

K ∝ ; (2-6) 

therefore, K and Cv are equivalent ways to describe the flow resistance. 

2.7.2 Using K to Present Results 

Raw data from a typical debris test are shown in Figure 2-24. The figure shows the transient 

variation of pressure drop across the valve and the flow rate measured at the upstream and 

downstream flow meters for test 45LDT4. In this and all subsequent similar plots, the vertical 

line indicates the time of debris insertion. In this test, 1 g of RMI measuring 6.35 mm × 6.35 mm 

(0.25 in. × 0.25 in.) was introduced at t = 1.64 min. The downstream flow-meter reading showed 

a pronounced dip after the debris was inserted, evidently the result of temporary lodging of 

debris in the meter. The upstream flow meter was relatively unchanged during the test. In this 

test, the pressure drop across the valve increased from ~242.7 to 267.5 kPa (35.2 to 38.8 psi) 

following debris insertion. Figure 2-25 shows the transient variation of the valve-loss-coefficient 

K, which was calculated based on the measured pressure difference and the flow rate from the 

upstream flow meter. K increased from ~88.0 to 98.4 following debris introduction. Thus, the 

pressure drop data and the K data exhibit similar behavior in this test. 

Raw data from another debris test are shown in Figure 2-26. The figure shows the transient 

variation of valve pressure drop and upstream and downstream flow-meter data for test 45LDT6, 

in which 10 g of RMI measuring 0.63 cm × 0.63 cm (0.25 in. × 0.25 in.) was introduced at 

t = 1.89 min. In this case, both the downstream and upstream flow meters recorded a pronounced 

dip after the debris was inserted. The upstream flow-meter data recovered to a higher value than 

the downstream meter, again presumably because of some temporary clogging of the 

downstream flow meter by the debris. In this test, the pressure drop data were relatively 

unchanged immediately after debris insertion, and they later stabilized to a lower value. The 

average pressure drop was ~239.9 kPa (34.8 psi) before debris insertion and 233 kPa (33.8 psi) 

following debris insertion. Although this reduction in pressure may appear to be counterintuitive, 

a more accurate assessment of clogging can be obtained by examining Figure 2-27, which shows 

the transient variation of the valve-loss-coefficient K. K increased from ~86.9 to 110.9 following 

debris introduction. The pressure drop reduced because the flow rate in the system dropped after 

debris introduction, possibly as a result of valve blockage and increased head loss in the system. 

The inferred valve blockage is supported by the 33 pieces of RMI that were found within the 

valve body after this test. Thus, although increased losses could be found in the valve as a result 
34

0

5

10

15

20

25

30

35

40

45

0123456

Time (min)

∆P (psi) 

60

65

70

75

80

85

90

Flow Rate (gpm)

 Delta P (psi) 

 Flow Rate (gpm) - Downstream flow meter

 Flow Rate (gpm) - Upstream flow meter

Figure 2-24. Transient Variation of Pressure Drop (psi) and Flow Rate (gpm) for Test 

45LDT4*

0

20

40

60

80

100

120

0123456

Time (min)

K

Figure 2-25. Transient Variation of Valve-Loss-Coefficient K for Test 45LDT4 

 

*

 In this and all similar plots, pressure drop is plotted in pounds per square inch (1 psi = 6.89 kPa) and flow rate is 

plotted in gallons per minute (100 gpm = 6.31 l/s). 
35

of clogging, it was compensated for by the reduction in the pressure drop as a result of the 

reduction in system flow. This result suggests that the valve-loss-coefficient K, rather than the 

valve pressure drop itself, is the appropriate indicator of debris clogging in these tests. The 

discussion of results in the remainder of the report is based on the valve-loss-coefficient K. 

0

5

10

15

20

25

30

35

40

45

01234567

Time (min)

∆P (psi)

40

45

50

55

60

65

70

75

80

Flow Rate (gpm)

 Delta P (psi) 

 Flow Rate (gpm) - Downstream flow meter

 Flow Rate (gpm) - Upstream flow meter

Figure 2-26. Transient Variation of Pressure Drop and Flow Rate for Test 45LDT6 
36

0

20

40

60

80

100

120

140

160

01234567

Time (min)

K

Figure 2-27. Transient Variation of Valve-Loss-Coefficient K for Test 45LDT6 
37

3 RESULTS OF BASELINE TESTS 

3.1 Baseline for Unblocked Flow 

Baseline tests for unblocked flow involved determining the flow loss characteristics of the valve 

at different valve openings for each valve configuration. The baseline performance of the valve 

configurations was initially determined at the beginning of the test program. Baseline testing was 

then repeated twice through the test program to track potential changes in the baseline as a result 

of wear or other processes. 

Baseline data for the 45L, 5L, and 5S valve stem configurations are shown in Figures 3–1 

through 3–3. Each figure contains data taken at different times through the test program. The 

first set of measurements was made in December 2004. Post-measurement inspection of the 

valve internals revealed evidence of marked galling at the stem-ring interface for the 5L 

configuration. The 5L configuration had been brought to full closure before taking measurements 

for the smallest opening condition. The galling evidently had occurred when the valve was fully 

closed. The subsequent measurement of the flow resistance for the smallest valve configuration 

was compromised by the surface defect. The 5S configuration also was observed to have 

evidence of galling, but to a much smaller extent. As a precaution, the surfaces of the stems and 

rings for all three valve configurations were machined. Data labeled “Dec-04” in Figures 3–1 

through 3–3 indicate tests that were done before the resurfacing. Data labeled “Jan-05-Run 1” 

and “Jan-05-Run 2” indicate tests that were done after resurfacing. Two runs were made to 

examine the repeatability of the data. The last two baseline tests for each stem were taken using 

single-point sampling rather than five-point averaging, as discussed in Section 2.3. 

Figure 3-1 shows the baseline data for the 45L valve configuration. Except for the smallest valve 

opening, K remained relatively unchanged over time. The value for the smallest valve opening 

appeared to increase with time. This observation was consistent with the fact that the smallest 

valve opening was most susceptible to changes in the wear conditions of the surface. As seen in 

Figures 3–2 and 3–3, K for the smallest opening also changed significantly after machining of 

the surfaces for the 5L and 5S valve configurations. Table 3-1 provides tabulated data for 

converting valve gap opening to flow area through the valve for the 45L, 5L, and 5S valve 

configurations. 

The changes in K over time discussed previously did not impact the results of the current study 

adversely. The objective of evaluating debris blockage effects primarily required consideration 

of the change in K relative to the baseline established just before each test. Therefore, the 

absolute value at the beginning of the test is not that important. Additionally, most testing was 

conducted using larger valve gaps where K values do not vary much throughout the various 

baseline measurements (Figures 3–1 to 3–3). 
38

0

50

100

150

200

250

300

350

400

450

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

Valve Gap (in.)

K

Dec-04

Jan-05-Run 1

Jan-05-Run 2

May-05

Jun-05

Figure 3-1. Baseline Data for 45L 

0

1000

2000

3000

4000

5000

6000

0 0.01 0.02 0.03 0.04 0.05 0.06

Valve Gap (in.)

K

Dec-04

Jan-05-Run 1

Jan-05-Run 2

May-05

Jun-05

Figure 3-2. Baseline Data for 5L 
39

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 0.02 0.04 0.06 0.08 0.1 0.12

Valve Gap (in.)

K

Dec-04

Jan-05-Run 1

Jan-05-Run 2

May-05

Jun-05

Figure 3-3. Baseline Data for 5S Stem 

Table 3-1. Throttle Valve Flow Area Conversions 

Throttle 

Valve Gap

Throttle Valve 

Flow Area 

Throttle 

Valve Gap

Throttle Valve 

Flow Area 

Throttle 

Valve Gap

Throttle Valve 

Flow Area 

(in.) (in.2

) (in.) (in.2) (in.) (in.2)

0.035400 0.200422 0.007600 0.050543 0.016980 0.073898

0.053000 0.318540 0.013100 0.087890 0.021844 0.096202

0.070700 0.449704 0.017620 0.119067 0.025554 0.113555

0.105746 0.746015 0.021316 0.144885 0.030236 0.135875

0.137152 1.052883 0.026232 0.179678 0.034724 0.157709

0.176800 1.496073 0.030060 0.207129 0.039024 0.179034

0.243606 2.383682 0.036874 0.256768 0.044304 0.205759

0.354304 4.243595 0.043336 0.304760 0.060736 0.292745

-- -- -- -- 0.079236 0.397590

45L 5L 5S

3.2 Baseline Data for Known Blockage Area 

A series of blockage tests was performed in the beginning of the test program using the 45L 

valve configuration. These tests were performed by placing shims of known areas on the valve 

ring so that a predetermined portion of the flow area in the valve throat could be blocked. Figure 
40

3-4 illustrates the use of a shim to simulate blockage in the valve. The shim consisted of a thin 

piece of rubber gasket material affixed to the valve seating ring via epoxy. 

 

Figure 3-4. Detail Showing Placement of a Shim on the Valve Ring 

Data from these tests helped to establish the threshold of blockage detection. In addition, K

determined for the different blocked area fractions was compared with the baseline data to 

establish the relation between an increase in K and the blocked area. Tests were conducted at the 

beginning and end of the test program for the 45L and 5L valve. No shim tests were performed 

for the 5S stem. All blockage tests were performed for two flow rates—4.73 l/s (75 gpm) and 

6.12 l/s (97 gpm). The 6.12 l/s (97 gpm) corresponded approximately to the highest flow rate 

possible in the system with the set of downstream orifice plates installed (see discussion in 

Section 2.2.5). 

Figure 3-5 shows the transient variation of calculated K for different blockage conditions in the 

45L/0.159-cm (0.0625-in.)-opening configuration. For clarity, only segments of the transient 

data for each case are shown. All test times were >3 min. The average values of K calculated for 

each case also are indicated in Figure 3-5. The standard deviation in all cases was ~0.8. The 

change from an unblocked condition to 6.2% blockage resulted in an increase in the average K of 

9.8. To conclude that the 6.2%-blockage condition could be detected by the measurement 

system, it had to be ascertained that the increase in K was substantially greater than the 

uncertainty in the data itself. 

The measurement standard deviation of the K data contained uncertainties, which theoretically 

could be propagated from first principles as in Eq. (3-1), 

⎥

⎦

⎤ ⎢

⎣

⎡ ∆

+

∆ = ∆

+

∆

+

∆ = ∆

Q

Q

Q

Q

K

K

P

P 2 2

P

(P )

P

(P )

2

2

1

1 . (3-1) 

A ∆K of 9.8 corresponded to a blocked area of 6.2%, which was greater than two standard 

deviations (4.8) from the baseline K as calculated using Eq. (3-1). Thus, the shim blockage test 

data showed that the 6.2% blockage in the 45L valve configuration was detectable by the system 

(i.e., the detection threshold was between 0% and 6.2%). Because no tests were done for 

blockages in this range, a more definitive estimate of the detection threshold was not possible, 

Shim 
41

but it is reasonable to estimate that the detection threshold for the 45L valve configuration was 

on the order of 5% blockage of the flow area. 

50

100

150

200

250

300

350

400

450

0.0 0.5 1.0 1.5 2.0 2.5

Time (min)

Calculated 

K

0% blocked

6.2%

14.6%

30.6%

60.2%

average=102.5

average=112.3

average=126.6

average=157.9

average=405.9

Figure 3-5. Transient Variation of K for Different Blockage Conditions 

Figure 3-6 also shows the shim test data for the 45L valve configuration, and Figure 3-7 presents 

the same data as a plot of the increase in K relative to unblocked flow (∆K%). As seen in Figure 

3-6 and Figure 3-7, the data for 45L, especially at 60% blockage, show a pronounced increase in 

K between the beginning and end of the test program. This increase is due to the combined 

effects of the pieces being remachined early in the test program followed by wear processes 

introduced during testing. However, there is essentially no K dependence on flow rate. 

A fourth-order polynomial fit for the ∆K% end of test program data (Figure 3-7) for the 45L 

configuration at 4.73 l/s (75 gpm) is 

B

2

B

3

B

4 ∆K% = - 3E - 05 AB + 0.0055 A - 0.1638 A + 4.0011 A , (3-2) 

where ∆K% is the increase in K and AB is the percentage of blocked area. 

Figure 3-8 and Figure 3-9 show the corresponding data for the 5L stem for a valve opening of 

0.13 cm (0.05 in.) The data for 4.73 l/s (75 gpm) indicated no appreciable increase in K for a 
42

blocked area of 5.7%, so the detection threshold for 5L was between 5.7% and 10%. A more 

precise estimate of the detection threshold for the 5L case could be established through 

additional testing. However, based on a detection threshold of two standard deviations, a 

reasonable estimate for the threshold for the 5L configuration was ~8%. For the 5L data at 

4.73 l/s (75 gpm), the corresponding equation is 

B

2

B

3

B

4 ∆K% = 8E - 05 AB - 0.0079 A + 0.3109 A -1.2808 A . (3-3) 

Figure 3-10 shows a comparison of the two polynomial curve fits (Equations 3-2 and 3-3) with 

the 45L and 5L data. Both equations show similar trends in valve blockage behavior. Additional 

data would be required to confirm the applicability of these equations to cases other than those 

used to develop them. 

Figure 3-11 and Figure 3-12 compare the valve loss coefficients between the shim blockage and 

baseline tests for the 45L and 5L stems, respectively. The comparisons are made on the basis of 

flow area. The flow area for the baseline tests was varied by changing the throttle valve gap 

opening. The flow area for the shim blockage tests was varied by changing the percent of the 

opening blocked by the shim while maintaining a constant gap opening for a given stem 

configuration. The agreement between the shim blockage and baseline data is very good for both 

the 45L and 5L stems. This agreement implies that debris blockage increases the valve loss 

coefficient primarily by decreasing the flow area. Consequently, blockage asymmetry has 

minimal or no effect. 

0

100

200

300

400

500

600

700

0 10 20 30 40 50 60 70

Percent of Flow Area Blockage

K

45L - 75 gpm - Beginning of test program

45L - 97 gpm - Beginning of test program

45L - 75 gpm - End of test program

45L - 97 gpm - End of test program

Figure 3-6. Blockage Test Data for 45L, Valve Opening = 0.159 cm (0.0625 in.) 
43

0

50

100

150

200

250

300

350

400

450

0 10 20 30 40 50 60 70

Percent of Flow Area Blockage

Percent Increase in 

K Relative to Zero Blockage

45L - 75 gpm - Beginning of test program

45L - 97 gpm - Beginning of test program

45L - 75 gpm - End of test program

45L - 97 gpm - End of test program

Figure 3-7. Percentage Increase in K as a Result of Blockage [45L, 0.159-cm (0.0625-in.) 

Opening] 

0

100

200

300

400

500

600

700

800

0 10 20 30 40 50 60

Percent of Area Blockage

K

75 gpm

97 gpm

Figure 3-8. Blockage Test Data for 5L, Valve Opening = 0.13 cm (0.05 in.) 
44

0

50

100

150

200

250

300

350

0 10 20 30 40 50 60

Percent of Area Blockage

Percent Increase in 

K Relative to Zero Bloakage

75 gpm

97 gpm

Figure 3-9. Percentage Increase in K as a Result of Blockage [5L, 0.13-cm (0.05-in.) 

Opening] 

0

100

200

300

400

500

600

700

0 10 20 30 40 50 60 70 80

Percent of Flow Area Blockage

Percent Increase in 

K Relative to Zero Blockage

45L - 75 gpm

5L - 75 gpm

Eq. (3.2)

Eq. (3.3)

Figure 3-10. Comparing Curve Fits for ∆K% vs AB 
45

0

50

100

150

200

250

300

350

400

450

0.0 0.2 0.4 0.6 0.8 1.0

Flow Area (in.2)

K

Baseline

Blockage

Figure 3-11. Comparing Shim Blockage to Baseline (45L Stem, Beginning of Test 

Program, 75 gpm) 

0

1000

2000

3000

4000

5000

6000

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

Flow Area (in.2)

K

Baseline

Blockage

Figure 3-12. Comparing Shim Blockage to Baseline (5L Stem, Beginning of Test Program, 

75 gpm) 
46

This page intentionally left blank.
47

4 RESULTS OF SINGLE-DEBRIS TESTS 

The results of single-debris tests with RMI, NUKON, and CalSil are presented in this section. In 

each case, a single batch of debris was introduced into the system and the hydraulic behavior of 

the valve was recorded to infer any resulting blockage. The upstream temperature was for each 

test fell between 15°C (59oF) and 26°C (78oF). 

4.1 RMI Tests 

The results of single debris tests with RMI are presented in three categories: 

• Tests with a specified number of pieces of RMI: These initial scoping tests were 

performed early in the test program to test system performance and identify follow-up 

tests. All tests in this category used 10 pieces of RMI—the valve stem/ring combination 

and valve gap were varied. 

• Tests with a specified mass of RMI: These tests used between 1 and 10 g of RMI. In 

addition to the mass of RMI introduced, the valve stem/ring combination and valve gap 

also were varied. 

• Tests to examine repeatability of data: A limited number of replicate RMI tests with a 

specified mass were conducted to assess data repeatability. 

4.1.1 Tests with a Specified Number of Pieces of RMI 

These tests were performed early in the test program. All tests in this category used 10 pieces of 

RMI. The valve stem/ring combination and valve gap were varied. Post-test collection of debris 

was not recorded for these tests, so no data are available regarding how many of the debris pieces 

were recovered either downstream of the valve or in the valve itself. 

The results of this series of tests are summarized in Table 4-1.*

 The increase in K was found to 

be significant (>5%) only when the pieces had at least one characteristic dimension >0.63 cm 

(0.25 in.) and only for the 5L stem when the smallest gap setting [0.13 cm (0.05 in.)] was 

evaluated. For the two cases that had measurable increases in loss coefficient, the greatest 

increase was ~7%. Test data in this category were limited, but they indicated that a small number 

of RMI pieces would not normally cause appreciable valve blockage. 

 

*

 The ∆K% data for the full data set are compiled in Appendix D. The plots of measured valve pressure drop and 

calculated K are compiled in Appendix E. 
48

Table 4-1. Results of Tests with Specified Number of Pieces of RMI Introduced 

K

Test ID Stem 

Gap 

[cm 

(in.)] 

Number of RMI 

Pieces Inserted 

N1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change 

5SDT1a 5S 

0.158 

(0.0622) 10 

0.32 × 0.32 

(1/8 × 1/8) 293 293 <5 

5SDT1b 5S 

0.158 

(0.0622) 10 

0.63 × 0.63 

(1/4 × 1/4) 291 289 <5 

5SDT1c 5S 

0.158 

(0.0622) 10 

0.32 × 1.27 

(1/8 × 1/2) 290 289 <5 

5SDT2a 5S 

0.2543 

(0.1001) 10 

0.32 × 0.32 

(1/8 × 1/8) 179 178 <5 

5SDT2b 5S 

0.2543 

(0.1001) 10 

0.63 × 0.63 

(1/4 × 1/4) 180 178 <5 

5SDT2c 5S 

0.2543 

(0.1001) 10 

0.32 × 1.27 

(1/8 × 1/2) 178 178 <5 

5LDT1a 5L 

0.127 

(0.0499) 10 

0.32 × 0.32 

(1/8 × 1/8) 154 154 <5 

5LDT1b 5L 

0.127 

(0.0499) 10 

0.63 × 0.63 

(1/4 × 1/4) 152 157 <5 

5LDT1c 5L 

0.127 

(0.0499) 10 

0.32 × 1.27 

(1/8 × 1/2) 153 165 7 

45LDT1a 45L 

0.180 

(0.0707) 10 

0.32 × 0.32 

(1/8 × 1/8) 107 107 <5 

45LDT1b 45L 

0.180 

(0.0707) 10 

0.63 × 0.63 

(1/4 × 1/4) 107 109 <5 

45LDT1c 45L 

0.180 

(0.0707) 10 

0.32 × 1.27 

(1/8 × 1/2) 107 106 <5 

45LDT2a 45L 

0.3124 

(0.1230) 10 

0.32 × 0.32 

(1/8 × 1/8) 88.4 87.9 <5 

45LDT2b 45L 

0.3124 

(0.1230) 10 

0.63 × 0.63 

(1/4 × 1/4) 88.6 89.2 <5 

45LDT2c 45L 

0.3124 

(0.1230) 10 

0.32 × 1.27 

(1/8 × 1/2) 88.3 88.2 <5 

Transient data from two typical tests in this category are shown in Figure 4-1 and Figure 4-2. 

Figure 4-1 shows the data for Test 45LDT1a, which had essentially no evidence of blockage, and 

Figure 4-2 shows data from test 5LDT1c, which had a 7% increase in K. 
49

20

25

30

35

40

45

50

55

0123456

Time (min)

∆P (psi)

80

90

100

110

120

130

140

150

K

Figure 4-1. Transient Variation of Valve Pressure Drop and Calculated K for Test 

45LDT1a* 

56

58

60

62

64

66

68

70

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

120

130

140

150

160

170

180

K

Figure 4-2. Transient Variation of Valve Pressure Drop and Calculated K for Test 

5LDT1c 

 

*

NOTE: In this and all similar plots, unless otherwise indicated, the blue (or lighter) curve denotes ∆P and the red 

(or darker) curve denotes K. Also, the vertical line marks the time of debris addition. 
50

4.1.2 Tests with Specified Mass of RMI 

These tests used between 1 and 10 g of RMI. In addition to the mass of RMI introduced, the 

valve stem/ring combination and valve gap also were varied. For tests in this class, debris was 

collected during the test and when the system was flushed following the test. The procedure is 

described in Sections 2.2.5 and A.3. For some of the tests, an additional debris recovery step was 

added by opening the trap and back flushing the system. The valve was opened and inspected 

after each test, and the number of RMI pieces recovered from the valve was recorded. Note that 

the recovery of RMI debris from the valve body does not necessarily mean that the RMI was 

trapped in the gap between the valve stem and seat. 

The results of this series of tests are summarized in Table 4-2. In general, a correlation is 

apparent between the number of RMI pieces recovered from the valve following a test and the 

increase in the valve-loss-coefficient K. The higher the number of pieces found in the valve, the 

larger the calculated increase in the valve-loss-coefficient K. This general trend is evident from 

the data shown in Figure 4-3. 

A companion plot, Figure 4-4, presents the percent increase in K for different debris loadings as 

a function of the ratio of the maximum RMI dimension to the valve gap size. If Figure 4-3 and 

Figure 4-4 are considered together; the following general trends are apparent. The performance 

of the 5S valve configuration was only minimally degraded by RMI debris (smallest observed 

increase in K), regardless of the initial RMI loading, the ratio of RMI size tested to the gap size, 

or the number of RMI pieces recovered from the valve body. The implication of this result is that 

the geometry of the 5S valve configuration was such that RMI was less likely to be trapped 

within the valve and that those pieces that were recovered from the valve may have been trapped 

in areas other than the gap and did not affect the flow area through the valve. 

The 5L valve configuration appears to have been less likely to trap RMI than the 45L valve 

configuration for the same initial RMI loadings. However, once the RMI was trapped within the 

5L valve configuration, the performance degradation appeared to have been higher for the 5L 

valve configuration for the same number of recovered RMI pieces. In light of the inherent data 

variability, as well as the discrepancy in the number of tests between the 45L and 5L valve 

configurations, this apparent trend may not be actual. The physical size of the RMI debris was 

not as important as the debris loading quantity for degrading valve performance for debris size to 

gap ratios greater than ~3. 

The 45L valve configuration appears to have trapped the most number of RMI pieces and 

subsequently suffered the most performance degradation (exhibited the greatest increase in K) 

for a given debris quantity and size. The 45L test data also exhibited the most variability, but the 

number of tests using this configuration far exceeded the other configurations. Sample loadings 

of 1 g were generally not large enough to cause valve clogging of any significance, regardless of 

the valve configuration or the RMI sizes tested. This result indicates that a loading threshold may 

exist below which valve performance degradation will not occur. However, this result does not 

address the potential for cumulative effects from a continuous stream of small quantities of RMI 

debris. 
51

4.1.3 RMI Repeatability Tests 

A limited number of RMI tests were performed with test conditions identical to those in the 

above category to investigate the repeatability of data. Eight tests from Table 4-2 were selected 

for repeating—these included three cases where the original test showed a negligible change in K

(<5%), two for which the original test showed a detectable change in K (5%–12%), and two 

cases where the original tests showed a significant change in K (>50%). In addition, one test was 

repeated using a smaller debris size (a debris size slightly smaller than the valve gap). The results 

are summarized in Table 4-3. 

For test 45LDT5, the original test yielded a K increase of <5%, whereas the repeat test yielded 

24%. The increase in K was 51% for the original run of test 45LDT9. The repeated tests showed 

a great deal of variability (5%, 19%, and 54%). For test 45LDT11, the original run resulted in 

virtually no change in K, whereas the repeat run showed a moderate increase in K of 6%. For test 

45LDT18, the original run resulted in an increase in K of 51%, whereas the repeat run resulted in 

an increase of 20%. The data for test 5LDT3 were the most reproducible among cases where 

detectable increases in K were observed although only a single replicate test was performed. 

Repeat tests of the null tests (N-1_45L and N-4_45L), where the gap size was larger than the 

debris dimension, consistently showed no appreciable indication of clogging. 

The above results clearly show that debris clogging data are difficult to reproduce. This 

conclusion largely is consistent with the fact that debris clogging of the valve has an inherent 

randomness associated with it. The likelihood of debris getting trapped in the valve opening 

depends on the orientation of the debris piece relative to the flow in the valve throat; this process 

is random, especially when the flow is turbulent. In addition, the orientation of the pieces has an 

effect on whether, and by how much, the pieces get bent inside the valve; in turn, the change in 

shape of the pieces has an effect on their ability to pass through the valve or to be trapped inside 

it. A larger number of repeatability tests would be necessary to quantitatively assess variability. 

This was beyond the objective of these scoping tests. 

4.1.4 Estimating the Blockage Area 

As discussed in Section 3, baseline data for known blockage conditions were obtained for the 

45L and the 5L valve configurations for valve openings of 0.159 cm (0.0625 in.) and 0.13 cm 

(0.05 in.), respectively. Blockage-area fractions estimated using Eq. (3-2) for the RMI tests using 

the 45L/0.159-cm (0.0625-in.)-opening and Eq. (3-3) for the 5L/0.13-cm (0.05-in.)-opening 

combinations are listed in Table 4-4. The highest estimated blocked area fraction is ~20% and 

occurred with the largest RMI pieces tested [0.63 cm × 0.63 cm (1/4 in. × 1/4 in.)] in the 45L 

configuration. 
52

-10

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70

Number of RMI Pieces Recovered from Valve

Percent Increase in 

K

45L

5L

5S

5% Threshold

Figure 4-3. Observed Correlation between the Increase in K and the Number of RMI 

Pieces Recovered in the Valve 

-10

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9 10 11

Ratio of RMI (Maximum Dimension) to Gap Size

Percent Increase in 

K

10 g, 45L

 5 g, 45L

 1 g, 45L

10 g, 5L

 5 g, 5L

 1 g, 5L

10 g, 5S

 5 g, 5S

 1 g, 5S

 5% Threshold

Figure 4-4. Relation between the Increase in K and the Ratio of RMI Size to Gap Size 
53

Table 4-2. Results of Tests with Specified Mass of RMI Introduced 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

RMI 

Unaccounted 

for 

Wf=W1-W2 

P

45LDT1 45L 

0.3142 

(0.1237) 1.00 

0.32 × 0.32 

(1/8 × 1/8) 88.7 88.9 <5 0.79 0.21 

45LDT2 45L 

0.3142 

(0.1237) 5.00 

0.32 × 0.32 

(1/8 × 1/8) 89.0 89.2 <5 4.33 0.67 

45LDT3 45L 

0.3142 

(0.1237) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 87.9 87.4 <5 7.90 2.11 

45LDT4 45L 

0.3142 

(0.1237) 1.02 

0.63 × 0.63 

(1/4 × 1/4) 88.0 98.4 12 0.85 0.17 

45LDT5 45L 

0.3142 

(0.1237) 5.00 

0.63 × 0.63 (1/4 × 1/4) 88.9 92.6 <5 4.82 0.18 

45LDT6 45L 

0.3142 

(0.1237) 10.02 

0.63 × 0.63 (1/4 × 1/4) 86.9 111 28 8.95 1.07 

45LDT7 45L 

0.3142 

(0.1237) 0.99 

0.32 × 1.27 (1/8 × 1/2) 92.5 92.1 <5 0.98 0.01 

45LDT8 45L 

0.3142 

(0.1237) 5.03 

0.32 × 1.27 (1/8 × 1/2) 89.9 90.4 <5 4.57 0.46 

45LDT9 45L 

0.3142 

(0.1237) 10.00 

0.32 × 1.27 (1/8 × 1/2) 88.1 133 51 8.92 1.08 

45LDT10 45L 

0.166 

(0.0654) 1.02 

0.32 × 0.32 

(1/8 × 1/8) 126 126 <5 0.97 0.05 

45LDT11 45L 

0.166 

(0.0654) 4.99 

0.32 × 0.32 

(1/8 × 1/8) 125 124 <5 4.24 0.75 

45LDT12 45L 

0.166 

(0.0654) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 124 130 <5 7.84 2.16 

45LDT13 45L 

0.166 

(0.0654) 1.00 

0.63 × 0.63 (1/4 × 1/4) 122 136 11 0.98 0.02 

45LDT14 45L 

0.166 

(0.0654) 5.00 

0.63 × 0.63 (1/4 × 1/4) 124 165 32 4.54 0.46 

45LDT15 45L 

0.166 

(0.0654) 10.01 

0.63 × 0.63 (1/4 × 1/4) 121 186 53 8.68 1.33 

45LDT16 45L 

0.166 

(0.0654) 1.01 

0.32 × 1.27 (1/8 × 1/2) 126 126 <5 0.90 0.11 

45LDT17 45L 

0.166 

(0.0654) 5.02 

0.32 × 1.27 (1/8 × 1/2) 127 133 <5 4.95 0.07 

45LDT18 45L 

0.166 

(0.0654) 10.00 

0.32 × 1.27 (1/8 × 1/2) 127 192 51 9.42 0.58 

5LDT1 5L 

0.1269 

(0.04997) 1.01 

0.32 × 0.32 

(1/8 × 1/8) 174 175 <5 0.92 0.09 
54

Table 4-2. Results of Tests with Specified Mass of RMI Introduced (cont) 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

RMI 

Unaccounted 

for 

Wf=W1-W2 

P

5LDT2 5L 

0.1269 

(0.04997) 5.01 

0.32 × 0.32 

(1/8 × 1/8) 174 174 <5 4.56 0.45 

5LDT3 5L 

0.1269 

(0.04997) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 173 192 11 9.24 0.77 

5LDT4 5L 

0.1269 

(0.04997) 1.01 

0.63 × 0.63 (1/4 × 1/4) 173 186 8 0.77 0.24 

5LDT5 5L 

0.1269 

(0.04997) 5.01 

0.63 × 0.63 (1/4 × 1/4) 173 174 <5 4.75 0.26 

5LDT6 5L 

0.1269 

(0.04997) 10.01 

0.63 × 0.63 (1/4 × 1/4) 170 211 24 9.14 0.87 

5LDT7 5L 

0.1269 

(0.04997) 1.01 

0.32 × 1.27 (1/8 × 1/2) 172 173 <5 0.91 0.10 

5LDT8 5L 

0.1269 

(0.04997) 5.01 

0.32 × 1.27 (1/8 × 1/2) 172 171 <5 4.53 0.48 

5LDT9 5L 

0.1269 

(0.04997) 10.01 

0.32 × 1.27 (1/8 × 1/2) 171 220 29 8.61 1.40 

5SDT1 5S 

0.254 

(0.0999) 1.00 

0.32 × 0.32 

(1/8 × 1/8) 203 204 <5 0.97 0.03 

5SDT2 5S 

0.254 

(0.0999) 5.00 

0.32 × 0.32 

(1/8 × 1/8) 203 206 <5 4.52 0.48 

5SDT3 5S 

0.254 

(0.0999) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 203 202 <5 9.18 0.82 

5SDT4 5S 

0.254 

(0.0999) 1.00 

0.63 × 0.63 (1/4 × 1/4) 205 204 <5 0.8 0.18 

5SDT5 5S 

0.254 

(0.0999) 5.01 

0.63 × 0.63 (1/4 × 1/4) 205 205 <5 4.5 0.47 

5SDT6 5S 

0.254 

(0.0999) 10.00 

0.63 × 0.63 (1/4 × 1/4) 204 205 <5 9.0 1.00 

5SDT7 5S 

0.254 

(0.0999) 1.01 

0.32 × 1.27 (1/8 × 1/2) 204 203 <5 0.8 0.18 

5SDT8 5S 

0.254 

(0.0999) 5.01 

0.32 × 1.27 (1/8 × 1/2) 201 202 <5 4.6 0.42 

5SDT9 5S 

0.254 

(0.0999) 10.01 

0.32 × 1.27 (1/8 × 1/2) 202 203 <5 9.0 1.05 

5SDT10 5S 

0.161 

(0.0632) 1.00 

0.32 × 0.32 

(1/8 × 1/8) 311 309 <5 1.0 0.05 
55

Table 4-2. Results of Tests with Specified Mass of RMI Introduced (cont) 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

RMI 

Unaccounted 

for 

Wf=W1-W2 

P

5SDT11 5S 

0.161 

(0.0632) 5.00 

0.32 × 0.32 

(1/8 × 1/8) 311 310 <5 4.6 0.42 

5SDT12 5S 

0.161 

(0.0632) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 310 313 <5 9.0 0.98 

5SDT13 5S 

0.161 

(0.0632) 1.02 

0.63 × 0.63 (1/4 × 1/4) 316 316 <5 0.9 0.16 

5SDT14 5S 

0.161 

(0.0632) 5.00 

0.63 × 0.63 (1/4 × 1/4) 313 317 <5 4.6 0.42 

5SDT15 5S 

0.161 

(0.0632) 10.02 

0.63 × 0.63 (1/4 × 1/4) 314 326 <5 9.1 0.93 

5SDT16 5S 

0.161 

(0.0632) 1.01 

0.32 × 1.27 (1/8 × 1/2) 315 317 <5 0.9 0.08 

5SDT17 5S 

0.161 

(0.0632) 5.00 

0.32 × 1.27 (1/8 × 1/2) 313 311 <5 4.5 0.51 

5SDT18 5S 

0.161 

(0.0632) 10.00 

0.32 × 1.27 (1/8 × 1/2) 327 337 <5 9.2 0.75 

N-1_45L 45L 

0.6350 

(0.2500) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 105 108 <5 9.7 0.30 

N-4_45L 45L 

0.6350 

(0.2500) 10.01 

0.32 × 1.27 (1/8 × 1/2) 103 105 <5 9.9 0.13 

5 

0.32 × 1.27 (1/8 × 1/2) 

N-7_45L 45L 0.6350 (0.2500) 

5 

0.63 × 0.63 

(1/4 × 1/4) 

104 120 15 10.2 -0.21 

D-2_45L 45L 

0.159 

(0.0625) 10.01 

0.32 × 1.27 (1/8 × 1/2) 166 200 20 9.9 0.12 

D-3_5L 5L 

0.127 

(0.0500) 10.05 

0.32 × 1.27 (1/8 × 1/2) 173 186 8 9.9 0.15 

N-11_45L 45L 

0.3305 

(0.1301) 10.03 

0.32 × 0.32 

(1/8 × 1/8) 104 119 15 9.5 0.50 

N-21_45L 45L 

0.3305 

(0.1301) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 103 114 11 9.7 0.30 

N-31_45L 45L 

0.3305 

(0.1301) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 102 115 12 9.8 0.16 

N-41_45L 45L 

0.3305 

(0.1301) 10.00 

0.32 × 1.27 (1/8 × 1/2) 107 122 14 9.78 0.32 
56

Table 4-2. Results of Tests with Specified Mass of RMI Introduced (cont) 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

RMI 

Unaccounted 

for 

Wf=W1-W2 

P

N-51_45L 45L 

0.3305 

(0.1301) 10.00 

0.32 × 1.27 (1/8 × 1/2) 104 133 28 9.8 0.16 

N-61_45L 45L 

0.3305 

(0.1301) 10.00 

0.32 × 1.27 (1/8 × 1/2) 103 117 14 9.9 0.05 

Table 4-3. Results of Repeatability Tests 

K

No. Test ID Case Stem 

Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] Before After 

% 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

45LDT5 Original 45L 

0.3142 

(0.1237) 5.00 

0.63 × 0.63 

(1/4 × 1/4) 88.9 92.6 <5 4.82 

45LDTR5 Repeat 45L 

0.3124 

(0.1230) 5.01 

0.63 × 0.63 

(1/4 × 1/4) 107 133 24 4.39 

1 

45LDTR5x Gap>Debris Size 45L 

0.3269 

(0.1287) 5.07 

0.32 × 0.32 

(1/8 × 1/8) 105 105 <5 4.35 

45LDT9 Original 45L 

0.3142 

(0.1237) 10.00 

0.32 × 1.27 (1/8 × 1/2) 88.1 133 51 8.92 

45LDTR9 Repeat 45L 

0.3124 

(0.1230) 10.05 

0.32 × 1.27 (1/8 × 1/2) 105 111 5 4.98 

D-1_45L Repeat 45L 

0.3170 

(0.1248) 10.00 

0.32 × 1.27 (1/8 × 1/2) 104 124 19 9.88 

2 

D-1-2_45L Repeat 45L 

0.3180 

(0.1252) 10.00 

0.32 × 1.27 (1/8 × 1/2) 99.0 152 54 10.12 

45LDT11 Original 45L 

0.166 

(0.0654) 4.99 

0.32 × 0.32 

(1/8 × 1/8) 125 124 <5 4.24 

3 

45LDTR11 Repeat 45L 

0.156 

(0.0615) 5.03 

0.32 × 0.32 

(1/8 × 1/8) 126 133 6 9.99 
57

Table 4-3. Results of Repeatability Tests (cont) 

K

No. Test ID Case Stem 

Gap 

[cm (in.)] 

Mass of 

RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] Before After 

% 

Change 

RMI 

Recovered 

in Bucket 

(g) W2 

45LDT18 Original 45L 

0.166 

(0.0654) 10.00 

0.32 × 1.27 (1/8 × 1/2) 127 192 51 9.42 

4 

D-2_45L Repeat 45L 

0.159 

(0.0625) 10.01 

0.32 × 1.27 (1/8 × 1/2) 166 200 20 9.88 

45LDT14 Original 45L 

0.166 

(0.0654) 5.0 

0.63 × 0.63 

(1/4 × 1/4) 124 165 32 4.54 

5 

D-6_45L Repeat 45L 

0.159 

(0.0626) 5.00 

0.63 × 0.63 

(1/4 × 1/4) 155 194 25 5.07 

5LDT3 Original 5L 

0.127 

(0.0500) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 173 192 11 9.24 

6 

D-3_5L Repeat 5L 

0.127 

(0.0500) 10.05 

0.32 × 0.32 

(1/8 × 1/8) 173 186 8 9.90 

N-1_45L Original 45L 

0.6350 

(0.2500) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 105 108 <5 9.71 

N-2_45L Repeat 45L 

0.6350 

(0.2500) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 102 102 <5 9.73 

7 

N-3_45L Repeat 45L 

0.6350 

(0.2500) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 105 106 <5 9.83 

N-4_45L Original 45L 

0.6350 

(0.2500) 10.01 

0.32 × 1.27 

(1/8 × 1/2) 103 105 <5 9.88 

N-5_45L Repeat 45L 

0.6350 

(0.2500) 10.02 

0.32 × 1.27 (1/8 × 1/2) 99.5 102 <5 9.78 

8 

N-6_45L Repeat 45L 

0.6350 

(0.2500) 10.01 

0.32 × 1.27 (1/8 × 1/2) 99.3 101 <5 9.82 
58

Table 4-4. Estimates of Blockage-Area Fraction for RMI Tests 

K

Test ID Stem 

Gap 

[cm (in.)] 

Mass of RMI 

Inserted 

(g)W1 

RMI Size 

[cm × cm 

(in. × in.)] 

Before After % 

Change

Estimate 

Blocked A

Fraction 

45LDT12 45L 0.166 (0.0654) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 124 130 <5 <5% 

45LDT13 45L 0.166 (0.0654) 1.00 

0.63 × 0.63 (1/4 × 1/4) 122 136 11 <5% 

45LDT14 45L 0.166 (0.0654) 5.00 

0.63 × 0.63 (1/4 × 1/4) 124 165 32 12 

45LDT15 45L 0.166 (0.0654) 10.01 

0.63 × 0.63 (1/4 × 1/4) 121 186 53 20 

45LDT17 45L 0.166 (0.0654) 5.02 

0.32 × 1.27 

(1/8 × 1/2) 127 133 <5 <5% 

45LDT18 45L 0.166 (0.0654) 10.00 

0.32 × 1.27 

(1/8 × 1/2) 127 192 51 19 

D-2_45L 45L 0.159 (0.0625) 10.01 

0.32 × 1.27 

(1/8 × 1/2) 166 200 20 6.4 

D-6_45L 45L 0.159 (0.0626) 5.00 

0.63 × 0.63 

(1/4 × 1/4) 155 194 25 19 

45LDTR11 45L 0.156 (0.0615) 5.03 

0.32 × 0.32 

(1/8 × 1/8) 126 133 6 <5% 

5LDT3 5L 0.1269 (0.04997) 10.01 

0.32 × 0.32 

(1/8 × 1/8) 173 192 11 10 

5LDT4 5L 0.1269 (0.04997) 1.01 

0.63 × 0.63 (1/4 × 1/4) 173 186 8 8.7 

5LDT6 5L 0.1269 (0.04997) 10.01 

0.63 × 0.63 (1/4 × 1/4) 170 211 24 14 

5LDT9 5L 0.1269 (0.04997) 10.01 

0.32 × 1.27 

(1/8 × 1/2) 171 220 29 15 

D-3_5L 5L 0.127 (0.0500) 10.05 

0.32 × 0.32 

(1/8 × 1/8) 173 186 8 8.7 
59 

4.2 CalSil Tests 

Single-debris tests with CalSil used 50 or 100 g of material prepared, as described in 

Section 2.4. The results are summarized in Table 4-5. The various columns in the CalSil 

data table are explained below. 

Table 4-5. Results of CalSil Tests 

K

Test ID Stem Gap [cm (in.)] 

Mass of 

CalSil 

(g) WC 

Sieve 

# Before After 

% 

Change 

5sc1 5S 0.161 (0.0632) 50.04 4 312 319 <5 

5sc2 5S 0.161 (0.0632) 100.04 4 313 310 <5 

5sc3 5S 0.161 (0.0632) 51.01 8 314 314 <5 

5sc4 5S 0.161 (0.0632) 100.00 8 312 321 <5 

5sc5 5S 0.254 (0.0999) 50.06 4 205 202 <5 

5sc6 5S 0.254 (0.0999) 100.04 4 205 204 <5 

5sc7 5S 0.254 (0.0999) 49.98 8 205 204 <5 

5sc8 5S 0.254 (0.0999) 100.08 8 205 205 <5 

5LC1 5L 0.127 (0.0499) 50.08 4 177 179 <5 

5LC2 5L 0.127 (0.0499) 100.56 4 177 182 <5 

5LC3 5L 0.127 (0.0499) 50.12 8 177 179 <5 

5LC4 5L 0.127 (0.0499) 101.25 8 177 199 12 

Only one of the CalSil tests (5LC4) showed an appreciable increase in the valve-loss 

coefficient. This test used 101 g of #8-sieved CalSil with valve stem 5L and a valve gap 

of 1.3 mm (0.05 in.). For this case, the blocked area fraction, based on Eq. (3-3), is 10%. 

Transient data from the 5LC4 test are shown in Figure 4-5. 

In addition to the tests listed in Table 4-5, a test was performed with unsieved CalSil 

(Figure 2-23) using the 45L stem and an opening of 0.1 in. This bounding test was 

performed for the purpose of demonstrating test procedures to visiting NRC personnel, so 

the CalSil could not be characterized sufficiently before the test. The transient data are 

shown in Figure 4-6. The loss coefficient, K, increased by ~25% shortly after debris 

introduction but then decreased gradually over the remainder of the test. It appeared that 

unsieved CalSil clogged the valve initially but that the clogged debris eroded gradually 

over time, resulting in a reduction in the loss coefficient. 
60 

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

Figure 4-5. Transient Variation of Valve Pressure Drop and Calculated K for Test 

5LC4 

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12

Time (min)

∆P (psi) and Flow Rate (gpm)

0

50

100

150

200

250

300

K

 Delta P (psi) 

Flow rate (gpm)

K factor

Figure 4-6. Transient Variation of Valve Pressure Drop, Flow Rate, and 

Calculated K for Test 5sc9 
61 

4.3 NUKON Tests 

4.3.1 Tests with Specified Mass of NUKON 

Single-debris NUKON tests used ~50 or 100 g of material, prepared as described in 

Section 2.4. One test used 25 g of NUKON. The results are summarized in Table 4-6. 

Transient data from two typical tests in this category are shown in Figure 4-7, Figure 4-8, 

and Figure 4-9. Figure 4-7 presents the data for Test 45LN1, which showed a very small 

increase in the loss-coefficient K. Figure 4-8 shows the data for test 5LN3, which showed 

a significant increase in K following debris introduction. The average steady-state K

value over the post-debris test interval was 186% higher than the baseline value. Unlike 

RMI and sieved CalSil, K could be observed to decrease gradually over time in this test, 

possibly as a result of erosion of the debris trapped in the valve. Figure 4-9 shows data 

from test 45LN3, which showed a 222% increase in average steady-state K over the test 

interval following debris introduction. The erosion effects were pronounced in this case, 

as well. 

0

10

20

30

40

50

60

0 2 4 6 8 10 12 14

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

K

Figure 4-7. Transient Variation of Valve Pressure Drop and Calculated K for 

NUKON Test 45LN1 
62 

0

25

50

75

100

125

150

175

200

225

01234567

Time (min)

∆P (psi)

0

100

200

300

400

500

600

700

K

Figure 4-8. Transient Variation of Valve Pressure Drop and Calculated K for 

NUKON Test 5LN2 

0

20

40

60

80

100

120

140

160

180

200

01234567

Time (min)

∆P (psi)

0

100

200

300

400

500

600

K 

Figure 4-9. Transient Variation of Valve Pressure Drop and Calculated K for 

NUKON Test 45LN3 
63 

The results summarized in Table 4-6 and portrayed graphically in Figure 4-10 show that 

NUKON can cause significant clogging in the valve, as evidenced by the large increases 

in K in many of the tests. The effect was pronounced in tests with valve gaps less than 

0.16 cm (0.063 in.) for the 45L and 5L configuration. Gaps larger than 0.16 cm 

(0.063 in.) did not result in significant clogging. The single test performed using a 

smaller quantity (25 g) of NUKON (D-17_45L) showed no significant evidence of 

clogging; however, insufficient data exists to establish any possible clogging threshold. 

In addition to the observed gap-dependent behavior, the stem geometry affected the 

observed increase in K. The 5S stem showed essentially no increase in K for any quantity 

of NUKON introduced. The 5L and 45L stems showed substantial increases in K, with 

the 45L stem being somewhat higher than the 5L stem for comparable gap sizes. 

Table 4-6. Results of NUKON Tests 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

NUKON (g) 

WN Before After % 

Change 

45LN1 45L 0.3152 (0.1241) 49.92 105 106 <5 

45LN2 45L 0.162 (0.0636) 49.85 124 182 47 

45LN3 45L 0.160 (0.0629) 95.67 138 445 222 

45LN4 45L 0.160 (0.0629) 98.23 140 421 201 

D-17_45L 45L 0.159 (0.0626) 25.05 154 155 <5 

5LN1 5L 0.126 (0.0497) 50.07 175 198 14 

5LN2 5L 0.127 (0.0500) 97.99 170 488 187 

5LN3 5L 0.127 (0.0500) 97.47 170 385 126 

5SN1 5S 0.2540 (0.1000) 50.15 195 196 <5 

5SN4 5S 0.2543 (0.1001) 98.05 196 197 <5 

5SN2 5S 0.159 (0.0627) 50.07 313 318 <5 

5SN3 5S 0.159 (0.0627) 95.83 317 340 7 

4.3.2 NUKON Repeatability Tests 

A single test was done to gauge the repeatability of the NUKON data. The results are 

summarized in Table 4-7, and the transient data from the two tests are compared in 

Figure 4-11. It should be noted that the baseline K values were different in the two tests 

but, as discussed in Section 3.1, only the relative change in K is important for making 

inferences about debris-clogging effects. The table and the figure show that, as in the case 

of RMI data presented earlier, the results of these two nominally identical tests were 

highly variable. 
64 

0

50

100

150

200

250

0 20 40 60 80 100 120

Mass of NUKON (g)

Percent Increase in 

K

45L Stem [0.31 cm (0.12 in.) gap]

45L Stem [0.16 cm (0.06 in.) gap]

5L Stem [0.13 cm (0.05 in.) gap]

5S Stem [0.25 cm (0.10 in.) gap]

5S Stem [0.16 cm (0.06 in.) gap]

Figure 4-10. Observed Correlation between Mass of NUKON Introduced and the 

Increase in K. 

Table 4-7. Results of NUKON Repeatability Test 

K

Test ID Case Stem Gap [cm (in.)] 

Mass of 

NUKON

(g) WN Before After % 

Change 

45LN2 Original 45L 0.162 (0.0636) 49.85 124 182 47 

D-16 Repeat 45L 0.159 (0.0626) 50.01 158 375 137 

4.3.3 Estimating Blockage Area 

As discussed in Section 3, baseline data for known blockage conditions were obtained for 

the 45L and the 5L valve configurations for valve openings of 0.159 cm (0.0625 in.) and 

0.13 cm (0.05 in.), respectively. Blockage-area fractions estimated using Eq. (3-2) for the 

NUKON tests using the 45L/0.159-cm (0.0625-in.)-opening and Eq. (3-3) for the 

5L/0.13-cm (0.05-in.)-opening combinations are listed in Table 4-8. It should be noted 

that the shape of the blockage curves, as shown in Figure 3-6 and Figure 3-8, indicates 
65 

0

50

100

150

200

250

300

350

400

450

0123456

Time (min)

K

45LN2

D-16_45L

Figure 4-11. Transient Variation of K for NUKON Repeatability Tests 

that the sensitivity of the estimated blockage area decreases with increasing K. The 

highest estimated blocked area fraction was ~45%. Typically, the blockage fractions with 

NUKON were substantially higher than the largest fractions estimated for the RMI tests. 

Table 4-8. Estimates of Blocked Area Fraction for NUKON Tests 

K

Test ID Stem Gap 

[cm (in.)] 

Mass of 

NUKON

(g) WN Before After % 

Change 

Blocked Area 

Fraction (%) 

5LN1 5L 0126 (0.0497) 50.07 175 198 14 11 

45LN2 45L 0.162 (0.0636) 49.85 124 182 47 18 

5LN2 5L 0.127 (0.0500) 97.99 170 488 187 46 

5LN3 5L 0.127 (0.0500) 97.47 170 385 126 37 

45LN3 45L 0.160 (0.0629) 95.67 138 445 222 45 

45LN4 45L 0.160 (0.0629) 98.23 140 421 201 43 

4.4 Discussion 

Data from the tests discussed in this chapter provided some overall qualitative 

information on the potential clogging of the throttle valves by unmixed debris. In general, 

higher loading of larger debris sizes (relative to the throttle valve opening) resulted in the 

highest observed increase in valve-loss-coefficient K. 
66 

In RMI tests, the highest observed increase in K was ~50%. In tests for which an estimate 

of the corresponding blockage-area fraction could be estimated, this increase translated to 

a blocked area fraction of ~20% for RMI pieces 0.63 cm × 0.63 cm (1/4 in. × 1/4 in.) and 

valve openings of 0.159 cm (0.0625 in.). For RMI pieces smaller than 0.63 cm × 0.63 cm 

(1/4 in. × 1/4 in.), blockage in the valve appeared to be minimal for the valve clearances 

studied here. 

Based on the results of the screen penetration tests (Ref. 3), 0.63 cm × 0.63 cm (1/4-in. × 

1/4-in.) RMI pieces typically were less likely to penetrate screens with screen openings of 

0.63 cm (1/4 in.)—the data showed that <20% of the RMI pieces of this size penetrated 

the 0.63-cm (1/4-in.) screen for the highest flow velocities tested, as described in Ref. 3. 

A similar result was seen for 0.32-cm (1/8-in.) RMI pieces and a 0.32-cm (1/8-in.) 

screen. When the RMI debris had dimensions smaller than the screen size, a larger 

fraction of RMI penetrated the screen, but the current results show that the smaller-size 

RMI debris was able to clear the throttle valve, as well—at least for the range of valve 

openings tested here. The results for RMI debris alone (without any other debris) 

indicated that the smaller debris, which was more likely to pass through the sump screen, 

was also less likely to get caught in the valve. 

The screen penetration tests showed that a significant fraction of CalSil passed through 

the screen, regardless of the screen opening. The current results show that the same 

occurs in the valve, as well—practically all of the CalSil passed through the valve 

without causing appreciable blockage. 

As much as 80% of blender-processed NUKON debris was found to penetrate the screen, 

as described in Ref. 3. The current results show that K increases of between 7% and 

220% occurred when a stream of blender-processed NUKON reached the valve. For 

cases where an estimate of the corresponding blockage-area fraction was possible, this 

increase translated to between 10% and 45% blockage in the valve opening. Based on 

these results, NUKON is judged to be more likely then RMI or CalSil to cause throttle 

valve blockage. A large fraction of blender-processed NUKON was able to penetrate the 

screen, and a large fraction of this NUKON, in turn, could get trapped in the valve, 

resulting in significant increases in valve pressure loss. Note that this finding was based 

on tests involving a single batch or slug of NUKON. It is possible that the blockage 

effects of NUKON could be magnified in combination with other ingested materials or 

when a steady debris stream of NUKON over time is considered; these effects are 

examined in Section 6. 

The data also showed a high degree of variability in the valve-clogging data for RMI and 

NUKON. This observation was consistent with the inherent randomness involved in the 

process; the propensity for trapping of debris in the valve gap is a function of the random 

orientation of the individual pieces as they enter the valve gap. Further, the bending or 

thrashing of the debris pieces inside the valve is also a random process. 
67 

5 RESULTS OF MIXED-DEBRIS TESTS 

Section 4 focused on the clogging of the throttle valve by separate insulation components 

of the debris stream. This section now addresses the potential for clogging of the valve by 

mixtures of insulation debris. All of the mixed-debris tests were conducted within a 

temperature range of 19°C (66oF) and 27°C (80oF). All of the mixed-debris tests 

(Appendix D, Test Series 2) were taken using single-point sampling rather than five-point 

averaging, as discussed in Section 2.3. 

The debris mixtures tested included the following: 

1. NUKON combined with RMI; 

2. CalSil combined with RMI; 

3. NUKON combined with CalSil; 

4. homogeneous mixtures of CalSil, NUKON, and RMI; and 

5. CalSil, NUKON, and RMI introduced separately in a specific sequence. 

5.1 Mixtures of NUKON and RMI 

A series of tests was performed in which homogeneous mixtures of NUKON and RMI 

were introduced in the flow. The test conditions and results are summarized in Table 5-1. 

One test was repeated; the results are provided in Table 5-2. Blockage-area fraction 

estimates could be made only for the two tests that corresponded with the valve gap 

openings used in the shim blockage measurements. The results are listed in Table 5-3. 

The mixture test data are compared with the single-debris data in Table 5-4 and Figure 

5-1. Data Set 1 in Table 5-4 shows the results for a valve opening of 0.63 cm (0.25 in.) 

and an RMI of size 0.32 cm × 1.27 cm (1/8 in. × 1/2 in.) did not result in any appreciable 

increase in the valve-loss coefficient; however, the addition of 50 g of NUKON showed a 

nearly 13% increase in the loss coefficient. Single-debris tests were not performed with 

NUKON with this valve opening; however, a single-debris NUKON test performed for a 

smaller opening [0.317 cm (0.125 in.)] indicated no appreciable blockage. Based on this 

result, the increase in K for the RMI and NUKON mixture (test N-8_45L) may be 

attributed to the debris combination. Additionally, a total of 17 RMI pieces were 

recovered from the valve after the mixture test, whereas only between 1 and 6 pieces 

were recovered after the single-debris RMI tests. It is possible that some of the NUKON 

trapped in the valve also trapped some RMI pieces, resulting in an increased blockage 

compared to either debris form acting alone. However, given the inherent variability in 

the data discussed previously, additional repeatability tests would be necessary to 

determine if a statistically significant effect exists. Other mixture combinations (Data sets 

2, 3, and 4 in Table 5-4) showed relatively no effect when NUKON and RMI were 

combined. In all of these cases, the valve-loss-coefficients for the individual mixeddebris tests were within the range of variability for the single-debris cases. The number of 

RMI pieces recovered from the valve following the tests also was generally consistent 

with the RMI-only tests. As before, more testing is required to quantify any differences.
68 

Table 5-1. Results of Tests with NUKON-RMI Mixtures 

K

Test ID Stem 

Valve 

Opening 

[cm (in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN 

Before After % 

Change W2 Wf 

N-8_45L 45L 

0.6350 

(0.2500) 10.03 

0.32 × 1.27 

(1/8 × 1/2) 48.25 102 115 13 38.19 20.09 

D-4_45L 45L 

0.3170 

(0.1248) 10.00 

0.32 × 1.27 

(1/8 × 1/2) 50.24 101 152 51 39.87 20.37 

D-7_45L 45L 

0.159 

(0.0626) 5.01 

0.63 × 0.63 

(1/4 × 1/4) 25.14 154 180 17 21.23 8.92 

D-5_5L 5L 

0.127 

(0.0500) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 50.16 168 177 6 28.01 32.15 

Table 5-2. Results of Repeatability Test with NUKON RMI Mixtures 

K

Test ID Stem 

Valve 

Opening 

[cm (in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN 

Before After % 

Change W2 Wf 

D-4_45L 45L 

0.3170 

(0.1248) 10.00 

0.32 × 1.27 

(1/8 × 1/2) 50.24 101 152 51 39.87 20.3

D-4-2_45L 45L 

0.3180 

(0.1252) 10.03 

0.32 × 1.27 

(1/8 × 1/2) 50.00 98.1 132 35 40.21 19.8

Table 5-3. Estimates of Blocked Area Fraction for Tests with NUKON-RMI Mixtu

K

Test ID Stem 

Valve 

Opening 

[cm (in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN 

Before After % 

Change

Blocked A

Fraction (

D-7_45L 45L 0.159 (0.0626) 5.01 

0.63 × 0.63 

(1/4 × 1/4) 25.14 154 180 17 5.3 

D-5_5L 5L 0.127 (0.0500) 10.00 

0.32 × 0.32 

(1/8 × 1/8) 50.16 168 177 6 7.9 
69 

Table 5-4. Comparing NUKON-RMI Mixture Test Data with Baseline Single-Debris Te

Note 1: Valve opening value cited is approximate. Tests in each set did not all have identical valve openings but varied over a small range, typically w

Note 2: Mass cited is approximate. Tests in each set did not all have identical mass but varied over a small range, typically within 0.1 g. 

K

Data 

Set 

Stem 

Valve 

Opening 

[cm 

(in.)]1 W1 

RMI Size 

[cm × cm 

(in. × in.)] WN2 Debris Type 

Test ID Before After 

C

N-4_45L 103 105 

RMI only N-5_45L 99.5 102 

N-6_45L 99.3 101 

1 45L 0.6350 (0.2500) 10.00 0.32 × 1.27 (1/8 × 1/2) 50 

RMI + NUKON N-8_45L 102 115 

45LDT9 88.1 133 

45LDTR9 105 111 

D-1_45L 104 124 

RMI only 

D-1-2_45L 99.0 152 

NUKON only 45LN1 105 106 

2 45L 0.3175 (0.1250) 10.00 0.32 × 1.27 (1/8 × 1/2) 50 

RMI + NUKON D-4_45L 101 152 

45LDT14 124 165 

RMI only D-6_45L 155 194 

NUKON only D-17_45L 154 155 

3 45L 0.159 (0.0626) 5.00 0.63 × 0.63 (1/4 × 1/4) 25 

RMI + NUKON D-7_45L 154 180 

5LDT3 173 192 

RMI only D-3_5L 173 186 

NUKON only D-17_45L 175 198 

4 5L 0.127 (0.0500) 10.00 0.32 × 0.32 (1/8 × 1/8) 50 

RMI + NUKON D-5_45L 168 177 
70 

0

10

20

30

40

50

60

0 0.05 0.1 0.15 0.2 0.25 0.3

Valve Opening (in.)

% Increase in 

K

45L, 10 g RMI

45L, 10 g RMI, 50 g NUKON

45L, 5 g RMI

45L, 5 g RMI, 25 g NUKON

5L, 10 g RMI

5L, 10 g RMI, 50 g NUKON

Figure 5-1. Comparison of RMI-NUKON Mixed Debris to RMI Alone 

5.2 Mixtures of CalSil and RMI 

One test was performed with a mixture of CalSil and RMI (Table 5-5). The test used 50 g 

of CalSil mixed with 5 g of 0.63-cm × 0.63-cm (1/4-in. × 1/4-in.) RMI and a valve 

opening of 0.159 cm (0.0625 in.) in the 45L stem. The single-debris RMI tests showed an 

increase in K of between 25% and 32%. The mixed-debris test showed an increase of 

57%. A single-debris CalSil test was not performed for this valve opening; however, 

corresponding data for the 5S stem exhibited no blockage due to CalSil alone. 

The limited data in this category suggested a possible mixture effect, but additional 

testing would be necessary to establish this more conclusively. 

5.3 Mixtures of NUKON and CalSil 

Two tests were performed with a mixture of NUKON and sieved CalSil (Table 5-6). Both 

used 25 g each of NUKON and CalSil. The single-debris NUKON test and the mixeddebris tests showed no appreciable differences in light of the test to test variability in the 

results. When the mixture tests were repeated using unsieved CalSil mixed with 

NUKON, K increased by 27% to 33% relative to a <5% increase for the NUKON-only 

case. This increase was roughly equivalent to the increase observed earlier for unsieved 

CalSil and was most likely attributed to the unsieved CalSil rather than the mixture 
71 

effect. This increase is illustrated in the test 5sc9 (Figure 4-6), which also used unsieved 

CalSil. 

The transient data measured in one of the unsieved CalSil tests (D-19c_45L) are shown in 

Figure 5-2. Unlike in test 5sc9, K appears to be constant within several seconds after 

inserting debris, and does not degrade with time. 

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K

Figure 5-2. Transient Variation of Pressure Drop and K for Test D-19c_45L 

5.4 Mixtures of RMI, NUKON, and CalSil 

A series of tests was performed with mixtures of all three debris types. Most of the tests 

in this category used homogeneous combinations of the three debris types. A few tests 

were conducted with the debris types introduced sequentially. These two types are 

discussed separately below. 

5.4.1 Homogeneous Combination of RMI, NUKON, and CalSil 

In this series of tests, RMI, NUKON, and CalSil were premixed and introduced into the 

flow as a homogeneous mixture. A total of seven tests were conducted. The results of 

these tests are summarized in Figure 5-3 and Table 5-7. Four of the tests utilized two 

sizes of RMI. For these tests, the number of RMI pieces recovered from the valve 

following the tests is presented separately for each RMI size. Test D-15-2_5L was a 

replicate of test D-15_5L. 
72 

Table 5-5. Comparing CalSil-RMI Mixture Test Data with Baseline Single-Debris Te

K

Data 

Set Stem 

Valve 

Opening 

[cm (in.)]1 

Mass of 

RMI 2

(g) W1 

RMI Size 

(in. × in.) 

Mass of 

CalSil2 

(g) WC Debris Type Test ID Before After % C

45LDT14 124 165 

RMI only D-6_45L 155 194 

1 45L 0.159 (0.0625) 5.00 0.63 × 0.63 (1/4 × 1/4) 50 RMI + CalSil D-8_45L 152 239 

Table 5-6. Comparing NUKON-CalSil Mixture Test Data with Baseline Single-Debris T

K

Data 

Set 

Stem 

Valve 

Opening 

[cm 

(in.)]1 

Mass of 

CalSil2

(g) WC 

Mass of 

NUKON2 (g) 

WN Debris Type Test ID Before After 

NUKON only D-17_45L 154 155 

#8 sieved CalSil + 

NUKON D-18_45L 154 154 

D-19a_45L 154 196 

D-19b_45L 

1 45L 0.159 (0.0625) 25.00 25.00 

Unsieved CalSil + 

NUKON 

D-19c_45L 154 203 

NUKON only 45LN1 105 106 

2 45L 0.3175 (0.1250) 25.00 25.00 #8 sieved CalSil + NUKON D-13_45L 100 102 

Note 1: Valve opening value cited is approximate. Tests in each set did not all have identical valve openings but varied over a small range, typically wNote 2: Mass cited is approximate. Tests in each set did not all have identical mass but varied over a small range, typically within 0.1 g.
73 

Substantial increases in K were observed for all tests, except in test N-9_45L, which had 

a valve opening of 0.63 cm (0.25 in.). The two D-15 replicate tests yielded K increases of 

187% and 68%, indicating the high variability of this data as well. 

5.4.2 Sequential Addition of RMI, NUKON, and CalSil 

In this series of tests, the three types of debris were added in a sequence, rather than as a 

homogeneous composition. The objective was to examine whether the effect of a 

particular debris type would be enhanced by the debris type introduced previously and 

potentially already trapped in the valve. All tests in this category used the 45L stem with 

a valve opening of 0.159 cm (0.0625 in.). 

The results of this series of tests are summarized in Table 5-8. The increase in K ranged 

between 8% and 46%. The test where RMI was introduced first showed greater blockage 

than when NUKON was introduced first. The results of the tests summarized in Table 5-7 

and Table 5-8 are compared with analogous baseline single- and two-component debris 

tests in Table 5-9. When the variability exhibited in replicate tests was considered, there 

are no significant differences between either homogeneous or sequential mixtures of 

RMI, NUKON, and CalSil. 

5.4.3 Estimating Blockage-Area Fractions 

As discussed in Section 3, baseline data for known blockage conditions were obtained for 

the 45L and the 5L valve configurations for valve openings of 0.159 cm (00625 in.) and 

0.13 cm (0.05 in.), respectively. Blockage-area fractions estimated using Eq. (3-2) and 

Eq. (3-3) are listed in Table 5-10. The highest estimated blocked area fraction is ~42%. 

5.5 Discussion 

Tests using CalSil-RMI mixtures were the only combination that exhibited clear 

increases in K when compared with results from analogous single-debris CalSil and RMI 

tests. The results of tests performed using NUKON-RMI or CalSil-NUKON mixtures did 

not differ significantly from results for analogous separate tests, with one possible 

exception. One mixture test performed using unsieved CalSil with NUKON showed an 

appreciable increase in valve blockage compared to single-debris NUKON tests. 

However, it is unclear if this result is attributed to clumping within the unsieved CalSil or 

to retention by NUKON fibers within the valve. 

The three-component mixture tests were divided into two types of tests; homogeneous 

mixtures of RMI, CalSil, and NUKON and sequential additions of each debris type using 

different ordering. Tests using homogeneous mixtures of RMI, CalSil, and NUKON 

showed an increase in valve blockage when compared with analogous single-debris RMI 

tests. However, there was no particular debris introduction sequence that resulted in 

increases in valve blockage compared with results for homogeneous mixtures. Further, in 

the tests where NUKON was introduced first in the debris sequence, the blockage was 

much less than for homogeneous mixtures. The highest estimated blockage-area fraction 

when NUKON was introduced first was 46%—in the same range as the NUKON single-
74 

debris tests. Due to the high degree of variability observed it is difficult to identify trends 

in the data from these tests. 

0

10

20

30

40

50

60

70

80

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

Valve Opening (in.)

% Increase in 

K

45L, 10 g RMI

45L, 10 g RMI, 25 g NUKON, 25 g CalSil

45L, 5 g RMI

45L, 5 g RMI, 25 g NUKON, 25 g CalSil

Figure 5-3. Comparison of RMI-NUKON-CalSil Mixed Debris to RMI Alone 
75 

Table 5-7. Results of Tests with Homogeneous RMI-NUKON-CalSil Mixtures 

K

Test ID Stem 

Valve 

Opening 

[cm (in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN WC Before After ∆K% W2 W

5.02 0.32 × 1.27 (1/8 × 1/2) 

N-9_45L 45L 0.6350 (0.2500) 5.03 0.63 × 0.63 (1/4 × 1/4) 25.17 25.02 101 107 5 28.71 31.5D-9_45L 45L 0.159 (0.0626) 5.01 0.63 × 0.63 (1/4 × 1/4) 25.14 25.16 157 234 50 24.16 31.1

5.01 0.32 × 0.32 (1/8 × 1/8) 

D-11_5L 5L 0.127 (0.0500) 5.00 0.32 × 1.27 (1/8 × 1/2) 25.06 25.12 170 307 81 44.26 15.9

D-12_45L 45L 0.3175 (0.1250) 10.00 0.32 × 1.27 (1/8 × 1/2) 25.15 25.02 102 169 67 27.84 32.3D-14_45L 45L 0.159 (0.0625) 10.02 0.32 × 1.27 (1/8 × 1/2) 25.14 25.00 152 259 70 28.15 32.0

5.03 0.32 × 1.27 (1/8 × 1/2) 

D-15_5L 5L 0.127 (0.0500) 5.01 0.63 × 0.63 (1/4 × 1/4) 25.01 25.02 169 485 187 28.95 31.1

5.00 0.32 × 1.27 (1/8 × 1/2) 

D-15-2_5L 5L 0.127 (0.0500) 5.03 0.63 × 0.63 (1/4 × 1/4) 25.00 25.00 174 293 68 23.33 36.7
76 

Table 5-8. Results of Tests with Sequential Addition of RMI-NUKON-CalSil Mixtu

K

Test ID Stem 

Valve 

Opening 

[cm 

(in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN WC 

Order of 

Debris 

Introduction Before After ∆K% 

D-10_45L 45L 0.159 (0.0626) 5.03 0.63 × 0.63 (1/4 × 1/4) 25.01 25.05 1. RMI 2. NUKON 3. CalSil 154 224 46 

D-10-

2_45L 45L 0.159 (0.0626) 5.05 0.63 × 0.63 (1/4 × 1/4) 25.22 25.54 1. NUKON 2. RMI 3. CalSil 153 165 8 

D-12-

2_45L 45L 0.159 (0.0626) 10.02 0.32 × 1.27 (1/8 × 1/2) 25.00 25.00 1. NUKON 2. RMI 3. CalSil 137 155 13 
77 

Table 5-9. Comparing RMI-NUKON-CalSil Mixture Test Data with Baseline 1- and 2-Component 

K

Data 

Set 

Stem 

Gap1

[cm 

(in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN2 WC2 Debris Type Test ID Before After 

RMI only N-7_45L 104 120 

1 45L 0.6350 (0.2500) 

5 5 

0.32 × 1.27 

(1/8 × 1/2) 

0.63 × 0.63 

(1/4 × 1/4) 

25 25 

RMI + NUKON + CalSil N-9_45L 101 107 

RMI only 45LDT14 124 165 

NUKON only D-17_45L 154 155 

RMI + NUKON D-7_45L 154 180 

RMI + CalSil D-8_45L 152 239 

NUKON + CalSil D-18_45L 154 154 

Mixed together: RMI + 

NUKON + CalSil D-9_45L 157 234 

Sequence: RMI, NUKON, 

CalSil D-10_45L 154 224 

2 45L 0.159 (0.0625) 5 0.63 × 0.63 (1/4 × 1/4) 25 25 

Sequence: NUKON, RMI, 

CalSil 

D-10-

2_45L 153 165 

45LDT9 88.1 133 

45LDTR9 105 111 

D-1_45L 104 124 

RMI only 

D-1-2_45L 99.0 152 

NUKON only 45LN1 105 106 

RMI + NUKON D-4_45L 101 152 

3 45L 0.3175 (0.1250) 10 0.32 × 1.27 (1/8 × 1/2) 25 25 

RMI + NUKON + CalSil D-12_45L 102 169 

45LDT18 127 192 

RMI only D-2_45L 166 200 

Mixed together: RMI + 

NUKON + CalSil D-14_45L 152 259 

4 45L 0.159 (0.0625) 10 0.32 × 1.27 (1/8 × 1/2) 25 25 

Sequence: 

NUKON, RMI, CalSil 

D-12-

2_45L 137 155 

Note 1: Valve opening value cited is approximate. Tests in each set did not all have identical valve openings but varied over a small range, typically wNote 2: Mass cited is approximate. Tests in each set did not all have identical mass but varied over a small range, typically within 0.1 g. 
78 

Table 5-10. Estimates of Blockage-Area Fractions for RMI-NUKON-CalSil Mixtur

K

Test ID Stem 

Valve 

Opening 

[cm (in.)] W1 

RMI Size 

[cm × cm 

(in. × in.)] WN WC 

Order of 

Introduction Before After ∆K% 

D-9_45L 45L 0.159 (0.0626) 5.01 0.63 × 0.63 (1/4 × 1/4) 25.14 25.16 homogenized 157 234 50 

5.01 0.32 × 0.32 (1/8 × 1/8) D-11_5L 5L 0.127 (0.0500) 

5.00 0.32 × 1.27 (1/8 × 1/2) 25.06 25.12 homogenized 170 307 81 

D-14_45L 45L 0.159 (0.0625) 10.02 0.32 × 1.27 (1/8 × 1/2) 25.14 25.00 homogenized 152 259 70 

5.03 0.32 × 1.27 (1/8 × 1/2) D-15_5L 5L 0.127 (0.0500) 

5.01 0.63 × 0.63 (1/4 × 1/4) 25.01 25.02 homogenized 169 485 187 

5.00 0.32 × 1.27 (1/8 × 1/2) D-15-2_5L 5L 0.127 (0.0500) 

5.03 0.63 × 0.63 (1/4 × 1/4) 25.00 25.00 homogenized 174 293 68 

D-10_45L 45L 0.159 (0.0626) 5.03 0.63 × 0.63 (1/4 × 1/4) 25.01 25.03 1. RMI 2. NUKON 3. CalSil 154 224 46 

D-10-2_45L 45L 0.159 (0.0626) 5.05 0.63 × 0.63 (1/4 × 1/4) 25.22 25.54 1. NUKON 2. RMI 3. CalSil 153 165 8 D-12-2_45L 45L 0.159 (0.0626) 10.02 0.32 × 1.27 (1/8 × 1/2) 25.00 25.00 1. NUKON 2. RMI 3. CalSil 137 155 13 
79 

6 ACCUMULATION TESTS 

All of the tests described until now involved the addition of debris either as a single batch 

or, in some tests, as a sequential addition over 5 min. An additional series of tests was 

performed to examine the potential for clogging of the valve as a result of sustained 

addition of debris over a period of 3 h. All tests in this category were done for the 45L 

configuration with a valve opening of 0.159 cm (0.0625 in.) and were taken using singlepoint sampling rather than five-point averaging, as discussed in Section 2.3. 

Tests in this category introduced an additional complication that had to be addressed. As 

described in Section 2.2.3, the fluid temperature difference across the pump was between 

1.1°C (2oF) and 1.7°C (3oF) for the range of flow rates of interest. Sustained operation of 

the loop over 3 h therefore resulted in significant temperature increases in the fluid. For 

the tests of interest, it was desirable to avoid such an upward drift in the temperature. 

Additionally, operation at the high temperatures required evaluation of the potential for 

pump cavitation. For these reasons, temperature control was necessary. Moderate 

temperature variations would not affect either pump operation or the valve performance 

results, so precise temperature control schemes, such as the use of a chiller, were deemed 

unnecessary. The temperature control option chosen for the tests was to drain a fraction 

of the system water periodically and replace it with colder water from the reservoir. Some 

of the debris that passed through the valve was drained, along with the water at each 

drain-and-replace step. The objective of these tests was to assess the potential for valve 

clogging as a result of a series of debris additions and not from recirculation of 

previously introduced debris. The fine-mesh screen installed upstream of the flow meter 

on the pump suction side was used to trap debris from recirculating back to the valve. 

Three accumulation tests were performed and are subsequently described. 

6.1 Test A-1 

In this test, 10 g of RMI, 0.32 cm × 1.27 cm (1/8 in. × 1/2 in.), was introduced into the 

flow at time = 0 (when data acquisition started). Then a mixture of 25 g of NUKON and 

25 g of CalSil was added at time = 2 min and every 15 min thereafter, for a total test 

duration of ~3 h. This series of additions corresponded to 13 successive introductions of 

the NUKON-CalSil mixture, totaling 325 g each of NUKON and CalSil. The transient 

variation of the valve-loss-coefficient K is shown in Figure 6-1. The addition times of the 

NUKON-CalSil mixture are indicated by vertical dashed lines in the figure. 

K increased from approximately 132 to 233 at the end of the 3-h test. Segments of the full 

transient are shown in Figure 6-2 and Figure 6-3. Figure 6-2 shows data for the first 

10 min of the test. K increased ~21% from an initial value of 132 to 160 after the 

introduction of the RMI. The corresponding single-debris test (45LDT18) showed an 

increase of 51%. This difference is consistent with the range of variability of data that has 

been observed in other tests. K can be seen to spike briefly following the first 

introduction of the NUKON-CalSil mixture, presumably as a result of a plug of the 

mixture being slowed down in the valve throat, but K decreases to approximately 155 

shortly thereafter, yet remains within the threshold of discernable K differences (~5%) 
80 

Figure 6-3 shows the data between t = 15 min and t = 50 min. A definite increase in K

can be seen following the introduction of the second batch of the debris mixture. 

However, at about t = 28.3 min, K decreases sharply to the values seen before the 

introduction of the debris mixture. A similar pattern can be seen following the 

introduction of the third batch of the debris mixture. Evidently, plugs of the debris 

mixture were trapped in the valve throat for short periods of time and then were 

dislodged. Not all debris additions showed this behavior. Additions 6, 7, 10, and 11 do 

not show any increase in K while debris insertions 5, 8, and 12 result in K increases that 

do not erode over the course of the test. Overall, the valve-loss-coefficient K increases 

gradually over time as more debris progressively reaches the valve. 

Temperature data were taken at 5-min intervals to verify that the drain-and-replace 

method was controlling the temperature adequately. The data are shown in Figure 6-4. 

The upstream and downstream temperatures were within 1.8°C (3.3oF) for the duration of 

the test, which was more than adequate temperature control for these tests. 

6.2 Test A-2 

All test conditions for test A-2 were identical to those for A-1, except for reducing the 

quantity of the NUKON-CalSil mixture added in the batch. The 10 g of RMI, 0.32 cm × 

1.27 cm (1/8 in. × 1/2 in.), was introduced into the flow at time = 0 (when data 

acquisition started). Then a mixture of 13 g of NUKON and 12 g of CalSil was added at 

time = 2 min and every 15 min thereafter, for a total test duration of ~3 h. This series of 

additions corresponded to 13 successive introductions of the NUKON-CalSil mixture, 

totaling 169 g of NUKON and 156 g of CalSil. The transient variation of K is shown in 

Figure 6-5. The times of addition of the NUKON-CalSil mixture are indicated by vertical 

dashed lines in the figure. 

Figure 6-6 shows the data for the first 10 min of the test. The loss coefficient increased 

from 130 to 260 following RMI addition but then decreased to about 160 within one 

minute. This initial increase is very similar to the increase from the RMI debris in Test A1. The loss coefficient decreased further following the addition of the first batch of debris 

mixture. As seen in Figure 6-5, subsequent additions resulted in only small increases in 

the loss coefficient. The highest value was not more than approximately 160. 

This test was continued for ~1 h following the addition of the last batch of the NUKONCalSil mixture to investigate whether any existing debris in the valve might be eroded by 

the flow. The data showed no evidence of erosion during this time period. 
81 

0

50

100150200250300

0 20 40 60 80 100 120 140 160 180 2

Time (min)

K

RMI introduced at time = 0Dashed blue lines (1-13) indicate times of introduction of 25 g Nukon + 25 g CalSil

12 3 4 5 6 7 8 10 9 11 12 13

Figure 6-1. Transient Variation of K for Debris Accumulation Test A-1 
82 

120

130

140

150

160

170

180

190

200

0 1 2 3 4 5 6 7 8 9 10

Time (min)

K

RMI introduced at time = 0

First batch of 25 g Nukon + 25 g CalSil

Figure 6-2. Transient Data for RMI Addition, Followed by First Addition of 

NUKON-CalSil 

140

150

160

170

180

190

200

15 20 25 30 35 40 45 50

Time (min)

K

2nd addition 

of Nukon+CalSil

3rd addition 

of Nukon+CalSil

4th addition 

of Nukon+CalSil

Figure 6-3. Transient Data for Three Additions of NUKON-CalSil Mixture 
83 

76

77

78

79

80

81

82

83

84

0 20 40 60 80 100 120 140 160 180 200

Time (min)

Water Temperature ( oF)

upstream

dow nstream

Figure 6-4. Temperature Data for Test A-1 

6.3 Test A-3 

In Test A-3, 10 g of RMI, 0.32 cm × 1.27 cm (1/8 in. × 1/2 in.), was introduced into the 

flow at time = 0 (when data acquisition started). Then a mixture of 25 g of NUKON and 

25 g of CalSil was added at time = 3 min. Then 25 g of CalSil was added at time 17 min 

and every 15 min thereafter, for a total test duration of ~3 h. This series of additions 

corresponded to a total addition of 325 g of CalSil. The transient variation of K is shown 

in Figure 6-8. The times of addition of the debris are indicated by vertical dashed lines in 

the figure. 

Figure 6-9 shows the data for the first 20 min of the test. In contrast to Tests A-1 and A2, the loss coefficient shows no appreciable change after the RMI addition but increases 

from 138 to 260 following the addition of the NUKON-CalSil mixture. As seen from 

Figure 6-8, some additions of CalSil result in increases in the loss coefficient, whereas 

some do not. Overall, the highest average loss coefficient during the test was about 310. 

The data indicate the potential for buildup of CalSil over NUKON that was previously 

trapped in the valve. Single-debris tests with CalSil showed no appreciable buildup, but 

this test indicates that the presence of NUKON in the valve may cause some trapping of 

CalSil in the valve. 
84 

100120140160180200220240260280300

0 50 100 150 200 250 

Time (min)

K

RMI introduced at time = 0Dashed blue lines indicate times of introduction of 13 g Nukon + 12 g CalSil

No debris additions beyond 

Figure 6-5. Transient Data for Test A-2 
85 

100

120

140

160

180

200

220

240

260

280

300

0 1 2 3 4 5 6 7 8 9 10

Time (min)

K

RMI introduced at time = 0

First addition of 13 g Nukon + 12 g CalSil

Figure 6-6. Early Transient Data for Test A-2 

75

76

77

78

79

80

81

82

0 50 100 150 200 250

Time (min)

Water Temperature ( oF)

upstream

dow nstream

Figure 6-7. Temperature Data for Test A-2 
86 

As with Test A-2, Test A-3 was continued for ~1 h following the addition of the last 

batch of CalSil to investigate whether any existing debris in the valve might be eroded by 

the flow. In this case, appreciable erosion did occur, resulting in a decrease of the loss 

coefficient to approximately 235, below the K value after the initial NUKON-CalSil 

batch. 

6.4 Discussion 

The objective of the accumulation tests described in this section was to investigate the 

potential for cumulative increase in valve clogging as a result of a sustained stream or 

debris batches reaching the valve. Tests were done for three types of debris types; in each 

case, 10 g of RMI was added at the outset of testing to attempt to initiate blockage; then 

different combinations of NUKON and CalSil debris were introduced at 15-min intervals, 

for a total duration of 3 h. 

The test with batches of 25 g each of NUKON and CalSil showed a sustained increase in 

K over time as more and more debris reached the valve. However, consistent with the 

randomness described in previous sections, the increase in K was not observed following 

all additions of debris—some debris additions did not result in any increase in K, 

suggesting no net increase in valve blockage at that step. 

The test with smaller quantities of NUKON and CalSil introduced at each step (13 g 

each) showed a similar random behavior, except that the net increase over time was 

smaller than with the 25 g additions. This observation was consistent with single-debris 

results, which indicated relatively small blockage effects for lower debris loadings. 

Tests with periodic additions of CalSil alone also showed similar behavior—some debris 

addition events triggered increases in K, whereas others did not. Relative to single-debris 

CalSil tests, larger K increases were observed for some debris addition events, suggesting 

some potential for CalSil to be trapped in the valve by NUKON or RMI that may already 

be present there. When the test was continued for 1 h following the final addition of 

debris, K decreased precipitously at one point, suggesting erosion of the previously 

trapped CalSil debris. 
87 

0

50

100150200250300350400

0 50 100 150 200 2

Time (min)

K

Dashed blue lines indicate times of introduction of 25 g CalSil RMI introduced at time = 0

25 g Nukon + 25 g CalSil at 3 min

Figure 6-8. Transient Data for Test A-3 
88 

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16 18 20

Time (min)

K

25 g CalSil

RMI introduced at time = 0

25 g Nukon + 25 g CalSil at 3 min

Figure 6-9. Early Stage of Test A-3 
89 

7 CONCLUSIONS 

A series of tests was performed using the UNM Civil Engineering test facilities to 

investigate the effects of insulation debris streams composed of RMI, NUKON, and 

CalSil on PWR HPSI throttle valves. The current tests addressed the downstream effects 

of debris types and sizes that may penetrate sump screens. The test data provided 

information on the potential clogging of the throttle valves by unmixed debris and by 

combinations of debris types. 

Baseline tests were performed at the outset of the test program to determine the valveloss coefficient, K, for the valve stem configurations for different valve openings and 

flow rates. Limited tests also were performed with simulated blockage conditions using 

shims to correlate increases in the valve loss coefficient with the blocked area and 

determine the blockage detection threshold of the system. The data indicated that 

blockages on the order of ~5%–8% should be detectable. 

Data from tests with single batches of unmixed debris showed that, in general, higher 

RMI debris loadings and larger debris sizes (relative to the throttle valve opening) 

resulted in higher observed increases in K. In single-debris RMI tests, the highest 

observed increase in K was ~50% (corresponding to a blocked area fraction of ~20%) for 

RMI pieces of 0.63 cm × 0.63 cm (1/4 in. × 1/4 in.) and a valve opening of 0.159 cm 

(0.0625 in.). For RMI pieces smaller than 0.63 cm × 0.63 cm (1/4 in. × 1/4 in.), valve 

blockage appeared to be minimal for the valve clearances studied here. 

Based on the results of the screen penetration tests (Ref. 3), 0.63-cm × 0.63-cm (1/4-in. × 

1/4-in.) RMI pieces typically were less likely to penetrate screens with screen openings of 

0.63 cm (1/4 in.)—the data showed that <20% of the RMI pieces of this size penetrated 

the 0.63-cm (1/4-in.) screen for the highest flow velocities tested, as described in Ref. 3 

(20% may be significant, depending on the total mass of debris loading). A similar result 

was seen for 0.32-cm (1/8-in.) RMI pieces impinging on a 0.32-cm (1/8-in.) screen. 

When the RMI debris had dimensions smaller than the screen size, a larger fraction of 

RMI penetrated the screen; however, the current results show that the smaller-size RMI 

debris was able to clear the throttle valve as well—at least for the range of valve openings 

tested. The results for RMI debris alone (without any other debris) indicated that the 

smaller debris, which was more likely to pass through the sump screen, was also less 

likely to get caught in the valve. 

The screen penetration tests showed that a significant fraction of CalSil passed through 

the screen, regardless of the screen opening. The current results show that the same 

occurred in the valve, as well—when CalSil was the only debris present, practically all of 

the CalSil passed through the valve without causing appreciable blockage. 

As much as 80% of blender-processed NUKON debris was found to penetrate the screen, 

as described in Ref. 3. The current results show that NUKON can cause significant 

clogging in the valve, depending on the combination of stem geometry, gap spacing, and 

NUKON loading used. The increase in K was pronounced in tests with valve gaps of 0.13 

and 0.16 cm (0.05 and 0.063 in.) for NUKON loadings of 50–100 g in the 45L and 5L 
90 

configurations. Larger gaps [0.16 cm (0.063 in.)] or smaller NUKON loadings (25 g) did 

not result in significant clogging. The 5S stem showed essentially no increase in K for 

any quantity of NUKON introduced. The 5L and 45L stems showed substantial increases 

in K, with the 45L stem being somewhat higher than the 5L stem for roughly comparable 

gap sizes. 

The highest K increase observed (220%) occurred when the valve encountered a stream 

of NUKON. This increase translated to ~45% blockage in the valve-opening flow area. A 

large fraction of blender-processed NUKON was able to penetrate the screen, and a large 

fraction of this NUKON, in turn, could get trapped in the valve, resulting in significant 

increases in valve pressure loss. These results indicate that NUKON is more likely than 

RMI or CalSil to cause throttle valve blockage when each debris type is tested separately. 

Tests using CalSil-RMI mixtures were the only combinations that exhibited clear 

increases in K when compared with results from analogous single-debris CalSil and RMI 

tests. The results of tests performed using NUKON-RMI or CalSil-NUKON mixtures did 

not differ significantly from results for analogous separate tests for each debris 

component, with one possible exception. One mixture test performed using unsieved 

CalSil with NUKON showed an appreciable increase in valve blockage compared with 

single-debris NUKON tests. However, it is unclear if this result is attributed to clumping 

within the unsieved CalSil or to retention by NUKON fibers within the valve. 

The three-component mixture tests were divided into two types of tests: (1) homogeneous 

mixtures of RMI, CalSil, and NUKON; and (2) sequential additions of each debris type 

using different ordering. Tests using homogeneous mixtures of RMI, CalSil, and 

NUKON showed an increase in valve blockage when compared with analogous singledebris RMI tests. However, no particular debris introduction sequence resulted in 

increases in valve blockage compared with results for homogeneous mixtures. Further, in 

the tests where NUKON was introduced first in the debris sequence, the blockage was 

much less than for homogeneous mixtures. 

Three accumulation tests were performed to investigate the potential for a cumulative 

increase in valve clogging as a result of multiple debris batches reaching the valve 

sequentially. Tests were done for three types of debris types and loadings using the 45L 

configuration with a valve gap of 0.159 cm (0.0625 in); in each case, 10 g of 0.32 cm × 

1.27 cm (1/8 in. × 1/2 in.) RMI was added at the outset of testing in an attempt to initiate 

blockage. Then different combinations of debris were introduced at 15-min intervals, for 

a total duration of 3 h. 

Test A-1, with batches of 25 g each of NUKON and CalSil, showed a sustained increase 

in K over time as more and more debris reached the valve. However, consistent with the 

randomness observed in other tests, the increase in K was not observed following all 

additions of debris. Some debris additions did not result in any increase in K, suggesting 

no net increase in valve blockage at that step. 

Test A-2, with batches of 13 g each of NUKON and CalSil, showed a similar random 

behavior to Test A-1, except that the net increase over time was smaller. This observation 
91 

was consistent with single-debris results, which indicated smaller blockage effects for 

lower debris loadings. 

Test A-3, the accumulation test with periodic additions of CalSil alone, also showed 

similar behavior. Some debris addition events triggered increases in K, whereas others 

did not. Larger K increases were observed for some debris addition events compared with 

single-debris CalSil tests, suggesting that CalSil may have been trapped by NUKON or 

RMI that was already present in the valve. However, when the test was continued for 1 h 

following the final addition of debris, K decreased precipitously at one point, suggesting 

erosion of the previously trapped debris. 

The results for replicated single-debris, multiple-debris, and accumulation tests exhibit 

significant test-to-test variability. This variability was consistent with the inherent 

randomness involved in the process; the propensity for trapping of debris in the valve gap 

is a function of the random orientation of the individual pieces as they enter the valve 

gap. Further, the bending or thrashing of the debris pieces inside the valve also is a 

random process. 
92 

This page intentionally left blank. 
93 

8 REFERENCES 

1. C. J. Shafer, M. T. Leonard, B. C. Letellier, D. V. Rao, A. K. Maji, K. Howe, A. 

Ghosh, J. Garcia, W. A. Roesch, and J. D. Madrid, “GSI-191: Experimental Studies 

of Loss-of-Coolant-Accident-Generated Debris Accumulation and Head Loss with 

Emphasis on the Effects of Calcium Silicate Insulation,” United States Nuclear 

Regulatory Commission report NUREG/CR-6874 (May 2005), Los Alamos National 

Laboratory report LA-UR-04-1227 (April 2004). 

2. D. V. Rao, B. Letellier, C. Shaffer, S. Ashbaugh, and L. Bartlein, “GSI-191: 

Parametric Evaluations for Pressurized Water Reactor Recirculation Sump 

Performance,” United States Nuclear Regulatory Commission report NUREG/CR6762 (August 2002), Los Alamos National Laboratory report LA-UR-01-4083 

(August 2001). 

3. C. B. Dale, B. C. Letellier, A. K. Maji, K. Howe, and F. Carles, “Screen Penetration 

Test Report,” United States Nuclear Regulatory Commission report NUREG/CR6885 (October 2005), Los Alamos National Laboratory report LA-UR-04-5416 

(initial draft November 2004). 

4. ARES Corporation drawing No. 0391511.17-1-001, Revision A. 

5. Nuclear Energy Institute, “Condition Assessment Guidelines: Debris Sources inside 

PWR Containment,” Nuclear Energy Institute report NEI 02-01, Revision 1 

(September 2002). 

6. B. R. Munson, D. F. Young, and T. H. Okiishi, Fundamentals of Fluid Mechanics,

4th ed. (John Wiley & Sons, Hoboken, New Jersey, November 2001). 

7. Flow of Fluids through Valves, Fittings, and Pipe (CRANE Company Engineering 

Department, King of Prussia, Pennsylvania, Crane Co., 1988). 
94 

This page intentionally left blank. 
95 

APPENDIX A: TEST PROCEDURE 

The procedures used to perform the various types of tests discussed in Sections 3 through 

6 are outlined in this appendix. Figure A-1 shows the valve identification numbers 

referred to in the procedures. 

Figure A-1. Valve Identification Numbers Used in the Procedures 

Following each test, the throttle valve was opened and the debris trapped in the valve was 

recovered (see definition of variable NR in Section 2.6). Typically, the debris pieces were 

recovered from the bottom of the valve body. Debris found in the valve body following 

an RMI test is shown in Figure A-2, and that following a NUKON test is shown in 

Figure A-3. It is difficult to estimate how much of this debris actually was trapped in the 

valve throat during the test and how much was trapped elsewhere in the valve. The 

recovered debris was oven-dried, and the weight was recorded. 

1

2

3

4

To throttle From pump 

valve 
96 

Figure A-2. Debris Found in the Valve Body Following an RMI Single-Debris Test 

Figure A-3. Debris Found in Valve Body Following a NUKON Single-Debris Test 
97 

A.1 Baseline Tests 

1. Close gate valve at drain, close debris insertion port (valve 2 in Figure A-1), and 

open all other valves in debris insertion manifold (valves 1, 3, and 4 in Figure A1). Open globe valves downstream of throttle valve. 

2. Fill flume with water up to 22 in. 

3. Relieve air from the system by opening and closing air relief valve. 

4. Use desired stem. 

5. Set desired opening of the throttle valve. 

6. Set up computer station (via data logger). 

7. Turn system on and wait ~1 min until steady flow is read on the flow meter. 

8. Run desired test for ~3 min. 

a. Read temperatures from thermocouples upstream and downstream of the 

pump. 

b. Verify that pressure gauges and pressure transducers are reading 

approximately the same values. 

c. Verify that the flow meter is reading approximately the same value as the 

data logger. 

9. Turn off the system. 

10. Repeat steps 4 through 9 for different flows and openings for the same stem. 

11. Repeat steps 1 through 10 for different stems (45L, 5L and 5S). 

A.2 Shim Blockage Tests 

1. Close gate valve at drain, close debris insertion port (valve 2 in Figure A-1), and 

open all other valves in debris insertion manifold (valves 1, 3, and 4 in Figure A1). Open globe valves downstream of throttle valve. 

2. Fill flume with water up to 22 in. 

3. Relieve air from the system by opening and closing air relief valve. 

4. Use desired stem. 

5. Set desired opening of the throttle valve. 

6. Set up shim. 

7. Attach shim to the ring using a thin layer of epoxy. 

8. Attach shim to the ring, rather than to the stem, to minimize machining required 

in case of damage during attachment and detachment of the shim. 

9. Clean surface with acetone and soft lens-cleaning tissue after removal of the shim. 

10. If the epoxy cannot be removed, leaving a smooth ring surface, machine and 

rebaseline a new ring before proceeding to debris testing. 

11. Set up computer station (via data logger). 

12. Turn system on and wait ~1 min until steady flow is read on the flow meter. 

13. Run desired test for ~3 min. 

a. Read temperatures from thermocouples upstream and downstream of the 

pump. 

b. Verify that pressure gauges and pressure transducers are reading 

approximately the same values. 
98 

c. Verify that the flow meter is reading approximately the same value as the 

data logger. 

14. Turn off the system. 

15. Repeat steps 6 through 10 for different flows and percent blockage for the same 

stem. 

A.3 Tests with One Batch of Single Debris or Mixed Debris 

1. Close gate valve at drain, close debris insertion port (valve 2 in Figure A-1), and 

open all other valves in debris insertion manifold (valves 1, 3, and 4 in 

Figure A-1). Open globe valves downstream of throttle valve. 

2. Fill flume with water up to 22 in. 

3. Relieve air from the system by opening and closing air relief valve. 

4. Use desired stem (45o

 large stem in this case). 

5. Set opening of the throttle valve. 

6. Set up computer station (via data logger). 

7. Turn system on and wait ~1 min until steady flow is read on the flow meter. 

8. Run desired test for ~6-10 min. 

a. Read temperatures from thermocouples upstream and downstream of the 

pump. 

b. Verify that pressure gauges and pressure transducers are reading 

approximately the same values. 

c. Verify that the flow meter is reading approximately the same value as the 

data logger. 

9. Close valves 1 and 3 (Figure A-1). Open valve 2, and insert the debris. 

10. Close valve 2. Open valves 1 and 3 (Figure A-1). 

11. Turn off the system, and collect debris from the discharge bucket screens. 

12. Repeat steps 8 through 10 for different flows and debris types for the same stem. 

A.4 Accumulation Tests 

1. Close gate valve at drain, close debris insertion port (valve 2 in Figure A-1), and 

open all other valves in debris insertion manifold (valves 1, 3, and 4 in Figure A1). Open globe valves downstream of throttle valve. 

2. Fill flume with water up to 22 in. 

3. Relieve air from the system by opening and closing air relief valve. 

4. Use desired stem (45o

 large stem in this case). 

5. Set opening of the throttle valve. 

6. Set up computer station (via data logger). 

7. Continuously drain water from the flume at a rate of 0.946-1.26 l/s (15-20 gpm). 

8. Run the pump to fill the flume as needed so that a minimum depth of 21 in. and a 

maximum depth of 24 in. are maintained. (The purpose of steps 7 and 8 are to 

regulate temperature.) 

9. Verify that the temperature in the system has reached a near steady-state 

condition. The water exiting the throttle valve is ~10°C hotter than the water 
99 

entering the flume at steady state. The exact difference will depend on the drain 

rate, temperature of the inflow water, pumping rate, and air temperature. 

10. Wait until steady flow is read on the flow meter and steady temperature is 

measured by the thermocouples. 

11. Run desired test for ~180-240 min. 

a. Read temperatures from thermocouples upstream and downstream of the 

pump every 5 min. 

b. Verify that pressure gauges and pressure transducers are reading 

approximately the same values. 

c. Verify that the flow meter is reading approximately the same value as the 

data logger. 

12. Close valves 1 and 3. Open valve 2 and insert the debris (Figure A-1). (Trigger 

data acquisition coincident with the initial insertion of RMI debris.) 

13. Close valve 2. Open valves 1 and 3 (Figure A-1). 

14. Repeat steps 8-13 for each debris type with the pump continuously in operation. 

Periodically collect debris from the discharge bucket screens. 

15. Continue to monitor the flow, pressure, and temperature for 10-60 min after the 

last debris insertion, depending on the test specification. 

16. Turn off the system and collect debris from the discharge bucket screens. 
100 

This page intentionally left blank. 
101 

APPENDIX B: CALIBRATION 

B.1. Flow-Meter Calibration 

The upstream flow meter was calibrated simply by allowing a measured quantity of water 

to flow from a uniform tank while measuring the elapsed time using a stop watch. 

Starting at an initial depth of ~101.6 cm (40 in.) in a 275-gal. cylindrical tank, the water 

level in the tank was allowed to drop by roughly half of the initial depth over a period of 

~2 min. The flow rate was calculated based on the measured change in water level in the 

tank over the measured time period. The depth in the tank was measured to the nearest 

0.158 cm (1/16 in.), and the time was measured to the nearest 0.01 s. The tank had a 

diameter of 1.07 m (42 in.), which resulted in a cross-sectional area of 0.894 m2

(1385.4 in.2

). The calculated values were compared with the corresponding flow-meter 

readings in Figure B-1. All results show <1% difference. 

0

20

40

60

80

100

120

0 20 40 60 80 100 120

Calculated flow rate (gpm)

Flow meter reading (gpm)

Figure B-1. Measured Flow vs Flow-Meter Reading 
102 

B.2 Pressure Device Calibration 

The upstream and downstream pressure transducers and accompanying pressure gauges 

were calibrated by an external vendor.*

 The calibration test determined that both pressure 

transducers had accuracies consistent with the advertised values—within ±0.13% of the 

full range of the transducers [±0.0013 × 3.45 MPa = 4.48 kPa (±0.0013 × 500 psi = 

0.65 psi)]. 

B.3. Temperature Device Calibration 

Two thermocouples were used to measure the temperature during testing. To establish the 

accuracy of the thermocouples, two different calibrations were performed (see Table 

B-1). The first calibration was performed by measuring the water temperature in a 

container. The thermocouples were compared against an American Society for Testing 

and Materials (ASTM) mercury thermometer. All of the results showed <1% difference 

between thermocouples and the reference thermometer. 

Table B-1. Waterbath Thermocouple Calibration 

The second calibration was performed directly in the system. The linear hydraulic flume 

and pipe system were filled with water. An ASTM mercury thermometer was placed in 

the middle of the flume used in this calibration. The calibration was performed with no 

water flowing in the system. After 17 min, the temperature difference between the 

thermometer reading and the each of the thermocouples was <0.5o

C. Table B-2 shows the 

results of this calibration. 

 

*

 Instrument Service Laboratories, 680 Haines Avenue Northwest, Albuquerque, NM 87102. 

0.8 (33.4) 0.8 (33.4) 0.8 (33.4) 0 0

0.8 (33.4) 0.8 (33.4) 0.8 (33.4) 0 0

17.6 (63.7) 17.7 (63.9) 17.7 (63.9) 0.56 0

17.6 (63.7) 17.6 (63.7) 17.7 (63.9) 0.56 0.56

95.9 (204.6) 96 (204.8) 95.9 (204.6) 0 0.10

96 (204.8) 96 (204.8) 95.9 (204.6) 0.10 0.10

Percent 

Difference 

Downstream

Thermocouple 

Upstream [°C 

(°F)]

Thermocouple 

Downstream [°C 

(°F)]

Reference 

Thermometer [°C 

(°F)]

Percent 

Difference 

Upstream
103 

Table B-2. In-Situ Thermocouple Calibration 

15.2 (59.4) 15.5 (59.9) 15.9 (60.6) 4.40 2.52 8:57

15.3 (59.5) 15.5 (59.9) 15.8 (60.4) 3.16 1.90 9:02

15.4 (59.7) 15.6 (60.1) 15.8 (60.4) 2.53 1.27 9:07

15.5 (59.9) 15.7 (60.3) 15.9 (60.6) 2.52 1.26 9:14

Thermocouple 1 

TU [°C (°F)]

Thermocouple 2 

TD [°C (°F)]

Thermometer [°C 

(°F)]

Percent 

Difference 1

Percent 

Difference 2 Time (h)
104 

This page intentionally left blank. 
105 

APPENDIX C: STEPS TAKEN TO MINIMIZE DATA 

FLUCTUATIONS 

C.1 Background 

After completion of some of the early tests, it was observed that the recorded pressure 

readings had fluctuations that were considerably larger than could be attributed to the 

inherent measurement uncertainty of the pressure transducers. The measurements were 

fluctuating at ±13.79 kPa (±2 psi) from a general trend line. The recorded flow rates 

varied by ±0.0126 l/s (±0.2 gpm) from the general trend line at a flow of 4.73 l/s 

(75 gpm). A concern was raised that the level of data fluctuation could obscure important 

physical conditions that needed to be measured with the throttle valve tests. Numerous 

diagnostic studies were done to address this issue. 

C.2 Frequency Analyses 

The raw data from the pressure and flow meters were analyzed using Fast Fourier 

Transforms to determine if the fluctuations had a dominant frequency. The original data 

were acquired at 100-ms intervals (at 10 Hz); therefore, based on the Nyquist criterion, 

the data would not be useful to extract frequencies >5 Hz. To examine whether there was 

an effect due to the alternating current frequency, additional diagnostic tests were 

performed (without debris additions) and data were recorded at frequencies >120 Hz. The 

results of these tests showed that the fluctuations in the data were random. 

C.3 Mechanical Effects 

The unstable measurements could have been caused by mechanical vibration and 

resonance caused by the structural configuration of the apparatus. Testing was performed 

while hammering on pipes and fittings to see if mechanical vibration would affect the 

characteristics of the fluctuations. No differences were found. Concrete block weights 

were hung from the pipes to see if the system mass would change the measurement 

variability. Again, no measurable differences were found. 

C.4 Electrical Effects 

Because mechanical system modifications were unlikely to provide improvements to the 

measurements, the electrical system was a major focus of further evaluation. The 

electrical system evaluations are summarized as follows. 

The entire electrical system was inspected for loose wires, and all mechanical 

connections were checked. No loose connections were found, and retightening the 

connections did not change the measurement variability. It was noted that all gauge 

wiring in the system used shielded wires; thus, the type of wire used was considered 

appropriate for this application. 
106 

The power supply to the National Instruments Field Point Network Module (Model FP1601) was a separate unit provided by National Instruments. An alternate laboratorygrade power supply was substituted temporarily; however, this alternate unit provided 

less-stable results. The power supply provided by National Instruments for the FP-1601 

was used with all testing. 

The original wiring for the pressure transducers did not include a connection to the 

ground terminal that was available with the instrument. The grounding for the 

instrumentation power supplies and the National Instruments Field Point power supply 

used the grounding of a standard three-prong electrical plug. The shield wire for the 

electrical cable to the instruments was not grounded. To modify this condition, a new 

main ground-wire cable was extended from an existing building ground connection. A 

ground wire was run to each of the pressure transducers. The shield wire for each of the 

instrument electrical cables was connected to the building ground wire. The ground port 

to each of the instrument power supplies was connected to the building ground wire. 

Grounding the instruments produced a substantial improvement in the measurement 

fluctuations, with the amplitude reduced to nearly half of the fluctuations in tests 

performed before grounding. 

Some of the low-voltage cable to the instruments was parallel to and within a few feet of 

the three-phase, 208-230/460-V conductor and flexible conduit that supplied power to the 

30-kw (40-hp) continuous-duty motor. A concern was raised that some of the variation in 

data measurements could be due to this condition. The instrument electrical cable was 

replaced temporarily with a much longer cable that could be rerouted away from the 

three-phase, 208-230/460-V conductor. No difference in the measurement variability was 

detected with this alternate location, and the original location for the instrument electrical 

cable was immediately restored. 

The original electrical wiring to the pressure transducers and the flow meters used 

separate power supplies that were not directly connected to the National Instruments 

Field Point Analog Input Module (Model FP-AI-100). The electrical drawings for the FPAI-100 showed that a single power supply connected to the FP-AI-100 module could be 

used to supply power to the all of the instruments and that this arrangement might be 

preferable because of simpler wiring and less power supply equipment. The wiring to the 

instruments was revised to use a single power supply to the FP-AI-100 module; this 

arrangement produced a very small improvement in data measurement variation. 

When a single power supply was connected to the National Instruments Field Point 

Analog Input Module to supply power to the pressure transducers and flow meters, a 

separate power supply was used to supply power to the National Instruments Field Point 

Network Module (Model FP-1601). Tests were performed to determine if a single power 

supply to both instruments would provide improved results. Several different power 

supply units were tested, and it was found that in all cases, a single power supply 

produced greater data variation. Further consideration of a single power supply was 

abandoned. 
107 

If some of the measurement data variation came from the building electrical power 

system, then the use of an alternate source of stable electrical power could provide 

improved measurement. To test this hypothesis, the power supply to the FP-AI-100 was 

replaced with two 12-V wet-cell batteries connected in series. With this arrangement, it 

was found that the data variation was reduced slightly but not eliminated. Although the 

use of wet-cell batteries could be implemented, a concern was raised over the changes in 

instrument calibration with the change in battery voltage during power use. Because the 

benefits of using a wet-cell battery were small, the concern about instrument calibration 

caused this procedure to be abandoned. 

The upstream and downstream pressure transducers provided threaded fittings that 

allowed the use of electrical metal tubing (EMT) conduit; however, EMT was not 

installed originally in the throttle valve apparatus. During the course of the diagnostic 

testing, EMT was installed at the electrical lines to both pressure transducers and to the 

flow transmitter. The EMT was connected to the building ground. The entire electrical 

system was rewired substantially during installation of the EMT. No measurable 

improvement to the data measurement variability was observed with the EMT in place. 

The EMT protected the electrical system wiring while personnel were working around 

the throttle valve; thus, the EMT provided a benefit to test operations. 

Of all the methods tested, the grounding of the instruments was most efficacious in 

reducing the magnitude of the fluctuations in the data. 
108 

This page intentionally left blank. 
109 

APPENDIX D: COMPILATION OF K DATA 

The full first and second test series, summarized in Table 2-1 and Table 2-2 is presented 

in Table D-1, with an additional column listing for ∆K%. The name associated with each 

test was intended as an identifier only and was not generally meant to be descriptive. For 

Test Series 1, the test name begins with 45L, 5L, or 5S for the stem designator. The stem 

designator is followed by the debris designator; DT, DTR, C, or N, which stands for 

RMI, RMI repeated, CalSil, and NUKON. The debris designator is followed by the test 

sequence number, 1, 2, 3, etc. In some cases, the sequence number is followed by a, b, or 

c, designating changes to the debris geometry for otherwise identical test conditions. Test 

Series 2 has no naming convention. 

Table D-1. Summary of K Data 

Test Series 1 

No. Test Stem Gap CalSil NUKON RMI RMI Type ∆K%

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

1 45LDT1 45L 0.3142 (0.1237) 1 0.32 × 0.32 (1/8 × 1/8) 0

2 45LDT2 45L 0.3142 (0.1237) 5 0.32 × 0.32 (1/8 × 1/8) 0

3 45LDT3 45L 0.3142 (0.1237) 10.01 0.32 × 0.32 (1/8 × 1/8) 0

4 45LDT4 45L 0.3142 (0.1237) 1.02 0.63 × 0.63 (1/4 × 1/4) 11.84

5 45LDT5 45L 0.3142 (0.1237) 5 0.63 × 0.63 (1/4 × 1/4) 4.19

6 45LDT6 45L 0.3142 (0.1237) 10.02 0.63 × 0.63 (1/4 × 1/4) 27.56

7 45LDT7 45L 0.3142 (0.1237) 0.99 0.32 × 1.27 (1/8 × 1/2) 0

8 45LDT8 45L 0.3142 (0.1237) 5.03 0.32 × 1.27 (1/8 × 1/2) 0

9 45LDT9 45L 0.3142 (0.1237) 10 0.32 × 1.27 (1/8 × 1/2) 51.03

10 45LDT10 45L 0.166 (0.0654) 1.02 0.32 × 0.32 (1/8 × 1/8) 0

11 45LDT11 45L 0.166 (0.0654) 4.99 0.32 × 0.32 (1/8 × 1/8) 0

12 45LDT12 45L 0.166 (0.0654) 10 0.32 × 0.32 (1/8 × 1/8) 4.95

13 45LDT13 45L 0.166 (0.0654) 1 0.63 × 0.63 (1/4 × 1/4) 11.41

14 45LDT14 45L 0.166 (0.0654) 5 0.63 × 0.63 (1/4 × 1/4) 32.36

15 45LDT15 45L 0.166 (0.0654) 10.01 0.63 × 0.63 (1/4 × 1/4) 53.03

16 45LDT16 45L 0.166 (0.0654) 1.01 0.32 × 1.27 (1/8 × 1/2) 0

17 45LDT17 45L 0.166 (0.0654) 5.02 0.32 × 1.27 (1/8 × 1/2) 4.59

18 45LDT18 45L 0.166 (0.0654) 10 0.32 × 1.27 (1/8 × 1/2) 51.29

19 5LDT1 5L 0.1269 (0.04997) 1.01 0.32 × 0.32 (1/8 × 1/8) 0

20 5LDT2 5L 0.1269 (0.04997) 5.01 0.32 × 0.32 (1/8 × 1/8) 0

21 5LDT3 5L 0.1269 (0.04997) 10.01 0.32 × 0.32 (1/8 × 1/8) 11.18

22 5LDT4 5L 0.1269 (0.04997) 1.01 0.63 × 0.63 (1/4 × 1/4) 7.63

23 5LDT5 5L 0.1269 (0.04997) 5.01 0.63 × 0.63 (1/4 × 1/4) 0

24 5LDT6 5L 0.1269 (0.04997) 10.01 0.63 × 0.63 (1/4 × 1/4) 23.84

25 5LDT7 5L 0.1269 (0.04997) 1.01 0.32 × 1.27 (1/8 × 1/2) 0
110 

Table D-1. Summary of K Data, Test Series 1 (cont) 

No. Test Stem Gap CalSil NUKON RMI RMI Type ∆K%

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

26 5LDT8 5L 0.1269 (0.04997) 5.01 0.32 × 1.27 (1/8 × 1/2) 0

27 5LDT9 5L 0.1269 (0.04997) 10.01 0.32 × 1.27 (1/8 × 1/2) 28.87

28 5SDT1 5S 0.254 (0.0999) 1 0.32 × 0.32 (1/8 × 1/8) 0

29 5SDT2 5S 0.254 (0.0999) 5 0.32 × 0.32 (1/8 × 1/8) 0

30 5SDT3 5S 0.254 (0.0999) 10 0.32 × 0.32 (1/8 × 1/8) 0

31 5SDT4 5S 0.254 (0.0999) 1 0.63 × 0.63 (1/4 × 1/4) 0

32 5SDT5 5S 0.254 (0.0999) 5.01 0.63 × 0.63 (1/4 × 1/4) 0

33 5SDT6 5S 0.254 (0.0999) 10 0.63 × 0.63 (1/4 × 1/4) 0

34 5SDT7 5S 0.254 (0.0999) 1.01 0.32 × 1.27 (1/8 × 1/2) 0

35 5SDT8 5S 0.254 (0.0999) 5.01 0.32 × 1.27 (1/8 × 1/2) 0

36 5SDT9 5S 0.254 (0.0999) 10.01 0.32 × 1.27 (1/8 × 1/2) 0

37 5SDT10 5S 0.161 (0.0632) 1 0.32 × 0.32 (1/8 × 1/8) 0

38 5SDT11 5S 0.161 (0.0632) 5 0.32 × 0.32 (1/8 × 1/8) 0

39 5SDT12 5S 0.161 (0.0632) 10 0.32 × 0.32 (1/8 × 1/8) 0

40 5SDT13 5S 0.161 (0.0632) 1.02 0.63 × 0.63 (1/4 × 1/4) 0

41 5SDT14 5S 0.161 (0.0632) 5 0.63 × 0.63 (1/4 × 1/4) 0

42 5SDT15 5S 0.161 (0.0632) 10.02 0.63 × 0.63 (1/4 × 1/4) 3.84

43 5SDT16 5S 0.161 (0.0632) 1.01 0.32 × 1.27 (1/8 × 1/2) 0

44 5SDT17 5S 0.161 (0.0632) 5 0.32 × 1.27 (1/8 × 1/2) 0

45 5SDT18 5S 0.161 (0.0632) 10 0.32 × 1.27 (1/8 × 1/2) 0

46 45LDTR5-rep 45L 0.3124 (0.1230) 5.01 0.63 × 0.63 (1/4 × 1/4) 24.48

47 45LDTR9-rep 45L 0.3124 (0.1230) 10.05 0.32 × 1.27 (1/8 × 1/2) 5.27

48 45LDTR11-rep 45L 0.156 (0.0615) 5.03 0.32 × 0.32 (1/8 × 1/8) 5.61

49 45LDT×(gap) 45L 0.3269 (0.1287) 5.07 0.32 × 0.32 (1/8 × 1/8) 0

50 5sc1 5S 0.161 (0.0632) 50.04 0

51 5sc2 5S 0.161 (0.0632) 100.04 0

52 5sc3 5S 0.161 (0.0632) 51.01 0

53 5sc4 5S 0.161 (0.0632) 100 3.13

54 5sc5 5S 0.254 (0.0999) 50.06 0

55 5sc6 5S 0.254 (0.0999) 100.04 0

56 5sc7 5S 0.254 (0.0999) 49.98 0

57 5sc8 5S 0.254 (0.0999) 100.08 0

58 5sc9 5S 0.254 (0.0999) 50 g Unsieved 12.0

59 5LC1 5L 0.127 (0.0499) 50.08 0

60 5LC2 5L 0.127 (0.0499) 100.56 0

61 5LC3 5L 0.127 (0.0499) 50.12 0

62 5LC4 5L 0.127 (0.0499) 101.25 12.2

63 5LN1 5L 0.126 (0.0497) 50.07 13.61

64 5SN1 5L 0.254 (0.1000) 50.15 0

65 5SN2 5L 0.159 (0.0627) 50.07 0

66 45LN1 5L 0.3152 (0.1241) 49.92 0

67 45LN2 5L 0.162 (0.0636) 49.85 47.13
111 

Table D-1. Summary of K Data, Test Series 1 (cont) 

No. Test Stem Gap CalSil NUKON RMI RMI Type ∆K%

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

68 5SDT1a 5S 0.158 (0.0622) 10 pieces 0.32 × 0.32 (1/8 × 1/8) 0

69 5SDT1b 5S 0.158 (0.0622) 10 pieces 0.63 × 0.63 (1/4 × 1/4) 0

70 5SDT1c 5S 0.158 (0.0622) 10 pieces 0.32 × 1.27 (1/8 × 1/2) 0

71 5SDT2a 5S 0.2543 (0.1001) 10 pieces 0.32 × 0.32 (1/8 × 1/8) 0

72 5SDT2b 5S 0.2543 (0.1001) 10 pieces 0.63 × 0.63 (1/4 × 1/4) 0

73 5SDT2c 5S 0.2543 (0.1001) 10 pieces 0.32 × 1.27 (1/8 × 1/2) 0

74 5LDT1a 5L 0.127 (0.0499) 10 pieces 0.32 × 0.32 (1/8 × 1/8) 0

75 5LDT1b 5L 0.127 (0.0499) 10 pieces 0.63 × 0.63 (1/4 × 1/4) 3.33

76 5LDT1c 5L 0.127 (0.0499) 10 pieces 0.32 × 1.27 (1/8 × 1/2) 7.30

77 45LDT1a 45L 0.180 (0.0707) 10 pieces 0.32 × 0.32 (1/8 × 1/8) 0

78 45LDT1b 45L 0.180 (0.0707) 10 pieces 0.63 × 0.63 (1/4 × 1/4) 0

79 45LDT1c 45L 0.180 (0.0707) 10 pieces 0.32 × 1.27 (1/8 × 1/2) 0

80 45LDT2a 45L 0.3124 (0.1230) 10 pieces 0.32 × 0.32 (1/8 × 1/8) 0

81 45LDT2b 45L 0.3124 (0.1230) 10 pieces 0.63 × 0.63 (1/4 × 1/4) 0

82 45LDT2c 45L 0.3124 (0.1230) 10 pieces 0.32 × 1.27 (1/8 × 1/2) 0

83 5LN2 5L 0.127 (0.0500) 97.99 186.67

84 5LN3 5L 0.127 (0.0500) 97.47 126.34

85 5SN3 5S 0.159 (0.0627) 95.83 7.4

86 5SN4 5S 0.2543 (0.1001) 98.05 0

87 45LN3 45L 0.160 (0.0629) 95.67 222.19

88 45LN4 45L 0.160 (0.0629) 98.23 201.08

Test Series 2—Single-Debris and Mixed-Debris Tests 

No. Test Stem Gap CalSil NUKON RMI RMI Type ∆K%

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

1 N-1 45L 0.63 (0.25) 10 0.317 × 0.317 (0.125 × 0.125) 0

2 N-2 45L 0.63 (0.25) 10 0.317 × 0.317 (0.125 × 0.125) 0

3 N-3 45L 0.63 (0.25) 10 0.317 × 0.317 (0.125 × 0.125) 0

4 N-4 45L 0.63 (0.25) 10 0.317 × 1.270 (0.125 × 0.500) 0

5 N-5 45L 0.63 (0.25) 10 0.317 × 1.270 (0.125 × 0.500) 0

6 N-6 45L 0.63 (0.25) 10 0.317 × 1.270 (0.125 × 0.500) 0

5 0.317 × 1.270 (0.125 × 0.500)

5 0.63 × 0.63 (0.25 × 0.25)

8 D-1 45L 0.317 (0.125) 10 0.317 × 1.270 (0.125 × 0.500) 18.65

9 D-1-2 45L 0.317 (0.125) 10 0.317 × 1.270 (0.125 × 0.500) 53.67

10 D-2 45L 0.159 (0.0625) 10 0.317 × 1.270 (0.125 × 0.500) 20.19

11 D-3 5L 0.13 (0.05) 10 0.317 × 0.317 (0.125 × 0.125) 7.74

12 D-16 45L 0.159 (0.0625) 50 n/a 136.59

13 D-17 45L 0.159 (0.0625) 25 n/a 0

14 N-1-2 45L 0.33 (0.13) 10 0.317 × 0.317 (0.125 × 0.125) 14.62

15 N-2-2 45L 0.33 (0.13) 10 0.317 × 0.317 (0.125 × 0.125) 10.66

16 N-3-2 45L 0.33 (0.13) 10 0.317 × 0.317 (0.125 × 0.125) 12.14

7 N-7 45L 0.63 (0.25) 14.77
112 

Table D-1. Summary of K Data, Test Series 2 (cont) 

No. Test Stem Gap CalSil NUKON RMI RMI Type ∆K%

[cm (in.)] (g) (g) (g) [cm × cm (in. × in.)]

17 N-4-2 45L 0.33 (0.13) 10 0.317 × 1.270 (0.125 × 0.500) 14.4

18 N-5-2 45L 0.33 (0.13) 10 0.317 × 1.270 (0.125 × 0.500) 28.45

19 N-6-2 45L 0.33 (0.13) 10 0.317 × 1.270 (0.125 × 0.500) 14.01

20 N-8 45L 0.63 (0.25) 50 10 0.317 × 1.270 (0.125 × 0.500) 12.83

21 N-9 45L 0.63 (0.25) 25 25 5 0.317 × 1.270 (0.125 × 0.500) 5.07

22 D-4 45L 0.317 (0.125) 50 10 0.317 × 1.270 (0.125 × 0.500) 51.38

23 D-4-2 45L 0.317 (0.125) 50 10 0.317 × 1.270 (0.125 × 0.500) 35.5

24 D-5 5L 0.13 (0.05) 50 10 0.317 × 0.317 (0.125 × 0.125) 5.54

25 D-6 45L 0.159 (0.0625) 5 0.635 × 0.635 (0.250 × 0.250) 25.21

26 D-7 45L 0.159 (0.0625) 25 5 0.635 × 0.635 (0.250 × 0.250) 17.34

27 D-8 45L 0.159 (0.0625) 50 5 0.635 × 0.635 (0.250 × 0.250) 57.4

28 D-9 45L 0.159 (0.0625) 25 25 5 0.635 × 0.635 (0.250 × 0.250) 49.65

29 D-10 45L 0.159 (0.0625) 25 (3rd) 25 (2nd) 5 (1st) 0.635 × 0.635 (0.250 × 0.250) 45.94

30 D-10-2 45L 0.159 (0.0625) 25 (3rd) 25 (1st) 5 (2nd) 0.635 × 0.635 (0.250 × 0.250) 7.89

5 0.317 × 0.317 (0.125 × 0.125)

5 0.317 × 1.270 (0.125 × 0.500)

32 D-12 45L 0.317 (0.125) 25 25 10 0.317 × 1.270 (0.125 × 0.500) 66.51

33 D-12-2 45L 0.159 (0.0625) 25 (3rd) 25 (1st) 10 (2nd) 0.317 × 1.270 (0.125 × 0.500) 13.03

34 D-13 45L 0.317 (0.125) 25 25 n/a 0

35 D-14 45L 0.159 (0.0625) 25 25 10 0.317 × 1.270 (0.125 × 0.500) 70.05

5 0.317 × 1.270 (0.125 × 0.500)

5 0.63 × 0.63 (0.25 × 0.25)

5 0.317 × 1.270 (0.125 × 0.500)

5 0.63 × 0.63 (0.25 × 0.25)

38 D-18 45L 0.159 (0.0625) 25 25 n/a 0

39 D-19a 45L 0.159 (0.0625) 25 25 n/a 27.5

40 D-19b 45L 0.159 (0.0625) 25 25 n/a 166.2

41 D-19c 45L 0.159 (0.0625) 25 25 n/a 32.36

68.12

186.88

5L 0.13 (0.05) 25 25

36 D-15 5L 0.13 (0.05) 25 25

37 D-15-2

31 D-11 5L 0.13 (0.05) 25 25 80.54
113 

APPENDIX E: COMPILATION OF PLOTS 

Notes: 

1. The order of the figures is the same as that in Table D-1. 

2. In each figure, the blue or lighter curve shows pressure drop and the red or 

darker curve shows K. 

3. In each figure, the vertical line denotes the time of debris addition. 

4. Units for pressure drop are in pounds per square inch (1 psi = 6.89 kPa). 
114 

45LDT1

0

5

10

15

20

25

30

35

40

45

01234567

Time (min)

∆P (psi)

60

70

80

90

100

110

120

130

140

150

K

45LDT2

0

5

10

15

20

25

30

35

40

45

0123456

Time (min)

∆P (psi)

60

70

80

90

100

110

120

130

140

150

K
115 

45LDT3

0

5

10

15

20

25

30

35

40

45

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT4

0

5

10

15

20

25

30

35

40

45

50

0123456

Time (min)

∆P (psi)

60

70

80

90

100

110

120

130

140

150

K
116 

45LDT5

0

10

20

30

40

50

60

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT6

0

5

10

15

20

25

30

35

40

45

50

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
117 

45LDT7

0

10

20

30

40

50

60

70

80

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT8

0

5

10

15

20

25

30

35

40

45

50

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
118 

45LDT9

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT10

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
119 

45LDT11

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT12

0

10

20

30

40

50

60

70

80

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
120 

45LDT13

0

10

20

30

40

50

60

70

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT14

0

10

20

30

40

50

60

70

80

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
121 

45LDT15

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT16

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
122 

45LDT17

0

10

20

30

40

50

60

70

80

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT18

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
123 

5LDT1

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT2

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
124 

5LDT3

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT4

66

68

70

72

74

76

78

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
125 

5LDT5

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT6

0

20

40

60

80

100

120

140

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
126 

5LDT7

66

68

70

72

74

76

78

80

82

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT8

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
127 

5LDT9

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT1

78

79

80

81

82

83

84

85

86

87

0123456

Time

∆P (psi)

0

50

100

150

200

250

300

350

400

K
128 

5SDT2

0

20

40

60

80

100

120

01234567

Time

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT3

0

20

40

60

80

100

120

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
129 

5SDT4

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT5

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
130 

5SDT6

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT7

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
131 

5SDT8

0

20

40

60

80

100

120

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT9

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
132 

5SDT10

116

118

120

122

124

126

128

130

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT11

117

118

119

120

121

122

123

124

125

126

127

128

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
133 

5SDT12

118

119

120

121

122

123

124

125

126

127

128

129

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT13

118

120

122

124

126

128

130

132

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
134 

5SDT14

118

120

122

124

126

128

130

132

134

136

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT15

110

115

120

125

130

135

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
135 

5SDT16

120

121

122

123

124

125

126

127

128

129

130

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT17

110

112

114

116

118

120

122

124

126

128

130

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
136 

5SDT18

0

20

40

60

80

100

120

140

160

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDTR5

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
137 

45LDTR9

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDTR11

0

10

20

30

40

50

60

70

80

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
138 

45LDTX

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5sc1

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
139 

5sc2

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5sc3

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
140 

5sc4

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5sc5

72

74

76

78

80

82

84

86

88

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
141 

5sc6

70

72

74

76

78

80

82

84

86

88

0 1 2 3 4 5 6 7 8 9 10

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5sc7

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
142 

5sc8

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5sc9

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12

Time (min)

∆P (psi) and flow rate (gpm)

0

50

100

150

200

250

300

K

 Delta P (psi) 

Flow rate (gpm)

K factor
143 

5LC1

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LC2

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
144 

5LC3

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LC4

0

10

20

30

40

50

60

70

80

90

100

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
145 

5LN1

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SN1

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
146 

5SN2

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LN1

0

10

20

30

40

50

60

0 2 4 6 8 10 12 14

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

K
147 

45LN2

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT1a

0

20

40

60

80

100

120

140

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
148 

5SDT1b

0

20

40

60

80

100

120

140

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT1c

0

20

40

60

80

100

120

140

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
149 

5SDT2a

0

20

40

60

80

100

120

140

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SDT2b

0

10

20

30

40

50

60

70

80

90

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
150 

5SDT2c

0

10

20

30

40

50

60

70

80

90

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT1a

0

10

20

30

40

50

60

70

80

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
151 

5LDT1b

0

10

20

30

40

50

60

70

80

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5LDT1c

56

58

60

62

64

66

68

70

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

120

130

140

150

160

170

180

K
152 

45LDT1a

20

25

30

35

40

45

50

55

0123456

Time (min)

∆P (psi)

80

90

100

110

120

130

140

150

K

45LDT1b

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
153 

45LDT1c

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT2a

0

5

10

15

20

25

30

35

40

45

50

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
154 

45LDT2b

0

5

10

15

20

25

30

35

40

45

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

45LDT2c

0

5

10

15

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3 3.5 4

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

K
155 

5LN2

0

50

100

150

200

250

01234567

Time (min)

∆P (psi)

0

100

200

300

400

500

600

700

800

K

5LN3

0

20

40

60

80

100

120

140

160

180

200

01234567

Time (min)

∆P (psi)

0

100

200

300

400

500

600

K
156 

5SN3

0

20

40

60

80

100

120

140

160

180

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

5SN4

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K
157 

45LN3

0

20

40

60

80

100

120

140

160

180

200

01234567

Time (min)

∆P (psi)

0

100

200

300

400

500

600

K 

45LN4

0

50

100

150

200

250

012345678

Time (min)

∆P (psi)

0

100

200

300

400

500

600

700

K
158 

N-1_45L

0

10

20

30

40

50

60

70

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

N-2_45L

0

5

10

15

20

25

30

35

40

45

50

0123456

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

160

180

200

K
159 

N-3_45L

0

10

20

30

40

50

60

0123456

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

160

180

200

220

K

N-4_45L

0

10

20

30

40

50

60

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

K
160 

N-5_45L

0

5

10

15

20

25

30

35

40

45

50

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K

N-6_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K
161 

N-7_45L

0

10

20

30

40

50

60

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

K

D-1_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K
162 

D-1-2_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K

D-2_45L

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
163 

D-3_5L

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K

D-16_45L

0

20

40

60

80

100

120

140

160

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

450

K
164 

D-17_45L

0

10

20

30

40

50

60

70

80

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K

N-1-2_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K
165 

N-2-2_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K

N-3-2_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
166 

N-4-2_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K

N-5-2_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K
167 

N-6-2_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

K

N-8_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K
168 

N-9_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-4_45L

0

10

20

30

40

50

60

70

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
169 

D-4-2_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-5_5L

0

10

20

30

40

50

60

70

80

90

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
170 

D-6_45L

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K

D-7_45L

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K
171 

D-8_45L

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K

D-9_45L

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K
172 

D-10_45L

0

10

20

30

40

50

60

70

80

90

100

01234567

 Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-10-2_45L

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
173 

D-11_5L

0

20

40

60

80

100

120

140

160

0123456

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

450

K

D-12_45L

0

10

20

30

40

50

60

70

80

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K
174 

D-12-2_45L

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-13_45L

0

10

20

30

40

50

60

01234567

Time (min)

∆P (psi)

0

20

40

60

80

100

120

140

160

180

200

K
175 

D-14_45L

0

20

40

60

80

100

120

140

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-15_5L

0

20

40

60

80

100

120

140

160

0123456

Time (min)

∆P (psi)

0

100

200

300

400

500

600

K
176 

D-15-2_5L

0

20

40

60

80

100

120

140

160

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-18_45L

0

10

20

30

40

50

60

70

80

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

K
177 

D-19a_45L

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

400

K

D-19b_45L

0

10

20

30

40

50

60

70

80

90

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K
178 

D-19c_45L

0

10

20

30

40

50

60

70

80

90

100

01234567

Time (min)

∆P (psi)

0

50

100

150

200

250

300

350

K