NUREG/CR-6913

 ANL-06/41

Chemical Effects Head-Loss 

Research in Support of

Generic Safety Issue 191

Argonne National Laboratory

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research

Washington, DC 20555-0001
 

 NUREG/CR-6913

 ANL-06/41

Chemical Effects Head-Loss

Research in Support of

Generic Safety Issue 191

Manuscript Completed: October 2006

Date Published: December 2006

Prepared by

J. H. Park, K. Kasza, B. Fisher, J. Oras

K. Natesan and W. J. Shack

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

P.A. Torres, 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 N6100 
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Abstract

This summary report describes studies conducted at Argonne National Laboratory on the potential for

chemical effects on head loss across sump screens. Three different buffering solutions were used for these

tests: trisodium phosphate (TSP), sodium hydroxide, and sodium tetraborate. These pH control agents used

following a LOCA at a nuclear power plant show various degrees of interaction with the insulating materials

Cal-Sil and NUKON. Results for Cal–Sil dissolution tests in TSP solutions, settling rate tests of calcium

phosphate precipitates, and benchmark tests in chemically inactive environments are also presented. The

dissolution tests were intended to identify important environmental variables governing both calcium

dissolution and subsequent calcium phosphate formation over a range of simulated sump pool conditions.

The results from the dissolution testing were used to inform both the head loss and settling test series. The

objective of the head loss tests was to assessthe head loss produced by debris beds created by Cal–Sil,fibrous

debris, and calcium phosphate precipitates. The effects of both the relative arrival time of the precipitates and

insulation debris and the calcium phosphate formation process were specifically evaluated. The debris

loadings, test loop flow rates, and test temperature were chosen to be reasonably representative of those

expected in plants with updated sump screen configurations, although the approach velocity of 0.1 ft/s used

for most of the tests is 3–10 times that expected in plants with large screens . Other variables were selected

with the intent to reasonably bound the head loss variability due to arrival time and calcium phosphate

formation uncertainty. Settling tests were conducted to measure the settling rates of calcium phosphate

precipitates (formed by adding dissolved Ca to boric acid and TSP solutions) in water columns having no bulk

directional flow.

For PWRs where NaOH and sodium tetraborate are used to controlsump pH and fiberglassinsulation is

prevalent, relatively high concentrations of soluble aluminum can be expected. Tests in which the dissolved

aluminum (Al) resulted from aluminum nitrate additions were used to investigate potential chemical effects

that may lead to high head loss. Dissolved Al concentrations of 100 ppm were shown to lead to large pressure

drops for the screen area to sump volume ratio and fiber debris bed studied. No chemical effects on head loss

were observed in sodium tetraborate buffered solutions even for environments with high ratios of submerged

Al area to sump volume. However, in tests with much higher concentrations of dissolved Al than expected in

plants, large pressure drops did occur. Interaction with NUKON/Cal–Sil debris mixtures produced much

lower head losses than observed in corresponding tests with TSP, although tests were not performed over the

full range of Cal–Sil that might be of interest.
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Contents

Abstract........................................................................................................................................................ iii

Foreword...................................................................................................................................................... v

Contents....................................................................................................................................................... vii

Figures ......................................................................................................................................................... ix

Tables........................................................................................................................................................... xiii

Executive Summary.................................................................................................................................... xv

Acknowledgments....................................................................................................................................... xvii

Acronyms and Abbreviations..................................................................................................................... xviii

1 Introduction........................................................................................................................................... 1

2 Head loss tests in ICET–3 environments............................................................................................ 5

2.1 ANL test facility .......................................................................................................................... 5

2.2 Background .................................................................................................................................. 6

2.3 Approach ...................................................................................................................................... 7

2.4 Individual ICET–3 test procedures and results.......................................................................... 10

2.4.1 ICET-3-1 test procedure and results............................................................................... 10

2. 4.2 ICET-3-2 test procedure and results............................................................................... 13

2. 4.3 ICET-3-4 test procedure and results............................................................................... 14

2. 4.4 ICET-3-5 test procedure and results.............................................................................. 16

2. 4.5 ICET-3-6 test procedure and results.............................................................................. 17

2. 4.6 ICET-3-7 test procedure and results.............................................................................. 18

2. 4.7 ICET-3-8 test procedure and results.............................................................................. 20

2. 4.8 ICET-3-9 test procedure and results.............................................................................. 21

2. 4.9 ICET-3-10 test procedure and results............................................................................ 22

2. 4.10ICET-3-11 test procedure and results............................................................................ 23

2.4.11 ICET-3-12 test procedure and results............................................................................ 25

2.4.12 ICET-3-13 test procedure and results............................................................................ 26

2.4.13 ICET–3–14 test procedure and results .......................................................................... 28

2.4.14 ICET-3–15 test procedure and results........................................................................... 28

2.4.15 ICET-3–16-A1 test procedure and results..................................................................... 29

2.4.16 ICET-3–17-A1 test procedure and results..................................................................... 29

2.4.17 ICET-3–18-A1 test procedure and results..................................................................... 30

2.4.18 ICET-3–19-A2 test procedure and results..................................................................... 31

2.5 Discussion of the ICET–3 series test results.............................................................................. 33
viii

2.6 Particle sizes of the chemical products in ICET–3.................................................................... 37

2.7 Calcium phosphate settling tests................................................................................................. 38

2.8 Small–scale dissolution testing................................................................................................... 40

3 Head loss tests in ICET–1 and ICET–5 environments ...................................................................... 45

3.1 Background .................................................................................................................................. 45

3.2 Chemical Surrogates for ICET–1 and ICET–5.......................................................................... 46

3.2.1 Solubility of Aluminum Hydroxides.............................................................................. 46

3.2.2 Aluminum nitrate surrogates........................................................................................... 47

3. 3 Relationship of ICET–1 environments to plant environments ................................................. 50

3.4 Individual ICET–1 test procedures and results.......................................................................... 52

3.4.1 ICET-1-3 test procedure and results.............................................................................. 52

3.4.2 ICET-1-1-B2_100ppm test procedure and results........................................................ 54

3.4.3 ICET-1-2-B2_200ppm test procedure and results........................................................ 55

3.4.4 ICET-1-3-B2_375ppm test procedure and results........................................................ 56

3.4.5 ICET-1-1-B2_100ppm repeat test procedure and results............................................. 57

3.4.6 ICET-1-1-B2_100ppm repeat2 test procedure and results........................................... 59

3.5 Individual test procedures and results for tests with sodium tetraborate buffering (ICET–5

environments) .............................................................................................................................. 60

3.5.1 ICET-5-1-B2_042606 test procedure and results......................................................... 60

3.5.2 ICET-3-STB1-A2 test procedure and results................................................................ 61

3.6 Discussion of the ICET–1 and ICET–5 loop test results .......................................................... 62

4 Benchmark tests.................................................................................................................................... 65

4.1 Background .................................................................................................................................. 65

4.2 Procedures and test matrix .......................................................................................................... 65

4.3 Results of the benchmark tests.................................................................................................... 66

5 Summary ............................................................................................................................................... 75

References ................................................................................................................................................... 77

Appendix A: Chemical compatibility tests on CPVC and LEXAN ........................................................ A1

Appendix B: Cal–Sil leaching tests........................................................................................................... B1

Appendix C: Surrogates for the ICET-1 environment.............................................................................. C1

Appendix-D: Visual Observations of a 375-ppm-Al solution as a function of time and

temperature .......................................................................................................................... D1

Appendix E: NUKON dissolution tests..................................................................................................... E1

Appendix F: Test plan for comparison benchmark testing of PNNL and ANL test loops .................... F1
ix

Figures

1. Schematic of the test loop .................................................................................................................. 5

2. Perforated plate test screen with 51% flow area and 3/16 in. holes with 1/4 in. staggered

centers.................................................................................................................................................. 6

3. Flow rate and pressure drop as a function of time in ICET–3–1..................................................... 11

4. NUKON/Cal–Sil bed before formation of the Ca3(PO4)2 precipitate ........................................... 11

5. Ca3(PO4)2 forming after addition of CaCl2 and approaching the debris bed. ............................. 12

6. Precipitate buildup on the fiber debris bed just after the pump was turned off............................. 12

7. Flow rate and pressure drop as a function of time in ICET–3–2..................................................... 13

8. Flocculent precipitates observed at 0.01 ft/s in ICET–3–2............................................................. 14

9. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-4. ............................................................................................................................................ 15

10. Expanded view of bed approach velocity and differential pressure across the screen during the 

initial 15 minutes of test ICET-3-4.................................................................................................... 15

11. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-5. ............................................................................................................................................ 16

12. Expanded view of bed approach velocity and differential pressure across the screen during the 

initial 10 minutes of tests ICET-3-4 & 5........................................................................................... 17

13. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-6. ............................................................................................................................................ 18

14. Expanded view of bed approach velocity and differential pressure across the screen during the 

initial 45 minutes of tests ICET-3-1, 2 & 6. ..................................................................................... 18

15. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-7. ............................................................................................................................................ 19

16. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-8. ............................................................................................................................................ 20

17. (a) Debris bed from ICET-3-8 after removal from the loop: (b) Debris bed in the loop at the

end of the test with the loop almost drained. .................................................................................... 21

18. Pressure drop across the NUKON bed in test ICET-3-9 at an approach velocity of 0.1 ft/sec..... 22

19. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-9. ............................................................................................................................................ 22
x

20. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-10. .......................................................................................................................................... 23

21. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-11. .......................................................................................................................................... 24

22. Change in pressure drop across the bed as the velocity is cycled from 0.1 ft/s to 0.01 ft/s to

0.14 ft/s and back to 0.1 ft/s............................................................................................................... 24

23. Bed approach velocities and differential pressures across the screen as a function of time for 

tests ICET-3-7 & 11. .......................................................................................................................... 25

24. Bed approach velocities and differential pressures across the screen as a function of time for 

test ICET-3-1, 2, & 11........................................................................................................................ 25

25. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-12. .......................................................................................................................................... 26

26. ICET–3–12 bed after removal from the loop. The smooth appearance is typical of the beds in

the tests................................................................................................................................................ 27

27. Bed approach velocities and differential pressures across the screen as a function of time for 

tests ICET-3-12 and 3–13. ................................................................................................................. 27

28. Bed approach velocities and differential pressures across the screen as a function of time for 

tests ICET-3-11 and 3–14. ................................................................................................................. 28

29. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-15. .......................................................................................................................................... 29

30. Bed approach velocities and differential pressures across the screen as a function of time for 

tests ICET-3-15 and 3–16. ................................................................................................................. 30

31. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-17–A1.................................................................................................................................... 30

32. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-18–A1.................................................................................................................................... 31

33. Plan view of debris bed formed by pure Cal–Sil loading in ICET–3–19–A2. ............................... 32

34. Side view of debris bed formed by pure Cal–Sil loading in ICET–3–19–A2. ............................... 32

35. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-19–A2.................................................................................................................................... 33

36. Bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-19–A2.................................................................................................................................... 33
xi

37. (a) Bed approach velocities and differential pressures across the screen as a function of time

for test ICET-3-6 & 11; (b) Bed approach velocities and differential pressures across the

screen as a function of time for test ICET-3-10 & 11...................................................................... 35

38. Bed approach velocities and differential pressures across the screen as a function of time for 

test ICET-3-8 & 9............................................................................................................................... 36

39. Comparison of the increase of pressure drop in ICET-3-8, which is bounding case for 

complete dissolution of Cal–Sil prior to formation of the debris bed, and ICET-3-10, which

represents the minimum expected dissolution of Cal–Sil prior to bed formation.......................... 36

40. Bed approach velocities and differential pressures across the screen as a function of time for 

test ICET-3-4 & 5............................................................................................................................... 37

41. Schematic dependence of head loss on fiber loading on the screen for a given particulate 

loading................................................................................................................................................. 37

42. Particle size histogram for chemical product from ICET-3 simulation experiment analyzed

with no ultrasound deflocculation. The median particle size was 7.1 μm..................................... 38

43. Particle size histogram for chemical product from ICET-3 simulation experiment analyzed

with no ultrasound deflocculation. The median particle size was 4.7 μm..................................... 38

44. Settling front in test with 300 ppm Cl.............................................................................................. 39

45. Time history of the motion of the settling front in the two 300 ppm dissolved Ca settling tests.. 39

46. Assumed exponential decay of volume of suspended precipitate in 75 ppm dissolved Ca test... 40

47. (a) Dissolution of Cal–Sil at a loading of 1.5 g/l for three different histories of TSP addition;

(b) Dissolution of Cal–Sil at a loading of 0.5 g/l for three different histories of TSP addition. ... 42

48. Normalized dissolution data, dissolved Ca/Ca for full dissolution for loadings of 1.5 g/l and

0.5 g/l for three different histories of TSP addition. ........................................................................ 42

49. Aluminum concentration trend in ICET–1 daily water samples. .................................................... 45

50. Aluminum concentration trend in ICET–5 daily water samples. .................................................... 45

51. Equilibrium solubility of amorphous Al(OH)3 as a function of (a) pH at 25°C and (b) 

temperature at pH =9.6....................................................................................................................... 47

52. Al(NO3)3 100, 200, & 375 ppm surrogates. .................................................................................... 48

53. Particle size histogram for chemical product from an ICET-1 simulation experiment analyzed

with no ultrasound deflocculation.. ................................................................................................... 49

54. Particle size histogram for chemical product from an ICET-1 simulation experiment analyzed

with ultrasound deflocculation.. ........................................................................................................ 49

55. Particle size distribution for an Al(OH)3 surrogate reported in Ref. (10). .................................... 49
xii

56. Estimated sump temperature histories for different types of Westinghouse plants and

containments....................................................................................................................................... 51

57. “Snowfall” as Al(NO3)3 solution was added to the loop. .............................................................. 53

58. "Snow" dissolved in a relatively few minutes. The initiation of cracking in the LEXAN is

also evident. ........................................................................................................................................ 53

59. 375 ppm Al additions resulted in large increases in pressure drop ................................................ 54

60. Pressure and temperature history in test ICET-1-1-B2_100ppm .................................................... 55

61. Pressure and temperature history in test ICET-1-2-B2_200ppm .................................................... 56

62. Pressure and temperature history in test ICET-1-3-B2_375ppm .................................................... 57

63. Pressure and temperature history in test ICET-1-1-B2_100ppm repeat ......................................... 58

64. Pressure and velocity history in test ICET-1-1-B2_100ppm repeat................................................ 59

65. Pressure and velocity history in test ICET-1-1-B2_100ppm repeat2 ............................................. 60

66. Pressure and velocity history in test ICET-5-1-B2_042606............................................................ 61

67. Pressure and velocity history in test ICET-5-1-B2_042606............................................................ 62

68. Viscosities for ultra high purity (UHP) water and solutions with 50–375 ppm dissolved Al

concentrations. .................................................................................................................................... 62

69. Pressure and velocity history in test BM–1–A2–N4.6..................................................................... 66

70. Pressure and velocity history in test BM–1–A2–N4.6_repeat_2 .................................................... 67

71. Pressure and velocity history in test BM–2–A2–N15.5................................................................... 67

72. Pressure and velocity history in test BM–2–A2–N15.5_repeat_2 .................................................. 68

73. Pressure and velocity history in test BM–3–A2–N15.5–C3.1......................................................... 68

74. Pressure and velocity history in test BM–3–A2–N15.5–C3.1......................................................... 69

75. Pressure drop as a function of flow velocity (a) ANL BM–1, (b) replicate test ANL BM–1,

and (c) PNNL BM–1 .......................................................................................................................... 70

76. Pressure drop as a function of flow velocity (a) ANL BM–2, (b) replicate test ANL BM–2,

and (c) PNNL BM–2 .......................................................................................................................... 71

77. Pressure drop as a function of flow velocity (a) ANL BM–3, (b) replicate test ANL BM–3,

and (c) PNNL BM–3 .......................................................................................................................... 72
xiii

Tables

Table 1. Insulation materials and buffering agents used in the ICET tests.......................................... 2

Table 2. Summary of the head loss tests performed at ANL................................................................ 3

Table 3. ICET-3 Environment head loss tests....................................................................................... 9

Table 4. Summary of results for the small–scale dissolution tests at T= 60°C. .................................. 43

Table 5. Summary of results for the small–scale dissolution tests at T= 90°C. .................................. 44

Table 6. Estimated dissolved Al levels for NaOH buffer based on ICET Plant Survey............................. 52

Table 7. ICP-chemical analysis on the supernate solutions from samples taken from loop tests

with 100, 200, and 37 5 ppm Al............................................................................................ 63

Table 8. Benchmark test cases for ANL and PNNL test loops ............................................................ 65

Table 9. Velocity sequence for the ANL and PNNL test loop benchmark cases................................ 66

Table 10. Bed heights in benchmark test ................................................................................................. 73

Table 11. Initial debris load and final weight of the bed ........................................................................ 73
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Executive Summary

The U.S. Nuclear Regulatory Commission (NRC) and the nuclear utility industry undertook a joint

series of tests, the Integrated Chemical Effects Test (ICET) project, that would simulate the chemical

environment present inside the sump after a LOCA. This joint effort was undertaken through a memorandum 

of understanding between the NRC and the Electric Power Research Institute (EPRI). The ICET tests were

conducted by Los Alamos National Laboratory (LANL) at the University of New Mexico (UNM) and

simulate the chemical environment present in the water of the containment sump after a loss-of-coolantaccident (LOCA). The chemical systems were monitored for an extended time to identify the presence,

composition, and physical characteristics of any chemical products that form during the test. Five different

environments were studied in the tests. Large amounts of chemical products were observed to form in the

ICET–1 and ICET-3 tests. In ICET–1 with NaOH for pH control and NUKON fiberglass insulation, the 

product was due to dissolution of aluminum metal and subsequent formation of aluminumoxyhydroxides.. In

ICET–3 with a trisodium phosphate (TSP) buffer and NUKON fiberglass and Cal–Sil insulation, the product

was due to the formation of calcium phosphates due to the reaction of Ca leached from the Cal–Sil insulation .

The ICET–3 environment appeared to have the most potential for significant head loss, because the product

formed very early in the test, corresponding to a time when the need for cooling would be greatest in an

accident situation.

A test loop was constructed at Argonne National Laboratory to study the effects of the chemical

products observed in the ICET tests on head loss. Significant effects on head loss due to chemical products

were observed in environments associated with the Integrated Chemical Effects Test –3 (ICET-3). Significant

chemical effects are also observed in environments with significant dissolved aluminum and NaOH buffers

which correspond to the ICET–1 test.

In ICET–3 environments, the effects are due to the formation of calcium phosphate precipitates. The

head losses associated with pure physical debris beds of NUKON and Cal–Sil are generally much smaller

than those that occur across debris beds in which some of the Cal–Sil has been replaced with a corresponding

amount of calcium phosphate precipitates. For a screen loading corresponding to 0.71 kg/m2 of Cal–Sil and

an ≈ 12 mm thick NUKON bed (0.71 kg/m2), the pressure drop across the physical debris bed in benchmark

testing in chemically inactive environments is approximately 1.4 psi at an approach velocity of 0.1 ft/s. With

TSP, and thus calcium phosphate precipitates present, the same debris loading caused the pressure drop across

the bed to be greater than 5 psi for the same approach velocity. For a thin NUKON bed (≈ 3 mm), very large

pressure drops were observed for the lowest tested Cal–Sil loading, 0.47 kg/m2. However, with thicker

≈ 12 mm NUKON beds, little chemical effect could be observed for Cal–Sil loadings ≤ 0.47 kg/m2. These

results show that the relation between head loss and fiber loading for a given particulate loading is highly

nonlinear and not monotonic.

Beds in which no NUKON was present were also examined. In this case, a significant portion of the 

screen remains open for the highest screen loading of Cal–Sil tested, 1.2 kg/m2. The pressure drops are very

low with this open area.

It can take one to four or more days to reach the equilibrium concentration of calciumresulting fromthe

leaching of Cal-Sil insulation depending on the TSP dissolution rate and the Cal–Sil concentration.

Dissolution of 1.5 g/l Cal–Sil concentrations is retarded if all TSP is dissolved prior to the Cal–Sil addition

(i.e., simulating a plant LOCA with instantaneous TSP dissolution). However, the Cal–Sil dissolution rate 

(for the concentrations studied) is not strongly dependent on the TSP dissolution rate for more realistic TSP

dissolution rates. Even with instantaneous TSP dissolution, the equivalent dissolved Ca will exceed 75 mg/l

in a few hours for Cal–Sil concentrations as low as 0.5 g/l. Such an equivalent dissolved Ca concentration

was shown to produce pressure drops on the order of 5 psi at an approach velocity of 0.1 ft/s across a

0.71 kg/m2 NUKON debris bed.
xvi

In the loop tests, essentially all the calcium phosphate that is formed is transported to the screen.

Settling tests were performed to determine settling ratesfor calcium phosphate under conditions with no bulk

directional flow. At higher dissolved calcium concentrations (300 ppm), the precipitates can agglomerate.

The agglomerated precipitates settle more quickly, but approximately one half of the total precipitate settles

more slowly than the agglomerated precipitate. At a lower dissolved calcium concentration (75 ppm), which

is probably more representative of plant conditions, the estimated settling velocity is 0.8 cm/min.

The chemical products in the ICET–1 environment that can have significant effects on pressure drop are

amorphous aluminum hydroxides. Pressure drops much larger than would be expected from corresponding

debris beds in an inert environment have been observed in environments with NaOH buffer for dissolved Al

levels of 375 and 100 ppm. These high pressure drops can occur with no visible precipitates. They occur in

spite of the very small changes in bulk fluid properties like viscosity for these solutions.

To form the chemical products that can result in large pressure drops across sump screen debris beds,

the dissolved Al concentration (which is controlled by the amount of Al in containment) must exceed the

solubility limit. Literature data suggest that for a temperature of 4°C (40°F) and a pH of 9.2, this is ≈ 30 ppm.

However, because of the complexity of the sump environment, it is difficult to justify the applicability of

literature data to this situation. Current industry guidance recommends that all the dissolved Al be assumed to

form a precipitation product.

Although a dissolved Al level of 100 ppm resulted in large pressure drops, the actual potential for

increased head loss depends not only on this concentration, but also on the loop volume and screen size. For

the ANL loop the volume is 119 liters, and the screen area with the PVC section is 0.016 m2. In the ANL

tests with 100 ppm dissolved Al, it appears that ≈ 50 ppm of the Al has been precipitated out as a product, this

means that there is about 1 kg/m2 of chemical product impinging on the screen and debris bed. With a

NUKON loading of 0.7 kg/m2, this is sufficient to produce a very high pressure drop. With a much larger

ratio of screen area to sump volume or a different NUKON, different results may be obtained.

Subsequent tests with a surrogate precipitate produced externally and then added to the loop suggest

that even much lower loadings of precipitation product (< 0.1 kg/m2) are sufficient to produce high head

losses in debris beds with a NUKON loading of 0.7 kg/m2.

Sodium tetraborate buffers seem more benign than NaOH or TSP. A submerged Al area and sump

volume that results in a 375 ppm dissolved Al concentration in a NaOH environment, results in a 50 ppm 

dissolved Al concentration with a sodium tetraborate buffer. The 375 ppm concentration resulted in high

head loss in 0-2 h with a NaOH buffer; the corresponding 50 ppm concentration produced no significant head

loss observed in ≈ 11 days with a STB buffer. Interaction with NUKON/Cal–Sil debris mixtures produced

much lower head losses than observed in corresponding tests with TSP, although tests were not performed

over the full range of Cal–Sil loadings that might be of interest.
xvii

Acknowledgments

The authors wish to acknowledge D. Engel and R. McDaniel for their assistance in the test program.

They were primarily responsible for the building and operation of the test loop. They also provided valuable

assistance in the design of the test loop and the associated systems and development of the head loss test

procedures.
xviii

Acronyms and Abbreviations

ACRS Advisory Committee for Reactor Safeguards

ANL Argonne National Laboratory

BWR Boiling water reactor

CNWRA Center for Nuclear Waste Regulatory Analyses

CPVC Chlorinated polyvinyl chloride

CSS Containment Spray System

ECCS Emergency core cooling system

EDS Energy Dispersive X-ray Spectroscopy

GSI Generic Safety Issue

ICET Integrated Chemical Effects Test

ICP Inductively Coupled Plasma

LANL Los Alamos National Laboratory

LN Liquid Nitrogen

LOCA Loss of coolant accident

MHO Reciprocal ohms (used as a measure of conductivity

NPSH Net positive suction head

NRC Nuclear Regulatory Commission

PNNL Pacific Northwest National Laboratory

PVC Polyvinyl chloride

PWR Pressurized water reactor

RWST Refueling water storage tank

SEM Scanning Electron Microscope

STB Sodium tetraborate

TEM Transmission Electron Microscopy

TSP Trisodium phosphate

UHP Ultra High Purity

UNM University of New Mexico

Symbols

Al Aluminum

Al

+3 Aluminum Ion

Al(OH)3 Aluminum Hydroxide

Al(OH)4

-

Aluminate Ion

Al(NO3)3 Aluminum Nitrate

Al(NO3)3·9H2O Aluminum Nitrate Nonahydrate

Al2O3 Aluminum Oxide or Alumina

Au Gold

B Boron

B(OH)3 Boric Acid

Ca Calcium
xix

Symbols (continued)

CaCl2 Calcium Chloride

Ca3(PO4)2 Calcium Phosphate

Ca3(PO4)2·H2O Tricalcium Phosphate Hydrated

Ca9HPO4(PO4)5OH Calcium Hydrogen Phosphate Hydroxide

Ca10(PO4)6(OH)2 Hydroxyapatite

Cu Copper

Fe Iron

Fe3O4 Magnetite or Iron Oxide

H+ Hydrogen Ion

H2O Water

H2O2 Hydrogen Peroxide

HCl Hydrochloric Acid

H3BO3 Boric Acid

HNO3 Nitric Acid

K Potassium

LiOH Lithium Hydroxide

Mg Magnesium

Na Sodium

Na+ Sodium Ion

NaOH Sodium Hydroxide

NaAlO2 Sodium Aluminate

Na2SiO3 Sodium Silicate

Na2B4O7 Sodium Tetraborate

Na3PO4 Trisodium Phosphate

NO3

!

Nitrate Ion

OH- Hydroxide

P Phosphorous

PO4

3!

Phosphate Ion

Si Silicon

SiO3

!

Silicate

Zn Zinc
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1

1 Introduction

The emergency core cooling system (ECCS) provides water to cool the core of the nuclear reactor in

case of a loss of coolant accident (LOCA) that would result, for example, from a reactor coolant system pipe

break. The water supplied by the ECCS comes from the refueling water storage tank (RWST) and safety

injection tanks. The water supplied by the ECCS flows through the core and typically spills out the break and

collects in the sump at the bottom of the containment. When the low level limit is reached in the RWST, the

water that has accumulated in the containment sump will be recirculated through the reactor core using the 

ECCS system. This process provides long-term cooling for the core. Recirculation could start as soon as

twenty minutes after the break for a large break LOCA.

The steam-water jet that issues from a break can dislodge thermal insulation and other materials in the

vicinity of the rupture. Some fraction of this dislodged insulation and other materials,such as paint chips and

concrete dust, will be transported to the containment floor by the steam–water flows from the break and the

containment sprays and may accumulate on sump screens intended to prevent debris fromentering the inlet of

the ECCS and containment spray system (CSS) pumps.

This build up of debris will result in an increase in head loss across the sump screens and if the head

loss across the screen becomes too large, the pumps will no longer have adequate net positive suction head

(NPSH), which could result in cavitation and failure of the pumps to deliver the amount of water needed.

The U.S. Nuclear Regulatory Commission (NRC) first published regulatory guidance on the

performance of pressurized-water reactor (PWR) containment sump screens and boiling-waterreactor(BWR) 

suction strainers in 1974 in Regulatory Guide (RG) 1.82, “Water Sources for Long-Term Recirculation

Cooling Following a Loss-of-Coolant Accident.” (BWR suction strainers perform the same function as PWR

containment sump screens.)

In the early 1990s, an event at the Barseback BWR in Sweden and several events at BWRs in the 

United States raised concern about potential blockage of sump screens. In 1996, the NRC asked BWRs to

conduct plant-specific evaluations of their suction strainer performance and, if necessary, modify their plant

design and/or operation.

A Generic Safety Issue (GSI) 191 was established to address the potential for debris accumulation on

PWR sump screens to affect emergency core cooling system (ECCS) pump net positive suction head margin.

On September 13, 2004, NRC issued Generic Letter 2004-02, which required PWR licensees to perform a

mechanistic evaluation of the potential for debris blockage and operation with debris-laden fluids to impede

or prevent the recirculation functions of the ECCS.

Until recently, these evaluations focused on physical debris — insulation, dust, paint chips, etc.

However, the NRC Advisory Committee on Reactor Safeguards (ACRS) raised the possibility that chemical

reactions in the sump could produce additional productsthat would increase the potential for sump blockage.

The U.S. Nuclear Regulatory Commission (NRC) and the nuclear utility industry undertook a joint

series of tests, the Integrated Chemical Effects Test (ICET) project, that would simulate the chemical

environment present inside the sump after a LOCA. This joint effort was undertaken through a memorandum 

of understanding between the NRC and the Electric Power Research Institute (EPRI). The ICET tests were

conducted by Los Alamos National Laboratory (LANL) at the University of New Mexico (UNM) and

simulate the chemical environment present in the water of the containment sump after a loss-of-coolantaccident (LOCA). The chemical systems were monitored for 30 days to identify the presence, composition,

and physical characteristics of any chemical products that formed during the test.

The containment sump environments selected for study were based on input from the Westinghouse

Electric Company, the NRC, and EPRI. The specific conditions, material types, and parameters in the ICET

test series are intended to be broadly representative of all domestic PWRs. The Westinghouse Owners Group
2

and the Babcock & Wilcox Owners Group aided in soliciting information. To obtain the necessary details of

plant-specific conditions within containment (materials present, containment sump conditions, etc.),

Westinghouse reviewed plant-specific documents, (such as Post-LOCA Hydrogen Generation Evaluations),

other available plant documents (e.g., updated final safety analysis reports), and submitted survey questionsto

plant personnel. The plant survey responses formed the primary source of data for determining the

parameters used to define the ICET test conditions.

1

Five types of environments were considered in the ICET tests. They differed in the types of insulating

materials that were present and the choice of pH buffering agent. A summary of the test conditionsis given in

Table 1.

1

Table 1. Insulation materials and buffering agents used in the ICET tests

ICET test Buffering agent pH Insulation

1 NaOH 10 100% fiberglass

2 TSP 

(Na3PO4.12H2O) 7 100% fiberglass

3 TSP 

(Na3PO4.12H2O) 7 80% Cal–Sil / 20% fiberglass

4 NaOH 10 80% Cal–Sil / 20% fiberglass

5

Sodium 

Tetraborate

(Na2B4O7)

8.0–8.5 100% fiberglass

The corrosion/dissolution/precipitation products observed in the tests have been described in a series of

reports.

2–6 In these tests the precipitate products that appear to have the greatest potential for increasing

head–loss are aluminum hydroxides, which were observed in ICET–1 and to a lesser extent in ICET–5, and

calcium phosphates, which were observed in ICET–3. Measurement of the head loss associated with these

chemical products was outside the scope of the ICET program.

The chemical effects head loss test program at Argonne National Laboratory (ANL) was intended to

determine the potential for chemical products observed in ICET program to contribute to head loss. In

addition to measuring head loss under ICET conditions, the tests at ANL examined a broader range of

conditions than examined in ICET. In some cases the tests at ANL used surrogate chemical products in lieu

of an integrated test in which the chemical products were formed by the dissolution and reaction of actual

containment materials. Use of the surrogate forms was justified by comparisons with the chemistry of the 

products formed in the integral tests and other important physical characteristics such as the amorphous

structure of the product. A summary description of the head loss tests run in the program is given in Table 2.

More detailed descriptions of the tests and results are provided in the remainder of the report.
3

Table 2. Summary of the head loss tests performed at ANL

Test Description

Test

section Screen Date

ICET-3-1 NUKON 15 g; Cal–Sil 15 g; 200 ppm Ca A 1 8/26/05

ICET-3-2 NUKON 15 g; Cal–Sil 15 g; 10, 25,

50 ppm Ca

A 1 9/1/05

ICET-1-3 NUKON 15 g; Cal–Sil 15 g;NaOH,

375 ppm Al

A 1 10/7/05

ICET-3-4 NUKON 7 g; Cal–Sil 25 g; TSP A 1 11/15/05

ICET-3-5 NUKON 7 g; Cal–Sil 25 g; NoTSP A 1 11/18/05

ICET-3-6 NUKON 15 g; Cal–Sil 15 g; TSP 1/8, 7/8 A 1 11/29/05

ICET-3-7 NUKON 15 g; Cal–Sil 15 g; No TSP A 1 12/1/05

ICET-3-8 NUKON 15 g; CaCl2 mixed together A 1 12/7/05

ICET-3-9 NUKON 15 g; CaCl2 added after bed

stabilized

A 1 12/9/05

ICET-3-10 NUKON 15 g; Cal–Sil 15 g; TSP:

190g premix/190g loop

A 1 12/13/05

ICET-3-11 NUKON 15 g; Cal–Sil 15 g; No TSP A 1 12/15/05

ICET-3-12 NUKON 15 g; Cal–Sil 5 g; TSP:

190g premix/190g loop

A 1 1/6/06

ICET-3-13 NUKON 15 g; Cal–Sil 5 g; NoTSP A 1 1/11/06

ICET-3-14 NUKON 15 g; Cal–Sil 15 g; NoTSP A 1 1/13/06

ICET-3-15 NUKON 15 g; Cal–Sil 10 g; No TSP A 1 1/17/06

ICET-3-16-A1 NUKON 15 g; Cal–Sil 10 g; TSP:

190g premix/190g loop

A 1 1/19/06

ICET-3-17-A1 NUKON 15 g; Cal–Sil 15 g; TSP:

190g premix/190g loop

A 1 1/25/06

ICET-3-18-A1 NUKON 5 g; Cal–Sil 10 g; TSP:

190g premix/190g loop

A 1 1/31/06

ICET-3-19-A2 Cal–Sil 25 g; TSP: 190g premix/190g

loop

A 2 2/2/06

BM-2-A2-N15.5 NUKON 15.494 g A 2 2/8/06

BM-1-A2-N4.6 NUKON 4.593 g A 2 2/10/06

BM-3-A2-N15.5-C3.1 NUKON 15.5 g; Cal–Sil 3.108 g A 2 2/14/06

BM-2-A2-N15.5 repeat NUKON 15.494 g A 2 2/22/06

BM-1-A2-N4.4 repeat NUKON 4.4 g; invalid test A 2 2/24/06

BM-1-A2-N4.4 repeat2 NUKON 4.4 g A 2 2/28/06

BM-3-A2-N15.5-C3.1

repeat

NUKON 15.5 g; Cal–Sil 3.1 g A 2 3/2/06

ICET-1-1-B2_100ppm NUKON 15.015g; Al Nitrate 164.06 g;

100 ppm Al

B 2 3/9/06

ICET-1-2-B2_200ppm NUKON 11.57g; Al Nitrate 328.12 g;

200 ppm Al

B 2 3/14/06

ICET-1-3-B2_375ppm NUKON 11.57g; Al Nitrate 615 g;

375 ppm Al

B 2 3/16/06
4

Table 2. Summary of the head loss tests performed at ANL (continued)

Test Description

Test

section Screen Date

ICET-1-1-B2_100ppm 

repeat

NUKON 11.5g; Al Nitrate 164 g;

100 ppm Al

B 2 3/23/06

ICET-1-1-B2_100ppm 

repeat2

NUKON 11.5g; Al Nitrate 164 g;

100 ppm Al

B 2 4/13/06

ICET-5-1-B2_042606 NUKON 11.5g; STB 1248g; LiOH

0.247g

B 2 4/26/06

ICET-3-STB1-A2 NUKON 15g; Cal–Sil 15g; STB 1248g;

LiOH 0.287g

A 2 5/16/06

A LEXAN test section

B PVC test section

1 Perforated plate with 51% flow area and 3/16 in. holes with 1/4 in. staggered centers

2 Perforated plate with 40% flow area and 1/8 in. holes with 3/16 in. staggered centers
5

2 Head loss tests in ICET–3 environments

2.1 ANL test facility

A schematic of the ANL test loop is shown in Fig. 1. The piping in most of the loop is CPVC; the clear

test section containing the testscreen was either LEXAN or clear PVC. LEXAN has better high temperature

strength; PVC is more resistant to NaOH solutions. The heater and cooler sections are stainless steel. The

stainless steel pipe in the heater section is wrapped with heater tapes. In the cooler section, the pipe is

surrounded by an outer shell which is filled with cooling water from the building water supply. Temperatures

around the loop during operation are typically ±0.6°C (1°F). Loop velocities can be controlled overthe range

from 0.02 to 2 ft/s. Compatibility tests for the LEXAN and CPVC in the environments of interest are

described in Appendix A.

The inner diameter of the LEXAN section is 6.5 in.; the inner diameter of the PVC section is 5.625

inches. Because of the mounting ring, the test screen has an effective flow diameter of 6 in with the LEXAN

test section and an effective flow diameter of 5.125 in with the PVC test section. The fluid volume in the loop

is 119 liters (4.2 ft3). At 0.1 ft/s, the transit time around the loop is about 4 minutes. The sump screen in

these tests is a flat perforated plate. Two different perforated plates have been used. One has a 51% flow area 

and 3/16 in. holes with 1/4 in.staggered centers; the other has a 40% flow area and 1/8 in. holes with 3/16 in.

staggered centers. A test screen is shown in Fig. 2. Two pairs of pressure taps are installed. One pair is 2.5

in above and below the screen and the other is 12 in. above and below the screen. Differential pressure

transducers measure the differential pressures across these pairs of taps.

In scaling results from the ANL test facility, the mass of chemical product and physical debris per unit

area of screen must be considered. The amount of chemical product produced scales with fluid volume while

the screen area per fluid volume determines the product mass per unit screen area. A 15 g loading of debrisin

the LEXAN section corresponds to a loading of 0.7 kg/m2. To maintain the same loading per unit area in the 

PVC section requires 11.5 g of debris.

Figure 1. Schematic of the test loop
6

Figure 2. Perforated plate test screen with 51% flow area and

3/16 in. holes with 1/4 in. staggered centers.

Physical debris and chemicals are introduced to the loop through a charging port at the top of the loop.

The horizontal configuration of the screen is not intended to reflect, but rather to permit the development of

uniform beds with well–defined characteristics. The head loss behavior for such beds would characterize the

local head loss behavior of more complex nonuniform beds that might form on more complex screen

geometries.

2.2 Background

Initial investigation focused on the chemical precipitate formed from the combination of calcium

silicate and TSP buffer since this precipitate formed very early in ICET 3, during a time when plant pump

NPSH margins are lowest. Once testing was completed in the ICET 3 type environment, subsequent tests

were performed with other buffers (e.g., sodium hydroxide and sodium tetraborate) where precipitation was

observed when test solution was removed from the ICET tank and allowed to cool.

After a LOCA, physical debris will reside in the containment pool for some period of time before the

initiation of emergency core cooling system recirculation. During this time, for plants using TSP for pH

control, the containment pool environment will be changing as the TSP dissolves. After recirculation starts,

debris will begin arriving at the sump screen to form a debris bed. If both NUKON and Cal–Sil debris are

present, the sump screen debris bed will consist ofsome mix of plant debris, including Cal–Sil, NUKON, and

calcium phosphate precipitates. The relative amounts of Cal–Sil and calcium phosphate precipitates in the 

debris bed as it initially forms will vary depending on the residence time in the containment sump prior to the

onset of recirculation, the transport time to the sump screen, the initial containment sump pH, the containment

sump temperature, and the TSP dissolution rate.

For some conditions, e.g., long residence times, a large fraction of the soluble constituents of Cal–Sil

(primarily CaSiO3 with some Na2SiO3) may have dissolved before the debris actually reaches the sump
7

screen. In such cases, the debris bed will primarily contain a mix of NUKON fibers and calcium phosphate

precipitates. In other cases, e.g.,short residence times, little Cal–Sil dissolution may have occurred before the 

debris reaches the sump screen, and the bed that is initially formed will consist predominantly of a mix of

NUKON fibers and Cal–Sil particulates. In this case, with time, the Cal–Sil within the bed can continue to

dissolve, and any dissolved calcium (Ca) that is released will react with the available phosphate to form

additional calcium phosphate precipitates, since the precipitation reaction will be Ca limited, i.e., there is

typically much more phosphate available than is stoichiometrically required for all the Ca to precipitate.

2.3 Approach

Following the initial two teststo evaluate head loss in an ICET 3 environment, ANL performed a series

of follow-up tests (ICET-3-4 to ICET-3-11) that evaluated the potential for head loss due to chemical effects

in a TSP-buffered environment. The tests were designed to explore conditions corresponding to a range of

debris amounts, containment sump residence times, and TSP dissolution times. The two basic physical

parameters that are affected by these variables are the degree of Cal–Sil dissolution that will occur priorto the

formation of the debris bed and the interaction between the chemical products and the physical debris during

bed formation. For instance, some fraction of chemical precipitates and the debris will arrive at the sump

screen together and some fraction of precipitates will form due to Cal–Sil dissolution within the debris bed

after the bed has initially formed.

The NUKON and Cal–Sil mass loading per unit screen area utilized in these tests are reasonably

representative of those plantsthat currently have, or will have after sump screen modifications, relatively low

debris mass loading (i.e., less than 2 kg/m2). Because the Argonne test loop has a fixed ratio of screen area to

fluid volume ratio, it is impossible in most cases to simultaneously match both the debris loading per unit

screen area and the debris loading per unit volume of fluid that would be encountered in an actual sump

configuration. In assessing the head loss, the screen loading per unit area is the critical scaling parameter.

The Cal–Sil dissolution rate, however, can be a function of the debris loading per unit volume. The current

plant estimates of the Cal–Sil loading per unit volume of the containment sump are less than 1.5 g/l,for plants

with both Cal–Sil insulation and TSP buffer. The small–scale dissolution test data presented later in this

report show that the Cal–Sil dissolution rate at these low concentrations is not too strongly dependent on the

concentration. Therefore, it is not too important to match the plant debris loading per unit volume within the 

test loop.

The NUKON fiberglass insulation and the Cal–Sil insulation used in the tests were prepared from

materials obtained from Performance Contracting Inc. (PCI), Lenexa, Kansas. The NUKON was originally

produced in the form of insulating blankets. The blankets were rough shredded to get a collection of loose

fibers and clumps of fibers ranging in size from 1–2 cm in diameter. The shredded fiberglass is then mixed

with water (≈ 1 g/65 ml water) in a blender for a short time (≈10 s) to produce a relatively smooth slurry. The

Cal–Sil was originally produced in the form of molded blocks. The material is friable and was first broken up

by hand–crushing with a mortar and pestle. The crushed material was mixed with water (≈ 1 g/65 ml water)

in a blender for about a minute to produce a smooth slurry. In the present tests, the two slurries were then

mixed together. The preparation of the slurry is done just prior to the performance of the head loss tests.

To simulate the dissolution of the Cal–Sil that occurs during the residence time in the containment

sump prior to the onset of recirculation, the Cal–Sil and NUKON slurry was presoaked at temperature (60oC)

in the baseline boric acid, lithium hydroxide (LiOH) solution for 30 minutes, and then added as a slurry to the

loop. Since only 2.5 liters of solution were used for the presoak, the Cal–Sil concentration is much higher 

than it would be in the loop or in an actual sump. At high Cal–Sil concentrations (≥ 6 g/l), the total amount of

Cal–Sil dissolution is limited by the solubility of calcium silicate (CaSiO3).

7 Regardless of the initial pH or 

the rate of addition of TSP, the pH of solution rises to about 7, primarily because Cal–Sil contains sodium 

silicate (Na2SiO3) as an impurity. The sodium silicate is very soluble, and as it dissolves, the dissolved

sodium (Na) causes the pH of the initial boric acid/LiOH solution to increase. At these high concentrations,
8

the dissolved Ca level rises quickly to a saturation value of ≈200 ppm.7 In highly concentrated solutions,

addition of TSP increases the amount of Cal–Sil that will eventually dissolve, because the phosphate

combines with the dissolved Ca and forms calcium phosphate precipitates, lowering the dissolved Ca level,

and permitting further dissolution of the Cal–Sil. Thus, the highly concentrated presoak slurry is expected to

form lower initial dissolved Ca concentrations than are realistically expected. In contrast, as subsequent

dissolution data presented in this report show, at lower Cal–Sil concentrations, the increase in pH due to the

dissolution of the sodium silicate impurity is much smaller, and rapid addition of TSP can decrease the Cal–

Sil dissolution rate. Thus, because of the increase in pH, the highly concentrated presoak slurry, even with

TSP additions to prevent the dissolved Ca from reaching saturation levels, is expected to have lessleaching of

Ca from the Cal–Sil than would occur under prototypical conditions.

The head loss tests were performed under isothermal conditions at 60°C (140°F). The debris in all the 

tests was introduced into the loop with the flow velocity in the loop at 0.1 ft/s. The intent in these tests wasto

maintain a constant velocity through the test until a stable bed configuration steady-state head loss was

reached and then to cycle the velocity to examine the effect on head loss. In most the tests, the head losses

were too large to maintain a constant flow of 0.1 ft/s. [The maximum head loss that currently can be

maintained in the loop is about 6 psi (≈13.8 ft of water).] Because a flow velocity of 0.1 ft/s is higher than

expected at the sump screen in most planned modified sump configuration, the head loss measurements are

conservative with respect to this variable. However, although the measured head loss is conservative with

respect to velocity, as noted previously, the maximum reported head loss in many cases was a function of the 

test loop capacity.

The test conditions used in this series of tests are summarized in Table 3. The judgments expressed in

the Table 3 comment section that the test conditions represent “minimal”, “maximum”, or “typical” test

values for the amount of Cal–Sil dissolution during the initial debris bed formation is based on the results of

the Cal–Sil dissolution testsreported in the previous Quick Look Report7, the new dissolution tests described

in this report, and expected plant TSP dissolution times.

8

Each head loss test utilized a slightly different procedure for simulating specific chemical product

formation rates and debris arrival sequences depending on the test objective. While the general test

procedures are similar to those described in Ref.(7), the unique procedures associated with each test were

varied to obtain the conditions described in Table 3. Descriptions of the unique procedures associated with

each test are subsequently presented along with a summary of the results.
9

Table 3. ICET-3 Environment head loss tests

Test No.

NUKON

(g)

a Cal–Sil

(g)

30 min

Presoak TSPb

Additional

dissolved

Ca (ppm) Comment

ICET-3-1 15 15 No Initially in loop 200 Simulates initial conditions in ICET3; precipitates arrive after bed forms

ICET-3-2 15 15 No Initially in loop 10, 25,

50 ppm Cad

Parametric test starting with 1/20th

dissolved Ca of ICET-3: precipitates

arrive after bed forms

ICET-3-4 7 25 Yes 1/8th initially in

loop; 7/8th

metered in

None Minimal Cal–Sil dissolution prior to

initial bed formation; continued

dissolution as test continues

ICET-3-5 7 25 Yes None None Baseline physical debris only

ICET-3-6 15 15 Yes 1/8th initially in

loop; 7/8th

metered in

None Minimal Cal–Sil dissolution prior to

initial bed formation

ICET-3-7 15 15 Yes None None Baseline physical debris only

ICET-3-8 15 0 No Initially in loop 43.5c CaCl2 & NUKON added

simultaneously; Maximum Cal–Sil

dissolution prior to bed formation

ICET-3-9 15 0 No Initially in loop 9, 18, 27 ppm

Cad

CaCl2 added after NUKON bed

stabilizes maximizes arrival time of

precipitates to bed; Maximum Cal–

Sil dissolution prior to arrival at the

bed

ICET-3-10 15 15 Yes 1/2 metered

presoak;

1/2 metered

None Intended to represent a “typical”

degree of Cal–Sil dissolution prior

to bed formation

ICET-3-11 Replicates ICET-3-7

ICET-3-12 15 5 1/2 metered

presoak;

1/2 metered

None Lower Cal–Sil loading

ICET-3-13 15 5 Yes None None Baseline for ICET-3-12

ICET-3-14 Replicates ICET-3-7 & 11

ICET-3-15 15 10 Yes None None Baseline physical debris only

ICET-3-16-A1 15 10 Yes 1/2 metered

presoak;

1/2 metered

None Lower Cal–Sil loading

ICET-3-17-A1 Replicates ICET-3-10

ICET-3-18-A1 5 10 Yes 1/2 metered

presoak;

1/2 metered

None Thinner NUKON bed

ICET-3-19-A2 – 25 Yes 1/2 metered

presoak;

1/2 metered

None Cal–Sil/calcium phosphate

precipitate only debris

a1 g of debris corresponds to a screen loading of 47.6 g/m2

bThe total amount of TSP in each test where TSP was added was always 3.4 g/l. Some fraction was either

dissolved initially in the test loop or metered in during the presoak period. The remaining fraction was

metered in during a 30-60 minute period after the debris was added to the loop.

cCa equivalent to full dissolution of 15 g Cal–Sil.

dCa additions added incrementally to sequentially reach values of dissolved Ca listed.
10

2.4 Individual ICET–3 test procedures and results 

2.4.1 ICET-3-1 Test procedure and results

ICET-3-1 test procedure

The initial testsin the Argonne National Laboratory (ANL) chemical effects/head–losstesting program

were intended to investigate the potential head loss associated with the chemical products observed in the

third Integrated Chemical Effects Test (ICET–3).

In the ICET–3 tests, the TSP was added to the Cal–Sil solution through the sprays. In the ANL tests,

the loop is filled with a solution containing boric acid, LiOH, and TSP. The concentration of TSP

corresponds to that metered into the test solution over 4 hours in ICET–3 (about 4 g/l). Calcium chloride

(CaCl2) solution is then added to supply the desired inventory of dissolved Ca. In the first head loss test, the

Ca inventory was taken to be that corresponding to the estimated Ca concentration in the ICET solution at the

start of the TSP spray, which, as discussed previously, has been estimated to be about 200 ppm. As noted

previously, this will result in the formation of an amount of calcium phosphate (Ca3(PO4)2) per volume of

solution comparable to that observed in the initial stages of ICET–3.

The loop was filled with deionized water and heated to 130°F. Boric acid in powder form was slowly

added to the loop and circulated until it was dissolved. The LiOH and TSP were added as solutions. The

concentrations of these chemicals in the loop were also chosen to match those in ICET–3. The test

temperature was lower than that in ICET–3 (140°F), because the test loop was not fully insulated. Because of

the retrograde solubility of Ca3(PO4)2, the lower temperature results in the formation of slightly less

precipitate.

After the chemical solution was prepared, the physical debris bed was built by adding a slurry

containing 15 g NUKON/15 g Cal–Sil to the loop with the loop flow at 0.1 ft/s. This corresponds to a debris

loading of 0.7 kg/m2. The bed was about 3/4 in thick. The NUKON bed formed essentially in the first pass

of the debris past the test screen.

ICET-3-1 test results

The pressure drop across the bed slowly increased as the test loop solution recirculated, presumably due

to increasingly effective filtration of fine Cal–Sil particles. After recirculating for about 45 minutes, the flow

rate was then increased to 0.2 ft/s. At this flow rate, the bed compressed to about 5/8 in thick. The flow rate

was then reduced back to 0.1 ft/s. The pressure drop and flow velocity at each stage of the debris bed

formation is shown in Fig. 3. The physical debris bed at this point in the test is shown in Fig. 4.

The CaCl2 was then added to the vertical part of the test loop just above the clear test section. A total

of 400 ml of CaCl2 solution was added over a 4 minute period (the transit time around the loop at 0.1 ft/s) to

obtain the 200 ppm dissolved Ca inventory. A fine, milky precipitate was observed as shown in Figure 5 just

after the introduction of the CaCl2. The pressure drop across the bed increased from 1.7 psi to greater than

7.0 psi within 10 minutes of introducing the CaCl2. An accurate pressure drop measurement could not be

obtained beyond this point, because the loop was running unpressurized, and the pump started to cavitate as

the precipitate continued to accumulate on the bed. The flow rate and pressure drop as a function oftime after

CaCl2 addition are also shown in Fig. 3. As discussed previously, the 200 ppm Ca inventory is likely not

sufficient to produce the full amount of Ca3(PO4)2 formed during ICET–3. However, no additional Ca was

added to simulate the depletion of all the available phosphate as in ICET–3,since the pressure drop acrossthe

bed had already caused the pump to cavitate. Figure 6 shows the accumulation of the precipitate on the debris

bed just before the pump was shut off.
11

Figure 3. Flow rate and pressure drop as a function of time in ICET–3–1.

Figure 4. NUKON/Cal–Sil bed before formation of the Ca3(PO4)2 precipitate
12

Figure 5.

Ca3(PO4)2 forming after addition of CaCl2 and

approaching the debris bed.

Figure 6.

Precipitate buildup on the fiber debris bed just

after the pump was turned off.
13

2. 4.2 ICET-3-2 test procedure and results

The initial procedure for the second test was similar to the first test. The loop was filled with deionized

water and heated to 130°F. Boric acid in powder form was slowly added to the loop and circulated until it

was dissolved. The LiOH and TSP were added as solutions.

The physical debris bed was again built from 15 g of NUKON and 15 g of Cal–Sil. The bed was built

at 0.1 ft/s and the flow rate was not increased above this value in contrast to the previoustest. The debris bed

was somewhat thinner than the initial debris bed for ICET–3-1 at 0.1 ft/s (5/8 in for ICET–3–2 and 3/4 in for

ICET–3–1). The pressure drop across the bed was also slightly smaller at thisflow rate (0.4 psi in ICET–3–2

and about 0.6 psi for ICET–3–1).

For this test, the CaCl2 additions were made in stepwise fashion starting with an initial addition

equivalent to 10 ppm (one-twentieth of the simulated ICET-3 inventory) of dissolvedCa. Then amounts were

added incrementally corresponding to total dissolved Ca inventories of 25 ppm, and 50 ppm. Each addition

was metered in over a 4 minute period as in the first test.

When CaCl2 equivalent to an inventory of 10 ppm dissolved Ca in the loop volume was added, the

pressure drop at a flow rate of 0.1 ft/s increased from 0.4 psi to 1.4 psi. The Ca3(PO4)2 precipitate was again

visible, but the cloud was much fainter than the previoustest which had a 200 ppm Ca inventory. Additional

CaCl2 was then added to simulate a 25 ppm inventory. The pressure drop increased from 1.4 psi to 6.4 psi

and the pump again started to cavitate, since the test loop was unpressurized. The velocity was then

decreased to 0.01 ft/s at which point the pressure drop decreased to 0.5 psi. A final increment of CaCl2 was

added to simulate a 50 ppm inventory of total dissolved Ca. At a flow rate of 0.01 ft/s, the pressure drop

increased from 0.5 psi to 1.0 psi within 4 minutes. Under continuing operation for another 12 minutes, the

pressure drop increased to 5.2 psi, but the velocity could not be maintained as the suction pressure on the 

pump dropped. The flow rate and pressure drop as a function of time in ICET–3–2 are shown in Fig. 7.

An interesting qualitative difference was noted between the CaCl2 additions at flow rates of 0.1 ft/s and

those at 0.01 ft/s. At 0.1 ft/s, the precipitate was a finely dispersed milky cloud. At 0.01 ft/s, these particles

seemed to agglomerate into light, flocculent assemblies up to perhaps 0.25 in. in diameter as shown in Fig. 8.

These larger assemblies appear similar to the material observed in the ICET–3 tank where velocities are likely

lower than 0.1 ft/s.

Figure 7. Flow rate and pressure drop as a function of time in ICET–3–2.
14

Figure 8.

Flocculent precipitates observed at 0.01 ft/s in

ICET–3–2

2. 4.3 ICET-3-4 test procedure and results

ICET-3-4 test procedure:

The physical debris in ICET-3-4 consisted of 25 g (1.19 kg/m2; 0.2 g/l) of Cal–Sil and 7 g of NUKON

(0.33 kg/m2; 0.06 g/l). The amount of Cal–Sil per unit area of the screen in this test was intended to bound

the values expected after plants have installed their modified screen designs.

8 The Cal–Sil and NUKON were 

heated outside the test loop for 30 minutes at 60°C (140oF) in borated water (2800 ppm B and 0.7 ppm Li) to

simulate the Cal–Sil/NUKON dissolution that occurs in the period between the LOCA and the onset of 

recirculation. Because no TSP was added during the presoak phase, the dissolution testing results for high

concentrations of Cal–Sil (> 6 g/l)7 show the concentration of dissolved Ca in the 2.5 L of presoak solution

will saturate at ≈200 ppm. This gives an effective inventory of dissolved Ca in the loop of ≈ 4 ppm when the

2.5 L of presoak solution is added to the loop, which has a volume of ≈120 L. One eighth of the desired TSP

concentration was premixed in the loop before the addition of the debris to simulate the TSP dissolution that

occurs prior to the start for recirculation. The remaining TSP was to be metered into the loop over an hour to

simulate the dissolution of the remaining TSP after the start of recirculation. Although there is uncertainty in

how long it will take for the TSP to dissolve, even one eighth of the TSP inventory is sufficient, on a 

stoichiometric basis, to convert to calcium phosphates the dissolved Ca level equivalent to full dissolution of 

0.2 g/l of Cal–Sil. Thus, the amount of precipitate that is formed as the debris slurry is added to the loop is

limited by the amount of dissolved Ca available.

This test was intended to be a lower bound (for this Cal–Sil loading) for the amount of calcium

phosphate precipitate arriving at the screen as the initial debris bed is formed. However, additional Cal–Sil

dissolution and calcium phosphate formation was expected to occur after the initial formation of the bed.

Therefore, it was planned that the test would proceed until either all the calcium phosphate had formed (based

on stabilized dissolved phosphorus levels in the loop mixture), or the head loss reached steady state. It was

anticipated that the test could last up to three days.
15

ICET-3-4 test results:

The test started at 7:45 am and terminated at 12:07 pm on November 15, 2005. Figure 2 shows the bed

approach velocity and differential pressure across the screen, as a function of time during the test. Figure 10

shows an expanded view of the velocity and pressure during the first 15 minutes of the test. After the

introduction of the debris, the pressure drop across the bed increased very rapidly to 6.5 psi, before any

additional TSP could be metered into the loop. The pump started to ingest air so the flow velocity was

reduced to 0.03 ft/s. However, after operating for several minutes at that velocity it became apparent that

large amounts of air had accumulated under the test screen and the test was terminated.

Figure 9. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-4.

Figure 10. Expanded view of bed approach velocity and differential pressure across the screen during

the initial 15 minutes of test ICET-3-4.
16

2. 4.4 ICET-3-5 test procedure and results

ICET-3-5 test procedure

The type and amount of physical debris for this test was identical to that for test ICET-3-4. This was a

baseline test to determine the effects of the debris alone with no calcium phosphate precipitates. The Cal–Sil

and NUKON were again heated outside the test loop for 30 minutes at 60° (140oF) in borated water

(2800 ppm B and 0.7 ppm Li), but no TSP was added either to the presoak or to the loop during this test.

ICET-3-5 Results

This test again resulted in high head loss. Figure 11 shows the bed approach velocity and differential

pressure across the screen, as a function of time during the test. After the debris was added to the loop, the

pressure drop increased very rapidly. When the pressure drop across the bed increased to about 3 psi, jetting

through the debris bed was observed at 25 minutes and the test was terminated at 35 minutes. It is not clear

whether the difference in the peak values of ∆p attained between this test (3 psi) and ICET-3-4 (6 psi)reflects

simple scatter in when jetting can occur or whether the presence of the chemical product helps prevent jetting

by more effectively plugging weak spots in the bed. Figure 12 shows an expanded view of the velocity and

pressure during the first 10 minutes of tests ICET-3-4 & 5. Head loss for the debris loading in these tests was

substantial and occurred within the first six minutes (or after approximately one test loop recirculation) after

introducing debris. Other than the maximum pressure reached during the test, the presence of calcium

phosphate did not clearly alter the observed accumulation of head loss during these tests.

Figure 11. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-5.
17

Figure 12. Expanded view of bed approach velocity and differential pressure across the screen during

the initial 10 minutes of tests ICET-3-4 & 5.

2. 4.5 ICET-3-6 test procedure and results

ICET-3-6 test procedure

Due to the high head losses observed with the debris bed loading used in the previous tests, the debris

loading in ICET-3-6 was changed to 15 g of Cal–Sil and 15 g of NUKON. The intent of this test was

identical to that of test ICET-3-4, i.e., to minimize the amount of initial calcium phosphate precipitate arriving

at the screen as the debris bed is formed for a given Cal–Sil loading. The motivation for decreasing the

loading was to attempt to more clearly understand the head loss contribution that could be attributed to

calcium phosphate formation. This debris loading had been previously used in ICET-3-1 & 2 and exhibited

only modest increases in head loss in the portions of those tests in which chemical effects were absent. The

15 g Cal–Sil loading (0.13 g/l) is also representative for some plants containing TSP and Cal–Sil.

8

ICET-3-6 test results

Figure 13 shows the bed approach velocity and differential pressure across the screen, as a function of

time during the test. Figure 14 compares the head lossin thistest during the first 45 minutes after introducing

NUKON and Cal–Sil to the test loop with the earlier ICET 3-1 & 2 tests. Tests ICET-3-1 & 2 had similar

amounts of debris loading as ICET-3-6, although the NUKON and Cal–Sil in ICET-3-6 came from different

batches of materials. Additionally, the debris materials were not presoaked in ICET-3-1 & 2 to create an

initial dissolved Ca inventory, thusless calcium phosphate would be expected initially in tests ICET-3-1 &2.

However, the initial amount of dissolved Ca in ICET-3-6 is minimized because no TSP was added during the

30 minute presoak. It is therefore not surprising that the difference in head loss between test ICET-3-6 and

tests ICET-1 & 2 within the first 30 minutes is not too large. However, compared with ICET-1 & 2, the head

loss in ICET-3-6 continues to increase as the test proceeds, more Cal–Sil dissolves, and more calcium

phosphate is subsequently formed.
18

Figure 13. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-6.

Figure 14. Expanded view of bed approach velocity and differential pressure across the screen during

the initial 45 minutes of tests ICET-3-1, 2 & 6.

2. 4.6 ICET-3-7 test procedure and results

ICET-3-7 test procedure:

Test ICET-3-7 was a baseline test with a debris loading of 15 g of Cal–Sil and 15 g of NUKON and no

TSP in the loop or in the presoak at any time. Therefore, no calcium phosphate precipitate is present to

contribute to head loss. The Cal–Sil and NUKON were again heated outside the test loop for 30 minutes at

60°C (140°) in borated water (2800 ppm B and 0.7 ppm Li) and then added to the loop.
19

ICET-3-7 test results:

Figure 15 shows the bed approach velocity and differential pressure across the screen, as a function of

time during the test. The pressure drop across the bed increased rapidly (within 25 minutes) to about 2.8 psi

and then stabilized. It was suspected that, at this point, the bed had perforated and jetting was occurring even

though the bed appeared smooth and uniform. However, a considerable layer of air had developed

underneath the bed and this precluded the actual identification of any jet. To determine if jetting was

occurring, the inlet tee, which is normally left open, was filled to the top with about one liter of demineralized

water and sealed with a closure flange. The loop was then pressurized to 13 psi using demineralized water 46

minutes after the debris was added. Under pressure, the air layer under the bed was greatly reduced and it

became possible to confirm that jetting was occurring and to identify jet locationsin the bed, although the bed

still exhibited no observable defects.

The pressure drop across the debris bed increased very rapidly compared to the corresponding pressure

drops observed in ICET-3-1, 2, & 6 which had similar debris loadings. Because no TSP was introduced at

any time during the test, no calcium phosphate precipitates were expected to form. Chemical analysis of grab

samples taken periodically through the test confirmed that P levels were very low, as expected. Because the

magnitude and rapidity of the pressure drop increase in this test are much greater than observed in both earlier

tests with similar debris loading and in subsequent replicate tests under the same nominal conditions, the 

results of this test are believed to be anomalous. Two replicate tests (ICET–1-11 and 14) were performed to

substantiate this conclusion.

During this test,some release of noncondensible gases was observed as the pressure drop acrossthe bed

increased to about 1.4 psi. This led to a re-evaluation of the procedure for deaerating the loop. In thistest and

in previous tests, the loop had been deaerated on the day prior to the test day by heating the water to 71°C

(160°F) and circulating the test loop fluid at fairly high speeds (2 ft/s) for several hours. The loop was then

allowed to cool overnight. This procedure had been chosen to avoid running the pump overnight unattended.

However, as the test loop fluid cooled, additional gases were re-entrained in the fluid and thus, were available

to be released at relatively low pressures. Exploratory tests had shown that heating of the water induced

sufficient natural circulation to maintain a uniform temperature in the loop without the pump. The deaeration

procedure for subsequent tests was modified to never let the loop cool down after the initial heat–up in order

to minimize the noncondensible gases in the fluid. Natural circulation was used to maintain a uniform

temperature without the need to run the pump unattended overnight.

Figure 15. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-7.
20

2. 4.7 ICET-3-8 test procedure and results

ICET-3-8 test procedure:

ICET-3-8 was intended to represent the limiting case when the Ca is almost completely leached from

the Cal–Sil debris prior to the formation of the debris bed. In this test, the boric acid, lithium hydroxide and

all of the TSP were added to the loop water and heated to 60°C prior to adding the physical debris. The

physical debris consisted of 15 g NUKON which has been presoaked for 1⁄2 hour at 60°C. The NUKON slurry

was then combined with 14.3 g of CaCl2, which gives an amount of dissolved Ca level equivalent to complete

stoichiometric dissolution of 15 g Cal–Sil. The NUKON/CaCl2 mixture (about 2.5 L) was then added to the

loop. The addition was done in about 30 seconds. Because the reaction of the dissolved Ca with the 

phosphate is very rapid, the test screen debris bed was formed with a simultaneous mix of NUKON and

calcium phosphate precipitates.

ICET-3-8 test results:

Figure 16 shows the bed approach velocity and differential pressure across the screen as a function of

time. After adding the NUKON and CaCl2 mixture, the pressure drop across the bed increased very rapidly

and it was not possible to maintain the loop flow velocity at 0.1 ft/s through the pump. After ≈8 minutes, the

flow rate was decreased to 0.03 ft/s, and the pressure drop stabilized at ≈5 psi. The debris bed appeared to be

uniform with a thickness between 8 – 10 mm early in the test before the pressure drop got too large. The bed

compressed to a thickness of approximately 6 mm at the end of the test. The loop water quickly cleared

indicating rapid debris bed filtration. No jetting through the bed was observed.

Figure 17 shows the photographs of the debris bed from this test after removal from the loop and at the 

end of the test with the loop almost drained. The debris bed height (see Figure 17b) has increased slightly

compared with thickness at the end of the test. Additionally, the debris bed is comprised oftwo distinct layers

(Figure 17b). The bottom layer is mixed NUKON and calcium phosphate precipitate while the top layer is

predominantly calcium phosphate precipitate.

Figure 16. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-8.
21

(a) (b)

Figure 17. (a) Debris bed from ICET-3-8 after removal from the loop: (b) Debris bed in the loop at the

end of the test with the loop almost drained. The bed has two distinct layers. (Readers of the

electronic version may wish to zoom to 500% to see the layers more distinctly.)

2. 4.8 ICET-3-9 test procedure and results

ICET-3-9 test procedure:

ICET-3-9 was intended to evaluate the head loss from chemical phosphate precipitate arriving at the

test screen after the NUKON bed had formed. This test objective and procedure is similar to previous ICET3-1 & 2 tests. The physical debris bed consisted of 15 g of NUKON and was formed before the addition of 

any CaCl2, i.e., before the formation of any calcium phosphate precipitate. The loop initially contained a base

solution with 2800 ppm B, 0.7 ppm Li, and TSP (3.4 g/l). A total of 14.3 g of CaCl2 was chosen to give a

dissolved Ca inventory equivalent to a complete stoichiometric dissolution of 15 g Cal–Sil. The CaCl2

solution was planned to be added in 5 steps (1/5 of the total amount at each step) with the pressure drop

allowed to reach steady state between each step. Only 3 of the 5 CaCl2 additions were completed before the

test was terminated.

ICET-3-9 test results:

The pressure drop across the screen prior to the addition of the NUKON was 0.07±0.02 psi at an

approach velocity of 0.1 ft/s. [The pressures are recorded approximately every 5 sec by the data acquisition

system. When the pressure data are presented as a running average over a minute, the standard deviation of 

the running average is much smaller, ±0.005.] The pressure drop across the NUKON bed before the addition

of any CaCl2 is shown in Fig. 18. The steady state drop across the bed at this stage of the test was

0.14±0.02 psi and the debris bed was about 14 mm thick. A relatively stable value of the pressure drop was

reached after one pass around the loop (≈4 min).

Eighteen minutes after the NUKON was introduced, 200 ml of CaCl2 solution was added.This addition

represents the stoichiometric dissolved Ca equivalent (≈9 ppm) of 3 g of Cal–Sil. The pressure drop

increased to 0.242 psi (Fig. 19) and the bed compressed to 12 mm. Twenty–eight minutes after the NUKON

was introduced, a second 200 ml CaCl2 addition was made. The pressure drop increased to 1.2 psi and the

bed compressed to 9 mm. It appears from the data (Figure 19) that this value may not quite represent the 

steady state head loss for this condition. Forty–one minutes after the NUKON was introduced, the third 200

ml CaCl2 addition was made. After this addition, the pressure drop increased dramatically and the approach

velocity could not be maintained at 0.1 ft/s. The flow rate decreased to 0.02 ft/s 43 minutes after the initial

NUKON addition, and could no longer be controlled because the pump inlet pressure was at 0 psi. The flow

rate continued to slowly decrease while the pressure drop continued to rise gradually during the remainder of
22

the test. The pressure drop asymptotically increased to ≈5.2 psi, as the velocity decreased. The bed thickness

decreased to 7 mm at the highest pressure. Figure 19 shows the bed approach velocity and differential

pressure across the screen as a function of time for entire duration of the test.

2. 4.9 ICET-3-10 test procedure and results

ICET-3-10 test procedure:

ICET-3-10 also used a debris loading of 15 g NUKON and 15 g Cal–Sil. The debris was presoaked for

30 minutes at 60°C, prior to introduction into the loop. One half of the total TSP addition was added to the

debris slurry during the 30 minute presoak period,starting five minutes after the introduction ofthe debris and

Figure 18. Pressure drop across the NUKON bed in test ICET-3-9 at an approach velocity of 0.1 ft/sec.

Figure 19. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-9.
23

then continuing at a nominally uniform rate over the remaining 25 minutes. The remaining half of the TSP

was metered directly into the loop over 30 minutes at a nominally uniform rate after the introduction of the 

debris. This TSP addition sequence was intended to represent a plant where TSP begins to dissolve 5 minutes

after the start of a LOCA, and complete dissolution has occurred one hour after a LOCA. The conditions in

this test were intended to represent a “typical” degree of leaching of the Cal–Sil prior to formation of the bed.

However, because of the rapid rise in pH in the presoaking solution due to the high concentration of Cal–Sil,

the presoaking probably leads to somewhat less Cal–Sil dissolution than would occur at more realistic

concentrations for the same TSP history.

ICET-3-10 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-10 is shown in Fig. 20. This test resulted in a rapid buildup of head loss. After 10 minutes, the flow

velocity could not be maintained at 0.1 ft/s and the flow velocity gradually decreased. At the end of test, the

pressure drop across the bed was 4.7 psi (±0.9%) at a bed approach velocity of 0.06 ft/s (±0.8%).

Figure 20. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-10.

2. 4.10 ICET-3-11 test procedure and results

ICET-3-11 test procedure:

ICET-3-11 was a repeat of the baseline test, ICET-3-7, with a debris loading of 15 g NUKON and 15 g

Cal–Sil. No TSP was introduced in the test during either the presoak or in the loop.

ICET-3-11 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-11 is shown in Fig. 21. At 0.1 ft/s, the pressure drop stabilized at around 1.4±0.03 psi. After 210

minutes (≈52 recirculations) at a loop velocity of 0.1 ft/s, the loop velocity was cycled from 0.1 ft/s to

0.01 ft/s to 0.14 ft/s and back to 0.1 ft/s. Figure 22 shows the variation of the pressure drop across the bed as

the velocity is cycled. Comparison with Fig. 18 shows that it takes much longer for a NUKON/Cal–Sil bed to

reach a stable pressure drop than it does for a pure NUKON bed.
24

Test ICET-3-11 was a repeat of ICET-3-7. However, the pressure drop across the bed is very different

for the two tests as shown in Fig. 23. No reason for this difference in behavior has been determined. The

behavior illustrated in ICET-3-11 is consistent with the behavior observed in other tests without TSP while

the ICET-3-7 results are substantially different and appear to be subject to an unidentified experimental

interference. This point is illustrated in Fig. 24, which shows a comparison of bed approach velocities and

differential pressures across the screen as a function of time for tests ICET-3-1, 2, & 11. The results of the 

ICET 3-7 tests are considered anomalous and have not been used in the evaluation of chemical effects in this

report. An additional replicate test ICET 3–13, which will be discussed later in this report, was performed

and was consistent with the results of ICET 3–11. Therefore, the ICET-3-11 results have been used as the 

baseline for comparisons with tests in which precipitates are present.

0

0.05

0.1

0.15

0.2

0.25

0

1

2

3

4

5

0 40 80 120 160 200 240 280 320

Velocity

!p

Approach Velocity (ft/s)

Pressure Drop (psi)

Time (min)

NUKON & CalSil

added at t=0

ICET-3-11

NUKON 15 g

CalSil 15 g 

No TSP

Figure 21. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-11.

Figure 22.

Change in pressure drop across the bed

as the velocity is cycled from 0.1 ft/s to

0.01 ft/s to 0.14 ft/s and back to 0.1 ft/s.
25

Figure 23. Bed approach velocities and differential pressures across the screen as a function of time for

tests ICET-3-7 & 11.

Figure 24. Bed approach velocities and differential pressures across the screen as a function of time for

test ICET-3-1, 2, & 11.

2.4.11 ICET-3-12 test procedure and results

ICET-3-12 test procedure:

ICET-3-12 used a debris loading of 15 g NUKON and 5 g Cal–Sil. The debris was presoaked for 30

minutes at 60°C, prior to introduction into the loop. One half of the total TSP addition was added to the 

debris slurry during the 30 minute presoak period,starting five minutes after the introduction ofthe debris and

then continuing at a nominally uniform rate over the remaining 25 minutes. The bed was about 1/2 in thick.

The remaining half of the TSP was metered directly into the loop over 30 minutes at a nominally uniformrate

after the introduction of the debris.
26

ICET-3-12 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-12 is shown in Fig. 25. The head loss is not much greater than would be expected for a NUKON bed

alone. There was a measurable change in the thickness of the bed as velocity was cycled between 0.1 ft/s and

zero. Figure 26 shows the bed after removal from the loop. The smooth appearance is typical of the beds in

the tests.

Figure 25. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-12.

2.4.12 ICET-3-13 test procedure and results

ICET-3-13 test procedure:

ICET-3-13 also used a debris loading of 15 g NUKON and 5 g Cal–Sil. The debris was presoaked for

30 minutes at 60°C, prior to introduction into the loop. No TSP was added either to the slurry during the

presoak or to the loop during the test. This is a baseline test in a chemically inactive environment for

comparison with ICET–3–12.

ICET-3-13 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-13 is shown in Fig. 27 along with the corresponding results from ICET–3–12. The head loss is

virtually identical in the two tests, although TSP was present in ICET–3–12 and there was the potential for

Ca3(PO4)2 precipitation.
27

Figure 26. ICET–3–12 bed after removal from the loop. The smooth appearance is typical of the beds in

the tests.

Figure 27. Bed approach velocities and differential pressures across the screen as a function of time for

tests ICET-3-12 and 3–13.
28

2.4.13 ICET–3–14 test procedure and results

ICET-3-14 test procedure:

ICET-3-14 used a debris loading of 15 g NUKON and 15 g Cal–Sil. The debris was presoaked for 30

minutes at 60°C, prior to introduction into the loop. No TSP was added either to the slurry during the presoak

or to the loop during the test. This is a baseline test in a chemically inactive environment for comparison with

ICET–3–10. It replicates the conditions of ICET–3-7 and ICET–3–11.

ICET-3-14 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-14 is shown in Fig. 28 along with the corresponding results from ICET–3–11.

Figure 28. Bed approach velocities and differential pressures across the screen as a function of time for

tests ICET-3-11 and 3–14.

2.4.14 ICET-15 test procedure and results

ICET-3-15 test procedure:

ICET-3-15 used a debris loading of 15 g NUKON and 10 g Cal–Sil. No TSP was added either to the

slurry during the presoak or to the loop during the test. This is a baseline test in a chemically inactive 

environment for comparison with ICET–3–16.

ICET-3-15 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-15 is shown in Fig. 29.
29

Figure 29. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-15.

2.4.15 ICET-3–16-A1 test procedure and results

ICET-3-16-A1 test procedure:

ICET-3-16 also used a debris loading of 15 g NUKON and 10 g Cal–Sil. The debris was presoaked for

30 minutes at 60°C, prior to introduction into the loop. One half of the total TSP addition was added to the

debris slurry during the 30 minute presoak period,starting five minutes after the introduction ofthe debris and

then continuing at a nominally uniform rate over the remaining 25 minutes. The remaining half of the TSP

was metered directly into the loop over 30 minutes at a nominally uniform rate after the introduction of the 

debris.

ICET-3-16-A1 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-16 is shown in Fig. 30 along with the corresponding results from ICET–3–15. No effect of the

presence of the TSP can be observed.

2.4.16 ICET-17-A1 test procedure and results

ICET-3-17-A1 test procedure:

ICET-3-17–A1 used a debris loading of 15 g NUKON and 15 g Cal–Sil and was a replicate ofICET–3–

10. The debris was presoaked for 30 minutes at 60°C, prior to introduction into the loop. One half ofthe total

TSP addition was added to the debris slurry during the 30 minute presoak period, starting five minutes after

the introduction of the debris and then continuing at a nominally uniform rate over the remaining 25 minutes.

The designation A1 means that the screen with 3/16 in holes was used.

ICET-3-17-A1 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-17–A1 is shown in Fig. 31. This test resulted in a rapid buildup of head loss. After 30 minutes, the

flow velocity could not be maintained at 0.1 ft/s and the flow velocity gradually decreased. Comparison with

ICET–3–10 shows that the pressure increase is somewhat faster in ICET–3–10 and the pressure drop gets
30

somewhat higher before the velocity beginsto drop. However, the general behavior essentially replicatesthat

of ICET–3–10.

2.4.17 ICET-3–18-A1 test procedure and results

ICET-3-18-A1 test procedure:

ICET-3-18–A1 used a debris loading of 5 g NUKON and 10 g Cal–Sil. This resulted in a thin debris

bed about 3–4 mm thick. The debris was presoaked for 30 minutes at 60°C, prior to introduction into the

loop. One half of the total TSP addition was added to the debris slurry during the 30 minute presoak period,

starting five minutes after the introduction of the debris and then continuing at a nominally uniform rate over

Figure 30. Bed approach velocities and differential pressures across the screen as a function of time for

tests ICET-3-15 and 3–16.

Figure 31. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-17–A1.
31

the remaining 25 minutes. The remaining half of the TSP was metered directly into the loop over 30 minutes

at a nominally uniform rate after the introduction of the debris.

ICET-3-18-A1 test results:

The bed approach velocity and differential pressure across the screen as a function of time for test

ICET-3-18–A1 is shown in Fig. 32. This test resulted in a rapid buildup of head loss. After 10 minutes, the

flow velocity could not be maintained at 0.1 ft/s and the flow velocity gradually decreased. The thinner bed

plugged more rapidly than in either ICER–3–10 or ICET–3–17, which had 15 g NUKON and 15 g Cal–Sil

and was about 12 mm thick. This test result is consistent with the classic thin–bed head loss behavior

observed elsewhere (i.e., a thin fiber bed that becomes saturated with particulate can result in high head loss).

2.4.18 ICET-3–19-A2 test procedure and results

ICET-3-19-A2 test procedure:

ICET-3-19-A2 used a debris loading of 25 g Cal–Sil with no NUKON. This test also used the finer 

1/8 in hole screen with the more restricted 40% flow area. The debris was presoaked for 30 minutes at 60°C,

prior to introduction into the loop.

ICET-3-19-A2 test results:

The 25 g of Cal–Sil used in this test corresponds to a screen loading of 1.2 kg/m2, which is probably

conservative for most plants after their sump screens are updated. The debris bed that formed on the screen is

shown in Figs. 33 and 34. Although a portion of the flow area is blocked by the Cal–Sil, a significant portion

of the screen remains open with this loading. The bed approach velocity and differential pressure across the 

screen as a function of time for test ICET-3-19–A2 is shown in Fig. 35. The pressure drops are very low as

expected with a significant open area. The bed approach velocity and differential pressure across the screen

are replotted with an expanded scale in Fig. 36. This test is intended to represent a plant condition where a

bare screen (i.e., no fiber insulation loading) is loaded with Cal–Sil insulation and calcium phosphate

precipitate.

Figure 32. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-18–A1.
32

Figure 33. Plan view of debris bed formed by pure Cal–Sil loading in ICET–3–19–A2.

Figure 34. Side view of debris bed formed by pure Cal–Sil loading in ICET–3–19–A2.
33

Figure 35. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-19–A2.

Figure 36. Bed approach velocity and differential pressure across the screen as a function of time for

test ICET-3-19–A2.

2.5 Discussion of the ICET–3 series test results

The pressure drops across the bed for tests with physical debris of 15 g NUKON/15 g Cal–Sil and TSP

present (ICET-3-6 and ICET-3-10) are compared with the baseline test ICET-3-11, which had 15 g

NUKON/15 g Cal–Sil but no TSP, in Figs. 37a and b, respectively. In ICET-3-6, no TSP was added to the

presoak in order to limit the possible dissolution of the Cal–Sil. This scenario was intended to give a lower

bound for the amount of calcium phosphate precipitate arriving as the debris bed isformed. As expected, the

initial pressure drop behavior in ICET-3-6 is very similar to the baseline case ICET-3-11 in which no

chemical precipitates are present (Figure 37a). However, a comparison of the maximum pressure drops

reached in ICET-3-6 and -11 (Figs. 13 and 21) show that the difference in the pressure drop increases with
34

time. The increase of the pressure drop with time in ICET–3-6 is attributed to the continuing dissolution of 

Cal–Sil and additional formation of calcium phosphate precipitates.

Test ICET-3-10 was intended to give the “typical” amount of calcium phosphate precipitate arriving as

the bed is formed in design basis analyses. As noted previously, at the end of the presoak period, a much

larger amount of CaSiO3 will have dissolved, and much larger amount of calcium phosphates precipitates will

have formed compared to the ICET-3-6 case. This results in a much more rapid increase in head loss than in

ICET-3-6 (Figure 37b), although the pressure drop in ICET-3-6 eventually approaches the steady state value 

obtained in ICET-3-10. Although this argument qualitatively explainsthe differences between ICET-3-6 and

10, the “lag” in the pressure drop is greater than the 30 minutes that would be expected due to differences in

the amounts of Cal–Sil dissolved during the presoak.

A comparison of the pressure drops in ICET-3-8 and ICET-3-9, shown in Fig. 38, suggests a strongly

nonlinear relationship between the amount of the calcium phosphate precipitate and the pressure drop. The

first two additions of CaCl2 in ICET-3-9 produced relatively small increases in pressure drop. The third

addition resulted in a very rapid increase in pressure drop. The total inventory of dissolved Ca added in

ICET-3-9 is equivalent to complete dissolution of 9 g of Cal–Sil. The pressure drop observed in ICET-3-8

after addition of 43.5 ppm of dissolved Ca as CaCl2 is almost as the same as that observed in the ICET-3-2

test (see Reference 3) in which 50 ppm Ca as CaCl2 was added to the loop. However, this comparison may be

confounded by the difference in precipitate distribution through the bed. The bed in ICET-3-8 was formed

from the simultaneous arrival of fiber and precipitate. In ICET-3-9, the precipitate was deposited on a

preformed fibrous bed. Since precipitate can presumably move through and into the bed, the difference in the

way the beds were formed may not completely define the actual structure. An additional test would be

required to directly compare the effects of either simultaneous or sequential arrival of the chemical precipitate

associated with the complete dissolution of 9 g of Cal–Sil.

The pressure drop increases with time occur because more debris is trapped during each pass through

the debris bed during recirculation and because of continued Cal–Sil dissolution and formation of additional

precipitates. In ICET-3-10, which represents a “typical” amount of Cal–Sil dissolution before the formation

of the bed, it takes about 3 recirculations (or approximately 12 minutes) of the test loop fluid to build to the 

maximum pressure drop. In ICET-3-8, which represents the maximum Cal–Sil dissolution before the

formation of the bed, the maximum pressure drop is reached after 1 test loop recirculation. The head losses

due to chemical products in both of these tests are dominated by the precipitates that form due to dissolution

prior to the initial bed formation, and the pressure drop increases as more of these precipitates are trapped

during recirculation. The effect of continued dissolution could not be determined because the pressure drop

quickly reached the capability of the loop. However, in ICET-3-6, which represents the minimum Cal–Sil

dissolution that would occur before the formation of the bed, it takes about 15 passes test loop recirculations

to approach the maximum pressure drop. In this case the pressure increase is probably dominated by the time

needed for additional Cal–Sil dissolution.

The degree of dissolution that would occur before the debris reached the sump screen in a prototypical

situation would presumably be bounded by the ICET-3-6 and ICET-3-8 limiting cases, and may be most

similar to the ICET-3-10 case. Figure 39 shows a comparison of the increase of pressure drop in ICET-3-8

and ICET-3-10. These results suggest that variability in the degree of Cal–Sil dissolution is likely to have a 

relatively small effect on chemical effects on head loss in this system. Differences in debris transport time

would probably have a much large effect on the rate of pressure increase. The actual amount of head loss for

a plant specific case is also dependent on many additional factors such as the sump screen debris loading,

uniformity of the screen debris loading, propensity for flow bypass (i.e., jetting) through the debris bed, debris

bed screen approach velocity, and transport of chemical precipitate not addressed in these tests.
35

(a)

(b)

Figure 37. (a) Bed approach velocities and differential pressures across the screen as a function of time

for test ICET-3-6 & 11; (b) Bed approach velocities and differential pressures across the

screen as a function of time for test ICET-3-10 & 11.

In the tests with 15 g NUKON/15 g Cal–Sil, the strong effect of the chemical precipitates on pressure

drop is readily evident. Such an effect is less evident in the comparison of the tests with 7 g NUKON/25 g

Cal–Sil. The pressure drops in ICET-3-4, in which some precipitation of calcium phosphate would occur, and

ICET-3-5, in which no precipitation would occur are compared in Fig. 40. Since no TSP was added to the

presoak, the Cal–Sil dissolution in ICET-3-4 was limited similarly to ICET-3-6, so that a strong chemical

effect would not be expected until there was time for additional dissolution in the loop. However, with this

Cal–Sil loading, even without the effect of calcium phosphate precipitates, the head loss increases very

rapidly to a high level.
36

Figure 38. Bed approach velocities and differential pressures across the screen as a function of time for

test ICET-3-8 & 9.

Figure 39. Comparison of the increase of pressure drop in ICET-3-8, which is bounding case for

complete dissolution of Cal–Sil prior to formation of the debris bed, and ICET-3-10, which

represents the minimum expected dissolution of Cal–Sil prior to bed formation.
37

Figure 40. Bed approach velocities and differential pressures across the screen as a function of time for

test ICET-3-4 & 5.

Comparison of ICET–3–10, 12, 16, and 18 (Figs. 20, 25, 30, and 32, respectively) shows that the

relative contribution of calcium phosphate to head loss depends strongly on the debrisloading. These results

along with the results for ICET–3–19 (Fig. 35) suggest that there is a highly nonlinear relation between head

loss and fiber loading for a given particulate loading as shown schematically in Fig. 41.

Figure 41.

Schematic dependence of head loss on

fiber loading on the screen for a given

particulate loading

2.6 Particle sizes of the chemical products in ICET–3

The particle sizes of the chemical products in the ICET–3 experiments have been measured by a laser

granulometry technique. This technique uses the diffraction of light passing though a suspension of the 

particles to measure the size of particles present in the solution. A CILAS Model 1064 granulometer was

used for the measurement, and the results are shown in Figs. 42 and 43. The distributions with and without

ultrasonic deflocculation are fairly similar suggesting that the median particle size of 4.7 μm that was

observed is a reasonable “unit” for the precipitate particles.
38

Figure 42.

Particle size histogram for chemical

product from ICET-3 simulation

experiment analyzed with no ultrasonic

deflocculation. The median particle size

was 7.1 μm.

Figure 43.

Particle size histogram for chemical

product from ICET-3 simulation

experiment analyzed with ultrasonic

deflocculation. The median particle size

was 4.7 μm.

2.7 Calcium phosphate settling tests

In the head loss loop tests, virtually all the calcium phosphate precipitates that form are transported to

the bed. In an actual sump, there is a potential for the precipitates to settle before they reach the sump screen.

Settling tests were performed to determine settling ratesfor calcium phosphate under conditions with no bulk

directional flow. Tests were performed in a settling tower with an effective height of 71.5 cm. The tower was

filled with a solution containing LiOH (0.7 ppm Li) and boric acid (2800 ppm B) and TSP (3.4 g/l). CaCl2

solution was then added to the tower. The dissolved Ca reacts with the TSP in the solution to form calcium

phosphate precipitate. The solution is stirred to get a uniform mixture and then the precipitates are allowed to

settle. Two different CaCl2 concentrations were tested. One produced a dissolved Ca inventory equivalent to

300 ppm and the other an inventory equivalent to 75 ppm. The 300 ppm inventory is roughly equivalent to

full stoichiometric dissolution of a 1 g/l concentration of Cal–Sil; the 75 ppm inventory isroughly equivalent

to full stoichiometric dissolution of a 0.25 g/l concentration of Cal–Sil. In both cases, the solutions are

phosphate-rich for a TSP concentration of 3.4 g/l, i.e., the formation of calcium phosphate precipitates is

limited by the amount of Ca available. Replicate settling tests were conducted for each concentration.

In the 300 ppm tests, there was more of a tendency for precipitate particles to agglomerate and a visible

settling front was observed, as shown in Fig. 44. Grab samples taken before and after the front passed suggest

that about half the precipitate was removed as the front passed. The mixture behind the front looked

relatively uniform and gradually became less cloudy. In the 75 ppm tests, a front was not visible. The

mixture looked relatively uniform throughout most of the tower and gradually became less cloudy. There was

a more noticeable mix of upward and downward moving individual particles.
39

The time histories of the settling front in the 300 ppm dissolved Ca tests were estimated by taking a

sequence of pictures of the front at intervals and noting the location of the front relative to a scale mounted on

the settling cylinder. As shown in Fig. 45, the front velocity is relatively constant until it approaches the

bottom of the settling tower. The average velocity of the front in the 300 ppm testsis 3.8 cm/min. Settling of

remaining particulate behind the front occurred much more slowly and the settling velocities are likely more

consistent with those measured in the 75 ppm tests.

In the 75 ppm dissolved Ca tests where no front was evident, the settling velocities were estimated by

taking three grab samples at intervals from the top of the settling column and noting the relative decrease in

the amount of precipitate in the samples with increasing time. The decay in the amount of precipitate in the

samples can be modeled as exponential as shown in Fig. 46. The time constant for the decay is approximately

87.5 minutes. This corresponds to a settling velocity of 0.8 cm/min. This is more representative of the

settling characteristics of the calcium phosphate precipitates at the concentrations of most interest.

Figure 44.

Settling front in test with 300 ppm Cl

(a) (b)

Figure 45. Time history of the motion of the settling front in the two 300 ppm dissolved Ca settling tests.
40

Figure 46.

Assumed exponential decay of volume of

suspended precipitate in 75 ppm dissolved Ca test.

2.8 Small–scale dissolution testing

The objective of the small–scale dissolution testing is to identify important environmental variables

governing both dissolution of Cal–Sil and the subsequent formation of calcium phosphate precipitates over a

range of simulated sump pool conditions. The variables considered in the results reported herein are the

effect of the rate of TSP addition to the Cal–Sil solutions for various Cal–Sil concentrations.

Three different histories of TSP addition were studied. These histories are intended to encompass the 

range of histories of TSP dissolution expected within an actual containment sump:

1. Add TSP before Cal–Sil addition (instantaneous dissolution of TSP).

2. Titrate TSP over 1 hr period into solution after Cal–Sil addition (nominal case).

3. Titrate TSP over 4 hr period into solution after Cal–Sil addition (very slow addition of TSP).

The test temperature was 60°C. The base solution consisted of 2800-ppm-B and 0.7-ppm Li. The TSP

concentration was 3.4 g/l which results in a nominal pH value of 7.1 in the buffered solution. The Cal–Sil

concentrations for the tests were 0.5 and 1.5 g/l. The 0.5 g/l Cal–Sil concentration is generally

representative of current plant design basis concentrations based on a survey of plants that utilize TSP

buffering and expect Cal–Sil to be present in the containment sump.

8 The 1.5 g/l concentration is greater

than the postulated post-LOCA containment pool concentration for existing plants with both Cal–Sil

insulation and TSP buffer. At these concentrations, the formation of calcium phosphate precipitates is

expected to be Ca limited, since Ca3(PO4)2 [tricalcium phosphate] or Ca10(PO4)6(OH)2 [hydroxyapatite] 

are the two most likely forms for the calcium phosphate precipitates at this pH.

9

The results from small–scale dissolution tests performed at 60°C to date are summarized in Table 4.

Time, in these tables, represents the elapsed time after the Cal–Sil was added to the base solution. However,

grab samples were taken only after the TSP additions were completed in each test. The values for Ca, P, Si,

and Na in the tables were determined by inductively coupled plasma (ICP) measurements on the grab

samples. ICP measures the total amount of elements present in a sample whether they are present as solutes

or solid species. However, the samples were filtered prior to ICP analysis and the ICP results are expected to

represent only species in solution.

The Na arises as an impurity in the Cal–Sil, probably sodium silicate. It is expected to be extremely

soluble and in most of the tests, it appears to dissolve very rapidly. In the testsets denoted as “II” and “III” in

Table 4, the Na levels are lower than in any of the other tests. It is not clear why this is the case.

Since the Ca which is released (as the Cal–Sil dissolves) quickly combines with the available dissolved

phosphate to form a solid calcium phosphate precipitate, the ICP measurements of Ca in the filtered supernate
41

are not representative of the amount of Ca that has actually dissolved. The measurements of dissolved P have

been used to estimate the amount of Ca that has been precipitated. If all the P that was added as TSP

remained in solution, the P concentration would be 277 mg/l. The measured P concentrations are alwaysless

than this concentration. It is assumed that the missing P has all combined with Ca to form solid calcium

phosphate precipitates. There are a variety of calcium phosphate species having different stoichiometries.

The least soluble species at the pH values of interest are Ca3(PO4)2 [tricalcium phosphate] and

Ca10(PO4)6(OH)2 [hydroxyapatite].9 Values of the amount of Ca residing in calcium phosphate precipitate 

have been calculated for each of these assumed species based on the missing P in solution. This information

is summarized in the last two columns of Table 4. The total dissolved Ca can be estimated by adding the 

measured Ca (column 4 in Table 4) with the Ca from either of the last two columns in Table 4.

The dissolved Ca that has combined to form calcium phosphate can be estimated based on the

assumption that the precipitates are primarily hydroxyapatite. These values are shown in Figs. 47a and 47b.

In these graphs, the time, once again, is measured from the time that the Cal–Sil is added to the solution. The

data legend indicates if the TSP dissolution was instantaneous (“instant”), completed in 1 hour (“nominal”),

or completed in 4 hours (“slow”). While there is variability in the data, it appears that the TSP dissolution

history has a larger effect at the higher Cal–Sil loading (1.5 g/l) than it does at 0.5 g/l. It appears from the

data in Table 2, that it takes substantial time (approximately 4 days) to achieve full dissolution for the 1.5 g/l

Cal–Sil concentration while the 0.5 g/l concentration appears to be completed within approximately 1 - 3

days. For both Cal–Sil concentrations,substantial Ca dissolution (> 75 mg/l) has occurred within a few hours

regardless of the TSP addition rate.

These data are replotted in normalized form in Fig. 48. In this figure, the total dissolved Ca at each

point in time is normalized by the Ca concentration corresponding to complete stoichiometric dissolution of 

the total amount of Cal–Sil present. The figure shows that for the case of instantaneous TSP dissolution, the 

fractional amounts of dissolved Ca are significantly different for the two different Cal–Sil loadings. For the

more realistic 1 h TSP dissolution history and the bounding 4 h TSP dissolution history, the normalized Ca

values are close for the two loadings, i.e., the amount of dissolved Ca just scales with concentration. Even for

the case of instantaneous TSP dissolution, the normalized dissolution rate of the 0.5 g/l Cal–Sil loading is

similar to that observed for the 1 and 4 h TSP addition rates for the 0.5 and 1.5 g/l loadings. This supportsthe

assumption stated earlier that the Cal–Sil dissolution rate is not too strongly dependent on the Cal–Sil

concentration for these low Cal–Sil concentrations. Thus, the screen loading per unit area is the most

important scaling parameter for head loss tests with calcium phosphate precipitates.

The data from the small–scale dissolution tests at 90°C are summarized in Table 5. The Na levels are

much higher than in the corresponding tests at 60°C, indicating more leaching of the Na from the Cal–Sil.

The Ca in solution is lower reflecting the retrograde solubility of Ca3(PO4)2. The measured P levels are,

however, much higher than those at 60°C indicating that not as much Ca3(PO4)2 has formed, which implies

that less Ca has leached from the Cal–Sil at the higher temperature.
42

(a) (b)

Figure 47. (a) Dissolution of Cal–Sil at a loading of 1.5 g/l for three different histories of TSP addition; (b)

Dissolution of Cal–Sil at a loading of 0.5 g/l for three different histories of TSP addition.

Figure 48. Normalized dissolution data, dissolved Ca/Ca for full dissolution for loadings of 1.5 g/l and

0.5 g/l for three different histories of TSP addition.
43

Table 4. Summary of results for the small–scale dissolution tests at T= 60°C.

Test series Time (h) pH (RT) Ca

(mg/l)

P

(mg/l)

Si

(mg/l)

Na

(mg/l)

Cal–Sil

(g/l)

Ca equiv

(mg/l)

(Ca3(PO4)2 )

Ca equiv

(mg/l)

Ca10(PO4)

6(OH)2

0.08 7.04 39 263 23 536 1.5 28 31

0.50 7.17 25 252 24 554 1.5 49 55

2.67 7.38 16 232 36 549 1.5 88 98

24.50 7.24 8 165 60 534 1.5 217 242

71.25 7.33 4 135 67 557 1.5 276 306

I

TSP is added

before the Cal–

Sil is

introduced

119.00 7.48 3 132 68 567 1.5 281 313

1.08 6.83 58 65 21 159 1.5 412 458

1.5 6.79 54 66 22 168 1.5 409 454

3.67 7.1 11 131 25 357 1.5 283 315

25.5 7.1 5 103 46 382 1.5 337 375

72.25 7.15 3 67 62 405 1.5 407 452

II

TSP metered

over an hour

after the Cal–

Sil is added

120 7.26 3 57 65 395 1.5 427 474

4.08 7.12 19 102 26 289 1.5 339 377

4.5 6.85 14 104 28 295 1.5 336 373

6.67 6.92 6 95 30 297 1.5 353 392

28.5 6.99 5 67 42 292 1.5 408 453

75.25 7.1 3 36 60 327 1.5 467 519

III

TSP metered

over a 4 hour

period.

123 7.25 3 22 65 331 1.5 494 549

0.08 7.13 9 250 7 598 0.5 54 59

0.50 7.29 9 241 9 585 0.5 70 78

2.67 7.4 10 223 20 594 0.5 105 117

24.00 7.37 4 208 36 600 0.5 134 149

72.00 7.26 3 198 42 579 0.5 154 171

IV

TSP is added

before the Cal–

Sil is

introduced

120.00 7.26 3 199 42 577 0.5 152 168

1.08 7.2 14 211 9 512 0.5 128 142

1.5 7.25 14 249 12 618 0.5 55 61

3.67 7.26 13 237 20 620 0.5 78 87

25.5 7.32 7 222 37 627 0.5 108 120

72.25 7.23 4 216 45 631 0.5 118 131

V

TSP metered

over an hour

after the Cal–

Sil is added

120 7.2 4 225 47 642 0.5 101 112

4.08 7.24 21 230 22 585 0.5 91 102

4.5 7.24 18 229 24 600 0.5 93 104

6.67 7.26 7 212 28 582 0.5 126 140

28.5 7.35 4 201 37 583 0.5 148 164

75.25 7.24 3 206 44 600 0.5 139 154

VI

TSP metered

over a 4 hour

period.

123 7.24 4 203 46 601 0.5 143 159
44

Table 5. Summary of results for the small–scale dissolution tests at T= 90°C.

Test series Time (h) pH (RT) Ca

(mg/l)

P

(mg/l)

Si

(mg/l)

Na

(mg/l)

Cal–Sil

(g/l)

Ca equiv

(mg/l)

(Ca3(PO4)2 )

Ca equiv

(mg/l)

Ca10(PO4)

6(OH)2

0.08 7.29 16 272 15 633 1.5 10 11

0.50 7.35 10 250 28 658 1.5 52 58

2.67 7.41 3 193 59 671 1.5 163 181

24.50 7.50 1 143 77 648 1.5 259 288

71.25 7.51 1 141 77 666 1.5 263 292

I

TSP is added

before the Cal–

Sil is

introduced

119.00 7.48 2 144 75 686 1.5 257 286

1.08 7.52 13 206 41 599 1.5 137 153

1.5 7.48 6 213 55 678 1.5 124 138

3.67 7.49 3 173 68 651 1.5 201 224

25.5 7.50 1 149 85 673 1.5 248 275

72.25 7.42 2 150 85 718 1.5 246 273

II

TSP metered

over an hour

after the Cal–

Sil is added

120 7.33 2 171 88 829 1.5 205 228

4.08 7.38 2 207 62 663 1.5 135 151

4.5 7.38 3 197 63 647 1.5 155 172

6.67 7.44 2 172 64 608 1.5 203 226

28.5 7.45 1 136 76 619 1.5 273 303

75.25 7.45 1 133 75 625 1.5 279 310

III

TSP metered

over a 4 hour

period.

123 7.49 1 135 70 650 1.5 275 305

More complete descriptions of the dissolution tests and additional experimental results are contained in

Appendix B.
45

3 Head loss tests in ICET–1 and ICET–5 environments

3.1 Background

As noted in Table 1, the ICET–1 environment is a NaOH buffer with NUKON insulation; the ICET–5

environment is a sodium tetraborate buffer with NUKON. Both environments resulted in significant dissolved

Al levels: ICET–1 ≈ 375 ppm Al, pH ≈ 9.4; ICET–5 ≈ 50 ppm, pH ≈ 8.4. The dissolved Al concentration in

ICET–1 increased linearly over the first 15 days of the test to ≈375 ppm and remained relatively constant for

the duration of the test.

2 The dissolved Al concentration is shown in Fig. 49. No precipitates were observed

in the ICET test chamber during ICET–1, but cooling of ICET–1 solution produced visible precipitates.

Traces of chemical products could be observed at the bottom of sample bottles from early in the test. The

volume and rapidity of formation increased as the test continued. Near the end of the 30 day test period,

product formed almost as soon as samples were removed from the test chamber.

Figure 49. Aluminum concentration trend in ICET–1 daily water samples.

2

Figure 50. Aluminum concentration trend in ICET–5 daily water samples.

6
46

The dissolved Al concentration in ICET–5 also increased linearly for the first portion of the test. The

Al concentration peaked at about 55 ppm on days 12 and 13 and then decreased slightly and varied between

35 and 50 ppm for the remainder of the test as shown in Fig 50.

4 Cooling of ICET-5 solution eventually

produced small amounts of precipitates. The amount of product was small compared to that observed in

ICET–1, and it took much longer times (several days) for the products to become visible.

The low levels of dissolved Al in the ICET–2 and 3 environments3,4 are not unexpected due to the

relatively low pH. Because of the high pH, the ICET–4 environment might be expected to produce 

comparable dissolved Al levels. It did not, due probably to passivation of the metal surface.10 Similarly, the

leveling off of the dissolved Al concentrations in ICET–1 and 3 is not due to saturation of the Al due to

equilibrium between the dissolved Al and a precipitate. Instead a variety of evidence indicates that the

behavior is due to passivation of the surface of the aluminum metal.

10

Thermodynamically–based speciation model predictions14 made prior to the ICET tests suggested that

sodium aluminum silicate might be an important precipitate product. It was not observed in the ICET

tests,

2–6 apparently because in the tests in which significant amounts of Al dissolved, dissolution of the 

NUKON (which would produce silicates) was inhibited. To ensure that this was not an artifact due to the

relatively high area of the Al metal in the ICET test series, a series of small–scale dissolution tests were

performed on NUKON in different environments, including one with roughly 1/4 the relative surface area of

Al metal as in ICET–1. These tests are described in Appendix E. The inhibition of NUKON dissolution

observed in ICET–1 was also observed in the case of the lower surface area of Al metal.

3.2 Chemical Surrogates for ICET–1 and ICET–5

3.2.1 Solubility of Aluminum Hydroxides

Aluminum hydroxides, nominally Al(OH)3, are the principal chemical product with potential to cause 

head loss observed in ICET–1 and 5 environments. The most stable form of Al(OH)3 is the crystalline form

gibbsite. Although gibbsite is thermodynamically the most stable form of Al(OH)3, Van Straten et al.

11

showed that in precipitation of aluminum hydroxides from a basic supersaturated solution the first productsto

form are the less thermodynamically stable forms and then the product transforms through a series offormsto

reach the thermodynamically stable form, gibbsite. The progression suggested by Van Straten et al11 is

amorphous, pseudo boehmite, bayerite, and then gibbsite.

For the pH range of interest the primary solubility product is aluminate, Al(OH)

4

!

and the equilibrium 

reaction with the solid phase is given by:

Al(OH)

3 (solid) + H2O = H+ (aq) + Al(OH)4

– (aq) The Al(OH)

4

!

concentration at equilibrium is a function of pH:

log Al(OH)

4

–

 = log Ksp - log H+ = log Ksp + pH

At 25°C the equilibrium constant Ksp = 8.0 x 10–13 (amorphous), ≈ 1 x 10–14 (bayerite), and ≈ 1.9 x 10–15

(gibbsite).11 Data on the solubility as a function of temperature are given by Benezeth et al.

13. Estimates

of the equilibrium concentration of Al with amorphous Al(OH)3 as functions of pH and temperature are

shown in Fig. 51. The solubilities of the crystalline forms are smaller by a factor of ≈100–500 than that

of the amorphous form. These values are for simple solutions and the solubilities could be influenced by

borates, organics. There are also uncertainties in thermodynamic values, although the values given by

Van Straten et al.

11 are consistent with those reported by Langmuir.12
47

(a) (b)

Figure 51. Equilibrium solubility of amorphous Al(OH)3 as a function of (a) pH at 25°C and (b)

temperature at pH =9.6

The predicted solubility limit for amorphous Al(OH)3 at 60°C and pH 9.6 is almost 1000 ppm. The

corresponding result for gibbsite is ≈ 2 ppm. For a temperature of 20°C, the equilibrium solubility at pH 9.6

for the amorphous Al(OH)3 is ≈ 60 ppm.

Although there are uncertainties associated with the values of these equilibrium solubilities, these

results provide strong evidence that the productsin ICET–1 are amorphous rather than crystalline and that the

leveling off of the Al concentration after day 15 was due to passivation of the surface of the aluminum plates,

not due to reaching a solubility limit for Al.

Klasky et al.

10 provide additional discussion and evidence that the products in ICET–1 are amorphous

aluminum hydroxides.

3.2.2 Aluminum nitrate surrogates

Surrogate solutions for ICET–1 environments were developed using aluminum nitrate, Al(NO3)3-

9H2O. Since in ICET–1, the solutions arise from the dissolution of aluminum in a basic solution containing

boric acid, the surrogate solutions were prepared by dissolving commercial aluminum nitrate, Al(NO3)3-

9H2O powder in a base solution containing 2800 ppm B added as boric acid, 0.7 ppm Li as LiOH, and NaOH

sufficient to get a pH of 9.6. A detailed description of the benchtop experiments and analyses supporting the

development of the surrogates is given in Appendices C and D.

Samples of surrogate solutions containing 100, 200, and 375 ppm Al are shown in Fig. 52. When

samples were taken through heating and cooling cycles, the sediments would redissolve at high temperatures.

This together with measurements of the Al level in the supernate suggests thatsolubility behaviorissimilarto

that shown in Fig. 51 and thus the sediments are amorphous or at least act like amorphous Al(OH)3.
48

Figure 52. Al(NO3)3 100, 200, & 375 ppm surrogates. The photo on left was taken without flash to

heighten the contrast between sediment and supernate. The photo on the right characterizes

better the semi–translucent nature of the sediment. The bottles on the far left in each photo

have no Al additions.

The particle sizes of the chemical products in an ICET–1 experiment were measured by the laser 

granulometry technique discussed in Section 2.5. The results are shown in Figs. 53 and. 54. The measured

particle sizes after ultrasonic deflocculation are much smaller than those measured before deflocculation.

This is consistent with the results reported by Klasky et al.

10, which suggest that products are agglomerations

of much finer, nano–sized particles. Thus it may be difficult to define a particle size since it may depend on

the local stress state and its ability to disturb the agglomerations of smaller particles. No corresponding

particle size measurements are available for the actual products from ICET–1. However, the particle size 

distribution for an aluminum hydroxide surrogate produced at LANL10 is shown in Fig. 55. Although the

results in Fig. 55 are also based on a laser diffractometry technique, it is not clear that the results are directly

comparable. The distribution in Fig. 55 is narrower and the median value is probably more like 0.5 μm rather

than 1.7 μm. Nevertheless, it appears that the distributions in Figs. 54 and 55 are not too dissimilar.
49

Figure 53.

Particle size histogram for chemical

product from an ICET-1 simulation

experiment analyzed with no ultrasound

deflocculation. The median particle size

was 18.6 μm.

Figure 54.

Particle size histogram for chemical

product from an ICET-1 simulation

experiment analyzed with ultrasound

deflocculation. The median particle size

was 1.7 μm.

Figure 55.

Particle size distribution for an Al(OH)3

surrogate reported in Ref. (10).

The use of aluminum nitrate to create surrogate solutions has some disadvantages. It introduces a

species (nitrate) that is not typically present in the sump environment, and tends to drive the pH down. An

alternate approach to developing a surrogate solution was investigated in which sodium aluminate (NaAlO2)

was used to create the surrogate solutions. This approach would introduce no new species, would not tend to

decrease the pH, and better mimics the actual corrosion process since the formation sodium aluminate

(NaAlO2) is probably an intermediate step in the actual dissolution of metallic Al in NaOH solutions.
50

Benchtop experiments were performed to evaluate the use of sodium aluminate to produce a surrogate.

The results are described in Appendix C. The decision was made to use the aluminum nitrate surrogate,

because the behavior and appearance of the precipitates in these solutions seemed to better mimic the 

behavior and appearance of the precipitates in the ICET-1 test.

3. 3 Relationship of ICET–1 environments to plant environments

Although the final level of dissolved Al in ICET–1 was ≈ 350 ppm, actual plant levels of dissolved Al

for same environments would “scale” with amount of Al exposed which is plant specific. In addition, the

ICET–1 test was run isothermally at a temperature of 60°C (120°F), whereas the actual temperatures will vary

considerably over the whole course of the accident. The amount of Al exposed to the environment depends

strongly on whether the sprays are on. In most plants, the amount of submerged Al is a small fraction of the 

total Al in containment.

1 To obtain a better estimate of the range of Al that may be expected in the

recirculating water, calculations were performed using more realistic thermal histories for 17 plantsfor which

estimates of the amount of Al in containment were available in Ref. (1).

The time–temperature histories used for the calculations are shown in Fig. 56 and are taken from Ref.

(1). As shown in Fig. 49, the dissolved Al concentration in ICET–1 increases linearly over the first 10 days of

the test with a rate of ≈ 25 mg/l/day. This corresponds to a corrosion rate of 30.1 mg/m2/min. For the same

pH (9.6) and temperature (60°C),similar corrosion rates were observed in the small–scale tests conducted at

CNWRA14 and at Westinghouse.15 The corrosion rates of the Al increase with increasing temperature. The

data in Ref. (14) give an exponential dependence e0.0195T for temperature in Fahrenheit. The data inRef.(15) 

give a somewhat greater temperature dependence, but the results in Ref. (14) were used for the calculations.

Because the spray phase has a higher pH, the corrosion rates in the spray were taken as twice those in the 

submerged phase, based on literature data cited in Ref. (14). When benchmarked against the results of the

ICET–1 test, this overestimated the dissolution that occurred in the spray phase. To fit the ICET–1 data, it

was necessary to assume that the corrosion rate in the spray phase was 0.6 that in the submerged phase.

Nevertheless, a factor of 2 was used for the calculations as being more consistent with our general

expectations of the effects of increased pH.

With these assumptions, the time–temperature histories can be digitized and total amount of Al

dissolved can be calculated by numerically integrating the corrosion rate over the history to obtain the weight

of Al per unit area dissolved from submerged areas over a 30 day period and from areas subjected to sprays

over a 4 h period at the initial portion of the accident. These results are summarized in Fig. 56 for the

different plant histories and for the isothermal history of ICET–1. For the plant history calculations, no

passivation of the Al was assumed to occur. For ICET–1 the corrosion loss per unit area over 30 days would

be 878 g/m2 and half that (439 g/m2) if passivation is assumed to occur on day 15.

With these results and estimates of the sump volume and the areas of Al that are submerged and that are

subjected to wetting by sprays, the concentration of dissolved Al in the sump after 1 day and after 30 days can

be estimated. Such estimates are shown in Table 6 for 17 plants that responded to the ICET plant survey.

1 it

should be noted that all the plants in the table may not use NaOH buffers and so the results may not actually

be applicable to the plant. The results suggest that the dissolved Al concentration in ICET-1 is conservative,

and most plants with NaOH buffering would be expected to have dissolved Al concentrations at 30 days

below 100 ppm. Although comparable time–temperature–dissolution history calculations were not

performed, the dissolved Al concentration in ICET-5 is probably similarly conservative. Based on the

corrosion rates inferred from ICET–5 and the relative amounts of Al in containment compared to ICET–5,

most plants with STB buffering would be expected to have dissolved Al concentrations at 30 days below

15 ppm.
51

4 loop 3 Loop

Ice Condenser

Type Al 30 days Al spray

g/m

2

g/m

2

4 loop 836 30

3 loop 1395 29

Ice 441 3

ICET-1 878(439) 5

Figure 56. Estimated sump temperature histories for different types of Westinghouse plants and

containments1
52

Table 6. Estimated dissolved Al levels for NaOH buffer based on ICET Plant Survey1

Plant Plant Type

Al / vol.

ft2/ft3

Al / vol.

(Submerged)

Al / vol.

(Spray)

1 day

total ppma,b

30 day total

ppmc

T B&Wd 0.29 0.003 0.29 65 80

U CEd 0.02 0.000 0.02 5 6

J 3 Loop 0.02 0.02 0.000 2 34

K 3 Loop 0.01 0.01 0.000 1 17

Q 4 Loop 0.05 0.003 0.051 13 20

BB B&Wd 0.08 0.001 0.08 18 22

N 2 Loopd 0.005 5e-05 0.005 1 1

JJ 4 Loop 0.12 0.001 0.12 27 33

S, KK, LL B&Wd 1.91e-05 5e-05 0 0 0

R CEd 3.360 0.840 2.510 678 5026

O,P 2 Loopd 0.02 0.002 0.02 5 15

RR 4 Loop 0.04 0.001 0.04 10 13

QQ 3 Loop 0.02 0.000 0.02 4 4

X 4 Loop 0.01 0.001 0.01 3 5

ICET–1 3.5 0.18 3.3 57 375

aSprays active for 4 h

bSpray corrosion rates = 2* submerged, except for ICET–1 where the factor is 0.6

cNo passivation of surfaces except in ICET–1

dThe time–temperature history for 3–loop plants was used to calculate the results for B&W, CE,

and 2–loop plants.

3.4 Individual ICET–1 test procedures and results

3.4.1 ICET-1-3 test procedure and results

ICET-1-3 test procedure

The loop was filled with deionized water and heated to 77°C (170°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was allowed to cool to room temperature overnight. Boric acid in powder

form was slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution.

NaOH was added to make the pH 10. These conditions were chosen to match those in ICET–1. The loop was

operated at 1 ft/s for 15 minutesto mix the chemicals. After the chemical solution was prepared, the physical

debris bed was built by adding a slurry containing 15 g NUKON to the loop with the loop flow at 0.1 ft/s.

The bed was about 1/2 in thick. The NUKON bed formed essentially in the first pass of the debris past the 

test screen.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 71°C (160°F)

and the Al(NO3)3 solution was added. One liter of solution was metered in over a 4–minute period (1

recirculation). The concentration of the solution was chosen so that the concentration in the loop was

375 ppm after all the solution was added. The temperature was reduced to 60°C (140°F). The test plan was

to decrease the temperature in stages, and wait for the pressure to equilibrate at each step. However, even
53

before the Al(NO3)3 solution was added, cracks started to appear in the LEXAN test section. To try to

complete the test before the test section failed, the holds were shortened and the pressures recorded at each

stage may not represent steady–state conditions at that temperature.

ICET-1-3 test results

Although bench tests had shown that a 375 ppm Al solution at pH 9.6 and 60°C (140°F) could readily

be achieved and was below the solubility limit for those conditions, a heavy “snowfall” was observed as the

Al(NO3)3 solution was added to the loop at 71°C (160°F) as shown in Fig. 57.

Figure 57.

“Snowfall” as Al(NO3)3 solution was

added to the loop.

The “snow” dissolved in a few minutes (Fig. 58) and there was no visible buildup of precipitate on the 

bed during most of the test, although the initially clear solution became noticeably cloudier asthe temperature 

decreased. The initiation of cracking in the LEXAN is also evident in Fig. 58. Although the Al(NO3)3

solution was metered in slowly enough so that the average concentration in a control volume extending over

the whole cross–section at the injection point, the local concentration was obviously higher. The locally high

concentration and corresponding local decrease in pH caused the solubility limit to be exceeded locally,

although as mixing occurred, the precipitates redissolved.

Figure 58.

"Snow" dissolved in a relatively few

minutes. The initiation of cracking in the

LEXAN is also evident.
54

The pressure and temperature histories during the test are shown in Fig. 59. An increase in pressure is

noted almost immediately after the Al(NO3)3 is added even at 71°C (160°F). There does seem to be a slight

lag in the pressure increase as the temperature is rapidly decreased. The test was halted as temperature

dropped to ≈ 90°F, and the 0.1 ft/s velocity could not be maintained. Although the test was compromised by

the formation of the nonprototypical “snowfall”, it does indicate a strong potential for Al concentrations of

this magnitude to greatly increase pressure drops across a bed.

After test was halted, the loop was kept at rest overnight. Due to the cracking, most of the fluid drained

from the top half of the loop, and a thick white “jello” layer formed on top of the bed.

The cracking in the LEXAN was not completely unexpected. The susceptibility of LEXAN to

degradation in NaOH environments has been noted in the literature, but a polycarbonate window (LEXAN is

a GE trade name for their polycarbonate material) had performed without any problems in a similar

environment for 30 days in the ICET chamber at UNM. The difference in performance may be due to

differences in the particular resins used or in the higher residual stresses that may occur in an extruded tube

versus a flat plate. A clear PVC test section was used for all subsequent tests in NaOH environments.

To minimize premature precipitation of Al(OH)3, instead of a single injection point as in the first test in

an ICET–1 environment, in all subsequent tests with dissolved Al, a sparger was used to get a more uniform

distribution over the cross section of the Al(NO3)3 solution during injection. The injection rate was also

decreased. This reduced, but did not completely eliminate the problem.

Figure 59.

375 ppm Al additions resulted in large

increases in pressure drop

3.4.2 ICET-1-1-B2_100ppm test procedure and results

ICET-1-1-B2_100ppm test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution. NaOH was

added to make the pH 10. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. After the

chemical solution was prepared, the physical debris bed was built by adding a slurry containing 15 g NUKON

to the loop with the loop flow at 0.1 ft/s. The bed was about 5/8 in thick. The flow velocity was maintained

at 0.1 ft/s for the whole test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 100 ppm after all the solution was added. The temperature was then decreased to 16°C(60°F)
55

with short holds at 49°C (120°F), and 38°C (100°F). The test was continued at 16°C (60°F) for a hour and

then terminated.

ICET-1-1-B2_100ppm test results

The temperature and pressure history during the test is shown in Fig. 60. There is a small decrease in

pressure drop as the temperature increases and a small increase in the pressure drop as the temperature

decreases that are consistent with the changes in viscosity. No significant increase in pressure drop over that

expected for the NUKON bed alone was observed and no precipitation products were observed either during

the test or after the loop was allowed to remain still overnight.

Figure 60. Pressure and temperature history in test ICET-1-1-B2_100ppm

3.4.3 ICET-1-2-B2_200ppm test procedure and results

ICET-1-2-B2_200ppm test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution. NaOH was

added to make the pH 10. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. After the

chemical solution was prepared, the physical debris bed was built by adding a slurry containing 11.6 g

NUKON to the loop with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The flow velocity was

maintained at 0.1 ft/s for the whole test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 200 ppm after all the solution was added. The temperature was then decreased to 21°C(70°F)

with short holds at 49°C (120°F), and 38°C (100°F) and then terminated.

ICET-1-2-B2_200ppm test results

The temperature and pressure history during the test is shown in Fig. 61. There is a small decrease in

pressure drop as the temperature increases and a small increase in the pressure drop as the temperature

decreases that are consistent with the changes in viscosity. No significant increase in pressure drop over that

expected for the NUKON bed alone was observed and no precipitation products were observed either during

the test or after the loop was allowed to remain still overnight.
56

3.4.4 ICET-1-3-B2_375ppm test procedure and results

ICET-1-3-B2_375ppm test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. LiOH was added as a solution. NaOH was

added to make the pH 10. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. After the

chemical solution was prepared, the physical debris bed was built by adding a slurry containing 11.6 g

NUKON to the loop with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The flow velocity was

maintained at 0.1 ft/s for the entire test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. At this higher concentration the initial “snowfall” was more significant

and appears to have caused a small, very short duration, increase in the pressure drop. The concentration of

the solution was chosen so that the concentration in the loop was 375 ppm after all the solution was added.

The temperature was then decreased to 38°C (100°F) with a short hold at 49°C (120°F). The temperature was

then held at 38°C (100°F) for the duration of the test.

ICET-1-3-B2_375ppm test results

The temperature and pressure history during the test is shown in Fig. 62. There is a small decrease in

pressure drop as the temperature increases and a small increase in the pressure drop as the temperature

decreases that are consistent with the changes in viscosity. There is, as noted previously, a small, very short

duration, increase in the pressure drop just as the Al solution is added. No significant increase in pressure

drop over that expected for the NUKON bed alone was observed until the temperature was decreased to 38°C

(100°F) and held there. However, at that point the pressure drop began to increase and rapidly rose until the 

test had to be terminated because the pump could no longer maintain the flow. This increase in pressure drop

occurred with no visible build–up of precipitation products during the test, although a 20–in. high layer of 

“jello” was observed on top of the bed after the loop was allowed to remain still overnight.

Figure 61. Pressure and temperature history in test ICET-1-2-B2_200ppm
57

In the previous test with 375 ppm of dissolved Al, ICET–1–3, an increase in pressure drop was

observed almost instantly after the Al was introduced even at 71°C (160°F). The reasons for the differences

in behavior are not clear. J. Apps* has suggested that one possibility is that the system needs certain critical

embryos to be present before nucleation can proceed, and that the activation energy for formation of these

embryos is so high that the system persists metastably without their formation unless a criticalsupersaturation

is reached. Although the heavy “snowfall” observed in the previous test appeared to have quickly

redissolved, it might have provided such critical embryos. However, Apps also noted that it is difficult to

imagine that the system would be so clean that no preexisting nuclei were present that could not have induced

nucleation without the presence of embryos. To eliminate heterogeneous nuclei would have required

draconian preparation procedures.

Figure 62. Pressure and temperature history in test ICET-1-3-B2_375ppm

3.4.5 ICET-1-1-B2_100ppm repeat test procedure and results

Because the kinetics of precipitation, especially in systems like aluminum hydroxides where the

initiation precipitation product can be an amorphous colloid, are complex and difficult to control, it was

decided that longer term tests needed to be run. Sufficient experience with the test loop had been gained that

is was deemed acceptable to run it overnight and over weekends unattended. This was the first long–duration

test.

ICET-1-1-B2_100ppm repeat test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution. NaOH was

added to make the pH 10. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. After the

chemical solution was prepared, the physical debris bed was built by adding a slurry containing 11.6 g

NUKON to the loop with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The flow velocity was

maintained at 0.1 ft/s for the whole test.

 

* Personal communication, John Apps, Lawrence Berkeley Laboratory, to W. J. Shack, Tuesday, April 11,

2006.
58

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 100 ppm after all the solution was added. The temperature was then decreased to 27°C

(80°F). For the first two days, the system run with no cooling water overnight so the pump heat increased the

temperature to ≈32°C (90° F) overnight, then the system was cooled back to 27°C (80°F). Over the weekend

the pump was turned off and the system remained at 27°C (80°F). The system was run under these conditions

for about 8 days. Then nitric acid was added to the loop to decrease the pH from 9.6 to 9.4. The system was

then run for another 6 days until the test was terminated.

ICET-1-1-B2_100ppm repeat test results

The temperature and pressure history during the test is shown in Fig. 63. The velocity and pressure

history isshown in Fig. 64. There are small variations in pressure with the diurnal cycles. Part of the change

is due to changes in viscosity as temperature changes; another part is probably an artifact of the temperature

compensation of the pressure transducers. Over the weekend when the pump was off (≈2000–6000 minutes)

the pressure drop vanished. No significant increase in pressure drop over that expected for the NUKON bed

alone was observed until the addition of the nitric acid and the associated decrease in pH. The pressure

variations associated with the diurnal temperature changes are much larger after the pH change. It appears

that once formation of the chemical had been initiated, it was highly reversible with changes in temperature.

No precipitation products were observed either during the test or after the loop was allowed to remain still

overnight after the test was terminated.

Figure 63. Pressure and temperature history in test ICET-1-1-B2_100ppm repeat
59

Figure 64. Pressure and velocity history in test ICET-1-1-B2_100ppm repeat

3.4.6 ICET-1-1-B2_100ppm repeat2 test procedure and results

The ICET-1-1-B2_100ppm repeat test had shown that large pressure drops were possible in a system

with 100 ppm, although the pH had to be decreased to induce an effect. The test was repeated to determine

whether in a longer–term test, it was possible to get a large head loss without the pH change.

ICET-1-1-B2_100ppm repeat2 test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution. NaOH was

added to make the pH 9.5. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. After the

chemical solution was prepared, the physical debris bed was built by adding a slurry containing 11.6 g

NUKON to the loop with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The flow velocity was

maintained at 0.1 ft/s for the whole test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 100 ppm after all the solution was added. The system was held at 60°C (140°F) overnight

The temperature was then decreased to 21°C (70°F). About 2 g of alumina nanoparticles (15 nm) were added

to provide potential nuclei for precipitation. If fully dissolved, they would increase the dissolved Al level by

≈ 8 ppm. Over the weekend the system was run with no cooling water overnight so the pump heat increased

the temperature to ≈32°C (90° F). When the cooling water was turned back on, the temperature decreased to

about 18°C (65°F). The system was held at that temperature 

ICET-1-1-B2_100ppm repeat2 test results

The temperature and pressure history during the test is shown in Fig. 65. These is a rapid increase in

pressure drop starting at ≈ 7500 min (5 days), there seems to a much slower but steadier rise stating at about

3500 min (≈ 1day after the nanoparticles were added). The large pressure drops again occurred with no

visible precipitation products on the bed or cloudiness in the solution were observed either during the test or

after the loop was allowed to remain still overnight after the test was terminated.
60

Figure 65. Pressure and velocity history in test ICET-1-1-B2_100ppm repeat2

3.5 Individual test procedures and results for tests with sodium tetraborate buffering

(ICET–5 environments)

3.5.1 ICET-5-1-B2_042606 test procedure and results

ICET-5-1-B2_042606 test procedure

The loop was filled with deionized water and heated to 60°C (140°F) and circulated at 2 ft/s for 15

minutes to remove dissolved air. It was kept at about 27°C (80°F) overnight. Boric acid in powder form was

slowly added to the loop and circulated until it was dissolved. The LiOH was added as a solution. Sodium 

tetraborate was added to get a pH of 8.3. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals.

After the chemical solution was prepared, the physical debris bed was built by adding a slurry containing

11.6 g NUKON to the loop with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The flow velocity

was maintained at 0.1 ft/s for the whole test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 50 ppm after all the solution was added. The temperature was then decreased to ≈ 21°C

(70°F) and held there for ≈ 6 days. No significant increase in pressure drop was observed. Hydrochloric acid

was used to reduce the pH 0.2 units. No change in pressure drop was observed as the test was run for another

day. Two g of 30 nm alumina particles were then added and the test was continued for another 5 days. At

that time additional Al(NO3)3 was added so that the total Al concentration was increased to 100 ppm. The

pressure drop began to quickly rise and the test was terminated when the pump could no longer maintain flow.

ICET-5-1-B2_042606 test results

The temperature and pressure history during the test isshown in Fig. 66. Despite a decrease in pH and

the addition of nanoparticles, no significant increase in pressure drop in was observed ≈ 11 days of testing.

Only after the Al level was raised to 100 ppm did the pressure drop increase significantly. The large pressure

drops again occurred with no visible precipitation products on the bed or cloudiness in the solution were

observed either during the test or after the loop was allowed to remain still overnight after the test was

terminated.
61

Figure 66. Pressure and velocity history in test ICET-5-1-B2_042606

3.5.1 ICET-3-STB1-A2 test procedure and results

ICET-3-STB1-A2 test procedure

This test was run with the LEXAN test section. The loop was filled with deionized water and heated to

60°C (140°F) and circulated at 2 ft/s for 15 minutes to remove dissolved air. It was kept at about 27°C(80°F)

overnight. Boric acid in powder form was slowly added to the loop and circulated until it was dissolved. The

LiOH was added as a solution. The loop was operated at 1 ft/s for 15 minutes to mix the chemicals. The loop

was heated to 60°C (140°F). A slurry containing 15 g NUKON and 15 g of Cal–Sil was prepared and

maintained at 60°C (140°F) for 30 min prior to adding to the loop. During the 30 min, 1/2 of the sodium 

tetraborate was titrated into slurry at a approximately constant rate. The slurry was then added to the loop

with the loop flow at 0.1 ft/s. The bed was about 1/2 in thick. The remainder of the sodium tetraborate was

titrated in over a 30 min period. The flow velocity was maintained at 0.1 ft/s for the whole test.

After the bed had formed and the pressure drop stabilized, the temperature was raised to 60°C (140°F)

and the Al(NO3)3 solution was added. The concentration of the solution was chosen so that the concentration

in the loop was 50 ppm after all the solution was added. The temperature was then decreased to ≈ 21°C

(70°F) and held there for ≈ 6 days. No significant increase in pressure drop was observed. Hydrochloric acid

was used to reduce the pH 0.2 units. No change in pressure drop was observed as the test was run for another

day. Two (2) g of 30 nm alumina (Al2O3) particles were then added and the test was continued for another 5

days. At that time additional Al(NO3)3 was added so that the total Al concentration was increased to

100 ppm. The pressure drop began to quickly rise and the test was terminated when the pump could no longer

maintain flow.

ICET-3-STB1-A2 test results

The temperature and pressure history during the test is shown in Fig. 67. The initial pressure drop is

somewhat higher than seen in tests with similar NUKON/Cal–Sil loadings and no additional chemical effects.

The pressure drop decreases with time to levels more typical of pure NUKON loading. Thisis consistent with

dissolution of the Cal–Sil from the bed. At least at the Cal–Sil loadings in this test (0.12 g/l), no chemical

products appear to form that could lead to significant additional head losses over those expected from the 

corresponding debris in a chemically inert environment.
62

Figure 67. Pressure and velocity history in test ICET-5-1-B2_042606

3.6 Discussion of the ICET–1 and ICET–5 loop test results

Pressure drops much larger than would be expected from corresponding debris beds in an inert

environment have been observed in environments with NaOH buffer for dissolved Al levels of 375 and

100 ppm. These high pressure drops can occur with no visible precipitates. The increases in pressure drops

are much larger than those expected due to the small changes in bulk fluid properties like viscosity for these 

solutions which are shown in Fig. 68.

Figure 68. Viscosities for ultra high purity (UHP) water and solutions with 50–375 ppm dissolved Al

concentrations.

In Table 7 are shown the results of ICP measurements of supernate solutions from samples taken

periodically during a head loss test. When allowed to remain at room temperature for some time, all the 

samples formed emulsions that settled to the bottom of the sample containers. All the solutions were made by

aluminum nitrate additions to an initially alkaline solution. The samples in Table 7 are from the clear

supernate solutions above the emulsions. This does not, however, preclude the possibility that some fine

precipitates remain. The measurements may somewhat overestimate the solubility of amorphous Al(OH)3 at

room temperature at nominally pH 9.6 in sump solutions. The variability in the results is probably due 

primarily to small variations in pH. Literature estimates of the solubility at room temperature11,12 such as
63

those shown in Fig. 51 give values of 37–59 ppm for pH values 9.4–9.6, which are reasonably consistent with

the results in Table 7.

Table 7. ICP-chemical analysis on the supernate solutions from samples taken from loop

tests with 100, 200, and 375 ppm Al.

Samples

Dissolved Al

[mg/l] Si Ca B Na

Al in

Emulsiona

1-375 - 1.23 2.54 2570.00 4420.30 -

3-375 49.88 0.84 1.31 2380.00 4254.00 325.12

4-375 59.28 0.84 2.39 2390.00 4274.90 315.72

5-375 55.12 0.84 1.01 2370.00 4240.20 319.87

6-375 46.03 0.84 0.82 2310.00 4145.60 328.97

1-200 - 1.57 8.31 2460.00 3831.80 -

2-200 38.42 1.13 3.49 2450.00 3901.10 161.58

4-200 32.00 0.84 2.83 2090.00 3360.90 168.00

5-200 37.49 0.84 2.72 2400.00 3837.70 162.51

6-200 31.14 0.84 2.79 2480.00 3949.00 168.87

1-100 - 4.22 2.47 2470.00 3582.50 -

2-100 50.46 1.30 4.12 2370.00 3471.40 49.544

3-100 37.84 1.29 3.06 2390.00 3468.30 62.163

5-100 62.99 1.44 3.91 2460.00 3559.00 37.013

6-100 44.28 1.14 3.67 2410.00 3509.40 55.720

aEstimate based on the total Al in the base solution and the measured value in the supernate.

Thus for the 100 ppm solution, about half of the Al is estimated to remain in solution and half forms a 

precipitation product. The actual loading on the screen depends not only on this concentration, but also on the

loop volume and screen size. For the ANL loop the volume is 119 liters, and the screen area with the PVC

section is 0.016 m2. Assuming that 50 ppm of the Al has been precipitated out as a product, this means that

there is about 1 kg/m2 of chemical product impinging on the sump screen. With a NUKON loading of 

0.7 kg/m2, this is sufficient to produce the very high pressure drops observed in ICET-1-1-B2_100ppmrepeat

and ICET-1-1-B2_100ppm repeat2.

These estimates assume that the product is Al(OH)3. The real amount of product is probably larger

since water is undoubtedly incorporated into the structure. However, whatever the real product is, this

approach can be used to scale the loading on the screen in the test to the loading in situations with a different

screen area/ volume ratio.

Subsequent tests with a surrogate precipitate produced externally following the procedure outlined in

Reference (15) and then added to the loop suggest that even much lower loadings of precipitation product

(< 0.1 kg/m2) are sufficient to produce high head losses in debris beds with a NUKON loading of 0.7 kg/m2.

To form a product, the dissolved Al concentration (which is controlled by the amount of Al in

containment) must exceed the solubility limit. The literature data suggest that for a temperature of 4°C(40°F)

and a pH of 9.2, this is ≈ 30 ppm in Al/NaOH solutions. This might be considered a practical lower bound on

Al concentrations that can form precipitates and would increase with the pH and temperature of the sump. At

60°C(140°F) and a pH of 9.2, the amorphous solubility is ≈370 ppm. However, because of the complexity of

the sump environment, it the applicability of the literature data to this situation has not been established. In

Ref. (15) it is recommended that all the dissolved Al be assumed to form a precipitation product.
64

In short–term laboratory testing with surrogate solutions, the kinetics of the formation of chemical

products can lead to substantial test–to–test variability. The rapidity with which precipitation products

formed towards the end of the 30 day test period in the ICET–1 test

2 suggests that kinetics will be less

limiting in an actual plant situation.

Sodium tetraborate buffers seem more benign than NaOH or TSP. A submerged Al area and sump

volume that results in a 375 ppm dissolved Al concentration in a NaOH environment, results in a 50 ppm 

dissolved Al concentration with a sodium tetraborate buffer. The 375 ppm concentration resulted in high

head loss in 0-2 h with a NaOH buffer; the corresponding 50 ppm concentration produced no significant head

loss observed in ≈ 11 days with a STB buffer. Interaction with NUKON/Cal–Sil debris mixtures produced

much lower head losses than observed in corresponding tests with TSP, although tests were not performed

over the full range of Cal–Sil loadings that might be of interest.
65

4 Benchmark tests

4.1 Background

Baseline tests with minimal chemical effects were performed for comparison with tests in which

chemical effects might be expected to occur. However, to facilitate comparison with ongoing related work at

Pacific Northwest National Laboratory (PNNL) additional benchmark tests were run at relatively low

temperatures with no chemical additions to minimize potential chemical effects. The PNNL tests are

described in Ref. 16. The objective of the tests was to benchmark the test loops against each other by

comparing head loss measurements as a function of screen approach velocity, debris bed dimensions, and

post-test debris mass measurements.

4.2 Procedures and test matrix

The target NUKON and Cal–Sil loadings for each of the tests are shown in Table 8. A repeat test was

performed for each of the loading conditions in Table 8. In order to minimize any differencesin results due to

differences in test procedures, this series of tests was performed under detailed test protocols that were

coordinated with the researchers at PNNL in order to obtain a measure of laboratory to laboratory variability

due to uncontrolled or unknown variables. Detailed test protocols were developed by C. W. Enderlin and B.

E. Wells of PNNL and are described in Appendix F. They include details on the preparation of the NUKON

and Cal–Sil in order to get a consistent “fineness” of the debris. The two types of debris were thoroughly

mixed before adding to the loop and no presoak period was used. The debris slurry is to be introduced into

the test loop with the screen approach velocity at 0.1 ft/s. During debris bed formation the screen approach

velocity isto be maintained between 0.09 and 0.1 ft/s. The fluid temperature during bed formation and forthe

duration of the test is to be maintained at 25° ± 5°C (77° ± 9°F). In order to assure that measurements were

made under steady–state conditions, the absolute change in head loss was to be lessthan 2% over a 10 minute

measurement period. The criteria had to be assessed and satisfied three times. The minimum time between

assessments was one minute.

The tests were performed with the LEXAN cross–section and the flow screen with 40% flow area and

1/8 in. holes with 3/16 in. staggered centers. After the initial formation of the bed, a prescribed velocity

sequence was followed in each test. The sequence is shown in Table 9. The test times at each point in the test

sequence were not prescribed, but were determined based on whether the pressure at that point met the criteria

for a steady–state value.

Table 8. Benchmark test cases for ANL and PNNL test loops

Test No.

Nukon Mass

Loading

lb/ft2 (kg/m

2

)

Cal–Sil Mass

Loading

lb/ft2 (kg/m

2

)

Total Mass

Loading

lb/ft2 (kg/m

2

)

Cal–Sil to

Nukon Mass

Ratio

BM-1 0.044

(0.217)

0.0

(0.0)

0.044

(0.217)

0.0

BM-2 0.148

(0.724)

0.0

(0.0)

0.148

(0.724)

0.0

BM-3 0.148

(0.724)

0.030

(0.145)

0.178

(0.869)

0.2
66

Table 9. Velocity sequence for the ANL and PNNL test loop benchmark cases

Test point

Velocity

(ft/s) Test sequence

Initial condition 0.10 Bed Formation

1 0.10 Ramp down 1

2 0.05 Ramp down 1

3 0.02 Ramp down 1

4 0.05 Ramp up 1

5 0.10 Ramp up 1

6 0.05 Ramp down 2

7 0.02 Ramp down 2

8 0.10 Ramp up 2

9 0.15 Ramp up 2

10 0.20 Ramp up 2

11 0.15 Ramp down 3

12 0.10 Ramp down 3

13 0.15 Ramp up 3

14 0.20 Ramp up 3

15 0.10 Ramp down 4

16 0.05 Ramp down 4

17 0.02 Ramp down 4

18 0.10 Ramp up 4

*Up and down indicate a velocity increase or decrease,

respectively

4.3 Results of the benchmark tests

The pressure and velocity in the benchmark tests as a function of time during the test are shown in Figs.

69–74. In these tests some drift is occurring in the p1 transducer, which measures the pressure difference

between two points, one 2.5 inches above the screen and the other 2.5 inches below the screen. The p2

transducer, which measures the pressure difference between points 12.0 inches above and below the screen,

was used in all tests for the reported values of the pressure drop.

Figure 69. Pressure and velocity history in test BM–1–A2–N4.6
67

Figure 70. Pressure and velocity history in test BM–1–A2–N4.6 repeat 2/28/06

Figure 71. Pressure and velocity history in test BM–2–A2–N15.5
68

Figure 72. Pressure and velocity history in test BM–2–A2–N15.5 repeat

Figure 73. Pressure and velocity history in test BM–3–A2–N15.5–C3.1
69

Figure 74. Pressure and velocity history in test BM–3–A2–N15.5–C3.1 repeat

The results of the benchmark tests are summarized in terms of the relation between pressure and flow

velocity in Fig. 75–77. The relation is close to linear over the velocity range in the tests. Some hysteresis is

observed, i.e., the pressure at a given velocity (e.g., 0.1 ft/s) is not unique. It depends on the previous flow

history. This can also be seen in Table 10, which gives the approximate bed thickness at the final step in the 

flow history. The beds compress as the velocities and pressure drops increase. Some of this change in

thickness is elastic and a bed that is compressed at a higher velocity tends to expand as the velocity is

subsequently decreased. But some of the thickness change is irrecoverable, and all the beds are more

compressed at the end of the test sequence, although the final velocity is the same as the initial velocity.

Table 11 compares the amount of debris added with the final weight of the dried bed. For tests BM–1 and

BM–2 the recovered fraction is higher for the thicker bed. This may reflect the greater filtering capability of 

the bed and its ability to remove smaller fines that could pass through a thinner bed. The recovered fraction is

lower for BM–3 than for BM–2. This may reflect the fineness of some of the particulate generated by the

Cal–Sil. The high effective surface area of the Cal–Sil may also lead to dissolution even at the low

temperature of these tests. Although the primary component of Cal–Sil is CaSiO3, it could contain ≈5%

Na2SiO3, which is relatively soluble and would be expected to dissolve.

Figures 75a and b, 76a and b, and 77a and b show the repeatability of the tests. The variability in the 

slopes between the replicate tests is about ±10%; the uncertainty in the slope for an individual test is about

±5%. Figures 75c, 76c, and 77c show PNNL results for their parallel BM–1, 2, and 3 tests. The agreement

with ANL results is good for BM–3. Their results are within the scatter for the two ANL BM–3 tests.

However, there are significant differences between the ANL and PNNL results for BM–1 and 2. The increase 

in pressure drop per unit increase in velocity determined in the PNNL tests is about twice that determined in

the ANL, which is much larger than would be expected just from test to test variability.

The reasons for these differences are not clear. The processing of the NUKON fiberis done similarly at

the two laboratories, but the equipment used is different and thus different blending times may be used.

PNNL developed a test based on the amount of water retained by the shredded fiber blanket that wasintended

to assure the processing results were consistent even though different equipment and processing times were

used. The processing at PNNL and ANL resulted in processed fiber that retained similar amounts of water.

However, it may be for the relatively thin beds in BM–1 and BM–2, that this was not sufficient to ensure

similar flow resistances. In the BM–3 test the presence of the particulate from Cal–Sil may overwhelm any
70

differences due to the processing of the fiber, and the differences in the pressures drops between the ANL

results and the PNNL results are on the order of the test–to–test variability at ANL.

There may also be variations due to the differences in the sensitivities of the pressure measurement

instruments in the two flow loops. The transducers in the ANL loop are rated at 1.5% error at full scale,

150 psi. The PNNL measurements were made with transducers rated at ≈ 1 or 5 psi. Thus their uncertainty

would be expected to be smaller for these tests. However, independent checks show that the transducers used

in the ANL tests are in fact more accurate than implied by their rating and that the differences between the

ANL and PNNL are much larger than can be explained by transducer error. This is consistent with the results

of the BM–3 tests where the pressure drops are still small, but the agreement between the two labs is within

the test–to–test variability. Thus it seems more likely that differences between the ANL and PNNL results in

the BM–1 and 2 tests reflect genuine differences in flow resistance from beds developed from fibers with

different processing histories. A more definitive assessment would require additional testing using the ANL

procedure for preparing the fibers and pressure transducers better matched to actual pressure drops.

(a) ANL BM–1 (b) ANL BM–1 replicate

(c) PNNL BM–1

Figure 75. Pressure drop as a function of flow velocity (a) ANL BM–1, (b) replicate test ANL BM–1, and

(c) PNNL BM–1
71

(a) ANL BM–2 (b) ANL BM–2 replicate

(c) PNNL BM–2

Figure 76. Pressure drop as a function of flow velocity (a) ANL BM–2, (b) replicate test ANL BM–2, and

(c) PNNL BM–2
72

(a) ANL BM–3 (b) ANL BM–3 replicate

(c) PNNL BM–3

Figure 77. Pressure drop as a function of flow velocity (a) ANL BM–3, (b) replicate test ANL BM–3, and

(c) PNNL BM–3
73

Table 10. Bed heights in benchmark test

Bed Height (mm)

Test point

Velocity

(ft/s) BM–1

BM–1

repeat BM–2

BM–2

repeat BM-3

BM-3

repeat

1 0.10 4.0 5.5 12.0 12.0 12.0 12.0

2 0.05 5.0 5.5 13.0 12.5 12.0 12.0

3 0.02 5.5 6.5 13.5 13.5 12.5 13.0

4 0.05 5.0 6.0 13.5 12.5 12.0 12.0

5 0.10 4.5 5.5 11.5 12.5 9.0 11.5

6 0.05 5.0 5.5 12.0 12.0 12.0 11.5

7 0.02 5.0 6.0 13.0 13.0 12.0 11.5

8 0.10 4.5 5.0 11.0 11.5 10.0 10.5

9 0.15 4.0 5.0 10.5 9.0 12.0 10.0

10 0.20 4.0 4.5 9.0 9.5 8.0 9.5

11 0.15 4.0 4.5 9.0 9.5 9.5 9.5

12 0.10 3.5 4.5 9.0 9.5 10.0 10.0

13 0.15 3.5 4.5 9.0 9.5 9.5 9.5

14 0.20 3.5 4.5 9.0 9.5 8.5 9.5

15 0.10 4.0 4.5 9.5 9.5 10.0 9.5

16 0.05 4.0 5.0 10.0 10.0 10.0 10.0

17 0.02 4.0 5.0 11.0 11.5 10.0 10.0

18 0.10 3.5 4.5 9.5 10.5 9.0 10.0

Table 11. Initial debris load and final weight of the bed

Test run

Initial weight

NUKON, Cal–Sil

(g)

Weight,

dried bed (g)

Fraction

captured

BM-1 4.6 3.76 0.83

BM–1 replicate 4.6 3.80 0.83

BM-2 15.5 14.89 0.96

BM–2 replicate 15.5 14.58 0.94

BM-3 15.5, 3.1 15.63 0.84

BM-3-Repeat 15.5, 3.1 15.13 0.81
74

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75

5 Summary

A test loop that can be used to measure head losses due to chemical effects has been constructed. The

piping in most of the loop is CPVC; the clear test section containing the test screen was either LEXAN or

clear PVC. The heater and cooler sections are stainless steel. Temperatures around the loop during operation

are typically ±0.6°C (1°F). Loop velocities can be controlled over the range from 0.02 to 2 ft/s. Physical

debris and chemicals are introduced to the loop through a charging port at the top of the loop. The loop has a

horizontal screen. This orientation is not intended to reflect a plant situation in which the screen orientation

may be primarily vertical, but rather to permit the development of uniform beds with well–defined

characteristics. The head loss behavior for such beds would characterize the local head loss behavior of more

complex, nonuniform beds that might form on more complex screen geometries.

A series of tests were performed to evaluate the potential for head loss due to chemical effectsin a TSPbuffered environment with NUKON and Cal–Sil insulation. The tests were designed to explore conditions

corresponding to a range of debris amounts, containment sump residence times, and TSP dissolution times.

The NUKON and Cal–Sil mass loading per unit screen area utilized in these tests are reasonably

representative of those plantsthat currently have, or will have after sump modifications, relatively low debris

mass loading (i.e., less than 2 kg/m2).

The tests show that head losses associated with pure physical debris beds of NUKON and Cal–Sil are

typically much smaller than those that occur across debris beds in which some of the Cal–Sil has been

replaced with a corresponding amount of calcium phosphate precipitates. This increase in head loss was

observed both when significant dissolution of the Cal–Sil occurred prior to the formation of the bed, and

when the dissolution and formation of the precipitate occurred subsequent to the build–up of Cal–Sil in the

bed.

The relative importance of chemical effects depends strongly on the debris loading at the screen. For a

screen loading corresponding to 0.71 kg/m2 of Cal–Sil and an ≈ 12 mm thick NUKON bed (0.71 kg/m2), the

pressure drop across the physical debris bed in benchmark testing in chemically inactive environments is

approximately 1.4 psi at an approach velocity of 0.1 ft/s. With TSP, and thus calcium phosphate precipitates

present, the same debris loading caused the pressure drop across the bed to be greater than 5 psi for the same

approach velocity. For a thin NUKON bed (≈ 3 mm), very large pressure drops were observed for the lowest

tested Cal–Sil loading, 0.47 kg/m2. However, with thicker ≈ 12 mm NUKON beds, little chemical effect

could be observed for Cal–Sil loadings ≤ 0.47 kg/m2. These results show that the relation between head loss

and fiber loading for a given particulate loading is highly nonlinear and not monotonic.

Beds in which no NUKON was present were also examined. In this case, a significant portion of the 

screen remains open for the highest screen loading of Cal–Sil tested, 1.2 kg/m2. The pressure drops are very

low with this open area.

Dissolution tests showed that virtually complete leaching of calcium from the Cal–Sil could take one to

four days or more depending on the TSP dissolution rate and the Cal–Sil concentration. Dissolution of low

Cal–Sil concentrations (≤ 1.5 g/l) is retarded by instantaneous TSP dissolution. However, the Cal–Sil

dissolution rate (for the concentrations studied) is notstrongly dependent on the TSP dissolution rate for more

realistic TSP dissolution rates. Even with instantaneous dissolution of the TSP, the equivalent dissolved Ca 

exceeded 75 mg/l in a few hours for Cal–Sil concentrations as low as 0.5 g/l. Such an equivalent dissolved

Ca concentration was shown to produce pressure drops on the order of 5 psi at an approach velocity of 0.1 ft/s

across a 0.71 kg/cm2 NUKON debris bed.

Settling tests were performed to determine settling ratesfor calciumphosphate under conditions with no

bulk directional flow. At higher dissolved calcium concentrations (300 ppm), the precipitates can

agglomerate. The agglomerated precipitates settle more quickly, but approximately one half of the total

precipitate settles more slowly than the agglomerated precipitate. At a lower dissolved calciumconcentration
76

(75 ppm), which is expected to be more representative of plant conditions, the estimated settling velocity is

0.8 cm/min.

Significant chemical effects are also observed in environments with significant dissolved aluminumand

NaOH buffers which correspond to the ICET–1 test. Pressure drops much larger than would be expected

from corresponding debris beds in an inert environment have been observed in environments with NaOH

buffer for dissolved Al levels of 375 and 100 ppm. These high pressure drops can occur with no visible 

precipitates. They occur although there are very small changes in bulk fluid properties like viscosity forthese

solutions.

Tests were also performed to simulate environments in which sodium tetraborate is used to buffer pH.

Sodium tetraborate buffers seem more benign than NaOH or TSP. A submerged Al area and sump volume

that resultsin a 375 ppm dissolved Al concentration in a NaOH environment, results in a 50 ppmdissolved Al

concentration with a sodium tetraborate buffer. A submerged Al area sump volume that resulted in high head

loss in 0-2 h in NaOH buffer, no significant head loss observed in ≈ 11 days with STB buffer. Interaction

with NUKON/Cal–Sil debris mixtures produced much lower head losses than observed in corresponding tests

with TSP, although tests were not performed over the full range of Cal–Sil that might be of interest.

Small–scale dissolution tests were performed on NUKON in different environments, including one with

roughly 1/4 the relative surface area of Al metal as was present in ICET–1. The inhibition of NUKON

dissolution observed in ICET–1 was also observed in the case of the lower surface area of Al metal.

To facilitate comparison with ongoing related work at Pacific Northwest National Laboratory (PNNL) 

additional benchmark tests were run at relatively low temperatures with no chemical additions to minimize

potential chemical effects. The objective of the tests was to benchmark the test loops against each other by

comparing head loss measurements as a function of screen approach velocity, debris bed dimensions, and

post-test debris mass measurements. Three test series were run. Two had NUKON only debris beds with

thicknesses of ≈ 4 and 12 mm, respectively. The third had a NUKON/Cal–Sil bed ≈ 12 mmthick. The results

of the testsshowed good reproducibility of test resultsin the ANL flow loop. There was also good agreement

between the ANL and PNNL tests with the NUKON/Cal–Sil beds. However, for the tests with NUKON only

beds, the flow resistance determined in the tests at PNNL was about twice that observed in the corresponding

tests at ANL.

The reasons for these differences are not clear. It is most likely due to differences in the processing of

the NUKON fiber. This processing is done similarly at the two laboratories, but the equipment used is

different and thus different blending times may be used. PNNL developed a test based on the amount of

water retained by the shredded fiber blanket that was intended to assure the processing results were consistent

even though different equipment and processing times were used. The processing at PNNL and ANL did

results in processed fiber that retained similar amounts of water. However, it may be for relatively thin

NUKON beds, this was not sufficient to ensure similar flow resistances. In the test with the NUKON/Cal–Sil

bed, the presence of the particulate from Cal–Sil may overwhelm any differences due to the processing ofthe

fiber, and thus good agreement is obtained between the results developed at the two laboratories.
77

References

1. T. S. Andreychek, Test Plan: Characterization of Chemical and Corrosion Effects Potentially Occurring

Inside a PWR Containment Following a LOCA (ADAMS ML052100426)

2. J. Dallman, B. Letellier, J. Garcia, J. Madrid, W. Roesch, D. Chen, K. Howe, L. Archuleta, and F.

Sciacca, F. Integrated Chemical Effects Test Project: Test # 1 Data Report, NUREG/CR-6914, Volume 

2, U.S. Nuclear Regulatory Commission, Washington, D.C., 2006.

3. J. Dallman, B. Letellier, J. Garcia, M. Klasky, W. Roesch,J. Madrid K. Howe, and D. Chen,Integrated

Chemical Effects Test Project: Test # 2 Data Report, NUREG/CR-6914, Volume 3, U.S. Nuclear

Regulatory Commission, Washington, D.C., 2006.

4. J. Dallman, B. Letellier, J. Garcia, J. Madrid, W. Roesch, D. Chen, K. Howe, L. Archuleta, and F.

Sciacca, Integrated Chemical Effects Test Project: Test # 3 Data Report, NUREG/CR-6914, Volume 4,

U.S. Nuclear Regulatory Commission, Washington, D.C., 2006.

5. J. Dallman, B. Letellier, J. Garcia, J. Madrid, W. Roesch, D. Chen, K. Howe, L. Archuleta, and F.

Sciacca, Integrated Chemical Effects Test Project: Test # 4 Data Report, NUREG/CR-6914, Volume 5,

U.S. Nuclear Regulatory Commission, Washington, D.C., 2006

6. J. Dallman, B. Letellier, J. Garcia, J. Madrid, W. Roesch, D. Chen, K. Howe, L. Archuleta, and F.

Sciacca, Integrated Chemical Effects Test Project: Test # 5 Data Report, NUREG/CR-6914, Volume 6,

U.S. Nuclear Regulatory Commission, Washington, D.C., 2006.

7. ANL Quick Look Report Tests 1 & 2, September 16, 2005 (ADAMS ML052590238)

8. MEMORANDUM on "Summary of Meeting on September 30, 2005, to Discuss GSI-191 Chemical

Effects Head Loss Information," dated November 2, 2005, ADAMS Accession Number

ML053060359, http://www.nrc.gov/reactors/operating/ops-experience/pwr-sump-performance/publicmtgs/2005/index.html

9. Solubility of Calcium Phosphates, http://www.azom.com/details.asp?ArticleID=2140.

10. M. Klasky, J. Zhang, M. Ding, , B. Letellier, D. Chen, and K. Howe, Aluminum Chemistry in

Prototypical Post-LOCA PWR Containment Environment, NUREG/CR-6915, U.S. Nuclear Regulatory

Commission, Washington, D.C., 2006

11. H. A. van Straten, B. T. W. Holtkamp, and P. L. de Bruyn, “Precipitation from Supersatured Aluminate 

Solutions”, Journal of Colloid and Interface Science V. 98, No 2, April 1984, pp 342–362

12. D. Langmuir, Aqueous Environmental Geochemistry, Prentice Hall, New York, 1996

13. P. Benezeth, D.A. Palmer and D.J. Wesolowski (2001) Aqueous high-temperature solubility studies.II.

The solubility of boehmite at 0.03m ionic strength as a function of temperature and pH as determined

by in situ measurements, Geochimica et Cosmochimica Acta, v. 65, pp. 2097-2111.

14. J. McMurry, V. Jain, X. He, D. Pickett, R. Pabalan, and Y. M. Pan, GSI-191 PWR Sump Screen

Blockage Chemical Effects Tests-Thermodynamic Simulations, NUREG/CR-6912, U.S. Nuclear

Regulatory Commission, Washington, D.C., 2006.

15. A. E. Lane, T. S. Andreychek, W. A. Byers, R. J. Jacko, E. J. Lahoda, and R. D. Reid, Evaluation of

Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191, WCAP-16530-NP,

Revision 0, 2006.
78

16. C. W. Enderlin, B.E.Wells, M. White, F. Nigl, A. Guzman, D. R. Rector, T. J. Peters, and E. S. Mast,

Experimental Measurements of Pressure Drop Across Debris Beds on PWR Sump Screens in Support

of Generic Safety Issue 191, NUREG/CR-6917, U.S. Nuclear Regulatory Commission, Washington

D.C., 2006.

For more information on the ICET program see: http://www.nrc.gov/reactors/operating/opsexperience/pwr-sump-performance/tech-references.html
Appendix A Chemical Compatibility Tests on CPVC and LEXAN

Two polymers, CPVC and LEXAN, were selected as candidates for portions of the flow loop. Solution

leaching tests for the candidate polymers were performed to support the design of the flow loop. The

leaching tests at were performed at 200°F in ultra high purity (UHP) water; in a solution with B 2800-

ppm, Li 3-ppm, HCl 100-ppm, and pH = 10 with NaOH additions; and in a solution with B 2800-ppm, Li

3-ppm, HCl 100-ppm, and pH = 7 from trisodium phosphate additions. 

A1. Weight change

The test samples were prepared from samples of CPVC and LEXAN tubing. The physical shape for both

polymers was made identically for targeting the direct comparison on the compatibility. The test was

performed in open air in quartz containers with a cooling condenser to avoid changes in the solution

during the test. The test results are summarized in Fig. A1 and Table A1. Both the CPVC and LEXAN

gained weight by water absorption. 

Figure A1.

Compiled weight change data for the

CPVC and LEXAN exposed time period

22 to 117-h at 93  ̊C in the UHP-water,

pH = 10.0 solution, and pH = 7.0 TSP

solutions.

Transparent corrosion products were observed in both the CPVC and LEXAN tests. The products grew into

large thin flat crystals (1.0-1.5 cm sharp leaf shape) during the tests. When agitated slightly with a glass

bar, the large thin crystals disintegrated into fine fragments (1-mm size) and settled down to the bottom of

the chambers. The container with CPVC samples had more corrosion product than the container with the

LEXAN samples, and it showed qualitatively more corrosion product than that of LEXAN throughout the

test. All the samples gained weight due to the absorption during the leaching test as shown in Figs. A1-A3.

However, if the sample was dried in air for a weekend (70-h), most of the absorbed water in the LEXAN

was released, but about 30% was left in the CPVC as shown in Fig. A2. 

A1
-0.20

0.00

0.20

0.40

0.60

0.80

1.00

CPVC-1CPVC-2CPVC-3

LEXAN-1LEXAN-2LEXAN-3

After 22-h Tested (air dried 1-h)

After 70-h air dried

Weight Changed (mg/cm

2

-22-h)

Figure A2

Weight change (mg/cm2) vs. various samples for

22-h leaching test at T= 93 ̊C.

Table A1. Compiled weight change data for the CPVC and LEXAN exposed time period at 93  ̊C

in the UHP-water, pH = 10.0 solution, and pH = 7.0 TSP solution.*

# Solution Wi (g) Wf (g) ΔW (g) A(cm2)

ΔW/A

(mg/cm2) Note

CPVC 1

2

3

LEXA

N

1

2

3

UHP

93 ̊C

22-h

1.073 1.078 0.005 6.96 0.70

1.046 1.051 0.005 6.81 0.70

1.168 1.174 0.005 7.49 0.72

1.377 1.382 0.006 9.98 0.57

1.399 1.405 0.006 10.1 0.57

1.323 1.329 0.005 9.66 0.56

Wt. gain by water absorption

CPVC 4

5

6

LEXA

N

4

5

6

pH =

10.0

93 ̊C

116-h

1.076 1.087 0.011 6.98 1.59

1.152 1.164 0.012 7.40 1.64

1.348 1.361 0.014 8.48 1.61

1.393 1.398 0.004 10.08 0.48

1.469 1.474 0.005 10.54 0.500

1.430 1.435 0.005 10.31 0.49

Wt. gain by water absorption

CPVC 7

8

9

1

LEXA

N

7

8

9

1

pH =

7.0

TSP

93 ̊C

52-h

1.043 1.052 0.008 6.73 1.25

1.109 1.118 0.009 7.16 1.26

0.964 0.972 0.008 6.22 1.34

0.919 0.927 0.007 5.93 1.23

0.682 0.684 0.002 3.94 0.52

0.931 0.934 0.003 5.38 0.49

0.906 0.908 0.003 5.23 0.52

0.910 0.913 0.003 5.26 0.56

Wt. gain by water absorption and

loosed by the corrosion product

transferred into the solutions

*Wi initial weight; Wf final weight; ΔW=Wf-Wi; A area of sample exposed

A2. Electrical conductivity and SEM/EDS analysis of leachants

In-situ electrical conductivity was also monitored throughout the leaching tests. The leached solutions

were dried and the residues examined by SEM/EDS.

Ultra high purity (UHP) water

The in-situ electrical conductivity during the leaching tests is shown in Fig. A3. The electrical

conductivity measured and determined by EIS analysis within the frequency ranges between 1-Hz and

300-kHz for leaching in UHP water near 93°C for the period between 6 and 22-h for as received CPVC

and LEXAN.

A2
Figure A3.

The electrical conductivity measured and

determined by electrochemical impedance

spectroscopy (EIS) analysis within the

frequency ranges between 1-Hz and 300-kHz

for leaching in UHP water near 200 ̊F for

periods of 6-h (closed symbols) and 22-h

(open symbols) for CPVC (circle symbols) and

LEXAN (square symbols).

The organic polymer residues left after the leached solution was dried were examined by

SEM/EDS. The residue of the LEXAN leached solution dried on the platinum foil under vacuum

had a long (2-3 mm long) fiber form as shown in Fig. A4(a), likewise the residue of the CPVC

leached solution had a similar fiber form as shown in Fig. A4(b) and A4(c).

(a) (b) (c)

Figure A4. EDS view for the fiber form residue on the platinum for the (a)

LEXAN; (b) and (c) CPVC leached solution.

NaOH buffer pH = 10

The conductivities of the solutions during the tests in the NaOH environment are shown in Fig. A5 as the

ratio of conductivity at time t, σ(t) to the initial conductivity, σ(0). The CPVC has a higher leaching rate

and a higher absorption rate than the LEXAN in both the UHP-water and the pH = 10.0 solution

Figure A5.

Ratio of conductivity at time t with initial conductivity during

the leaching test at 293°C in the pH = 10.0 solution for the

LEXAN and the CPVC leaching test in the 125-ml solutions.

A3
(a) (b) (c)

Figure A6. (a) SEM views for the dried from the CPVC leached pH = 10 solution,

(b) extended view from (a), and (c). LEXAN leached pH = 10.0.

The conductivity results suggest that the leaching has greatly slowed after ≈ 100 h. The residues after

drying are shown in Fig. A6.

pH = 7 (RT) TSP solution

The conductivity in the TSP solution is shown in Fig. A7 in terms of the ratio of conductivity at time t,

σ(t), with initial conductivity, σ(0).

Figure A7.

Ratio of conductivity at time t with initial conductivity

during the leaching test at 93°C in the pH = 7.0 (RT)

solution for the LEXAN (3.5-g) and the CPVC (4-g)

leaching test in the 125-ml solutions.

Based on the results our leaching tests, it can be concluded that the CPVC has higher leaching and also

water absorption rate than the LEXAN in the UHP-water and in the pH = 10.0 solution, but CPVC less

absorption in the pH = 7.0 TSP solution. No clouding of the LEXAN was observed nor was cracking

observed in either of the materials in any of the environments. 

A4
Appendix B Cal–Sil leaching tests

B1. Background

The Cal–Sil leaching tests for the ICET-3 environments focused on temperatures between 60 and 85°C, a

pH range between 4 and 10, and times between 5 min and 15 days.

 

Preliminary experiments were performed to compare the dissolution rate of pulverized Cal–Sil and a

much coarser Cal–Sil debris, roughly 6 x 6 x 6 mm blocks. The two types of debris were exposed to a

simulated sump solution with 2800-ppm-B, 7-ppm-Li, and 100-ppm-HCl and TSP additions to adjust the

solution pH to 7.0. Electrical conductivity was used to continuously monitor the Cal–Sil dissolution.

Figure B1(a) shows the electrical conductivity of the solution vs. time of exposure for the two types of

Cal–Sil/l debris, and for the solution without debris. Figure B1(b) shows the net variation of electrical

conductivity vs. time after subtracting off the contribution from the solution. The dissolution kinetics of

the two types of debris are quite similar. The very high porosity of the Cal–Sil makes the leaching

kinetics of the nominally solid blocks comparable to the pulverized Cal–Sil. A SEM picture of the

pulverized Cal–Sil is shown in Fig. B2. 

The chemical composition of the Cal–Sil is shown in Table B1. The composition is consistent with the

assumption that Cal–Sil is primarily CaSiO3. The dominant elements are Ca (21%) and Si (17%), but

there are also about 2% alkali metals present. The Na and K compounds will dissolve rapidly and

increase the pH. Ca also tends to increase the pH, but the Ca compounds will dissolve more slowly. 

Dissolved Ca reacts quickly with anions such as PO4

-3

in aqueous environments. The solubility of most

Ca-compounds is very low compare with the other inorganic compounds, and Ca-compounds typically

have retrograde solubility, i.e., the solubility decreases with increasing temperature. The solubility of

Ca3(PO4)2 at pH = 6.8–7.1 in the presence of excess phosphate is shown in Fig. B3. 

When trisodium phosphate is added to the leached Cal–Sil solution, the calcium and phosphate can

combine to form a variety of compounds. X–ray diffraction studies at the University of New Mexico by

K. Howe and D. Cheng (Fig. B4) show that the spectrum from deposits in the ICET–3 test match well

with Ca3(PO4)2·x H2O (tricalcium phosphate hydrate), Ca5(PO4)3(OH) (hydroxyapatite), and

Ca9HPO4(PO4)5OH (calcium hydrogen phosphate hydroxide).

For simplicity the chemical reaction of the Ca and silicate leached from the Cal–Sil with the trisodium

phosphate can be considered as

3Ca

+2+ 3SiO3-2 + 6Na+ + 2PO4-3 = Ca3(PO4)2↓ + 6Na++ 3SiO3-2

(B1)

with Ca3(PO4)2 as the primary precipitation product. As discussed previously, at the temperatures of

interest in the sump Ca3(PO4)2 is relatively insoluble (Fig. B3).

B1
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

powder

Block

∆σ (m-M

HO)

t (h)

CalSil in TSP T = 85

o

C

(a) (b)

Figure B1 (a) Measured electrical conductivity change of the solution during the leaching of Cal–Sil

blocks and powder in an ICET-3 type solution at 85°C with B = 2800-ppm, Li = 3-ppm,

HCl = 100-ppm in pH = 7.0 by TSP addition, and (b) the net variation of electrical

conductivity vs. t after subtracting the contribution of the base TSP solution,

Figure B2

Powdered Cal–Sil.

B2
0.0

0.5

1.0

1.5

2.0

2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4

L

o

g (C

a-p

p

m)

1000/T(K)

Loop Test :Aug. 25, 05 ANL

200-ppm-Ca + TSP 3-g/l

Solubility of Ca

3

(PO

4

)

2

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0

C

a-ppm

T(C)

Solubility of Ca

3

(PO4)

2

6.8 < pH < 7.14

TSP excessive

Figure B3. Log Ca (ppm) in the saturated solution of Ca3(PO4)2 vs. inverse temperature(K) and T(C).

Table B1. Elemental ICP-analysis for the as–received Cal–Sil

B3
Figure B4. X–ray diffraction spectrum of deposits from the ICET–3 test and matches with Ca3(PO4)2·x H2O

(tricalcium phosphate hydrate), Ca5(PO4)3(OH) (hydroxylapatite), and Ca9HPO4(PO4)5OH

(calcium hydrogen phosphate hydroxide)

B2. Initial Rate of Dissolution

Electrical conductivity and pH measurements were used to monitor the initial, relatively rapid dissolution

of Cal–Sil when it is added to simulated sump solutions. The behavior of the conductivity and pH for the

first 10 minutes after 1.2 g of Cal–Sil was added to 200 ml of base solution (6 g/l) with B = 2800-ppm, Li

= 3-ppm, HCl = 100-ppm at 60°C are shown in Fig. B5. There is a rapid increase within a few minutes in

both pH and conductivity. The rate of change and presumably the rate of dissolution slows significantly

after 4 to 5- min have passed. 

A second test was performed with a higher loading 25 g/l of Cal–Sil for 120 min. Again the conductivity

and pH rise very rapidly initially. With the higher loading of Cal–Sil the initial pH ≈ 4 increases to ≈ 6.8.

The decrease in dissolution rate is due in part to the increase in pH from the dissolution of the Na2SiO3

present in Cal–Sil. More importantly, for these high loadings, the dissolved Ca probably reaches a

saturation value which inhibits further dissolution of the CaSiO3. If TSP were present, the phosphate

would combine with the Ca and remove it from solution and permit the dissolution of the Cal–Sil to

continue. 

B4
0

1

2

3

4

5

6

7

8

20

30

40

50

60

-10 -5 0 5 10

leaching kinetics

σ (m

M

H

O) &

p

H

@T

T(C)

t (min)

pH

σ

T

CalSil

inserted

Figure B5.

Leaching kinetics for the initial 10-min after

addition of 6 g/l Cal–Sil at t = 0.

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

2.0

3.0

4.0

5.0

6.0

7.0

-40 -20 0 20 40 60 80 100 120

p

H

@T

o

r

T(

o

C) /10

C

o

n

d

u

ctivit y, σ(m

M

H

O)

Time (min)

25-g CalSil/liter solution

T = 60

oC & pH(rt) = 4.0

5-g CalSil inserted

200-ml solution

@ t = 0

pH

σ

T/10

Figure B6.

Leaching kinetics for the initial 120-min after

addition of 25 g/l Cal–Sil at t = 0. The

temperature is plotted as T/10 for

convenience.

A series of tests were performed with Cal–Sil loadings ranging from 2.0 to 166.0-g/l, and different initial

pH values achieved by additions of HCL or NaOH. The results of the tests are shown in Table B2.

Although the initial pH is controlled, for the solutions that are initially acidic, the final pH tends to

increase as material is leached from the Cal–Sil. Except for the shortest exposure of 35 minutes, the Ca

level in the solution is essentially independent of the Cal–Sil loading over the range from 6-166 g/l,

although it is markedly smaller for the case of 2 g/l. 

More detail on the sequence of tests with initial pH = 4.51 is given in Table B3 and Fig. B7. The Na

levels increase with loading as expected for a species that is not approaching a solubility limit. The pH

increases with increasing Cal–Sil loading consistent with the rise in the Na level. The Ca concentration is

almost independent of loading except perhaps at the highest loading where it decreases. This may be due

to a change in solubility at the relatively high pH associated with the high Cal–Sil loading. 

B5
Table B2. Compiled data for the Cal–Sil leaching performed in the various pH and temperatures.

No.

Leaching

Solution,

pH (RT)

T(C) time Cal–Sil-g/l

Final Solution

pH (RT)

Ca

(ppm)

Note

1 4.00 60 35 min 6 7.52 176

2

4.00

60 35 min

15 6.87

256

3 4.00 60 35-min 25 6.78, 6.66@T 244

4 4.00 60 35-min 166 6.50 228

5 4.00 60 4-h 6 6.74/*6.74 196

6 4.00 60 4-h 15 6.91/*6.94 195

7 4.00 60 4-h 25 7.09/*7.05 195

8 4.00 60 4-h 166 7.71/*7.68 168

Solution pH = 4.0

B(OH)3 + Li(OH) + HCl

9 4.51 60 4-h 6 6.72 156

10 4.51 60 4-h 15 6.87 169

11 4.51 60 4-h 25 7.12 184

12 4.51 60 4-h 166 7.98 127

Solution pH = 4.5

B(OH)3 + Li(OH) + HCl

13 6.80 85 2-h 166 - 22 UHP: Pure water

14 7.00 85 2-h - - 2 No 13 (pure water) supernate

solution +TSP

15 7.00 60 2-h CaCl2 6.80 7

16 7.00 rt 2-h CaCl2 - 75

Ca-200-ppm by CaCl2 reacted with

TSP; Cal–Sil leaching at rt > 60°C.

17 7.00 54.3 ~2 h 0.13 7.00 11 Loop Test #1, pH = 7.0 by TSP

excess 

18 7.00 62 4-h 2 7.14 45

19 7.00 62 4-h 6 7.37 88

20 7.00 62 4-h 25 7.24 69

21 7.00 62 24-h 2 7.19 73

22 7.00 62 24-h 6 7.27 108

23 7.00 62 24-h 25 7.42 102

Solution pH =7 made

by B(OH)3 + Li(OH) + HCl + NaOH

addition (No TSP added)

24 10.06 60 3.5-h 6 10.04 17

25 10.06 60 3.5-h 15 9.99 18

26 10.06 60 3.5-h 25 9.94 19

27 10.06 60 3.5-h 166 9.73 22

Solution pH = 10.0 made

by B(OH)3 + Li(OH) + HCl + LiOH

excess addition (No TSP added)

Table B3. Elemental chemical analysis (in mg/l) by the ICP emission spectra for the Cal Sil leached solution

of pH = 4.51 at 60°C for 4-hrs

Loading 166-g Cal–Sil/l 25-g Cal–Sil/l 15-g Cal–Sil/l 6-g Cal–Sil/l

Element start end start end start end start end

Ca none 127.0 none 184.0 none 169.0 none 156.0

Si none 113.0 none 66.40 none 51.40 none 49.00

Na none 1500. none 386.0 none 237.0 none 169.0

pH 4.51 7.85 4.51 7.12 4.51 6.87 4.51 6.76

B6
10

100

1000

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

10.0 100.0

Ele

m

ents (m

g/L)

p

H (p

o

st le

a

c

hin

g)

Loading (g-CalSil/L)

pH

Na

Ca

Si

Figure B7.

Elemental chemical concentration determined

by ICP analysis and final pH for solutions with

different Cal–Sil loadings

B3. Benchmark tests with CaSiO3

Leaching tests were performed with commercial CaSiO3 to help benchmark results with Cal–Sil. The

Cal–Sil loading was 25-g/l in a base solution with 2800-ppm-B and 0.7-ppm-Li at 60°C with the initial

pH = 7.14 adjusted by adding either NaOH or TSP. 

The test results for the dissolved Ca and Na for solutions in which the pH is controlled by NaOH

additions are shown in Fig. B8 (a) for Cal–Sil and in B8 (b) for CaSiO3. As expected in the Cal–Sil, the

concentrations of the Na and Ca increase linearly with the dissolved Si level corresponding to the

dissolution of Na2SiO3 and CaSiO3. The slope of the Na curve is again as expected somewhat steeper

than the Ca curve. For the case of CaSiO3, the Na curve is flat since there is no Na2SiO3, but the Ca

concentration does increase linearly with the Si concentration. However, the actual values of the Ca

concentrations are shifted upwards about 50 ppm from those expected based on stoichiometric

dissolution. This 50-ppm-Ca shift could be from a surface carbonate or hydroxide that formed on the

chemicals due to exposure to the atmosphere or from the dissolution of other Ca compounds present in

the Cal–Sil. 

0

100

200

300

400

500

600

0 20 40 60 80 100

T = 60

oC

pH = 7.14 (NaOH)

25-g CalSil/L

C

a

or N

a (p

p

m)

Si (ppm)

Na

Ca

Ca predict

0

50

100

150

200

250

300

0 20 40 60 80 100 120 140 160

T = 60

oC, pH = 7.14 (NaOH)

25-g CaSiO3/L

C

a-p

p

m

Si-ppm

Ca predicted

by Si

Na

Ca

(a) (b)

Figure B8. Concentration of the elements in the solution with 25 g/l loading and pH = 7.14 with

NaOH as a function of Si in solution (a), Cal–Sil and (b), CaSiO3.

Dissolved Ca and Na levels for solutions in which the pH is controlled by TSP additions are shown in

Fig. B9 for Cal–Sil and in Fig. B10 for CaSiO3. In these tests there is excess Ca present and at about

100 h all the phosphate is consumed. 

B7
1

10

100

1000

0.1 1 10 100 1000

T = 60

oC

pH = 7.14 (TSP)

25-g CalSil/L

Ele

m

e

nt in

S

olutio

n (m

g/L)

t (h)

Na

Ca

Si

P

(a) (b)

Figure B9. Concentration of the elements in the solution as a function of leaching time (a) linear plot (b) loglog plot of (a) for the 25-g Cal–Sil/l loading pH = 7.14 with TSP.

10

100

1000

0.1 1.0 10.0 100.0

T = 60

oC

pH = 7.14 (TSP)

25-g CaSiO3/L

Ele

m

e

nt (mg/

L)

t (h)

Na

Si

Ca

P

(a) (b)

Figure B10. Concentration of the elements in the solution as a function of leaching time (a) linear plot (b)

log-log plot of (a) for the 25-g CaSiO3/l loading pH = 7.14 with TSP

B8
Table B4. Compiled results on the leaching tests of the Cal–Sil insulator & commercial CaSiO3 chemical vs.

time: Loading 25-g/l, T = 60°C, and pH = 7.14 adjusted by adding NaOH or TSP

Sample

Test condition

Leaching progress Leaching Rate

t (h) Ca (ppm)

in solution

Ca (ppm)

leached

Avg.

t (h)

Leaching rate

(Ca-ppm/h)

A

25-g Cal–Sil/l

T = 60°C. 

pH = 7.14

(NaOH)

0.12 103 103 0.06 858

0.50 96 96 0.31 190

2.67 99 99 2.59 2

16.00 140 140 9.34 3

72.00 224 224 44.00 2

B

25-g Cal–Sil/l

T = 60°C. 

pH = 7.14

(NaOH)

0.12 106 106 0.60 833

0.50 90 90 0.31 180

2.67 110 110 2.59 9

16.00 152 152 9.34 3

72.00 203 203 44.00 1

C

25-g CaSiO3/l

T = 60°C. 

pH = 7.14

(TSP)

0.12 20 36 0.05 360

0.50 16 53 0.40 28

2.67 11 128 1.60 34

16.00 7 356 9.35 17

72.00 22 522 44.00 297

D

25-g CaSiO3/l

T = 60°C. 

pH = 7.14

(NaOH)

0.26 50 50 0.13 191

0.51 56 56 0.38 337

2.75 79 79 1.63 10

23.83 152 152 12.79 5

47.64 186 186 35.74 2

72.89 209 209 60.26 1

192.50 252 252 132.70 0

362.00 254 254 277.25 0

E

25-g Cal–Sil/l

T = 60°C. 

pH = 7.14

(TSP)

0.21 21 28 0.10 131

0.50 25 26 0.25 51

2.92 7 136 1.71 46

23.83 7 380 13.37 11

47.61 7 465 35.72 4

72.89 13 501 60.25 1

192.50 65 577 132.70 0.64

362.00 116 629 277.25 0.30

B9
Amount of Ca3(PO4)2Sediment: Figure B11 shows the concentration of Ca and P in the sediment vs.

time during leaching in pH = 7.14 (TSP), and (b) re-plot as log t for the 25-g Cal–Sil/l loading pH = 7.14

with TSP at 60°C. The assumption is the precipitate is Ca3(PO4)2. This assumption is consistent with the

studies at the University of New Mexico and measurements of the composition of the precipitate at ANL.

0

100

200

300

400

500

600

0

50

100

150

200

250

300

0 50 100 150 200 250 300 350 400

C

a in

s

e

dim

e

nt (p

p

m)

P in

S

e

dim

e

nt (p

p

m)

t (h)

T = 60

o

C

pH = 7.143 (TSP)

25-g CalSil/L

Initial leaching solution

P = 264.2 (mg/L)

Ca sediment cal'd by Ca

3

(PO4)

2

"P limit condition"

 

0

100

200

300

400

500

600

0

50

100

150

200

250

300

0.1 1 10 100 1000

C

a in

s

e

dim

e

nt (p

p

m)

P in

S

e

dim

e

nt (p

p

m)

t (h)

Initial solution

P = 264.2 (mg/L)

Ca cal'd by Ca

3

(PO4)

2

"P limit condition"

T = 60

oC

pH = 7.143 (TSP)

25-g CalSil/L

(a) (b)

Figure B11. (a) Ca and P in the sediment vs. time during leaching in pH = 7.14 (TSP), and (b) replot as log t of (a) for the 25-g Cal–Sil/l loading pH = 7.14 with TSP.

B4. Influence of TSP dissolution rate

The dissolution of the Cal–Sil can be influenced by pH and the presence of phosphate to remove

dissolved Ca as a precipitate. Thus the dissolution of the Cal–Sil could be affected by the rate at which

TSP enters the sump. Since the TSP dissolution kinetics can vary, three cases were examined. In the

first, the TSP was added to the solution before the Cal–Sil was added. This corresponds to instantaneous

dissolution of the TSP and is clearly a bounding case. In the second case the TSP was added at a constant

rate to the solution over a 1 h period. This is probably reasonably representative of most cases. In the

third case the TSP was added at a constant rate over a 4 h period. This corresponds to the technical

specification limit for the dissolution of TSP for most plants, and is taken as a lower bound on the TSP

dissolution rate. 

Tests were performed for Cal–Sil loadings of 1.5 and 0.5 g/l. The 1.5 g/l is probably an upper bound for

the Cal–Sil loading. The 0.5 g/l is a more representative condition for most plants that use Cal–Sil. The

Cal–Sil and TSP were added to a base solution with 2800-ppm-B and 0.7-ppm-Li. The total TSP added

was equivalent to 3.4 g/l (264 ppm) and would be expected to give a pH of 7.14 without considering the

pH changes due to Cal–Sil dissolution. As noted three different rates of TSP addition were considered.

As shown in Table B5, a Cal–Sil loading of 1.5 g/l and a TSP addition of 264 ppm is the nominal

boundary between solutions with excess PO4

-3

and those with excess Ca if Ca3(PO4)2 is taken as the

precipitation product. 

Table B5. Calculated concentration of Ca and P forming Ca3(PO4)2

Cal–Sil

Loading, (g/l)

ppm-Ca

fully

dissolved

ppm-P to

exhaust

Ca

ppm-P in

solution

solution

ppm-Ca Note

0.0 0.0 0.0 *264.20

0.1 34.6 17.8 246.4

0.5 172.8 89.0 175.2

All the Ca in the

Ca3(PO4)2

Sediment

TSP pH=7.14

TSP excess condition

1.5 512.8 264.2 0.00 0.00 TSP pH = 7.14

B10
The tests results for the three TSP addition rates are shown in Table B6. Because of the difficulties in

obtaining a sample while simultaneously adding TSP, the sampling was done at times sampling times 5-

10 min, 30-min, 160-min, 24-h, 3-days, 5-days after the addition of TSP was completed. Thus for the

cases when the TSP was added over 1 and 4-h intervals, 1 or 4 h would have to be added to the reported

sampling time to get the actual time the Cal–Sil has been in the solution. 

The samples were taken from the supernate solution. A 5-ml syringe was used to take a 2-ml sample of

solution. In order to avoid including fine particles of pulverized Cal–Sil and/or of the reaction product,

i.e., Ca3(PO4)2 in the samples, the samples were filtered.. The tip of the syringe was wrapped with three

layers of filter paper (1-cm x 1-cm #42 commercial filter paper). Platinum wire was wrapped about the

filter paper to hold it in place. Because of the flow resistance introduced by the filter paper, it could take

2-3 min to obtain a sample. 

Table B6. Compiled results of the elemental ICP-analysis for the supernate/filtered solutions for the three

procedures of the TSP buffering during the 1.5-g CalSi/l leaching process.

TSP dissolution Time

(h)

pH

(RT)

Elemental ICP-analysis (mg/l)

Ca P K Si Na Caest

I

“Instantaneous”

0.08 7.04 38.5 263 17.0 23.3 536 66

0.50 7.17 24.6 252 4.44 24.4 554 74

2.67 7.38 15.6 232 3.63 36.0 549 103

24.50 7.24 7.91 165 6.58 59.7 534 225

71.25 7.33 4.11 135 7.5 66.9 557 280

118.5 7.48 3.29 132 4.29 68.2 567 285

II

“1-h dissolution”

0.08 6.83 58.4 64.6 <2.5 20.8 159 470

0.50 6.79 54.4 66.3 <2.5 22.0 168 463

2.67 7.10 10.5 131 2.74 25.1 357 294

23.50 7.10 4.68 103 4.76 45.6 382 342

70.25 7.15 <2.5 67.1 5.55 62.1 405 407

119.5 7.26 <2.5 56.8 3.59 65.2 395 427

III

“4-h dissolution”

0.08 7.12 18.7 102 6.29 26.2 289 358

0.50 6.85 14.4 104 32.5 27.6 295 350

2.67 6.92 6.29 95.0 8.09 30.1 297 359

19.50 6.99 4.77 66.7 4.75 42.0 292 413

66.75 7.10 <2.5 36.0 4.81 59.7 327 467

115.5 7.25 3.13 22.0 3.50 64.5 331 497

The difference between the total added 264-ppm-P and concentrations P in the solution gives the amount of P into the sediment. The measured Ca is

not the total Ca that has been leached from the Cal-Sil; since most of the dissolved Ca precipitates out. The total dissolved Ca can be estimated if it

is assumed that the precipitate is Ca3(PO4)2.

Figure B12(a) shows the elemental wt. % in the sediments for the procedure-I, II, and III. For procedure-I,

the ratio of P relative to the Ca and Si is smaller than for procedures II and III. This is due to Cal–Sil

residue. This residue visibly colors the sediment as shown in Fig. B13. The molar ratio of Ca/P in the

resulted sediments for procedures I, II, and III is shown in Fig. B12(b). The excess of the ratio value 1.5

B11
[status of the P in the sediment as Ca3(PO4)2 i.e., R = 1.5] is probably due to Cal–Sil residue. The ratio is

closest to 1.5 for procedure III which would be expected to have the most complete dissolution. 

0

20

40

60

80

100

120

I II III

Al

Si

P

Ca

Na

K

Fe

E

D

S (Wt.

%

S

E

DIM

E

N

T)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

I II III

R= (Ca/P)At.%

Excess Ratio

from R = 1.5

R

atio (At.%) = (C

a/P)

(a) (b)

Figure B12 (a) Elemental wt. % in the sediments for the I, II, and III. (b). Molar ratio of Ca/P in the

sediments for the I, II, and III.

Figure B13.

Precipitates from the three procedures: Proc-III (lef:

white ppt) , II (middle white ppt), and I (right side

mostly yellowish) photo taken at t time 

239-h.

The total weight of the recovered sediment is shown in Table B7 and compared to the initial weight of the

Cal–Sil added to the solutions. 

Table B7. Weight measurement for the dried sediments for the residue from Proc-I,

II, and III for the 1.5-g Cal–Sil/l loadings.

Procedure Cal–Sil initial 

Wt. (g)

Final collected 

sediment Wt.(g)

Wt. Yields (%)

 = Wt(f)/Wt(i)

I 0.225-g 0.195-g 87%

II 0.225-g 0.308-g 137%

III 0.225-g 0.272-g 121%

0.5-g Cal–Sil/l + 3.4-g TSP/l with three procedures; I, II, & III: The results from Cal–Sil leaching tests

performed with 0.5-g Cal–Sil/l addition of 3.4-g TSP/l with three procedures; I, II, & III are given in

Table B8 and in illustrated in the Fig. B14.

B12
Table B8. Compiled results of the elemental ICP-analysis for the supernate/filtered solutions for the

three procedures of the TSP buffering during the 0.5-g CalSi/l leaching process.

TSP buffering

procedure

Time (h)

Elemental ICP-analysis (mg/l)

Ca P K Si Na

I

“Instantaneous”

0.08 9 250 7 7 598

0.50 9 241 7 9 585

2.67 10 223 7 20 594

24.00 4 208 7 36 600

72.00 3 198 7 42 579

120.00 3 199 7 42 577

II

“1-h”

0.08 14 211 7 9 512

0.50 14 249 7 12 618

2.67 13 237 7 20 620

23.00 7 222 7 37 627

71.00 4 216 7 45 631

119.00 4 225 7 47 642

III

“4-h”

0.08 21 230 7 22 585

0.50 18 229 7 24 600

2.67 7 212 7 28 582

20.00 4 201 7 37 583

68.00 3 206 7 44 600

116.00 4 203 7 46 601

B13
1

10

100

1000

0.1 1.0 10.0 100.0

U. Minn

C

Ca Si P

o

n

c

e

ntratio

n (m

g/L)

t (h)

T = 60oC

0.5-g CalSil + 3.4-g TSP/L-0h

1

10

100

1000

0.1 1.0 10.0 100.0

Ca Si P C

o

n

c

e

ntratio

n (m

g/L)

t (h)

T = 60

oC

0.5-g CalSil + 3.4-g TSP/L-1h

(a) (b)

1

10

100

1000

0.1 1.0 10.0 100.0

C

Ca Si P

o

n

c

e

ntr

ation (m

g/L)

t (h)

T = 60

oC

0.5-g CalSil + 3.4-g TSP/L-4h

6.00

6.50

7.00

7.50

8.00

0.1 1.0 10.0 100.0

0.5g-CalSil-TSP.pH(T= 60

oC)

0.5g-proc.-I

0.5g-proc.-II

0.5g-proc.-III

p

H (6

0

oC)

t (h)

(c) (d)

Figure B14. Concentration of the element vs. time for the Cal–Sil loading of 0.5-g Cal–Sil/l process

at 60°C added total 3.4-gTSP/l as (a) procedure-I, t = 0, (b) procedure-II for t = 1-h,

(c) procedure-III for t = 4-h, and (d) the pH (60°C) vs. time for the three procedures.

B14
0

50

100

150

200

250

0.1 1.0 10.0 100.0

RYB.Ca,Si,P,Na,K

Ca

P

IC

P (m

g/L)

t(h)

0.1-g CalSil/L

0

50

100

150

200

250

300

0.1 1.0 10.0 100.0

RYB.Ca,Si,P,Na,K

Ca

P

IC

P (m

g/L)

t(h)

0.5-g CalSil/L

(a) (b)

0

50

100

150

200

250

300

0.1 1.0 10.0 100.0

RYB.Ca,Si,P,Na,K

Ca

P

IC

P (m

g/L)

t(h)

1.5-g CalSil/L

7.00

7.10

7.20

7.30

7.40

7.50

0.0 50.0 100.0 150.0 200.0

0.1,0.5, &1.5g-CalSil-TSPpH(T= 60

oC)

0.1-g CalSil/L

0.5-g

1.5-g

p

H (6

0

oC)

t (h) CalSil

(c ) (d)

Figure B15. For the element in the solution for the Cal–Sil loadings, 0.1, 0.5, and 1.5-g Cal–Sil with

3.4-g TSP/l and pH (60°C) vs. time for the three procedures Loading of 0.1, 0.5, and

1.5.

pH (60°C) vs .t for the progress [0.1, 0.5, and 1.5-g Cal–Sil with 3.4-g TSP]/l: Figure B15 shows the

result of the Cal–Sil leaching tests performed with 0.1, 0.5, 1.5-g Cal–Sil/l addition of 3.4-g TSP/l vs.

time.

Table B9. Measured pH values at 60°C in-situ dissolution tests, and pH (RT) for the ICP-samples 

Time (h) pH @60°C, in-situ pH (RT) for ICP-samples

0.1g 0.5-g 1.5-g 0.1g 0.5-g 1.5-g 

0.87 5.82 6.08 6.39

1.00

1.05 6.95 6.99 7.06

1.42 7.25 7.07 7.26 7.19 7.15 7.19

1.92 7.25 7.11 7.29 7.23 7.03 7.30

3.58 7.21 7.20 7.33

7.58 7.23 7.36 7.36 7.24 7.29 7.42

24.08 7.20 7.43 7.40 7.23 7.37 7.45

72.5 7.17 7.30 7.45 7.23 7.38 7.50

120.0 7.16 7.30 7.48 7.20 7.32 7.48

168.0 7.16 7.30 7.47 7.18 7.23 7.49

B15
1.5-g Cal–Sil Dissolution Tests T = 90°C procedures –I, II, and III: Figure B16 showed the results of the

elemental ICP-analysis on the 1.5-g/l Cal–Sil dissolution for the I, II, and III procedures and pH (RT) vs. t

, after TSP addition finished. The Na and Si concentrations are higher than that of the dissolution tests

performed 60oC, but the Ca levels are lower.

The data from the small–scale dissolution tests at 90°C are summarized in Table B10. The Na levels are

much higher than in the corresponding tests at 60°C, indicating more leaching of the Na from the Cal–Sil.

The Ca in solution is lower reflecting the retrograde solubility of Ca3(PO4)2. The measured P levels are,

however, much higher than those at 60°C indicating that not as much Ca3(PO4)2 has formed, which

implies that less Ca has leached from the Cal–Sil at the higher temperature. 

1

10

100

1000

0.01 0.1 1 10 100 1000

Ca

P

Si

Na

IC

P [m

g/L]

t (h)

90

oC [I]

1.5-g CalSil/L 1

10

100

1000

0.01 0.1 1 10 100 1000

90C I, II, III 10:43:34 AM 1/5/2006

Ca

P

Si

Na

IC

P [m

g/L]

t (h)

90

oC [II]

1.5-g CalSil/L

1

10

100

1000

0.01 0.1 1 10 100 1000

90C I, II, III

Ca

P

Si

Na

IC

P [

m

g/L]

t (h)

90

oC [III]

1.5-g CalSil/L

7.00

7.10

7.20

7.30

7.40

7.50

7.60

7.70

7.80

0.01 0.1 1 10 100 1000

90

oC 1.5-g CalSil/L

proc-I

proc-II

proc-III

p

H (rt)

t (h)

Figure B16. ICP-result on the 1.5-g/l Cal–Sil dissolution for the I, II, and III procedures and pH (RT). t =

after TSP addition finished.

B16
Table B10. Summary of results for the small–scale dissolution tests at T= 90°C.

Test series

Time

(h)

pH (RT)

Ca

(mg/l)

P

(mg/l)

Si

(mg/l)

Na

(mg/l)

Cal–

Sil

(g/l)

Ca equiv

(mg/l)

(Ca3(PO4)2 )

Ca equiv

(mg/l)

Ca10(PO4)

6(OH)2

I

TSP is added

before the

Cal–Sil is

introduced

0.08 7.29 16 272 15 633 1.5 10 11

0.50 7.35 10 250 28 658 1.5 52 58

2.67 7.41 3 193 59 671 1.5 163 181

24.50 7.50 1 143 77 648 1.5 259 288

71.25

7.51 1 141 77 666 1.5 263 292

119.00 7.48 2 144 75 686 1.5 257 286

II

TSP metered

over an hour

after the Cal–

Sil is added

1.08 7.52 13 206 41 599 1.5 137 153

1.5

7.48 6 213 55 678 1.5 124 138

3.67 7.49 3 173 68 651 1.5 201 224

25.5

7.50 1 149 85 673 1.5 248 275

72.25

7.42 2 150 85 718 1.5 246 273

120

7.33 2 171 88 829 1.5 205 228

III

TSP metered

over a 4 hour

period.

4.08 7.38 2 207 62 663 1.5 135 151

4.5

7.38 3 197 63 647 1.5 155 172

6.67 7.44 2 172 64 608 1.5 203 226

28.5

7.45 1 136 76 619 1.5 273 303

75.25

7.45 1 133 75 625 1.5 279 310

123

7.49 1 135 70 650 1.5 275 305

B17
Appendix C Surrogates for the ICET-1 environment

C1. Aluminum nitrate

Aluminum nitrate solutions with dissolved Al levels of 350 ppm, 150, ppm, and 50-ppm have been

investigated. The solutions were prepared by dissolving commercial aluminum nitrate, Al(NO3)3⋅ 9H2O

powder in solutions with 2800 ppm B added as boric acid and NaOH additions to make the pH = 10 at

room temperature. Table C1 shows the amount of aluminum nitrate added to each solution and the

appearance of the solutions after mixing as room temperature. 

Although the 350-ppm-Al solution was not fully dissolved at room temperature, virtually all (~95%) the

emulsion disappeared after the solution was reheated to 60°C. Figure C1a shows the appearance of the

solution at room temperature; Fig. C1b shows the solution at 96.3°C; and Fig. C1c shows the solution

after cooling to 28.0°C. A more complete sequence of images documenting the heat–up and cool–down

process is given in Appendix D. The relatively high degree of redissolution suggests that the emulsion is

primarily an amorphous Al(OH)3 solid, since the crystalline forms have very low solubility and would be

much less likely to redissolve. 

Table C1. Preparation and the visual observations of the 50, 150, and 350-ppm-Al solutions prepared

from aluminum nitrate, Al(NO3)3 ⋅ 9H2O.

Solution Al

(ppm)

Vol

(ml)

*Wt.

(g)

Visual observations

A 50 176 0.1 Initially gelatin like emulsion was revealed, but solution

becomes cleared after 2-h later

B 150 126 0.3 At room temperature bottom 10 % emulsion

C 350 122 0.6 At room temperature bottom 30 % emulsion, but at 93 ̊C the

solution was totally clear.

*Al (NO3)3-9H2O [MW = 375.13g for Al(NO3)3-9H2O]

(a) (b) (c)

Figure C1. 375-ppm-Al solution. (a) at 20.5°C (room temperature) 10-min after mixing. Note: S

= Solution level, E = Emulsion level; (b) heated up to 96.3°C, t = 53 min after

mixing; and (c) cooled down to 28.0°C , t = 247 min after mixing.

C1
The electrical conductivity was measured as a function of temperature and concentration to

characterize ionic behavior. The temperature dependence of the conductivity is shown in Fig. C2.

The conductivity decreases with increasing Al concentration. This suggests that the conduction is mostly

due to Na

+

 and OH

-

 ions, and the OH

-

 concentration is decreasing as more Al(NO3)3 is added. 

4NaOH = 4Na

+

 + 4OH

-

 (C1)

Al(NO3)3 = Al

+3

 + 3NO3

-

(C2)

4NaOH + Al(NO3)3 = Al(OH)4

-

 + 4Na

+

 + 3NO3

-

(C3)

The highly conductive hydroxyl ions are captured by the formation of Al(OH)4

-

, which are lower mobility

anions compared with the OH

-

ions. The measured solution pH values after the additions of the

aluminum nitrate were 10.06 for 50-ppm Al , 9.96 for 150-ppm Al, and 9.72 for 350-ppm-Al. The trend

in the pH values is consistent with Eq. (C3). 

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

2.70 2.80 2.90 3.00 3.10 3.20 3.30 3.40

Al50,150,350ppm.cond

50-ppm (Ea = 0.132 eV)

150-ppm (Ea = 0.134 eV)

350-ppm (Ea = 0.136 eV)

lo

g

σ (o

h

m-c

m)

-1

1000/T(K)

pH = 10.0 solution

Added Al

0.131

0.132

0.133

0.134

0.135

0.136

0.137

0 50 100 150 200 250 300 350 400

Ea

(e

V)

Al-ppm

pH = 10.0 (rt)

Al(NO

3

)

3

added

249-ppm Al

Figure C2. Electrical conductivity vs. 1/T. for the

pH = 10.0 solution added 50, 150,

and 350-ppm of aluminum ions.

Figure C3. Activation energy, Ea vs. Al-ppm in

the pH = 10.0 solution added

Al(NO3)3.

The activation energy, Ea vs. dissolved Al-ppm is shown in Fig C3. The 350-ppm does not behave as an

ideal solution, i.e., it deviates from the linear behavior that characterizes the lower concentration

solutions. This indicates that the solution may not be dissociating completely at these concentrations. 

Figure C4a compares the viscosities of a 370-ppm-Al solution and ultra–high–purity (UHP) water as a

function of temperature. Figure C4b shows the viscosities of solutions with 50, 150, and 350-ppm

dissolved Al and solutions from two head loss tests. The viscosity measurements were performed using

an Ostwald-viscometer. The measured viscosity for the 370-ppm-Al solution is somewhat greater than

the UHP water. The results shown in Figure C4 are for well mixed solutions. Separating off the

supernate, and then measuring the viscosity of the remaining solutions gives viscosity values

approximately twice those shown in the figure. 

The temperature dependence of the viscosity can be described in terms of an activation energy of

0.139 eV. This is close to the observed value for the activation energy for the conductivity, 0.136 eV, as

shown in Figure C2. The activation energy for the conductivity is related to the transport of mobile ionic

C2
species. The temperature dependence of the viscosity could also be related to an energy barrier for

transport. 

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4

Al-370-added at T

& measured down T

Al-370-added at RT

lo

g

η (c

St)

1000/T(K)

E

a

= 0.139 eV

"UHP-Water"

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

20 25 30 35 40 45 50 55 60

50.150.350.ppm-Al (Bench tests)

100-Al: ICET-5 (STB) & ICET-1(NaOH)

50-ppm-Al (Bench)

150-ppm-Al (Bench)

350-ppm-Al (Bench)

100-Al-LOOP (ICET-5)

100-Al-LOOP (ICET-1)

Vis

c

o

sity (c

St)

T(C)

((a) (b)

Figure C4. Temperature dependence of viscosity (η): (a) Black and red symbols are for

solutions with 370 ppm Al, and the blue symbols for the UHP-water, and (b)

Viscosity (η) of 50, 150, and 350-ppm-Al bench top solutions , and and 100-ppm-Al

solutions samples from the loop during head loss tests for the ICET-5 and ICET-1

environments.

Figure C5 shows the settlement of the Al emulsion. The emulsion was allowed to form, then the solution

was shaken to homogenize it and then allowed to settle. The volume of solution in which the emulsion

was visible was monitored as a function of time. 

0

50

100

150

200

250

100 1000 10

4

10

5

10

6

10

7

375-ppm-Al

Settlment ar RT

E

m

ulsio

n

v

ol (

ml)

t (s)

Figure C5.

Volume of the emulsion settled in the 375-

ppm-Al solution as a function of time at RT.

The total solution volume is 230 ml.

C2 Sodium Aluminate

The use of aluminum nitrate to create surrogate solutions has some disadvantages. It introduces a species

(nitrate) that is not typically present in the sump environment, and tends to drive the pH down. A peer

reviewer (C. Delegard, PNNL) suggested investigating the use of sodium aluminate (NaAlO2) to create

the surrogate solutions. This would introduce no new species, would not tend to decrease the pH, and

C3
better mimics the actual corrosion process since the formation sodium aluminate (NaAlO2) is probably an

intermediate step in the actual dissolution of metallic Al in a NaOH environment. 

To create a surrogate using sodium aluminate (NaAlO2), 250-ml of boric acid solution with LiOH

[pH(RT) = 5.01] was heated in a flask to 60°C and an appropriate amount of NaAlO2 to reach the target

concentration of Al was added. The solution pH was increased to 7.49 at 60°C by the addition of the

NaAlO2. The NaAlO2 was not fully dissolved. The solution was kept overnight at 60°C. Overnight, the

pH increased to 7.54, but the sediment was still not fully dissolved. NaOH was added incrementally to

increase the pH. The appearance of the solution during the test is described in Table C2, and shown in

Fig. C6. The solution become completely clear at pH = 9.54. However, more NaOH was added to

increase the pH to 10.0. 

Table. C2. Visual observation and the pH variation during the NaOH additions: 375-ppm-Al solution made

by adding NaAlO2 in the B(OH)3 + LiOH solution 250-ml.

Weight (g) pH at 60°C Solution state

0 5.01 (rt) Only B(OH)3 + LiOH

0 7.23 200-ppm-Al/ Not dissolved

0 7.49 375-ppmAl/ Not dissolved

0 7.54 After overnight 375-ppmAl/ Not dissolved

0.096 7.55 Not dissolved

0.194 7.77 “

0.983 “

1.081 8.93 Entire solution is slightly cloudy

1.278 9.00 Entire solution is cloudy

1.475 “

1.574 8.91(?)* Top cloud and bottom totally clear

1.771 9.54** Still cloud left

1.968 9.54-9.57 Solution much more clear

2.165 9.55-9.75 “

2.263 “

2.460 “

2.559 9.75 Solution clear

2.855 10.0 “

*Note: pH monitored at the top 20%. The solution separated; the top 60% was slightly cloudy, and at the bottom

40% was totally clear. The solution was shaken thoroughly before proceeding. 

**Note: Solution totally clear, but NaOH was keep adding to adjust the pH = 10.0

C4
375-pm-Al by adding 

NaAlO2

Solution cloudy and

undissolved sediment at the

bottom

pH = 7.54 (60°C)

time = 0 min

Relative uniform cloudiness

pH = 8.93 (60°C)

time = 22-min

All clear

pH = 10.0 (60.6°C)

time = 120-min

Figure C6. Visual and pH changes for the 375-pm-Al dissolution of NaAlO2 vs. addition of NaOH at 60°C.

The solution was then cooled. It remained clear down to room temperature as shown in Fig C7. After

over 5-days at RT , the solution was still clear, but some sediment could be seen at the bottom of the

flask as shown in Fig. C8.

Figure C7. NaAlO2 solution at T = 22.9°C, time

= 450-min

Figure C8. NaAlO2 solution after over 5-days

room temperature. A ring of white

sediment is seen at the bottom. The

sediment forms a ring because of

the magnetic stirring.

Since the behavior of the system is expected to be sensitive to pH, a new solution was prepared with a

target pH of 9.5. Boric acid with LiOH (pH RT = 5.01, 250-ml) solution was heated to 60°C and 0.28480-

g of NaAlO2 powder was added to obtain a 375-ppm Al solution (see Fig. C9). The flask with the test

solution is located inside the mineral oil bath and the pH probe is located at the center of the flask and is

submerged about 25%. The solution pH was adjusted to 9.50 at 60°C by adding NaOH (1.57375-g). The

solution became totally clear at 60°C (see Fig. C10).

C5
Figure C9. T = 60°C, pH = 9.5; 0.28480-g of

NaAlO2 equivalent to 375-ppm Al was

added to B(OH)3 + LiOH base

solution. Undissolved sediment

remained at the bottom.

Figure C10. T = 60°C, pH = 9.5 for the 375-ppm

Al. Test flask is inside the mineral oil

bath. Backside color level indicates

the solution is totally clear.

The solution was then cooled. The appearance of the solution during the cooling process is shown in Figs.

C11–C15.

Figure C11.

NaAlO2 solution at

38.9°C, still clear.

Cooling time = 90-

min.

Figure C12.

NaAlO2 solution 22.4°C. Cooling time =270-

min. Some cloudiness is visible.

Figure C13.

NaAlO2 solution at 21.5°C

Cooling time 273-min. Cloudiness

is visible and pH has increased to

9.58.

Figure C14.

NaAlO2 solution at 19.8°C.

Cooling time 17-h. pH

decreased to 9.46 (may be due

to CO2).

Figure C15.

NaAlO2 solution at RT after 46-h

Emulsion fills 15% height at the

bottom.

C6
The process was repeated with a lower target pH of 9.3. Boric acid with LiOH (pH RT = 5.01, 250-ml)

solution was again heated to 60°C in the two port flask and 0.28480-g of NaAlO2 powder was added to

get 375-ppm Al. The solution pH was then adjusted to 9.28 at 60°C by adding NaOH (1.08112-g). The

solution was initially cloudy (Fig. C16), but after about 60 min it became clear. 

Figure C16.

NaAlO2 solution at 60° pH = 9.28.

The solution was then cooled. Figure C17 showed the solution 17-h later at RT. The emulsion has

settled, and represents about 15% of the volume. The emulsion was still very transparent with no solid

sediment. The pH increased to 9.5. This increase in pH is expected as the aluminate ion dissociates to

form Al(OH)3, Al(OH)4

-

 = Al(OH)3 + OH

-

. Figure C18. shows the solution 46-h later at RT. The

emulsion cloud still occupies 15% height at the bottom there is little change in appearance. 

Figure C17. 17-h later at RT, a rather clear,

transparent emulsion cloud occupies

about 15% of the volume at the

bottom of the flask.

Figure C18. 46-h later at RT, the emulsion cloud

still occupies about 15% of the

volume and there is little change in

appearance.

Figure C19 compares the concentration of Al vs. pH in the supernate solutions based on the results of the

Inductively Coupled Plasma (ICP) analysis for the dissolved NaAlO2 equivalent Al concentration of 375-

ppm-Al. The measured results agree reasonably well with those expected assuming the soluble form is

Al(OH)4

-

. The higher the pH, the higher is the Al in the supernate solution, i.e., the higher the solubility.

Figure C20 shows the concentration of Al and B vs. pH for the 375-ppm-Al with dissolved NaAlO2. The

simultaneous decrease in concentration of both B and Al in the supernate solution with pH indicates that

the B is incorporated in the emulsion along with A. 

C7
Figure C19 

Concentration of Al vs. pH in the supernate

solutions

Figure C20.

Al and B vs. pH in the 375-ppm-Al with dissolved

NaAlO2 The simultaneous decrease in

concentration with pH indicates that the B is

incorporated in the emulsion along with Al.

The overall qualitative behavior of the 375-ppm-Al solution obtained by dissolution of NaAlO2 is

summarized in Table C3. 

A qualitative comparison of the behavior and appearance of the precipitates in the sodium aluminate and

aluminum nitrate solutions with the precipitate behavior observed in the ICET–1 test as described in

Reference (2) led to the judgment that precipitates in the aluminum nitrate solutions better reflected the

behavior of the precipitates in the ICET–1 test.

C3 Characterization of precipitates

Transmission electron microscopy (TEM) images were obtained from the precipitate from a 375-ppm-Al

solution. The precipitate gel had been stored in a closed container for about 6 months before the images

were taken. The gel was rinsed in UHP water. A small portion of the gel (≈ 0.3 g) was mixed with 250-

ml UHP water. The rinsed sediment was place on carbon film for TEM analysis. The results are shown

in Figure C21. The particles typically have chunky rectangular or triangular shapes and are 0.5–1 μm in

size. Energy dispersive x–ray spectroscipy (EDS) analysis of the particles shown in Fig. C22 showed the

particles are mostly Al [90.34 wt (89.40 at) %] with 6.78 wt (7.87at.) % Na, and 2.88 wt. (2.74 at) % Si.

C8
Table C3. Behavior of 375-ppm-Al solution from dissolution of NaAlO2 with pH = 10.0, 9.5, and 9.28

 pH at 60°C Note

 5.01 (rt) Base solution of current task [B(OH)3 + LiOH]

7.54 Only for the 375-ppm-Al dissolution of NaAlO2. A large pile of sediment

present at the bottom of the test flask after adding equivalent 375-ppm-Al.amount

of NaAlO2 in the time between 0 and 17-h period 

9.28 Little bit cloudiness at all temperatures, but becomes a little more transparent at

RT with the transparent particles sediment at the bottom.

9.50 Clear at 60°C, but becomes little cloudiness was shown at RT with a very pale

cotton pad shape emulsion arraying at the lower part of the solution.

10.0 Clear at all temperatures. But 5-days later, a very small amount of white

particle sediment was shown. But none of the cloudiness was shown in the

solution at all.

Figure C21. TEM views for the particles (black) on the carbon film collected from the 375-ppm-Al emulsion

after rinse with UHP water.

Figure C22. EDS chemical analysis of the Al(OH)3 precipitate after rinsing with UHP water.

C9

Element Wt% At%

Na 6.78 7.87

Si 2.88 2.74

Al 90.34 89.40
The shapes of the particles suggests that the material primarily crystalline, although no conclusive

electron diffraction patterns were obtained in the TEM analyses. This is consistent with the relative

insolubility of the aged product. At a given pH, the solubility of a crystalline phase like gibbsite is

smaller than that of the amorphous phase by a factor of about 500. Freshly precipitated material will

quickly redissolve if the temperature of the solution is raised to 60°C. The aged material shows little

tendency to redissolve if the temperature is increased. 

To try to visualize better the nature of the emulsion, a small portion of the fine emulsion from a 100-ppmAl solution was quenched at liquid-nitrogen (LN) temperature. To quench the sample, the scanning

electron microscopy (SEM) sample stage was cooled to LN temperature. A very small drop of the

solution was quickly rubbed onto the cooled sample stage. It immediately started vacuum drying at LN

temperature. These conditions were intended to minimize the tendency for the particles to migrate or

coagulate. Figure C23 shows SEM pictures of the vacuum dried emulsion particles on the Au-substrate.

The emulsion particles are evenly dispersed, and the clusters look elongated (0.2 x 0.5-2 μm size) in the

enlarged view. EDS for a single particle on the Au foil (without washing of the emulsion with UHP

water) gives 21.01 wt (24.47at.) % Na, 73.26 wt.(69.84at) % Si, and 5.73 wt (5.69 at)% Al.

Figure C23. SEM pictures of the vacuum dried emulsion particles on the Au-substrate.

C10
Appendix D Visual Observations of a 375-ppm-Al solution

Figure D1

T= 20.5°C (RT)

t = 10-min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 126.9 μ-MHO

Note: S = Solution level

E = Emulsion level

*Before adding the mineral oil into the

beaker.

Figure D2

T= 21 °C (RT)

t = 12 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 127.5 μ-MHO

Note: O = Oil bath level

S = Solution level

E = Emulsion level

*After adding the mineral oil for the oil

bath.

D1

Mineral Oil Bath

1-liter

Pyrex Beaker

Conductivity

probe

T control

(T.C)

 S

 E

O

S

E
Figure D3

T= 21 °C (RT)

t = 14 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 127.7 μ-MHO

Note: Emulsion level down

Figure D4

T= 21 °C (RT)

t = 20 min after mixing 123.0 grams of

pH =10.0 solution with 0.60g ram of

Al(NO3)3×9H2O.

σ = 128.3 μ-MHO

Figure D5

T= 21 °C (RT)

t = 21 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 128.6 μ-MHO

Note: Magnetic stirring bar inserted into

the oil bath

D2

Hot Plate
Figure D6

T= 21.8 °C (RT)

t = 27 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 133.5 μ-MHO

Figure D7

T= 30.1 °C

t = 30 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 164.7 μ-MHO

Figure D8

T= 44.1°C

t = 32-min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 215 m-MOH

Note: Emulsion is dispersed by

convection of solution

D3
Figure D9

T= 51.2°C

t = 32-min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 239 μ-MHO

Note: Scattered emulsion cloud appears

to be redissolving.

Figure D10

T= 63°C

t = 34 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 270 μ-MHO

Note: Emulsion cloud becomes less

visible. Solution volume expands with

increasing temperature (black dot level

at the rt)

Figure D11

T= 68.3°C

t = 37 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 283 μ-MHO

Note: Emulsion continues to disappear

but some sediment is evident. Many

very tiny bubbles (the 0.1 mm dia.

bubbles are not visible in the photo)

were generated inside the emulsion;

and traveled upward.

D4
Figure D12

T= 77.2°C

t = 39 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 283 μ-MHO

Note: Emulsion cloud has almost

disappeared except for a small amount

of sediment.

Figure D13

T= 79.5°C

t = 39 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O

σ = 306 μ-MHO

Note: Emulsion cloud has almost

disappeared, except for 0.5 x 0.5 x 0.12

cm volume of sediment left at the

bottom of the flask.

Figure D14

T= 81.4°C

t = 42 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 307 μ-MHO

Note: Emulsion cloud has almost

disappeared, except for 0.5 x 0.5 x 0.12

cm volume of sediment left at the

bottom of the flask.

D5
Figure D15

T= 96.3°C

t = 53 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 369 μ-MHO

Note: Oil bath removed.

Figure D16

T= 90.3°C

t = 61 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 357 μ-MHO

Note: Oil bath in place.

Figure D17

T= 87.0°C

t = 74 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 342 μ-MHO

Note: solution height.

D6
Figure D18

T= 79.0°C

t = 83 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 315 μ-MHO

Note: solution height.

Totally clear.

Figure D19

T= 71.2°C

t = 94 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 287 μ-MHO

Note: Totally clear

Figure D20

T= 37.0°C

t = 158 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 175 μ-MHO

Note: Totally clear

D7
Figure D21

T= 32.0°C

t = 215 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 175 μ-MHO

Note: First time cloudiness is visible

during cooling.

Figure D22

T= 32.0°C

t = 215 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 159 μ-MHO

Note: Cloudiness increases..

Figure D23

T= 30.0°C

t = 222 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O. Bottom emulsion

sediments

σ = 151 μ-MHO

Note: Emulsion thickens and settles.

D8
Figure D24

T= 28.0°C

t = 237 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 146 μ-MHO

Note: Oil bath removed for better view.

Figure D25

T= 28.0°C

t = 247 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O Solution stirred by a

magnetic stirrer, Oil bath out.

σ = 146 μ-MHO

Figure D26

T= 24.6°C

t = 300 min after mixing 123.0 grams of

pH =10.0 solution with 0.60 gram of

Al(NO3)3×9H2O.

σ = 137 μ-MHO (without siring)

σ = 136 μ-MHO (with siring)

Note: Solution stirred with a small

magnetic stirring bar (2 x 1.5 x 5 m)

stirrer inside the chamber is rotating.

D9
Appendix E NUKON dissolution Tests

Bench scale NUKON dissolution tests have been performed in four environments, ICET-1 with pH = 10

by NaOH buffering in the presence and absence of Al, ICET-3 pH = 7 with the buffering TSP, and the

ICET-5 pH = 8-9 of buffering STB. The NUKON samples were exposed in the test solutions at 60°C for

a test period of one month. ICP samples solution were taken at weekly intervals. 

Figures E1, and E2 show SEM micrographs and EDS spectra of the NUKON before exposure. Typical

fiber lengths and thicknesses were of the order of 5-mm in length and somewhat less than 10 μm in

thickness. The major elements in NUKON are Si and Na, but appreciable amounts of Ca, Al, and Mg are

present as shown in the EDS analysis in Fig. E2. 

(a) (b)

Figure E1. SEM view for the NUKON Fiber (a) normal length ~0.5 mm and fiber (b) normal thickness

~10 μm

Figure E2. EDS spectrum and elemental analysis for the NUKON Fiber

The NUKON dissolution tests were done at 60oC for a month period with a loading of 2-g NUKON/l.

Table-E1 shows the matrix of the bench scale NUKON dissolution tests. The solutions were stirred with

a magnetic stirrer. Samples of the supernate solution were taken each week for the ICP-analysis. 

E1
Table E1. Bench scale tests for the NUKON dissolution insulation test.

ICET T(C) Buffering

Agent

pH Boron

(mg/l)

Note

1 60 NaOH 10 2800 NaOH concentration as required by pH.

1 60 NaOH 10 2800 NaOH concentration as required by pH. A

small piece of Al metal mounted in epoxy

was immersed in the solution

2 60 TSP

(Na3PO4.12H2O)

7 2800 Trisodium Phosphate concentration as

required by pH.

5 60 STB

(Sodium

Tetraborate

Na2B4O7.10H2O)

8

to

8.5

2400 The sodium tetraborate (STB) level was

chosen to match the ICET–5 procedure. A

solution with 2800 ppm B from boric acid

and a solution with 2100 ppm B from STB,

were mixed together to get a final solution

with 2400 ppm B.

Table E2 summarizes the observations made during the dissolution tests. Figure E3 shows the three test

chambers; TSP (left), NaOH (middle), and STB (right) at 60°C. Immediately after the NUKON was

inserted, it sank, but in the NaOH, TSP, and STB solutions, bubbles form on the fibers and as shown in

Figure E4, the NUKON floats. After a 48–h exposure, the size of the bubbles was largest in the NaOH

solution, then the TSP solution, and smallest in the STB solution. In the test with Al and NaOH, the

NUKON did not float during the entire test period. Figure E5 shows the NaOH, TSP, and STB exposed

NUKON at the 6-days (144-h), and the Al/NaOH exposed NUKON at 73.5-h. Figure E6 shows the

NaOH, TSP, and STB exposed NUKON at 7-days, and the Al/NaOH exposed NUKON at 4-days.

In the test with metallic Al, the Al mounted in the epoxy with an exposed specific surface area of

57.5 mm2/l. Tiny bubbles could be seen forming and eventually collected as single, large bubble. Figure

E7a shows a NUKON sample taken from the NaOH/Al solution at t = 118-h to investigate a black

precipitate particle. A higher magnification view of the precipitate particle is shown in Fig. E7b. An

EDS analysis and elemental EDS data for the black precipitate are shown in Fig. E7c. The particle is rich

in Al, Na, and Si. An SEM micrograph of the Al sample after 118-h of exposure is shown in Fig. 8a, and

a higher magnification view of the surface is shown in Fig. 8b. 

EDS spectra with different e-beam energies were used to investigate the variation of the chemical

composition with depth. The results are shown in Fig. 8c. The lower energy 4–keV beam has the lowest

Si, the highest Na, and the lowest Al. This may be most representative of the chemical composition on

the surface. For 7 and 10-keV beams, the Na is low which indicates that the Na stays in the surface rather

penetrated into the material. The Si is higher for the high energy beams than for the 4-keV beam

indicating that the Si penetrated some distance into the material. The Al compositions for the 7 & and 10-

keV beams are higher than for the 4-keV beam suggesting that the corrosion product on the Al is rather

thin. 

ICP results for the composition of the solutions are shown in Fig. E9 and Table E3. The Si levels are

noticeably lower in the solution with the Al sample. The presence of this much Al (about 1/4 the area of

Al/volume as in ICET–1) clearly inhibits dissolution of the NUKON, and is consistent with the

observation that this is the only NUKON with no tendency to float. The Ca is lower the solution with the

E2
Al also, reflecting the lower dissolution rate of the NUKON. The Ca level is low in the TSP solution

also, but in this case the Ca has been removed from the solution by the formation of calcium phosphate. 

After about 21 days of testing, the NUKON in the STB solution disintegrated from a loose, but well–

defined clump into a collection of loose fibers. The NUKON in the other solutions remained in a clump

for the duration of the test. The results in Fig. E9 and Table E3 do not suggest that the dissolution rate of

the NUKON in the STB solution was markedly higher than in the NaOH or TSP solutions. 

Table E2. Observations of the bench scale NUKON 4 week dissolution tests at T = 60°C.

Date/time Day of

exposure

Buffering Agent Day of

exposure

Buffering

Agent

I, III, V NaOH

I

TSP

III

STB

V

I, Al Al/NaOH

I, Al

3-14-06 

11:40am

0

(Fig. E3)

R-0

NUKON

exposed

Y-0

NUKON

exposed

B-0

NUKON

 exposed

12:40 pm Float: small

bubbles stick

with fiber.

Remove

bubbles let sink

by glass bar

Float: small

bubbles stick

with fiber.

Remove bubbles

let sink by glass

bar

Float: small

bubbles stick

with fiber.

Remove bubbles

let sink by glass

bar

3-15-06

8:00 am

1 Vertical array

again bubbles

stick.

Vertical array

again bubbles

stick.

9:00 am 1 *Remove

bubbles let sink

by glass bar

Settled

*remove bubbles

let sink by glass

bar

Settled

*Settled

9:10am 1 pH = 10.11 pH = 7.13 pH = 8.88

Started two

days later]

3-16-06

14:10am

2

(Fig. E4)

0 Start I, Al

 (Fig. E4)

3-17-06

10:10am

3

3-17-06

12:30

**Vertical

array again big

bobbles stick.

**Vertical array

again bobbles

stick.

**Vertical array

again bobbles

stick.

1 *NUKON

settled no

bubbles

2

13:50 Ibid

pH = 10.09

Ibid

pH = 7.18

Ibid

pH = 8.84-8.88

(Fig. E5) Ibid

pH = 10.10

3-20-06

11:40

6 NUKON

float

NUKON 1⁄2 & 1⁄2

Sediment/float

NUKON

 float

4 * NUKON

settled no

bubbles

(Fig. E5)

3-21-06

8:15am

7 NUKON

 float

R-1

pH = 10.18

NUKON 1⁄2 & 1⁄2

Sediment/float

Y-1

pH= 7.45

NUKON

float

B-1

pH = 8.98

5 NUKON

settled.

Black

particles on

the NUKON

RAl-1

pH = 10.17

E3
Date/time Day of

exposure

Buffering Agent Day of

exposure

Buffering

Agent

I, III, V NaOH

I

TSP

III

STB

V

I, Al Al/NaOH

I, Al

14:00pm Enforced bubbles

detachment for

settlement of

NUKON

Enforced bubbles

detachment for

settlement of

NUKON

Enforced bubbles

detachment for

settlement of

NUKON

NUKON

settled.

14:40pm NUKON in the

all three

solutions stays

settle down. 

3-22-06

8:15am

8 NUKON settle

down. 

Looked

relevant

reaction 

ended (?)

NUKON settle

down. Looked

relevant reaction

ended (?)

NUKON settle

down. 

Looked relevant

reaction ended

(?)

6 NUKON

settle down.

Looked

relevant

reaction

ended (?)

 Black

particle EDS

analysis see

(Fig. E7,E8)

3-23-06

17:15

9 NUKON settle

down, but few

2-2.5 mm dia

bubbles

holding with

Nukon

Shaken remove

bubbles!

NUKON settle

down. Most

gentle among

three, but few 2-

2.5 mm dia

bubbles holding

with NUKON

Shaken remove

bubbles!

NUKON 1⁄2

floating (F)

settled (S)

Pushed but keeps

the same 1⁄2 & 1⁄2

F/S

7 Few very

small bubbles

holding with

Nukon

Shaken

remove

bubbles!

3-24-06

8:15 am

*Fig-9

10 Few big

bubbles hold

NUKON

settled

Most gently

settle down

couple bubbles

shown

ibid 8 Couple of

bubbles

(Fig. E9)

3-26-06

8:40am

12 Yellowish High

NUKON puffy

Pale disappeared

Yellowish

95% NUKON

float

10 Yellowish

high

3-26-06

8:40am

Yellowish High

NUKON puffy

pH = 10.16

Pale disappeared

Yellowish

pH = 8.96

95% NUKON

float

pH = 7.35

NUKON

settle down

Yellowish

high

pH = 10.12

3-30-06

8:40am

16 R-2 Y-2 B-2 14 RAl-2

Yellowish High

NUKON puffy

NUKON settled

down ; pale

NUKON float

but coagulated

not puffy

Same as

beginning

3-31-06

8:40am

17 Ibid Nukon

sink

Ibid Nukon sink Ibid more top

part of solution 

15 Ibid Nukon

sink

E4
Date/time Day of

exposure

Buffering Agent Day of

exposure

Buffering

Agent

I, III, V NaOH

I

TSP

III

STB

V

I, Al Al/NaOH

I, Al

4-4-06

8:40am

21 R-3 Y-3 B-3 18 RAl-3

NUKON down 

less puffy

pH = 10.19

NUKON down

pale

Puffy

pH = 7.53

*70% NUKON

powdered except

30%

coagulations in

float

Solution very

fuzzy

pH = 9.00

NUKON

down same

More black

ppt on the

NUKON

pH = 10.11

4-11.04

14:26 pm

28 R4 Y-4 B-4 25 RAl-4

Note: ICP-sample code as, R-#, RAl-#, Y-#, B-#, # = 0, t = 0, and # = 0, 1, 2, 3, 4. Where R = NaOH solution, RAl = Al/NaOH, Y

= TSP solution, and B = STB solution respectively. # stand for the week, e.g., R-1 = NUKON dissolution period one week in

NaOH solution.

E5
Figure E3.

NUKON (2-g/l ratio) exposed in three

different solutions; TSP (left), NaOH

(middle), and STB (right) at 60°C.

Figure E4. On the left are the tests in NaOH, TSP, and STB solutions at 48–h. The NUKON

floats due to the bubbles becomes stick on the fiber surface. On the right side is the

Al/NaOH test. The NUKON remained at the bottom of the chamber through the

whole test period.

E6
Figure E5.

The NUKON floating due to the bubbles

on the fiber surface at 144–h. NUKON

in NaOH (red) and STB (blue) totally

floating, and TSP 1⁄2 & 1⁄2 float/sediment

(Yellow). In the Al/NaOH solution at

73.5–h on the right, the NUKON

remains settled .

Figure E6. The NUKON enforced settled 40-min ago for popping up the bubbles by glass rod

to learn the bubble formation profile in this period of exposure. Time = 167.58-h,

T = 60°C. For the Al/NaOH, NUKON settled down from the beginning. Time =

97.08-h, T = 60°C

E7
(a) (b)

(c)

Figure E7.

(a) Sample of NUKON from the dissolution test

in NaOH/Al pH = 10 at 60°C (t = 118-h) with a

black-precipitate particle; (b) higher

magnification of the particle ; (c) EDS spectra

and EDS data for the black precipitate.

E8
(a) (b)

(c)

0

10

20

30

40

50

60

70

Na Mg Si Ca Fe Al

118-h @ 60

oC pH = 10. [NaOH]

4-KeV

7 KeV

10-KeV

E

D

S (at.%)

Element

(d)

Figure E8. (a) Al sample mounted in epoxy resin after 118 h of exposure at pH = 10 at 60°C, (b) enlarged

SEM micrograph for the corroded Al surface, and (c) EDS spectra of the surface of the Al

before exposures and after 118–h exposure and (d) composition of elements from EDS spectra

with different e-beam energy to assess the variation of the chemical composition with depth.

E9
0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

NUKON dissolution:

pH = 10 (NaOH) T = 60

oC

B

Na

P

Al

Ca

Si

K

Fe

ICP [mg/L]

t (week)

0.0

0.1

1.0

10.0

100.0

1000.0

10000.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

NUKON dissolution

pH = 10 (Al/NaOH) T = 60

oC

B

Na

P

Al

Ca

Si

K

Fe

ICP [mg/L]

t (week)

(a) NUKON/NaOH @ 60°C pH = 10 (b) NUKON/Al: NaOH @ 60°C pH = 10

0.1

1.0

10.0

100.0

1000.0

10000.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

NUKON dissolution

pH = 7 (TSP) T = 60

oC

B

Na

P

Al

Ca

Si

K

Fe

IC

P [m

g/L]

t (week)

0.1

1.0

10.0

100.0

1000.0

10000.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

NUKON dissolution

pH = 8-9 (STB) T = 60oC

B

Na

P

Al

Ca

Si

K

Fe

ICP [mg/L]

t (week)

(c) NUKON/TSP @ 60°C pH = 7-7.3 (d) NUKON/STB @ 60°C pH = 8-9

Figure E9. Elemental ICP for the bench NUKON dissolution testes in ICET-1 (a) NaOH, (b) NaOH/Al,

(c) ICET-3 (TSP), and (d) ICET-5 (STB) with the loading 2-g NUKON/l at 60°C in the

ambient condition for a period of 4 weeks.

E10
Table E3. Elemental ICP for the bench scale 4-week NUKON dissolution tests

Sample time Elements ICP (mg/l)

 wk Al B Ca Fe K Mg Na P Si

NaOH

ICET-1

0

1

2

3

4

<1.79 2,270 1.16 0.17 7.07 1.90 4,460.70 0.50 0.84

2,270 15.50 0.27 7.07 2.52 4,362.50 0.49 70.55

2,140 19.20 0.38 7.07 2.18 4,121.30 0.35 92.78

2,360 28.80 0.37 7.07 2.36 4,661.40 0.35 132.61

2,400 31.53 0.08 7.07 1.90 4,788.00 0.35 147.67

TSP

ICET-3

0

1

2

3

4

<1.79 2,610 1.38 0.17 7.07 1.90 619.21 257.25 1.51

2,740 14.02 0.17 7.07 5.64 667.10 262.98 61.81

2,720 13.11 0.17 7.07 7.25 683.81 251.66 86.51

2,850 5.71 0.25 7.07 8.29 794.48 267.95 102.82

2,950 5.45 0.17 7.07 4.21 830.55 266.62 106.29

STB

ICET-5

0

1

2

3

4

<1.79 2,270 0.96 0.17 7.07 1.90 3,567.30 0.35 0.84

2,610 15.15 0.22 7.07 5.32 3,518.50 0.35 61.72

2,270 19.44 0.24 7.07 6.31 3,453.90 0.35 85.29

2,360 28.10 0.51 7.07 9.39 3,732.90 0.35 115.32

2,390 33.33 0.71 7.07 11.19 3,893.70 0.35 138.37

Al/

NaOH

ICET-1

0 <1.79 2,270 1.16 0.17 7.07 1.90 4,460.70 0.50 0.84

1 29.21 2,200 5.27 0.17 7.07 1.90 4,206.80 0.35 16.16

2 61.89 2,240 6.01 0.17 7.07 1.90 4,324.90 0.35 23.77

3 90.80 2,390 5.65 0.17 7.07 1.90 4,650.30 0.35 12.81

4 107.48 2,450 5.20 0.09 7.07 1.90 4,780.20 0.35 11.28

A replicate test on NUKON dissolution in the various test environments was performed. In most respects

the behavior was similar in the two tests. However, in this case, in the STB solution only a small portion

of the NUKON was dispersed. In the NaOH/Al solution a portion of the NUKON did begin to float

during the test. 

E11
F1

Appendix F: Test plan for comparison benchmark testing of PNNL and ANL test

loops

C. W. Enderlin and B. E. Wells, Pacific Northwest National Laboratory

F1 Objective

The objective of the tests is to benchmark the test loops at PNNL and ANL against each other by

comparing head loss measurements as a function of screen approach velocity, debris bed dimensions,

and post-test debris mass measurements. These benchmark tests will allow for the comparison of the

debris injection processes and measurement systems for the two loops. The debris material preparation

and the debris bed formation process will be duplicated, as much as possible, to accomplish this.

F2 Background

The following items are issues that have been considered in selecting the benchmark test cases and for 

determining the test conditionsthat need to be defined in an attempt to ensure the initial conditions are

the same in each test loop:

• Both the ANL and PNNL test loops have 6-in. diameter test sections.

• The maximum head loss across the debris bed that can be measured is 165 and 2700 inches

H2O for the ANL and PNNL loops, respectively.

• The method of introducing the debris material into the test loop is different for each test loop.

• Testing conducted by PNNL has demonstrated that the degree of debris preparation for the 

Nukon debris material impacts the head loss of a debris bed. A metric (referred to as R4, see

Section 4.1.1) and associated method of evaluation have been developed for assessing the 

degree of Nukon preparation.

• For debris beds containing both CalSil and Nukon, preliminary testing conducted to date by

PNNL indicates that the loading sequence of the debris constituents can have a significant

impact on the measured head loss for the resulting debris bed.

1

• PNNL test results conducted in the bench top loop indicated that repeatable results were

obtained for CalSil-Nukon debris beds having a CalSil to Nukon mass ratio of approximately

0.2. Significant variations in measured head loss, in both the large-scale and bench top loops,

were obtained for debris beds having a CalSil to Nukon mass ratio of 0.5. The variation in the 

results for the higher mass ratios is still being investigated.

• Test 050803_NO_0682_2 conducted in the PNNL bench top loop consisted of a Nukon debris

bed with a target mass loading of 0.035 lbm/ft2(0.841 kg/m

2

) and an R4 of approximately 11.

Head loss measurements of approximately 14 and 124 inches H2O were obtained for screen

approach velocities of 0.16 and 0.65 ft/s respectively.

• Test 051004_NC_1469_1 conducted in the PNNL bench top loop consisted of a Nukon and

CalSil debris bed with a total target mass loading of 0.076 lbm/ft2 (1.812 kg/m

2

). The Nukon

target mass loading was 0.061 lbm/ft2 (1.449 kg/m

2

) with an R4 of approximately 11. The

CalSil target mass loading was 0.015 lbm/ft2(0.363 kg/m

2

), for a CalSil to Nukon massratio of

0.25. Head loss measurements of approximately 280 and 504 inches H2O were obtained for

screen approach velocities of 0.15 ft/s and 0.25 ft/s respectively.

 1 Investigation of the Effect of Loading Sequences for Significant Head Loss Differences from Similar

Nukon/CalSil Debris Beds, 1/16/05, CW Enderlin and BE Wells to WJ Krotiuk.
F2

• ANL testing indicates the resulting head loss measurements have been more stable when the

screen approach velocity is decreased following debris bed formation as opposed to increasing

the approach velocity following bed formation. When the approach velocity is decreased from 

that initially used to generate a debris bed, ANL has obtained steady state pressure drops very

quickly compared to the time duration required when the velocity is increased.

• The bulk of ANL testing has been conducted taking head loss measurements for approach

velocities in the range of 0.02 to 0.1 ft/s. The bulk of the ANL debris beds have bed formed at

an approach velocity of 0.1 ft/s followed by incrementally ramping down the approach

velocity.

• The PNNL testing has been conducted taking head loss measurements over the range of

approximately 0.02 to 1.0. ft/s with the bulk of the measurements taken between 0.1 to 0.4 ft/s.

Debris beds have been generated in the PNNL large scale test loop at approach velocities of

0.1 and 0.2 ft/s followed by incrementally ramping up the approach velocity.

• PNNL has formed the debris beds with the fluid temperature at approximately 20oC (68oF).

The PNNL loop in its current configuration is designed to introduce the debris material at a

fluid temperature ≤ 40oC (104oF).

F3 Test Matrix

The test cases were selected from the proposed test matrix, dated 12/1/05, WJ Krotiuk prepared forthe

Series II tests to be conducted at PNNL. The test cases were selected based on the following

objectives/criteria.

• Test two Nukon-only cases and one Nukon/CalSil case.

• The Nukon cases should consist of a relatively thin bed (app 0.04 lb/ft2 [0.2 kg/m

2

]) and a

relatively medium bed (app 0.16 lb/ft2 [0.8 kg/m

2

]).

• The Nukon/CalSil case will use the same Nukon mass loading as one of the two Nukon-only

cases to reduce variations in debris preparation process between debris beds.

• The CalSil/Nukon ratio should be ≤ 0.25.

• Only cases that have an anticipated head loss ≤ 160 inches H2O at an approach velocity of 0.2

ft/s should be selected to ensure head loss data can be obtained over a one order of magnitude

range of approach velocities in both test loops.

Based on the background information presented in Section 2.0 and the previously defined selection

criteria, the three cases presented in Table 1 have been selected for the benchmark tests. Each test case

will be conducted once and results submitted to the NRC for evaluation and direction on performing

repeat tests for selected test cases.

Table F1. Benchmark test cases for ANL and PNNL test loops

Case No.

Nukon Mass

Loading

lb/ft2

(kg/m

2

)

CalSil Mass

Loading

lb/ft2

(kg/m

2

)

Total Mass

Loading

lb/ft2

(kg/m

2

)

CalSil to Nukon

Mass Ratio

BM-1 0.044

(0.217)

0.0

(0.0)

0.044

(0.217)

0.0

BM-2 0.148

(0.724)

0.0

(0.0)

0.148

(0.724)

0.0

BM-3 0.148

(0.724)

0.030

(0.145)

0.178

(0.869)

0.2
F3

F4 Test Preparation

The test preparation is specified in an attempt to control the initial conditions at which the debris bed is

formed on the screen. Test preparation consists of the test loop conditions, the preparation of the 

debris material, and the conditions at which the debris bed is formed. The system and method by

which the debris material is physically introduced into the test loop will not be specified and is part of

the conditions being qualified by these benchmark tests. Section 4.1 summarizes how the debris

material will be prepared prior to introduction. The test loop conditions at the start of testing are

discussed in Section 4.2, and the parameters specifications for bed formation are presented in Section

4.3.

F4.1 Debris Preparation

The CalSil and Nukon debris material to be used for the tests will be from the following sources:

• The Nukon material will come from Vendor/Manufacturer: Performance Contracting Inc., Lot

No.: 09/06/5ND5, BS-4813 shipped: Oct. 8, 2005. This material was subjected to a 12 to 24

hr heat-treating process and shredded by the vendor/manufacturer prior to shipment.

• The CalSil material will come from Vendor/Manufacturer: Johns Manville, Lot No.: 017-276,

BS-4823,shipped: September 28, 2005. The received CalSil material will be in the form of 3-

in. by 12-in. by 48-in blocks. The CalSil material has not been subjected to any heat-treating

process.

The preparation of the Nukon and CalSil materials is discussed in Sections 4.1.1 and 4.1.2,respectively

F4.1.1 Nukon Preparation

The debris preparation method for the Nukon used in the benchmark tests will be characterized by the

R4 metric and the debris dilution used for blending. The R4 metric is defined by

R4 =

Nukon and Water Mass on Screen

Initial Nukon Mass (1)

The as-received “shredded” Nukon will be added to a specified volume of water and blended using an

industrial bench top blender to separate/breakdown (i.e. “reduce”) the fibrous material. The degree of

blending and the amount of dilution for each test case will be obtained from trying to replicate the

degree of material “reduction” performed by ANL for their most recent tests.

During past work at LANL the shredded Nukon fiber was boiled for duration of 10 to 15 minutes prior

to being introduced to the loop. The boiling was performed to break down organic binders. ANL

currently subjects the debris material to a “pre-soak,” which consists of soaking the material in 140oF 

water for 30 minutes prior to introduction into the loop. The 30-min. pre-soak is intended to simulate 

the approx. 30 min. delay that would exist between the occurrence of a LOCA and the start of the

circulation pump. To eliminate a potential source of variability, no “pre-soak” or boiling of the Nukon

will be performed for the benchmark tests.
F4

To determine the R4 metric, ANL will carry out their Nukon preparation method a minimum of three

times for each of the Nukon mass loadings specified in Table 1. The preparation method will use a

constant Nukon mass and water volume for each batch and sub-batch of material generated.

Definition: Debris batch – The entire mass of a debris constituent that needs to be prepared to

conduct a specific test. Example: Test case BM-2 requires 13.22 g of Nukon be 

introduced to the loop, therefore, the “batch” of Nukon for a test run for Case

BM-2 is 13.22 g.

Definition: Debris sub-batch – The amount of mass that is to be placed in a single mixer for

blending that isto be combined with other sub-batches to generate a single debris

batch for testing. If the entire mass of a debris batch can be prepared in a single

operation of the blender then no debris sub-batches are necessary.

The generation of a debris batch using sub-batches should attempt to use uniform sub-batches.

Example: Suppose the required debris batch has a mass of 45 g, and the blender to be used can hold

500 ml of water and concentrations up to 30 g Nukon in 500 ml water can successfully be blended. A

blend time and dilution rate should be determined for preparing three debris sub-batches of 15 g each.

It would not be desirable to prepare two sub-batches of 20 g each using a specified dilution rate and

blend time and then prepare a third sub-batch of 5 g using a second dilution rate and blend time.

Based on previous work conducted by LANL, the maximum concentration to be used for blending subbatches of Nukon is 25g Nukon per1000 ml water.

After ANL prepares each debris sub-batch intended for the purpose of determining R4, an R4 test will

immediately be conducted to determine the wet mass of material retained on the screen. The mass of

Nukon retained on the screen will be photographed after each R4 test. The R4 tests will be conducted

using 5-mesh screen. For each quantity of Nukon specified in Table 1, the following information will

be transmitted to PNNL:

• Individual R4 values calculated by ANL

• Dimensions of the 5-mesh screen used to conduct the R4 test,

• The volume or mass of water used to generate a debris batch/sub-batch,

• The mass of dry Nukon used to generate a debris batch/sub-batch,

• Blender make and model number,

• Photographs of the retained mass on the screen taken following each R4 test.

Note 4.1.1 - A: The debris material used to conduct an R4 test will never be introduced to the

test loop. Once the dilution ratio and blend times have been determined and assessed

via multiple R4 tests, the debris preparation procedure is executed to generate a debris

batch for introduction into the loop. This prepared debris batch does not undergo an

R4 test.

Note 4.1.1 – B: The retained mass on a screen following an R4 test is to be removed prior to

executing a new R4 test.

PNNL will attempt to use the same dilution ratios as ANL and determine blending times required to

achieve an average R4 value of within ± 1 of the average ANL value for each quantity of Nukon

required for the debris loadings specified in Table 1. Conducting R4 tests on a minimum of three

debris batch preparations will assess the final R4 value for the PNNL tests.
F5

F4.1.2 CalSil Preparation

The CalSil will be prepared by mortar and pestle on the dry debris material. The CalSil will be ground

until no visible large particles exist. The final product should have the CalSil material disassociated

from the fibrous component and the ground material should have the consistency of flour. Based on

past observations by LANL it is recommended that relatively small sub-batches of CalSil should be

ground separately to achieve the desired consistency. LANL observed that the separated fiber might

tend to aggregate during continued grinding.

The dry ground material (including both the fiber and particulate) will then be added to water and

blended in the blender. The dilution ratio of the dry CalSil and the blending time will be the same as

that currently employed by ANL.

No “presoak” or boiling of the CalSil will be performed for the benchmark tests.

ANL will provide PNNL with the following:

• Photographs of the dry CalSil material following grinding using mortar and pestle.

• The dilution ratio of CalSil to water used for blending operations.

• The blending time used for a CalSil debris batch/sub-batch.

• Blender make and model number.

• A physical description of the appearance and pour ability of the CalSil slurry following

blender operations.

• Photographs of the CalSil slurry.

PNNL will perform PSDA on a CalSil slurry prepared according to the final CalSil preparation

procedure used for the benchmark tests.

F4.1.3 Debris Preparation for Introduction to Loop

Following the preparation of the concentrated debris slurries discussed in Sections 4.1.1 and 4.1.2,

there are three imposed debris preparation requirements for introduction of the debris material into the

loop. This portion of the process is unique to the individual test loops and is being assessed by these 

benchmark tests. The three requirements are:

• The CalSil and Nukon materials are to be pre-mixed by manual stirring with a kitchen utensil

prior to introduction into the test loop.

• The concentrated CalSil and Nukon slurries are to be prepared just prior to testing.

• The prepared, mixed slurry is to continually experience some form of mild agitation to prevent

material settling and agglomeration prior to introduction into the test loop. Past experience has

demonstrated that manual stirring with a kitchen utensil is sufficient.

F4.2 Test Loop Conditions

The test loops will use perforated plate as the sump pump screen aligned in a horizontal orientation

perpendicular to the flow in a vertical test section. The perforated plate will have the dimensions

specified in Table 2. Due to the manufacturing process, the holes in the perforated plate will have a
F6

squared edge and a rounded edge. The plate is to be installed with the rounded edges of the holes

directed upstream.

Table 2. Perforated Plate Dimensions

Diameter of 

Perforations

(in.)

Center to Center 

Pitch

(in.)

Hole Pattern

Percent Open 

Area

(%)

Plate

Thickness

(in.)

1/8 3/16 Staggered 60o

centerline pattern

40 0.056

The test loop is to be flushed and inspected (based on past practices and assessments made for the

individual loops) to ensure minimal residual free debris material exists from past testing.

The loop is to be filled with DI water for testing. Degassing of the water should be conducted to

minimize/eliminate the presence of gas in the system during testing.

F4.3 Debris Bed Formation

The diluted, premixed debris slurry is to be continually agitated prior to introduction into the loop as

specified in Section 4.1.3. The debris slurry is to be introduced into the test loop with the screen

approach velocity adjusted to 0.1 ft/s. The approach velocity is defined as the average velocity in the 

upstream test section. The retention of debris material on the test screen will cause a change in the

system curve for the test loop resulting in an increase in pressure drop across the debris bed and a

corresponding reduction in screen approach velocity. During debris bed formation the screen approach

velocity is to be maintained between 0.09 and 0.1 ft/s.

The fluid temperature during bed formation and for the duration of the test isto be maintained at 25o ±

5oC (77o ± 9oF).

The indicated head loss is to be sampled at a minimum frequency of 0.5 Hz and monitored with a

running 1-minute average of the sampled data. The head loss data is to be logged at a minimum

frequency of 0.1 Hz. The debris bed formation process will be considered complete when both of the

following two criteria have been satisfied.

1. A minimum time equivalent to 20 calculated loop circulations assuming a constantscreen

approach velocity of 0.1 ft/s has elapsed.

2. The absolute change in head loss based on a 1-minute running average is less than 2%

over 10 minutes. The criteria will be assessed and satisfied three times. The minimum

time between assessments will be one minute. The criteria is expressed as

0.02 !

"Pt1# "Pt2

"Pt1

Where: ΔPt1 = the measured head loss across the bed at time t1.

ΔPt2 = the measured head loss across the bed at time t2.

t1 – t2 ≥ 10 minutes
F7

Exception: For head loss measurements less than 14 inches H2O (0.5 psi) the acceptance criteria

will be: 0.05 !

"Pt1# "Pt2

"Pt1

At the completion of bed formation the following will be recorded:

• Photographs of the debris bed

• Measurements of the debris bed thickness

• Time duration between debris introduction and steady state head loss readings.

F5 Testing & Measurements

The actual testing is considered to commence after the debris bed has been formed (data will be taken

over the entire test period including static loop conditions, flow initialization, bed formation, etc.). The

objective of the items discussed in Section 4.0 is to generate a debris bed in each loop for a given test

case that is similar. This section defines the success criteria for the benchmark tests in Section 5.1,

presents current issues associated with the test plan in Section 5.2, outlines the test process in Section

5.3, and discusses post test measurements in Section 5.4,

F5.1 Success Criteria

The success criteria for this test plan is to obtain, from both ANL and PNNL, data from one test for

each test condition listed in Table I. The data is to include head loss measurements for the velocity

sequence presented in Table 3. The steady state head loss measurements and post-test debris bed

measurements will be used to compare the measurement and debris injection systems for both loops.

Following the initial comparison of the test results, the NRC will determine if additional testing is

required under this test plan.

F5.1.1 Discussion of Success Criteria

Disregarding experimental uncertainty associated with carrying out the test preparation tasks, the 

differences between debris beds generated in the two loops should be the result of random variation

associated with the debris bed formation process and the differences in the debris injection methods.

The random variation associated with debris bed formation can be investigated with repeat tests in the

individual test loops. The variations due to the physical debris loading process may only be

distinguishable at small velocities (≤ the bed formation velocity) and may be eliminated with exposure

to higher velocities.

It is plausible that differences, which exist immediately following bed formation, between the debris

beds generated in the two tests loops will be eliminated or reduced as a result of subjecting the debris

bed to velocity cycling or increased pressure drop. Therefore, the two test loops may yield different

measurements of head loss until a threshold pressure drop is achieved, and then display acceptable

agreement. No definition has been given for acceptable benchmarking. Example: Has successful

benchmarking been achieved if it requires five velocity cycles or testing at velocities greater than 0.2

ft/s to achieve good agreement between the two test loops?
F8

No criteria have been given for the repeatability requirements of an individual test loop.

F5.1.2 Potential Success Criteria for the Benchmark Tests

• Complete one test in both the ANL and PNNL test loops for each test case (refer to Table 1).

• Obtain average steady state measurements as a function of approach velocity for the two test

loops that are within 10 % of each other after two cycles of velocity ramp up and down.

F5.2 Test Plan Issues

This section presents several issues that should be considered in determining whether the current test

plan is sufficient to meet the stated objectives and the project needs. The issues are also items that

should be considered when comparing the measurements obtained from the two loops .

The current test plan callsfor generating the debris beds at a screen approach velocity of 0.1 ft/s(0.030

m/s). During Series I testing at PNNL it appeared that debris settled within the loop during the debris

formation process. This settled material appeared to be resuspended at higher velocities later during

the test. If settling of debris material occurs, then the debris beds may vary in mass for the initial test

measurements until material is potentially resuspended at a higher velocity and deposited on the debris

bed. The material may not be resuspended since the critical velocity to sustain suspension for a given

material at a specific concentration can be lower than the critical velocity for resuspension. If

variations in the results are encountered between the two test loops and a discrepancy is observed in the

post-test debris bed mass measurements, it is recommended that consideration be given to repeating the

test case with a greater debris bed formation velocity.

The inventory of the PNNL test loop is approximately twice that of the ANL loop. The potential for

this difference between the test loops to create significant differences in head loss measurements is

considered minimal as long as debris material does not settle during the bed formation process. The

following issues should be considered when comparing test results from the two loops.

• If material settles during bed formation, at increased velocities the addition of debris to the 

retained debris bed could be expected to occur at twice the rate in the ANL loop. This effect

could explain the observation of results being comparable at lower velocities and then

deviating at higher velocities (at least for the first velocity ramp-up at velocities greater than

the bed formation velocity).

• The debris bed in the PNNL loop will be subjected to flow for a longer period of time to obtain

a similar retained mass as in the ANL loop.

It is recommended by PNNL that the test program should not rely on obtaining pressure drop data for 

screen approach velocities in the transition flow regime.

2 The current velocity sequence presented in

Section 5.3, Table 3 has head loss measurements being taken at steady state velocities predicted to

create a transition flow in the test section. At a temperature of 210C (70oF), the transition flow regime

is predicted to exist for screen approach velocities from 0.009 to 0.026 m/s (0.031 to 0.085 ft/s). At a

temperature of 93°C (140°F), the transition flow regime is predicted to exist for screen approach

velocities from 0.005 to 0.012 m/s (0.015 to 0.041 ft/s). It is recommended that the head loss

 2 Revised Memo on Impact of Test Section Diameter and Fluid Approach Velocity on Reynolds

Number, 5/19/05, CW Enderlin to WJ Krotiuk.
F9

measurements be taken for the entire velocity sequence, but the potential flow regime issue should be

considered when comparing test results between the two loops.

F5.3 Test Process

After the debris bed has been formed and the criteria for steady state conditions met, the bed will be

subjected to a sequence of velocities that are listed in Table 3. Each approach velocity will be 

maintained until a steady state head loss has been achieved. A steady state head loss will be assumed

after all of the following three requirements have been met:

1. The steady state velocity has been maintained for a minimum of 5 minutes.

2. If the current velocity is the peak velocity at the end of a ramp up, then the steady state

velocity has been maintained for a minimum of 10 minutes.

3. The absolute change in head loss based on a 1-minute running average is less than 2% over 5

minutes. (Exception: For head loss measurements less than 14 inches H2O (0.5 psi), the

absolute change in head loss based on a 1-minute running average will be less than 5% over 5

minutes). The criteria will be assessed and satisfied three times. The minimum time between

assessments will be one minute.

Table 3. Velocity sequence for the ANL and PNNL test loop benchmark cases

Test Point Velocity

(ft/s)

Test Sequence

Initial condition 0.10 Bed Formation

1 0.10 Ramp down 1

2 0.05 Ramp down 1

3 0.02 Ramp down 1

4 0.05 Ramp up 1

5 0.10 Ramp up 1

6 0.05 Ramp down 2

7 0.02 Ramp down 2

8 0.10 Ramp up 2

9 0.15 Ramp up 2

10 0.20 Ramp up 2

11 0.15 Ramp down 3

12 0.10 Ramp down 3

13 0.15 Ramp up 3

14 0.20 Ramp up 3

15 0.10 Ramp down 4

16 0.05 Ramp down 4

17 0.02 Ramp down 4

18 0.10 Ramp up 4

The fluid temperature during testing is to be maintained at 25o ± 5oC (77o ± 9oF). The velocity test

matrix/sequence to be performed is presented in Table 3.
F10

If ANL obtains head losses greater than 160 inches H2O for any test case, a velocity, which yields a 

head loss between 150 to 160 inches H2O, will be substituted, for the individual test case, for the peak

velocity in Table 3. The revised velocity sequence for the specified test case will be transmitted to

PNNL.

After a steady state head loss has been achieved:

• The head loss across the debris bed and fluid velocity measurements will be recorded for a

minimum of two minutes at a minimum of 0.1 Hz.

• The debris bed height will be measured

• The fluid temperature in the loop will be measured.

F5.4 Post Test Measurements

After the velocity sequence in Table 3 has been executed the debris bed is to be retrieved for post-test

analyses. Post-test measurements are to include:

• Debris bed height along two perpendicular diameters.

• The mass of the wet retrieved debris bed.

• The dry mass of the retrieved debris bed as a function of time demonstrating a constant mass

has been achieved at an elevated temperature. PNNL currently dries the debris beds at 90o C 

and ambient pressure.
NRC FORM 335

(9-2004)

NRCMD 3.7

U. S. NUCLEAR REGULATORY COMMISSION

BIBLIOGRAPHIC DATA SHEET

(See instructions on the reverse)

1. REPORT NUMBER

(Assigned by NRC. Add Vol., Supp., Rev.,

and Addendum Numbers, if any.)

NUREG/CR–6913

ANL–06/41

2. TITLE AND SUBTITLE 3. DATE REPORT PUBLISHED

MONTH YEAR

December 2006

4. FIN OR GRANT NUMBER

Chemical Effects Head-Loss Research in Support of Generic Safety Issue 191

N6100

5. AUTHOR(S) 6. TYPE OF REPORT

Topical

J.H. Park, K. Kasza, B. Fisher, J. Oras, K. Natesan, and W.J. Shack 7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION – NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor,

provide name and mailing address.)

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

9. SPONSORING ORGANIZATION – NAME AND ADDRESS (If NRC, type “Same as above”: if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission,

and mailing address.)

Division of Fuel, Engineering and Radiological Research

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555–0001

10. SUPPLEMENTARY NOTES

Paulette A. Torres, NRC Project Manager

11. ABSTRACT (200 words or less)

This report describes studies conducted at Argonne National Laboratory on the potential for chemical effects on head loss

across sump screens. Three different buffering solutions were used for these tests: trisodium phosphate, sodium hydroxide,

and sodium tetraborate. These pH control agents used following a LOCA at at a nuclear power plant show various degrees

of interaction with the insulating materials Cal-Sil and NUKON. Results for Cal–Sil dissolution tests in TSP solutions,

settling rate tests of calcium phosphate precipitates, and benchmark tests in chemically inactive environments are also

presented. The objective of the head loss tests was to assess the head loss produced by debris beds created by Cal–Sil,

fibrous debris, and calcium phosphate precipitates. The effects of both the relative arrival time of the precipitates and

insulation debris and the calcium phosphate formation process were specifically evaluated. The debris loadings, test loop

flow rates, and test temperature were chosen to be reasonably representative of those expected in plants with updated sump

screen configurations, although the approach velocity of 0.1 ft/s used for most of the tests is 3–10 times that expected in

plants with large screens . Other variables were selected with the intent to reasonably bound the head loss variability due to

arrival time and calcium phosphate formation uncertainty. Settling tests were conducted to measure the settling rates of

calcium phosphate precipitates (formed by adding dissolved Ca to boric acid and TSP solutions) in water columns having no

bulk directional flow.

Dissolved Al concentrations of 100 ppm were shown to lead to large pressure drops for the screen area to sump volume ratio

and fiber debris bed studied. No chemical effects on head loss were observed in sodium tetraborate buffered solutions even

for environments with high ratios of submerged Al area to sump volume

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating this report.) 13. AVAILABILITY STATEMENT

unlimited

14. SECURITY CLASSIFICATION

(This Page)

unclassified

(This Report)

unclassified

15. NUMBER OF PAGES

16.PRICE

Generic Safety Issue 191

Chemical Effects

Head-Loss

Sump strainer

Loss of coolant accident (LOCA)

NRC FORM 335 (9-2004) PRINTED ON RECYCLED PAPER