NUREG/CR-6873

Corrosion Rate Measurements and

Chemical Speciation of Corrosion

Products Using Thermodynamic

Modeling of Debris Components to

Support GSI-191

Center for Nuclear Waste Regulatory Analyses

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research -el ,Ot

Washington, DC 20555-0001 A
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NUREG/CR-6873

Corrosion Rate Measurements and

Chemical Speciation of Corrosion

Products Using Thermodynamic

Modeling of Debris Components to

Support GSI-191

Manuscript Completed: April 2005

Date Published: April 2005

Prepared by

V. Jain, X. He, Y.-M. Pan

Center for Nuclear Waste Regulatory Analyses

6220 Culebra Road

San Antonio, TX 78228-05 10

B.P. Jain, NRC Project Manager

Prepared for

Division of Engineering Technology

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

NRC Job Code N6061
ABSTRACT

This report documents thermodynamic simulations conducted to determine whether post

loss-of-coolant-accident (LOCA) debris generation and consequent sump screen head loss in a

pressurized water reactor containment can be affected by chemical interactions between the

emergency core cooling system/containment spray water and exposed materials. Based on the

measured corrosion rates, estimated exposed surface area, and exposure time, the

thermodynamics simulations indicated that the formation of dominant solid phases was

controlled by the presence of Nukon" low-density fiber insulation, aluminum, and concrete. The

predicted dominant solid phases consisted of potentially amorphous silicate phases such as

sodium aluminum silicate (NaAISi308), calcium magnesium silicate [Ca2MgSi8022(OH)2],

calcium silicate (CaSiO 3), and silica (SiO2). The results were based on the solid phases

included in the thermodynamic simulation program database. The formation of actual solid

phases may be different depending on the reaction kinetics. Although some constituents

decreased proportionally with increasing time, the solid NaAISi 308 phase continued to be a

dominant solid phase at all times. The formation of NaAISi308 in the presence of alkaline

solutions could lead to gel formation, which could result in clogging of containment area sump

pump suction strainers. Thermodynamic simulations indicate that in alkaline simulated

containment water at pH 10 there is no significant difference in corrosion product formation as

high-temperature and pressure conditions during the initial stages of a LOCA event approach

steady-state atmospheric pressure conditions. This report provides insight to and is useful in

understanding the evolution of solution chemistry and the formation of solid phases in integrated

chemical effects tests at the University of New Mexico.

iii
FOREWORD

The U.S. Nuclear Regulatory Commission (NRC) is engaged in research activities related to

resolving Generic Safety Issue (GSI) 191, "Assessment of Debris Accumulation on PWR Sump

Performance." During a review of those staff activities, the NRC's Advisory Committee on

Reactor Safeguards (ACRS) raised a concern that products attributable to chemical interactions

between the emergency core cooling system (ECCS)/containment spray water and exposed

materials (such as metal surfaces, paint chips, and fiberglass insulation debris) could impede the

performance of ECCS recirculation following a loss-of-coolant accident (LOCA) at a pressurizedwater reactor (PWR).

In response to that concern, the NRC's Office of Nuclear Regulatory Research (RES) sponsored

an integrated chemical effects test (ICET) program at the University of New Mexico,

under the direction of Los Alamos National Laboratory. In addition, in order to (1) determine the need

for a pressurized test loop for ICETs, (2) assess whether gelatinous products could form

following a LOCA, (3) gain insights into important parameters, and (4) attempt to predict the

ICET results, RES initiated the CNWRA study to perform computer-based thermodynamic

simulations of chemical effects in a typical post-LOCA PWR containment environment. This

model allows rapid and relatively inexpensive identification of the critical chemistry, time,

temperature, pressure, and pH variables that affect chemical product formation.

This report documents the results of experiments to determine corrosion rates for metals

and leaching rates for concrete and fiberglass, which were used as input parameters

to the thermodynamic model. The report also identifies the assumptions and simplifications

considered in the simulation modeling. One notable simplification is that the model does not

consider reaction kinetics, which may affect the types and amounts of chemical species

that form. However, these initial thermodynamic simulation results indicate that (1) chemical

interactions could lead to the formation of gelatinous products following a LOCA, (2) the

important parameters for solid formation include solution pH and temperature (among others);

and (3) the presence of low-density fiber insulation, aluminum, and concrete influences

the precipitation of chemical species.

This report also provides some initial understanding of the evolution of solution chemistry and

the formation of solid phases in the ongoing ICET program. However, a better understanding of

the impact of modeling assumptions and simplifications, including the effect of reaction kinetics,

is necessary by comparing simulation results with ICET observations. The staff is conducting

follow-on research to evaluate available analytical tools with the objective of gaining an

understanding of their accuracies, uncertainties, and limitations within the sump environment.

The insights gained in this report and recommendations from the follow-on research will assist

the NRC staff in conducting safety reviews of licensees' responses to Generic Letter (GL) 2004-

02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design-Basis

Accidents at Pressurized-Water Reactors," dated September 13, 2004.

Carl J. Paperello, Dir ctor

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

v
CONTENTS

Section Page

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

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

FIGURES ................... ix

TABLES ................... xi

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

ACKNOWLEDGMENTS..................................................... xvii

1 INTRODUCTION. 1-1

2 CORROSION RATES OF DEBRIS COMPONENTS .2-1

2.1 Zinc .2-1

2.2 Aluminum .2-2

2.3 Carbon Steel .2-2

2.4 Copper .2-3

2.5 Concrete. 2-4

2.6 Fiber Insulation .2-5

3 ESTIMATE OF DEBRIS COMPONENTS .3-1

4 ANALYSIS OF CORROSION PRODUCTS IN ALKALINE CONTAINMENT

WATER USING THERMODYNAMIC SIMULATIONS . .4-1

4.1 Effect of Temperature .4-1

4.2 Evolution of Solid and Aqueous Phases at 60 0C [140 F] .. 44

5 SUMMARY .. 5-1

6 CONCLUSIONS .6-1

7 REFERENCES .7-1

APPENDIX A - CORROSION RATE MEASUREMENT METHODS FOR METALS ..... A-1

APPENDIX B - CORROSION RATE MEASUREMENTS FOR FIBER

INSULATION GLASS AND CONCRETE ....... .................. B-1

APPENDIX C - CHEMICAL SPECIATION, USING THERMODYNAMIC MODELING,

DURING A REPRESENTATIVE LOSS-OF-COOLANT ACCIDENT

EVENT (CNWRA 2004-07, REVISION 1) ....... .................. C-1

vii
FIGURES

Figure Page

2-1 Relationship Between Release Rate and Temperature for Nukono Low-Density

Fiber Insulation Glass Between 60 and 110 'C [140 and 230 OF] at pH 7 and

pH 10 ................. ............................................ 2-6

4-1 Calculated Amount, in mol, of Predicted Potentially Amorphous Solid Phases

Formed As a Function of Temperature in 0.259 M [2,800 ppm] Boron in Borated

Alkaline Containment Solution at pH 10 ....................... 4-3

4-2 Calculated Percent Predicted Solid Phases Formed As a Function of Temperature

in 0.259 M [2,800 ppm] Boron in Borated Alkaline Containment Solution at pH 10 .. 4-3

4-3 Calculated Amount, in mol, of Predicted Solid Phases Formed As a Function of

Time, in Hours, in 0.259 M [2,800 ppm] Borated Alkaline Containment Water ..... 4-6

4-4 Calculated Percent Predicted Solid Phases Formed As a Function of Time

in 0.259 M [2,800 ppm] Boron in Borated Alkaline Containment Water at pH 10 .... 4-7

4-5 Calculated Sodium and Boron Concentrations, in mol/L, in Aqueous Phase As a

Function of Time in 0.259 M [2,800 ppm] Borated Alkaline Containment Water

in pH 10 ............... ............................................ 4-9

4-6 Calculated Calcium and Silicon Concentrations, in mol/L, in Aqueous Phase As a

Function of Time in 0.259 M [2,800 ppm] Borated Alkaline Containment Water

inpH10 ....... 4-9

4-7 Pourbaix Diagram foruAluminum in a pH 10 Borated Alkaline Solution at

60 0 C [140 -F] . ..................................................... 4-11

4-8 Pourbaix Diagram for Aluminum in a pH 10 Borated Alkaline Water

Containing Silica at 60 0C [140 OF] ...................................... 4-12

ix
TABLES

Table Page

1-1 Sources of Debris on the Sump Screen and Strainers ........................ 1-1

2-1 Measured Corrosion Rates for Debris Components in Borated Alkaline

Containment Water at pH 10 .............. ............................. 2-1

2-2 Measured Corrosion Rates for Debris Components in Borated Alkaline

Containment Water at pH 7 ............... ............................. 2-3

2-3 Constitution of Concrete Mixture ........... ............................. 2-4

2-4 Major Components of Portland Cement ......... .......................... 2-4

2-5 Leaching Rate of Calcium Oxide, Aluminum Oxide, and Silicon Dioxide from

Concrete in Borated Alkaline Containment Water at pH 10 ..... ............... 2-5

2-6 Analyzed Chemical Composition of Nukon' Fiber Insulation ....... ............ 2-7

2-7 Time Needed to Leach a 7-prm [0.28-mil]-Thick Nukon' Glass ..... ............ 2-7

3-1 Estimate of Release from Concrete Particulates ............................ 3-1

3-2 Estimation of Debris in pH 10 Borated Alkaline Containment Water Using Eq. 3-1 .. 3-2

3-3 Estimation of Debris in pH 10 Borated Alkaline Containment Water at

60 'C [140 'F] Using Eq. 3-1 .3-3

4-1 pH and Redox Potential [Eh (VSHE)] of Borated Alkaline Containment Water with

0.259 M [2,800 ppm B] and 0.23 M [5,300 ppm Na] NaOH .4-2

4-2 Predicted Percent of Solid Phases at pH 10 Using OLI StreamAnalyzer0 .... ..... 4-4

4-3 Predicted Percent Element Distribution in Solid Phases at pH 10 ..... .......... 4-4

4-4 Calculated Amount of Solid Phase Per Liter of Solution at pH 10, 60 *C [140 OF],

at 32 Hours .4-5

4-5 pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water with

0.259 M [2,800 ppm B] and 0.28 M [5,300 ppm Na] NaOH at 60 'C [140 F] .4-6

4-6 Percent of Potentially Amorphous Solid Phases at 60 °C [140 OF], 101 kPa [1 atm],

pH10 .4-7

4-7 Percent Element Distribution in Potentially Amorphous Solid Phases at 60 °C

[140 OF], 101 kPa [1 atm] pH 10 .4-8

xi
EXECUTIVE SUMMARY

A loss-of-coolant-accident (LOCA) event causes rapid changes in the time-temperaturepressure-chemistry-pH conditions in the containment environment. Changes in the coolant

chemistry are further complicated by interactions among materials typically present in the lower

regions of the containment. These complex interactions require extensive and time-consuming

experimentation to adequately analyze the potential for sump screen blockage caused by

chemical precipitation. Thermodynamic simulations allow rapid and relatively inexpensive

identification of critical variables from a large number of components present in the

containment system during and following a LOCA event.

The primary objective of this study is to improve the predictive capability of the simulation model

by reducing uncertainties in the corrosion rate values which underpin the data to the

thermodynamic simulation program. An earlier study presented in Appendix C was based on

available corrosion rate data in literature. This study, therefore, is focused on (i) determining

the dissolution rate of Nukon0 low-density fiberglass insulation and concrete in an alkaline

solution at pH 10 in borated sodium hydroxide solution at 60, 90, and 110 0C [140, 194, and

230 OF]; (ii) determining corrosion rates for aluminum, copper, galvanized steel, and carbon

steel in borated alkaline water at pH 10 at 60, 90, and 110 0C [140, 194, and 230 'F];

(iii) determining dissolution rate of Nukone low-density fiberglass insulation and the corrosion

rate of carbon steel in a borated trisodium phosphate solution at pH 7 at 60, 90, and 110 0C

[140,194, and 230 'F]; and (iv) thermodynamic modeling of the chemical speciation of plausible

reaction products in coolant waters after a postulated LOCA event using experimentally

determined corrosion rates.

Corrosion of galvanized steel, copper, aluminum, and carbon steel were measured using

ASTM G59-97 (ASTM Intemational, 2004a), and corrosion rates were calculated using

ASTM G102-89 (ASTM International, 2004b) at 60, 90, and 110 0C [140, 194, and 230 0F] in

borated {0.259 M [2,800 ppm] boron} alkaline containment water at pH 10. Corrosion rates for

Nukon' glass and concrete were determined using ASTM C1220-98

(ASTM Intemational, 2002) at 60, 90, and 110 0C [140, 194, and 230 OF] in borated {0.259 M

[2,800 ppm] boron} alkaline containment water at pH 10 and in borated {0.259 M [2,800 ppm]

boron} containment water at pH 7. A pH of 10 was adjusted by the addition of sodium hydroxide and a pH of 7 was adjusted by the addition of trisodium phosphate.

The thermodynamic simulations documented in this report were made using a thermodynamic

simulator for evaluating aqueous chemical processes in industrial and environmental

applications. Computational thermodynamics simulation calculations were conducted using

StreamAnalyzer° Version 1.2 (OLI Systems, Inc., 2002a). Key chemical components involved

in speciation simulation were copper, carbon steel, galvanized steel, aluminum, Nukon' lowdensity fiber insulation, and concrete. The amounts of corrosion products were determined

based on the surface areas exposed as discussed in the U.S. Nuclear Regulatory Commission

(NRC) test plan (NRC, 2005) and the experimentally determined corrosion rates. The

comparison of corrosion amounts indicates that corrosion amount for Nukon0 low-density fiber

insulation is two to three orders of magnitude higher in borated alkaline containment water

compared to carbon steel, galvanized steel, and copper. The amount of corrosion products

associated with these metals, except aluminum, can be neglected in simulations. Based on the

dissolution rate for Nukono low-density fiber insulation at 60 °C [140 °F3, an average 7-pm

[0.28-mil] diameter Nukono low-density fiber would leach in approximately 180 hours.

xiii
_ _ _ _ _ _ l

Furthermore, the leached contribution from Nukono low-density fiber insulation is approximately

10,000 times more than that for concrete walls. In this study, concrete particulates were

assumed to be released instantly.

Based on the measured corrosion rates, estimated exposed surface area, and exposure time,

the thermodynamic simulations indicate that formation of dominant solid phases is controlled by

the presence of Nukono low-density fiber insulation, aluminum, and concrete. The predicted

dominant solid phases consisted of potentially amorphous silicate phases such as sodium

aluminum silicate (NaAISi308), calcium magnesium silicate [Ca2MgSi8022(OH)2J, calcium silicate

(CaSiO 3), and silica (SiO2). Although some of these constituents decreased proportionally with

increasing time, the solid NaAISi 308 phase continued to be the dominant solid phase at all

times. The formation of actual solid phases may be different depending on the reaction kinetics.

The formation of NaAISi 308 coupled with the presence of alkaline solutions could lead to

gel formation.

This study provides, based on thermodynamic simulations, a description of the expected

evolution of soluble species in borated alkaline containment water at 60 0C [140 OF]. Both

silicon- and calcium-bearing soluble phases were predicted in borated alkaline containment

water. The dominant silicon-bearing soluble phases were SiO2 (aqueous), H3SiO4 ', and

NaHSiO3, and the dominant calcium-bearing soluble phase was CaH 2BO3*'. Furthermore, the

aqueous concentrations of boron and sodium increased with time.

Comparison of the calculations using measured corrosion rates with the calculations presented

in Appendix C using literature data in literature indicates formation of similar dominant solid

phases with the exception of iron silicates such as Fe3Si2O5(OH)4 and Ca3Fe2Si3 012. The

absence of iron-bearing silicate phases in calculations using measured corrosion rates was

attributed to extremely low corrosion rate measured for carbon steel at pH 10 compared to the

corrosion rate assumed in Appendix C calculations.

Thermodynamic simulations indicate that in alkaline simulated containment water at pH 10 there

is no significant difference in corrosion product formation as high-temperature and pressure

conditions during the initial stages of a LOCA event approach steady-state atmospheric

pressure conditions. These results support the conclusion reached in Appendix C that there is

no need for a pressurized test loop. The increases in silicon and calcium concentrations, along

with the increases in boron and sodium concentrations, in aqueous phase as a function of time

could be used to estimate and monitor ongoing corrosion in the system. This report provides

insight to and is useful in understanding the evolution of solution chemistry and the formation of

solid phases in integrated chemical effects tests at the University of New Mexico.

A comparison of constituents in pH = 7 and pH = 10 containment solution is provided in Table 1.

It should be noted that input for the simulations excludes organics to model formation of

complexes due to organic binder retained in fiber insulation after heat treatment. While

simulations examine complex interactions between metals and inorganic materials such as fiber

insulation and aluminum, the inputs are based on the dissolution rates of individual

components. Experimental studies to examine interactions between debris components were

not conducted. If leaching of fiber insulation or concrete is restricted due to a formation of a

coating on the surface, simulation results will be significantly different. For example, the

xiv
Table 1. Comparison of Constituents In pH = 7 and pH = 10 Containment Solutions

pH = 7 (Trisodium Phosphate pH = 10 (Sodium Hydroxide

Characteristic Moderator) Moderator)

Dominant Solid Phases Ca5(OH)(PO4)3 and NaAISi308 NaAISi308 and

with Fe3(PO4)2-8H20 {60 'C Ca2Mg5Si8022(OH)2 with

[140 'F]), Fe304, and Ca3Fe2Si3O,2 {60 0C [140 0F]}

Fe3Si20,(OH)4 {150 'C [302 'F]} and Fe3Si4O0,(OH) 4 {150 'C

[302 0F]}

Temperature Redistribution of iron and zinc Redistribution of iron phases

Dependencies phases

Sensitivity-Aluminum Increasing aluminum leads to Increasing aluminum leads to

increasing AI(OH)3 { 60 'C increasing AI(OH)3 {60 'C

[140 'F]} and AIO(OH) {130 'C [140 'F]} and increases

[266 0F]} NaAISi308 {130 'C [266 'F]}

Sensitivity-Carbon Steel Increasing iron leads to Increasing iron leads to

increasing Fe3(PO4)2-8H20 increasing Fe3Si2O5(OH)4

{60 °C [140 'F]}, Fe304, and {60 °C [140 °F]} and

Fe3Si2O5(OH)4 {130 °C [266 °F]} Ca3Fe2Si30,2 {130 °C

[266 OF])

Sensitivity-Zinc Increasing zinc leads to Increasing zinc leads to

increasing Zn3(OH)(PO4)3-2H20 increasing ZnO-Fe2O3 and

{60 °C [140 °F]}, Zn2SiO4

Zn3(OH)(PO4)3-2H20, and

ZnO-Fe2O3 {130 °C [266 °F])

Sensitivity-Copper No corrosion, no influence No corrosion, no influence

Sensitivity-Concrete Increasing concrete leads to Increasing concrete leads to

increasing Ca5(OH)(PO4)3 and increasing CaSiO3

S'02

Sensitivity-Fiber Increasing fiber insulations Increasing fiber insulations

Insulation leads to increasing NaAISi 308 leads to increasing NaAlSi 308

and Ca2MgSi,02(OH)2

Long-Term Trends (time) Major solid constituents: Major solid constituents:

Ca5(OH)(PO4)3, NaAlSi308, NaAISi 308

Ca 2 MgSi8 0 2 2(OH)2, Ca 2 MgSi8 022(OH) 2,

Fe3Si4010(OH)2, Ca3Fe2Si30,2, CaSiO3, and

Si02, and Zn2SiO4 Zn2SiO4

xv
Al - a l t3

Pourbaix diagram, shown in Figure 4-7, for aluminum in a pH 10 alkaline borated water at 60 OC

[140 OF] indicates that at a pH 10 or higher aluminum is predominantly present as a soluble

AI(OH) 4 complex. Results are in contrast to simulations in the presence of dissolution products

(silicate phases) from fiber insulation and concrete where aluminum is predominantly present in

a solid phase such as NaAISi308 (Table 4-6). The Pourbaix diagram, shown in Figure 4-8, for

aluminum in a pH 10 alkaline borated water containing silica at 60 0C [140 OF] indicates that the

NaAISi 308 solid phase is dominant up to a pH of 12.

xvi
ACKNOWLEDGMENTS

This report was prepared to document work performed by the Center for Nuclear Waste

Regulatory Analyses (CNWRA) for the U.S. Nuclear Regulatory Commission (NRC) under

Contract No. NRC-DR-04-04-087. The activities reported here were performed on behalf of

the NRC Office of Nuclear Regulatory Research, Division of Engineering Technology. This

report is an independent product of CNWRA and does not necessarily reflect the views or

regulatory position of NRC.

Authors gratefully acknowledge the helpful discussions and reviews by the NRC staff.

The authors gratefully acknowledge the technical review of D. Dunn, editorial reviews by

C. Cudd and J. Pryor, and the programmatic review of B. Sagar. Appreciation is due

J. Gonzalez for assistance in preparing this report.

QUALITY OF DATA: Sources of data are referenced in each chapter. CNWRA-generated

data contained in this report meet quality assurance requirements described in the CNWRA

Quality Assurance Manual. Data from other sources, however, are freely used. The respective

sources of non-CNWRA data should be consulted for determining levels of quality assurance.

Experimental data have been recorded in CNWRA scientific notebook number 676.

ANALYSES AND CODES: StreamAnalyzer0 Version 1.2 (OLI Systems, Inc., 2002a) and

Environmental Simulation Program" Version 6.6 (OLI Systems, Inc., 2002b) were used for the

thermodynamic simulations. These codes are controlled according to the requirements of

CNWRA Technical operating procedure (CNWRA, 2003). Detailed calculations can be found in

scientific notebook number 652E. Software validation specific to borated water is included in

Appendix C.

References

CNWRA. 'Development and Control of Scientific and Engineering Software." Technical

Operating Procedure (TOP)-018. Rev. 8, Change 2. San Antonio, Texas: CNWRA. 2003.

OLI Systems, Inc. "StreamAnalyzer0 Version 1.2." Morris Plains, New Jersey: OLI Systems,

Inc. 2002a.

.Environmental Simulation Program0 Version 6.6." Morris Plains, New Jersey:

OLI Systems, Inc. 2002b.

xvii
I INTRODUCTION

On March 29, 1979, the activation of the emergency core cooling system at the Three-Mile

Island nuclear reactor resulting from the pressure-operated relief valve being stuck in the open

position caused a release of 2,158 m3 [570,000 gal] of water, including 712 m3 [188,000 gal] of

Susquehanna River water, into the reactor building basement. Then, 153 days after this

loss-of-coolant-accident (LOCA) event, a green gelatinous precipitate material was observed

on the floors and walls of the containment building (Johns, et al., 2003). The July 28, 1992,

LOCA at Barseback-2 nuclear power plant led to emergency core cooling system failure as a

result of plugging of the sump pump (Hermannson and Erixon, 1997). Consequently, the

U.S. Nuclear Regulatory Commission (NRC) examined the strainer performance of United

States boiling water reactors. The NRC required boiling water reactor licensees to install

suction strainers with larger surface areas. For pressurized water reactors (PWRs), NRC

issued Generic Safety Issue (GSI)-1 91, (NRC, 2003).

A LOCA event results in rapid changes in the time-temperature-pressure-chemistry-pH

conditions in the containment environment of nuclear reactors. Changes in the coolant

chemistry are further complicated because of the interactions of the materials present in the

vicinity of a postulated LOCA pipe break. Typical materials in these areas include fiber

insulation, concrete, paints, carbon steel, galvanized steel, scaffolding, and insulation jackets.

Some of this debris could chemically react and eventually accumulate on the recirculation-sump

screens or strainers and challenge the emergency core cooling system and containment spray

system pumps. Table 1-1 shows the sources of various debris material and associated

corrosion products. These complex interactions require a large number of experiments to

obtain sufficient data to analyze the potential impact on a sump blockage caused by

chemical precipitation.

[ Table 1-1. Sources of Debris on the Sump Screen and Strainers |

Sources Corrosion/Erosion Products

Scaffold/insulation Jackets Aluminum, zinc

Insulation Fibers Silicon, aluminum, calcium,

magnesium, boron, alkalis

Heat exchangers, fan coolers, Copper

instrument-air lines

Steel Iron, nickel, sulfur

Galvanized Steel Zinc, iron

Concrete Calcium, silicon, aluminum

Cooling Water Boron, lithium, sodium

River Water Organics

pH adjusters Trisodium phosphate, hydrochloric

acid, sodium hydroxide

1-1
_ A at

In a previous study (Appendix C), thermodynamic simulations were used to identify critical

variables from a large number of components present during and subsequent to a LOCA event

in the containment system. Computational thermodynamics simulation calculations were

conducted using Environmental Simulation Program0 Version 6.6 (OLI Systems, Inc., 2002a)

and StreamAnalyzer 0 Version 1.2 (OLI Systems, Inc., 2002b). In the study, chemical speciation

of plausible reaction products in sump water after a representative LOCA event was modeled to

(i) determine the need for a pressurized test loop and (ii) assess whether gelatinous products

could form in the typical time-temperature-pressure-chemistry-pH regime following a LOCA

event. The corrosion rates were based on conservative values between pH 7 and pH 10 in

borated water, selected from the values published in the literature. The sensitivity analysis was

conducted over a wide range of amounts of each component to evaluate the effects of

temperature on speciation because the temperature-dependent data were not available in most

cases. The study indicated a strong influence of pH and temperature on the formation of the

dominant solid phases in the simulated containment water. In alkaline solutions at pH 10,

potentially amorphous silicates such as NaAlSi308, Ca3Fe2Si30,2, and Fe3Si40 10(OH)2 were

predicted as dominant corrosion products. The formation of gelatinous material in alkaline

solutions at pH 10 was inferred from the solids observed in the thermodynamic calculations.

Further simulations may be necessary to refine the predicted solid phase assemblages.

Furthermore, the study provided input to parameters for the development and operation of a

circulating water test loop at the University of New Mexico to study experimentally the chemical

reactions from metal and insulation corrosion and to examine the formation of precipitation

products including gelatinous products.

The primary objective of this study is to improve predictive capability of the simulation model by

reducing uncertainties in the corrosion rate values. Therefore, this study focused on

(i) determining leaching rate of Nukono low-density fiber insulation and concrete in borated

alkaline solution at pH 10 at 60, 90, and 110 0C [140, 194, and 230 0 F]; (ii) determining

leaching rate of Nukon' low-density fiberglass insulation and carbon steel at pH 7 in borated

trisodium phosphate solution at 60, 90, and 110 'C [140, 194, and 230 OF]; (iii) determining

corrosion rates for aluminum, copper, galvanized steel, and carbon steel in borated alkaline

water at pH 10 at 60, 90, and 110 0C [140, 194, and 230 OF1; and (iv) thermodynamic modeling

of the chemical speciation of plausible reaction products in coolant waters after a postulated

LOCA event using experimentally determined corrosion rates.

This report provides insight to and is useful in understanding the evolution of solution chemistry

and the formation of solid phases in integrated chemical effects tests at the University of

New Mexico.

1-2
2 CORROSION RATES OF DEBRIS COMPONENTS

Table 1-1 lists the source of various debris material and associated chemical elements.

Corrosion rates of debris components were measured at 60, 90, and 110 OC [140, 194, and

230 OF] in borated alkaline containment water at pH 10. A review of corrosion data from the

literature on similar components is provided in Appendix C, Chapter 2. Corrosion

measurements on carbon steel, concrete, and Nukone low-density insulation fiber were also

made in borated trisodium phosphate containment water at pH 7. Boron concentration was

fixed at 0.259 M [2,800 ppm]. A pH of 10 was adjusted by the addition of sodium hydroxide,

and a pH of 7 was adjusted by the addition of trisodium phosphate. Corrosion of galvanized

steel, copper, aluminum, and carbon steel was measured using ASTM G59-97

(ASTM International, 2004a), and corrosion rates were calculated using ASTM G102-89 (ASTM

International, 2004b). Experimental details are provided in Appendix A. Corrosion rates for

Nukone glass and concrete were determined using ASTM C1220-98 (ASTM International,

2002). Experimental details are provided in Appendix B.

2.1 Zinc

In a containment building, zinc is present in galvanized steel and zinc-based protective

coatings. Zinc coatings are top-coated with a design basis accident-qualified epoxy or a

modified phenolic-epoxy. These top-coated zinc paints do not readily participate in chemical

reactions. However, a small fraction of noncoated zinc paints could release zinc into solution.

The measured galvanized steel corrosion rates in a pH 10 borated alkaline containment water

at 60, 90, and 110 0C [140, 194, and 230 OF] are shown in Table 2-1. The corrosion rate for

galvanized steel increases with the increase in the temperature. The increase in the corrosion

rate is much larger between 90 and 110 0C [194 and 230 OF] compared to the increase in the

corrosion rate between 60 and 90 'C [140 and 194 OF]. The measured corrosion rates were

higher compared to the Griess and Bacarella (1969) study. Griess and Bacarella (1969)

measured the corrosion rates of galvanized steel and zinc metal in 0.278 M boric acid

[3,000 ppm boron] with 0.15 M sodium hydroxide [3,450 ppm sodium] solution between 55 and

140 'C [131 and 284 OF]. Both galvanized steel and zinc metal showed negligible corrosion.

Table 2-1. Measured Corrosion Rates for Debris Components In Borated Alkaline

Containment Water at pH 10*

Corrosion Rate {g/m2 h [mil/yr]}

Temperature Temperature Temperature

Debris Component 60 °C [140 OF] 90 °C [194 OF] 110 °C [230 OF]

Galvanized Steel (Zinc) 3.57 x 10-2 [1.73] 4.05 x 10-2 [1.96] 2.34 x 10-' [11.4]

Aluminum 0.986 [126] 1.89 [2411 2.20 [2811

Carbon Steel 1.35 x 10-2 [0.594] 2.95 x 10-2 [1.30] 8.21 x 10-2 [3.61]

Copper 4.78 x 10-3 [0.184] 5.19 x 10-2 [2.00] 9.91 x 10-2 [3.82]

Nukone Insulation 4.86 x 10-2 16.71] 2.32 x 10-1 [32.0] 4.53 x 10-' [62.6]

*Note: Details are provided in Appendixes A and B.

2-1
- - iAl

The measured corrosion rates in this study, however, are similar to the lower end of the

corrosion rates observed by Piippo, et al. (1997) at 90 0C [194 0F]. At 90 0C [194 'F], the zinc

corrosion rate varied from 0.04 g/m 2-h [1.9 mil/yr] in borated solution at a pH 9.2 to 0.163 g/m 2 h

[7.9 mil/yr] in aerated solution at a pH 8. In Appendix C, based on the literature review, a

corrosion rate of 0.163 g/m 2-h [7.9 mil/yr] was adopted to simulate speciation of zinc during a

postulated LOCA event because this value provided a conservative estimate. The measured

value at pH 10 is almost three times lower than the adopted value for simulations at 90 0C

[194 OF] in Appendix C. Simulations presented in Chapter 4 provide a realistic value for

galvanized steel speciation while simulations presented in Appendix C provide an upper bound

for chemical speciation during a postulated LOCA event in a PWR.

2.2 Aluminum

In a containment building, aluminum is present in scaffolding. Additional aluminum may come

from fiber insulation and concrete in oxide form. The measured corrosion rates in pH 10

borated alkaline containment water at 60, 90, and 110 0C [140, 194, and 230 OF] are shown in

Table 2-1. The corrosion rate for aluminum increases with the increase in the temperature. The

increase in the corrosion rate is much larger between 90 and 110 0C [194 and 230 OF]

compared to the increase in the corrosion rate between 60 and 90 0C [140 and 194 OF] .

Aluminum shows the highest corrosion rate among galvanized steel, copper, and carbon steel.

The corrosion rate of aluminum at 60 "C [140 OF] is one order of magnitude higher compared to

carbon steel and galvanized steel and at least two orders of magnitude higher compared to

copper. The measured corrosion rate for aluminum is higher compared to the corrosion rates

measured by Griess and Bacarella (1969) for several aluminum alloys in 0.278 M boric acid

[3,000 ppm boron] with 0.15 M [3,450 ppm sodium] sodium hydroxide solution between 55 and

140 0C [131 and 284 OF]. For aluminum alloys at 55 °C [131 OF], submerged corrosion rates

ranged from 0.35 to 0.61 g/m 2-h [45 to 78 mil/yr]. At 100 0C [212 OF], however, the measured

corrosion rates by Griess and Bacarella (1969) for submerged samples ranged from 14.0 to

18.0 g/m2 -h [1,800 to 2,300 mil/yr] and were significantly higher compared to the rates

measured in this study at 110 °C [230 OF]. At 90 "C [194 OF], Piippo, et al. (1997) measured

corrosion rates of 0.012 g/m2 -h [1.5 mil/yr] in aerated solution at a pH 10 and 1.45 g/m 2-h

[186 mil/yr] in borated water. The corrosion rate observed in this study for aluminum in borated

water at pH 10 is similar to the Piippo, et al. (1997) data. In Appendix C, based on the literature

review, a corrosion rate of 1.45 g/m 2-h [186 mil/yr] was adopted to simulate speciation of

aluminum because this value provided a conservative estimate. The measured value at pH 10

used in simulations presented in Chapter 4 is similar to the adopted value for simulations at

90 °C [194 OF] in Appendix C. Simulations presented in Appendix C provide a reasonable

assessment of aluminum speciation during a postulated LOCA event in a PWR.

2.3 Carbon Steel

Carbon steel is present as a structural steel in the containment building. Most of this carbon

steel is protected by design basis accident-qualified coatings or is encased in insulation. The

surface area of unprotected carbon steel is small. The measured corrosion rates in a pH 10

borated alkaline containment water at 60, 90, and 110 "C [140, 194, and 230 OF] are shown in

Table 2-1. The corrosion rate for carbon steel increases with the increase in the temperature.

At pH 10, the corrosion rate of the carbon steel was lower than the corrosion rate of galvanized

steel (zinc). Carbon steel corrosion rate was also measured at 60, 90, and 1100 C[140,194,

and 230 °F] in a borated trisodium phosphate solution at pH 7. The measured corrosion rates

2-2
are shown in Table 2-2. The corrosion rate at pH 7 was higher compared to the corrosion rate

at pH 10. The decrease in the corrosion rates at the higher temperature could be partly

attributed to the fact that at pH 10, carbon steel behaves like a passive metal. In addition, the

measured corrosion rate at pH 7 shows a decrease in the corrosion rate with an increase in

temperature. The decrease in corrosion rate with temperature has been reported by Hall (1988)

at 177 'C [350 OF]. Hall (1988) observed lower corrosion rates for SA-193 Grade B7 and

SA-540 Grade B23 carbon steels at higher temperatures, and higher corrosion rates for

SA-540 Grade B24 carbon steels at higher temperatures. This variability in corrosion is

attributed to the availability of oxygen. The higher the temperature, the lower the dissolved

concentration of oxygen in the solution. Griess and Bacarella (1969) measured the corrosion

rates of A-108 and A-210 carbon steels in 0.15 M NaOH [3,450 ppm] sodium solution between

55 and 140 OC [131 and 284 'F] and showed a negligible attack on carbon steels in alkaline

borated water regardless of the test conditions. Hall (1988) measured corrosion of SA-193

Grade B7, SA-540 Grade B23, and SA-540 Grade B24 carbon steels in borated water

{0.092 M [1,000 ppm] boron} from 79 to 204 °C [175 to 400 OFJ. At 79 0C [175 OF], a maximum

corrosion rate of 19.0 g/m2-h [833 mil/yr] was observed for SA-193 B7 carbon steel. In

Appendix C, based on the literature review, a corrosion rate of 19.0 g/m2-h [833 mil/yr] was

adopted to simulate speciation of carbon steel because this value provided a conservative

estimate. The measured values of corrosion rate used in simulations at pH 7 and pH 10 are

several orders lower in magnitude than the corrosion rate value initially adopted for simulations

at 90 °C [194 °F] in Appendix C. Simulations presented in Chapter 4 provide a realistic value

for carbon steel speciation, while simulations presented in Appendix C provide an extremely

conservative bound for carbon steel speciation during a postulated LOCA event in a PWR.

2.4 Copper

In a containment building, copper is present in fan coolers with small contributions from

instrument air lines. The measured corrosion rates in pH 10 borated alkaline containment water

at 60, 90, and 110 °C [140,194, and 230 °F] are shown in Table 2-1. The corrosion rate for

copper increases with the increase in the temperature. The increase in the corrosion rate was

much larger between 90 and 110 °C [194 and 230 OF] compared to the increase in the corrosion

rate between 60 °C and 90 °C [140 and 194 OF]. The measured corrosion rates were

comparable to the Griess and Bacarella (1969) corrosion rate data. Griess and

Bacarella (1969) measured the corrosion rate of copper in 0.15 M sodium hydroxide [3,450 ppm

sodium] solution between 55 and 140 °C [131 and 284 OF]. For copper at 100 °C [212 OF], the

average submerged corrosion rate was 0.013 g/m2-h [0.51 mil/yr], which is comparable to the

corrosion rates measured in this study at 90 and 110 °C [194 and 230 0

F]. In Appendix C,

Table 2-2. Measured Corrosion Rates for Debris Components in Borated Alkaline

Containment Water at pH 7

Corrosion Rate {g/m24h [mil/yr3}

Temperature Temperature Temperature

Debris Component 60 °C [140 OF] 90 °C [194 OF] 110 °C [230 OF]

Carbon Steel 1.27 x 10-' [5.59] 9.36 x 10-2 [4.12] 2.14 x 10-2 [0.944]

Nukon" Insulation 1.09 x 10-2 [1.50] 7.5 x 10-2 [10.4] 1.43 x 10-' [19.7]

2-3
__ I AlI

based on the literature review, a corrosion rate of 0.03 g/m 2-hr [1.2 mil/yr] to simulate speciation

of copper during a postulated LOCA event was adopted because this value provided a

conservative estimate. The measured value at pH 10 used in simulations presented in

Chapter 4 is almost four times lower than the corrosion rate value adopted for simulations at

90 'C [194 0F] in Appendix C. Simulations presented in Appendix C provide an upper bound for

chemical speciation during a postulated LOCA event in a PWR.

2.5 Concrete

Concrete contribution comes from the erosion of concrete surfaces caused by the impact of the

water stream around the LOCA location. While a protective paint is applied to concrete

surfaces in most plants, a small portion of the concrete is expected to be uncoated during the

LOCA event. Table 2-3 shows the fraction of stone, cement, sand, and water present in a

concrete mix. In determining the corrosion rate of concrete, it was assumed that the

contribution from stones in concrete was negligible. Table 2-4 shows the amount of key

components present in concrete. In Appendix C, based on the literature review, a dissolution

rate of 0.13 g/m2 -hr [14.7 mil/yr] was adopted to simulate cement speciation during a postulated

LOCA event, because this value provided a conservative estimate and was modeled as

dicalcium silicate. The corrosion rate of typical Portland cement was based on Jantzen (1984).

Jantzen examined the release of calcium from cast cement, cold-pressed cement, warmTable 2-3. Constitution of Concrete Mixture*

Component Amount kg [lb] Fraction

Stone 30.6 [68] 0.45

Sand 19.8 [44] 0.29

Portland Cement 11.7 [26] 0.17

Water 5.29 [11.71 0.08

*Holcim (US) Inc. 'Material Certification Report-Hydraulic Cement, Portland Cement." Holly Hill, South

Carolina: Holcim (US) Inc. 2004.

Table 2-4. Major Components of Portland Cement*

Major Components Fraction (Cement Basis) Fraction (Concrete Basis)

Calcium Oxide 0.63 0.109

Aluminum Oxide 0.05 0.009

Silicon Dioxide 0.21 0.036

Iron Oxide 0.04 0.006

*Holcim (US) Inc. 'Material Certification Report-Hydraulic Cement, Portland Cement." Holly Hill, South

Carolina: Holcim (US) Inc. 2004.

2-4
pressed cement (formed under elevated temperatures and pressures), and clinkered cement.

Based on 28-day tests at 60 0C [140 0F], the average release of calcium ions into the solution

was 0.13 g/m2 hr [14.7 mil/yr]. Table 2-5 shows measured release rates of oxides of calcium,

aluminum, and silicon from concrete based on respective element release rates in Table B-2 in

pH 10 borated alkaline containment water at 60, 90, and 110 'C [140, 194, and 230 OF].

Experimental details are provided in Appendix B. Because concrete is a heterogeneous mixture

of cement, sand, and stones with different leaching rates, congruent release is not expected

from its surfaces. In a 14-day leaching test conducted at 60, 90, and 110 lC [140,194, and

230 0F] in a 0.236 M [2,550 ppm] boron solution at pH 10 indicated that the test solution

saturates with leached products from concrete within 24 hours. The data shown in Table 2-5

were obtained by sampling the solution at four different times during the first 24 hours.

The measured leaching rate for concrete at pH 10 is almost an order of magnitude higher than

the adopted value for simulations at 90 0C [194 0F1 in Appendix C. The thermodynamic

simulations presented in Appendix C could underestimate the formation of corrosion products

from the leaching of concrete during a postulated LOCA event in a PWR. In simulations

presented in Chapter 4, the measured value of concrete dissolution rate was used.

2.6 Fiber Insulation

Fiber insulation is widely used as pipe insulation in containment buildings with the amount of

fiber insulation depending on the specific plant design. Nukon', an Owens-Corning brand, is

installed in a large number of containment buildings. Tables 2-1 and 2-2 show the measured

dissolution rates for Nukono fiber insulation glass in pH 10 borated alkaline and pH 7 trisodium

phosphate containment waters at 60, 90, and 110 'C [140, 194, and 230 'F].

Dissolution rates were measured on glass that is used for the manufacture of Nukon' fiber

insulation. The corrosion rate for Nukone low-density fiber insulation glass increases with the

increase in the temperature and follows an Arrhenius relationship as shown in Figure 2-1. As

expected, the measured dissolution rate in pH 10 solution is higher than the dissolution rate at

pH 7 solution. The analyzed chemical composition of Nukon" insulation glass is shown in

Table 2-6. Table 2-7 provides an estimate of the time required to leach a 7-pm [0.28-mil] plate

using the dissolution rate shown in Table 2-1 for Nukon' insulation glass. At 60 'C [140 °F],

7 pm [0.28 mil] of thickness would leach completely in 180 hours. An average diameter of a

Table 2-5. Leaching Rate of Calcium Oxide, Aluminum Oxide, and Silicon Dioxide from

Concrete in Borated Alkaline Containment Water at pH 10

Corrosion Rate [g/m2 h]

Temperature Temperature Temperature

Concrete Component 60 -C [140 0F] 90 -C [194 °F] 110 °C [230 °Fi

Calcium Oxide 1.02 1.65 3.08

Aluminum Oxide 5.7 x 10-2 1.11 x 10-' 1.68 x 10'

Silicon Dioxide 8.1 x 10.2 2.36 x 10' 3.21 x 10-'

Note: Details provided in Appendix B.

2-5
__ _.k IIl

0

_urH

E~y -5762.3x + 14.317

0j -1.

-2

M n1

y=-6701.9e + 15.68

-5 ,

0.0025 0.0026 0.0027 0.0028 0.0(29 0.0030 0.0031

1/Temperat~re (K)

Figure 2-1. Relationship Between Release Rate and Temperature for Nukon'

Low-Density Fiber Insulation Glass Between 60 and 110 0C [140 and 230 OF] at pH 7

and pH 10

Nukone low-density fiber insulation is 7 pm [0.28 mill. In simulations, presented in Chapter 4,

the contributions from Nukon' low-density fiber insulation beyond 182 hours at 60 0C [140 OF]

were fixed at the amount subjected to corrosion up to 182 hours. It should be noted, however,

that a complete corrosion does not mean that insulation has disappeared. It merely reflects a

change in chemical structure of the fiber. Most of the new solid phases formed in a fiber are

expected to adhere to the surface of the fiber. With time, a small fraction of these phases could

dislodge from the surface. A discussion on fiber insulation characteristics is provided in

Appendix C, page 2-5. In Appendix C, based on the literature review, a corrosion rate of

0.025 g/m2-hr [1.2 mil/yr] is adopted to simulate speciation of Nukon' low-density fiber insulation

during a postulated LOCA event because this value was expected to provide a conservative

estimate. The measured corrosion rate value at pH 10, however, was almost an order of

magnitude higher than the adopted value for simulations at 90 0C [194 0F] in Appendix C. The

thermodynamic simulations presented in Appendix C could underestimate formation of

corrosion products from the leaching of Nukon' low-density fiber insulation during a postulated

LOCA event in a PWR. In simulations presented in Chapter 4, measured value of Nukon'

dissolution rate was used.

2-6
Table 2-6. Analyzed Chemical Composition of Nukono Fiber Insulation

Component Weight Percent Molecular Weight Mole Fraction

SiO2 63.7 60 0.651

A1203 3.0 102 0.018

CaO 7.7 56 0.085

MgO 3.2 40 0.050

Na2O 16.3 62 0.161

B203 4.1 70 0.036

Table 2-7. Time Needed to Leach a 7-pm [0.28-mill-Thick Nukone Glass

Time to

Corrosion Rate Density Rate Corrode 7 prm

Temperature [gIm2-h] [kg/m'] p|m/h [millh] [hour]

60 0C [140 OF] 4.8 x 10-2 2,500 1.92 x 10-2 [7.56 x 10-4] 180

90 0C [194 OF] 2.41 x 10-2 2,500 9.64 x 10-2[3.80 x 103] 38

110 -C [230 OF] 4.3 x 10-' 2,500 1.72 x 10-' [6.75 x 10-3] 19

2-7
3 ESTIMATE OF DEBRIS COMPONENTS

Tables 1-1 and 2-1 list the sources of various elements present in debris components and their

corrosion rates, respectively. The amount of corrosion product (CP) for a given component at a

given elapsed time (t) is estimated based on Eq. (3-1).

CP = ESA x CR x t (3-1)

where

CP - corrosion product

ESA - exposed surface area per unit containment volume, m2/m3

CR - corrosion rate, gfm2-h

t - elapsed time, h

Exposed surface area is defined in the NRC test plan (NRC, 2005) and is discussed in

Appendix C, Chapter 2.

The estimates of debris amount, the exposed surface area for aluminum, copper, galvanized

steel, carbon steel, concrete walls, and Nukon' low-density fiber insulation are the same as

presented in Appendix C, Chapter 2. A change in methodology, however, was adopted for

estimating release from concrete particulates. Concrete contribution comes from exposed

concrete walls and concrete particulates. In the NRC test plan (NRC, 2005), the exposed

surface area of concrete walls per unit containment volume was estimated at 0.15 m2/m3

[0.045 ft2/ft3] and the total amount of concrete particulates was estimated at 22.43 g/m3

[0.0014 Ibm/ft3]. Because the specific surface area of particulates is not known, this report

conservatively assumes that oxides from cement and sand present in the concrete particulates

were instantly released. Table 3-1 provides an estimate of oxides of calcium, aluminum, iron,

and silicon released instantly from concrete particulates. The estimates shown in Table 3-1 are

a product of the fraction of the component present in the concrete as shown in Table 2-5 and

the amount of the concrete particulates per cubic meter. Tables 3-2 and 3-3 show the amounts

of the debris components used as an input to conduct chemical speciation simulations to study

the effect of temperature and to evaluate changes in the precipitation of solid and aqueous

phases at 60 0C [140 0F] up to 360 hours. It should be noted that the contribution from concrete

[ Table 3-1. Estimate of Release from Concrete Particulates

Amount per L

Components g [mol]

Calcium Oxide 2.42 x 10-3 [4.33 x 10-5]

Aluminum Oxide 2.00 x 10-4 [1.96 x 10-6]

Silicon Dioxide 8.01 x 10-4 [1.33 x 10-5]

Iron Oxide 1.44 x 10-5 [9.00 x 10-8]

Silicon Dioxide (Sand) 6.45 x 10-3 [1.07 x 10-41

3-1
-, iml

Table 3-2. Estimation of Debris Dissolution In pH 10 Borated Alkaline Containment

Water Using Eq. (3-1)*

Amount Released g/L [mol/L]

After 30 minutes at After 30 minutes at After 30 minutes at

Component 110 °C [230 OF] 90 °C [194 OF] 60 °C [140 OF]

Zinc from

Galvanized

Steel 1.5 x 10-4 [2.3 x 10-6] 2.7 x 10 5 [4.1 x 10-7] 2.4 x 10' [3.6 x 10-7]

Aluminum 6.3 x 10-4 [2.3 x 10-5] 5.4 x 10-4 [2.0 x 10-5] 2.8 x 10-4 [1.0 x 10-5]

Carbon Steel 7.0 x 10-6 [1.3 x 10-7] 2.5 x 10-6 [4.5 x 10-8] 1.1 x 10-6 [2.1 x 10-8]

Copper 2.4 x 10-4 [3.8 x 10-6] 1.3 x 10-5 [2.0 x 10-7] 1.2 x 10-5 [1.8 x 10-7 ]

Nukone 1.5 x 10'1 [2.6x 10-3] 7.9 x 10-2 [1.3x 10-3] 1.6 x 10-2 [2.7 x 10-4]

SiO2 9.9 x 10-2 [2.6 x 10-3] 5.1 x 10-2 [8.5 x 10-4] 1.1 X 10-2 [1.8 x 10-4]

A1203 4.7 x 10-3 [4.6 x 10-5] 2.4 x 10' [2.4 x 10-5] 5.0 x 10-4 [4.9 x 10-6]

CaO 1.2 x 10-2 [2.2 x 10-4] 6.2 x 10-3 [1.1 X 10-5] 1.3 x 10-3 [2.3 x 10-5]

MgO 5.1 x 10-3 [1.3 x 10-4] 2.6 x 10-3 [6.5 x 10-4] 5.4 x 104 [1.4 x 10`]

Na2O 2.6 x 10'2 [4.1 x 10-4] 1.3 x 10-2 [2.1 x 10-4] 2.7 x 10-3 [4.4 x 10-5]

B2 03 6.4 x 10-3 [9.2 x 10-5] 3.3 x 10-3 [4.7 x 10-5] 6.9 x 10-4 [9.9 X 10-6]

Concrete

(particulates)

SiO2 7.3 x 10-3 [1.2 x 10-4] 7.3 x 10-3 [1.2 x 10-4] 7.3 x 10-3 [1.2 x 10-4]

A12 03 2.0 x 10-4 [2.0 x 10-6] 2.0 x 10-4 [2.0 x 10-6] 2.0 x 10-4 [2.0 x 10-6]

CaO 2.4 x 10O3 [4.3 x 10-51 2.4 x 10-3 [4.3 x 10-5] 2.4 x 10-3 [4.3 x 10-51

Concrete

SiO2 8.0 x 10'6 [1.3 x 10-7] 5.9 x 10-6 [9.8 x 10-81] 2.0 x 10-6 [3.4 x 10-8]

A1203 4.2 x 10'6 [4.1 x 10-8] 2.8 x 10-6 [2.7 x 10-8] 1.4 x 10.6 [1.4 x 10-8]

CaO 7.7 x 10-5 [1.4 x 10-6] 4.1 x 10-5 [7.4 x 10-7] 2.6 x 10-5 [4.6 x 10-7]

*Note: Corrosion rates and estimated surface area are provided in Chapter 2 and Appendixes A, B, and C.

walls is negligible compared to the contribution from the concrete particulates. Furthermore, the

amounts of calcium oxide, aluminum oxide, and silicon dioxide from concrete walls are

negligible compared to the amounts released from Nukon" low-density fiber insulation. This

lower contribution is attributed to the fact that the exposed surface area for per unit containment

volume Nukone low-density fiber insulation {678 m2/m3 [207 ft2/ft3 } is 10,000 times the surface

area for exposed concrete walls {0.05 m2/m3 [0.15 ft2/ft3]}. After 148 hours at 60 °C [140 OF], the

contribution of concrete particulates becomes negligible compared to the contribution from

Nukono low-density fiber insulation. The review of input values also indicates that the

contributions from Nukone low-density fiber insulation, aluminum, and concrete particulates

dominate the concentration of input values.

3-2
Table 3-3. Estimation of Debris Dissolution in pH 10 Borated Alkaline Containment Water at 60 °C [140 °F] Using Eq. (3.1)*

cw

w

Amount Released g/L [mollL]

Component After 4 Hours After 72 Hours After 148 Hours After 360 Hours

Zinc from

Galvanized

Steel 1.9 x 10-4 [2.9 x 10-6] 3.4 x 10-3 [5.2 x 10-5] 6.9 x 10-3 [1.1 X 10-4] 1.7 x 10-2 [2.6 x 10-4]

Aluminum 2.2 x 10-3 [8.3 x 10-5] 4.0 x 10-2 [1.5 x 10-3] 8.3 x 10-2 [3.1 x 10-3] 2.0 x 10-1 [7.5 X 10-3]

Carbon Steel 9.1 x 10-6 [1.7 x 10-7] 1.7 x 10-4 [3.0 x 10-61 3.4 x 10-4 [6.1 x 10-61 8.2 x 10-4 [1.5 x 10-5]

Copper 9.4 x 10-5 [1.5 x 10-6] 1.7 x 10-3 [2.7 x 10-5] 3.5 x 10-3 [5.5 x 10-5] 8.4 x 10-3 [1.3 x 10-4]

Nukon 1.3 x 10-1 [2.2 x 10-3] 2.4 x 10' [4.0 x 10-1 4.9 [8.1 x 10-21 6.0 [1.0 x 10-1]

Si02 8.6 x 10-2 [1.4 x 10-3] 1.5 x 100 [2.6 x 10-1 3.2 x 100 [5.2 x 10-21 3.9 x 100 [6.5 x 10-21

A12 03 4.0 x 10-3 [3.9 x 10-5] 7.2 x 10-2 [7.1 x 10-4] 1.5 x 10-1 [1.5 x 10-3] 1.8 x 10-1 [1.8 x 10-3]

CaO 1.0 x 10-2 [1.9 x 10-4] 1.9 x 10-1 [3.3 x 10-3] 3.8 x 10-1 [6.9 x 10-3] 4.7 x 10-1 [8.4 x 10-3]

MgO 4.4 x 10-3 [1.1 x 10-4] 7.8 x 10-2 [2.0 x 10-3] 1.6 x 10-1 [4.0 x 10-3] 2.0 x 10-1 [4.9 X 10-3]

Na2 O 2.2 x 10-2 [3.5 x 10-4] 3.9 x 10-' [6.4 x 10-3] 8.1 x 10-1 [1.3 x 10-2] 1.0 x 10-0 [1.6 x 10-2]

B2 03 5.5 x 10-3 7.9 x 10-5] 9.9 x 10-2 [1.4 x 10-31 2.0 x 10-1 [2.9 x 10-31 2.5 x 10-1 [3.6 x 10-31

Concrete

(Particulates)

SiO2 7.3 x 10-3 [1.2 x 10-4] 7.3 x 10-3 [1.2 x 10-4] 7.3 x 10-3 [1.2 x 10-4] 7.3 x 10-3 [1.2 x 10-4]

A12 0 3 2.0 x 10-4 [2.0 x 10-6] 2.0 x 10-4 [2.0 x 10-61 2.0 x 10-4 [2.0 x 10-61 2.0 x 10-4 [2.0 x 10-61

CaO 2.4 x 10-3 [4.3 x 10-5] 2.4 x 10-3 [4.3 x 10-5] 2.4 x 10-3 [4.3 x 10-5] 2.4 x 10-3 [4.3 x 10-5]

Concrete

ST02 1.6 x 10-5 [2.7 x 10-1] 2.9 x 10-4 [4.9 x 10-5] 6.0 x 10-4 [1.0 x 10-5] 1.5 x 10-3 [2.4 x 10-5]

A1 2 0 3 1.1 x 10-5 [1.1 x 10-7] 2.1 x 10-4 [2.0 x 10-6] 4.2 x 10-4 [4.1 x 10-6] 1.0 x 10-3 [1.0 x 10-5]

CaO 2.0 x 10-4 [3.6 x 10-6] 3.7 x 10-3 [6.6 x 10-5] 7.5 x 10-3 [1.4 x 10-4] 1.8 x 10-2 [3.3 x 10-4]

*Note: Corrosion rates and estimated surface area are provided in Chapter 2 and Appendixes A, B, and C.
4 ANALYSIS OF CORROSION PRODUCTS IN ALKALINE CONTAINMENT

WATER USING THERMODYNAMIC SIMULATIONS

The simulations presented in this chapter are focused on the thermodynamic modeling of the

chemical speciation of plausible reaction products in coolant waters after a postulated LOCA

event using experimentally determined corrosion rates. Speciation simulations were conducted

(i) to study the effect of temperature, and (ii) to evaluate changes in the precipitation of solid and

aqueous phases at 60 'C [140 0F] up to 360 hours. The results are compared to the

simulations conducted in Appendix C, Chapter 3. Simulations are limited to the speciation in

pH 10 borated alkaline containment water. Dissolved gases such as 02 and CO2 were not

included in the input stream for the thermodynamic calculations. Because a majority of the

multivalence elements are already in the highest valence state, a minimal effect of dissolved

oxygen on the valence state of elements is expected. Furthermore, the atmospheric CO2 is not

expected to significantly change the pH of the solution, because the pH of the system is

dominated by the presence of high concentrations of NaOH and H3BO3. The simulations at

pH 7 were not conducted because corrosion rates of debris components, except carbon steel,

are expected to be similar or lower than the corrosion rates at pH 10. For example, Nukone

low-density fiber insulation glass shows a lower magnitude corrosion rate at pH 7 compared to

the corrosion rate at pH 10 (Chapter 2).

Simulations were made using a thermodynamic simulator developed by OLI Systems, Inc.

(2002a,b) for evaluating aqueous chemical processes in industrial and environmental

applications. The OLI Systems, Inc. data bank contains proprietary coefficients for predicting

thermodynamic, transport, and physical properties for 80 elements of the periodic table and their

associated aqueous inorganic species, as well as more than 5,000 organic species. The

thermodynamic framework used by the OLI Systems, Inc. (2002a,b) code predicts behavior of

multicomponent aqueous systems including aqueous liquid, vapor, organic liquid, and multiple

solid phases for the general ranges of 0 to 30 molal, -50 to 300 'C [-58 to 572 'F], and

0-150 MPa [0-1,480 atm]. The software was validated (Appendix C) to examine the likelihood

of formation and physical characteristics of any solid corrosion product that might be produced

from the environment surrounding a postulated LOCA event.

4.1 Effect of Temperature

Simulations were conducted using input values shown in Table 3-2 at pH 10. The formation of

solid phases as a function of temperature was examined at 110 CC 1230 0F] at 304 kPa [3 atm],

and 90 and 60 'C [194 and 140 0F] at 101 kPa [1 atm]. A pH 10 borated alkaline containment

solution was obtained by adding 0.23 M sodium hydroxide [5,300 ppm sodium] and 0.259 M

[2,800 ppm] boron as boric acid.

Table 4-1 shows the calculated pH and redox potential at different temperatures and pressures

in borated alkaline containment water. At 60 °C [140 0F], the pH in an alkaline borated

containment water was 10. A slight decrease in pH was observed with the increase in the

temperature and pressure. Similarly, redox potential at 60 °C [140 0F] was -0.58 V versus the

standard hydrogen electrode (VSHE), and changed to -0.62 V versus VSHE at 110 °C [230 OF].

These data are similar to simulation results cited in Appendix C, Table 3-1.

4-1
I I

Table 4-1. pH and Redox Potential [Eh (VSHE)1 of Borated Alkaline Containment Water

with 0.259 M [2,800 ppm B] and 0.23 M [5,300 ppm Na] NaOH

Test Conditions pH pH Neutral Eh (VSHE)

60 0C [140 OF] at 101 kPa [1 atm] 10.0 6.1 -0.58

90 0C [194 OF] at 101 kPa [1 atm] 9.7 5.8 -0.60

110 0C [230 OF] at 304 kPa [3 atm] 9.6 5.2 -0.62

Figures 4-1 and 4-2 show the predicted amount of solid phases formed and their relative mol

percent in a borated alkaline containment water, respectively. The mol percent distribution data

are also summarized in Table 4-2. At 60 0C [140 OF] at 101 kPa [1 atm] in borated alkaline

containment water, the calculated potentially amorphous solid phase was dominated by sodium

aluminum silicate (NaAlSi308) with approximately 9-percent contribution from calcium

magnesium silicate [Ca2Mg5Si8022(OH)2]. As the temperature increased to 110 0C [240 OF],

304 kPa [3 atm] pressure, the concentration of NaAlSi308 decreased to approximately

80 percent, while the concentration of Ca2Mg5Si8022(OH)2 increased to 17 percent. Irrespective of temperature and pressure, almost 100 percent of the solid phases formed at pH 10 were

silicates. Smaller quantities, as shown in Table 4-2, of calcium iron silicate (Ca3Fe2Si30, 2),

zinc-iron oxide (ZnO-Fe203), and zinc silicate (Zn2SiO4) were observed. Simulation results

indicate no phase change for copper. Most of the copper added as copper metal in the

simulation remained as copper metal. Corrosion of metals was dominated by aluminum. The

calculations are based on the solid phases in the OLI database. The presence of calcium,

magnesium, aluminum, iron, and silicon in the solid phases are confirmed by energy dispersive

spectroscopy (Appendix B, Figure B-6). The formation of actual solid phases may be different

depending on the reaction kinetics.

Table 4-3 shows the predicted percentage of each element distributed in potential solid phases.

Both magnesium and aluminum were fully incorporated in potentially amorphous solid phases.

Silicon-bearing phases were observed in both soluble and insoluble phases in borated alkaline

silicates. Approximately 30 percent of silicon was distributed within solid phases. The dominant

silicon-bearing soluble phases were Si0 2 (aqueous), H3SiO4-, and NaHSiO3. At 110 0C

[230 °F], 304 kPa [3 atm] 19 percent of calcium was present in calcium-bearing solid phases,

while at 60 0C [140 OF] 8 percent of calcium was present in calcium-bearing solid phases. The

dominant calcium-bearing soluble phase was CaH 2BO3 1 3.

The speciation of corrosion products based on corrosion rates from literature is presented in

Appendix C. Review of the simulation data presented in Appendix C, Figure 3-1, indicates

NaAlSi308 was a dominant potentially amorphous solid phase in borated alkaline containment

water with contributions from iron silicate [Fe3Si205(OH) 4], Ca3Fe2Si3012, and

Ca2Mg5Si8022(OH)2. The absence of iron-bearing silicate phases, in the data presented in

Figure 4-1 and Table 4-2, may be attributed to extremely low corrosion rates measured for

carbon steel in pH 10 borated alkaline containment water. The formation of iron-bearing solid

silicate phases was replaced by calcium magnesium silicate. With the exception of iron-bearing

silicate phases observed in simulations presented in Appendix C, the observed speciation of

solid phases was similar. The solid phases were dominated by the formation of silicates. The

4-2
I-

.0

CL

C)

4)

U)

M -

0

0

E

1. E-03

1.E-04

1.E-05

1.E-06

1.E-07

1.E-08

1.E-09

* A A

*A

A Ao

00

U1

ACu

A Ca2Mg5Si8O22(OH)2

o Zn2SiO4

* NaAISi308

o Ca3FeSiO3012

ZnO.Fe203

50 75 100 125

Temperature (°C)

Figure 4-1. Calculated Amount, in mol, of Predicted Potentially Amorphous Solid

Phases Formed As a Function of Temperature in 0.259 M [2,800 ppm] Boron in

Borated Alkaline Containment Solution at pH 10

(Note: OF = 1.8 x °C + 32)

4-

0

E

I-a

0.

CL

(A

0

w

.C

a)

IL.

100.0%

10.0%

1.0%

0.1%

w ~ 0

A A

A

A

A

0

A Cu

A Ca2Mg5Si8O22(OH)2

o Zr2SiO4

* NaAISi3O8

o Ca3FeSiO3O12

* Mg48Si35085(OH)62

* ZnO. Fe203

50 75 100 125

Temperature (°C)

Figure 4-2. Calculated Percent Predicted Solid Phases Formed As a Function of

Temperature in 0.259 M [2,800 ppm] Boron in Borated Alkaline Containment Solution at

pH 10 (Note: °F = 1.8 x °C + 32)

4-3

CoT
' l- I

Table 4-2. Predicted Percent of Solid Phases at pH 10 Using OLI StreamAnalyzer'

Temperature and NaAISi30, Ca2MgSSiO 22(OH)2 Ca3Fe2Si3O12 ZnO Fe2O3 Zn2SiO4

Pressure (Percent) (Percent) (Percent) (Percent) (Percent)

110 0C [240 OF], 79.7 16.8 0.04 0.66

304 kPa [3 atmJ

90 0C [194 OF], 84.2 15.6 0.02 - 0.09

101 kPa [1 atm]8421.

101 kPa [1 atm] 90.2 8.7 - 0.03 0.36

Table 4-3. Predicted Percent Element Distribution in Solid Phases at pH 10

Major Contributors Minor Contributors

Temperature Magnesium Aluminum Silicon Calcium Zinc Iron

and Pressure (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

110 C [230 F], 100 100 32 19 81 98

3 0 4 k P a [3 a tm l _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

90 0C [194 0F], 100 100 32 17 39 87 101 kPa [1 atm] 100 100 35 8 63_75

101 kCa[14 atm] 100 100 35 8 63 75

contributions to the solid phases from zinc and iron are less than one mol percent compared to

Nukono low-density fiber insulation, concrete, and aluminum.

These results support the conclusion reached in Appendix C that there is no need for a

pressurized test loop based on minimal changes observed in the speciation between 60 0C

[140 OF] at 101 kPa [1 atm] and 110 'C [230 OF] at 304 kPa [3 atm].

4.2 Evolution of Solid and Aqueous Phases at 60 °C (140 °F]

Table 3-3 summarizes the expected increase in the amount of debris components with time at

60 °C [140 OF]. The amounts of debris were calculated for 0.5, 4, 32, 72, 148, 240, and

360 hours. For Nukon" low-density fiber insulation, it was estimated that the fiber would leach

in 180 hours at 60 °C [140 OF]. Total amount from Nukon" low-density fiber insulation for time

periods greater than 180 hours was, therefore, fixed at the 180-hour release amount.

In the simulations conducted for time periods beyond 32 hours at 60 °C [140 °F], the debris

components carbon steel and copper were removed from the simulation input. The simulations

failed to reach convergence because of extremely low concentrations of copper and carbon

steel compared to the concentrations of Nukon" low-density fiber insulation, aluminum, and

concrete. The simulation results indicate that the total mol percent of solid phases formed from

carbon steel corrosion was less than 0.1 percent. Copper was thermodynamically stable and

showed no corrosion. Table 4-4 shows simulation results with and without iron and copper for a

32-hour simulation at 60 °C [140 OF]. Results indicate no influence of removal of iron and

copper on the dominant solid phases.

4-4
Table 4-4. Calculated Amount of Solid Phase Per Liter of Solution at pH 10, 60 0C

[140 OF], at 32 Hours

Potentially Amorphous 32-Hour Input 32-Hour Input without Iron

Phase (mol) and Copper (mol)

NaAISi308 1.29 x 10-3 1.29 x 10-3

Ca2Mg5Si8022(OH)2 1.76 x 10-4 1.72 x 10-4

CaSiO3 8.26 X 10-4 8.28 x 10-4

Zn2SiO4 1.14 x 10-5 1.14 x 10-5

Ca3Fe2Si3O12 6.60 x 10-7

Copper 1.18 x 10-5

Table 4-5 shows the calculated pH and redox potential at different temperatures and pressures

in borated water with 0.259 M [2,800 ppm] boron and 0.23 M sodium hydroxide [5,300 ppm

sodium]. At 60 'C [140 OF], the pH in the borated alkaline containment water with 0.259 M

[2,800 ppm] boron was approximately 10. The pH remained near 10 for the time period ranging

from 0.5 to 360 hours. The redox potential at 60 'C [140 OF] was approximately -0.61 VSHE at

0.5 hour and changed slightly to -0.64 VSHE. No significant changes were observed in either pH

or redox conditions.

Figures 4-3 and 4-4 show the amount of potentially amorphous solid phases formed and their

relative mol percent distribution in borated alkaline containment water, respectively, as a

function of time at 60 °C [140 OF]. The mol percent distribution data is also summarized in

Table 4-6. Simulation results show that the amount of solid phases observed at 60 °C [140 °F],

pH 10 increases with time. Results also indicate that at 0.5 hour, dominant potentially

amorphous solid phases consist of 89 mol percent NaAISi 308 and 10 mol percent

Ca2Mg5Si8022(OH)2. The formation of calcium silicate (CaSiO3) initiates at 32 hours and silica

(SiO2) at 72 hours. While the amount of calculated solid phases continues to increase, and

NaAISi308 continues to be a dominant solid phase with time (Figure 4-3), the formations of

CaSiO3 and SiO2 result in redistribution of solid phases (Figure 4-4). Beyond 72 hours,

dominant potentially amorphous solid phases consist of NaAISi 308, CaSiO3, and SiO2 with a

smaller quantity of Ca2Mg.Si8022(OH)2. Decrease in SiO2 mol percent and increase in

NaAISi308 mol percent after 148 hours are attributed to the fact that combination from the

Nukono low-density fiber insulation remains fixed beyond 180 hours while aluminum metal

continues to increase with time. The contribution from concrete walls remains insignificant.

Irrespective of time, at 60 °C [140 °F], the formation of solid phases is dominated by the

formation by silicates and silica.

Table 4-7 shows the calculated percentage of each element incorporated in dominant solid

phases. Both magnesium and aluminum were fully incorporated in solid phases. The

concentrations of the other two major components of the debris, calcium and silicon, continue to

increase in the solid phase with time. It should be noted that while the concentrations of silicon

and calcium in solid phases continue to increase with time (Table 4-7), the total amounts of

debris components that dissolve also continue to increase with time (Figure 4-3).

4-5
U

Table 4-5. pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water with

0.259 M [2,800 ppm B] and 0.23 M [5,300 ppm Na] NaOH at 60 °C [140 IF]

Time (Hour) pH Eh (VSHE)

0.5 9.96 -0.58

4 9.96 -0.61

32 9.95 -0.63

72 9.93 -0.63

148 10.0 -0.63

240 10.0 -0.64

360 10.0 -0.63

- 1.0E-01

6

_. 1.OE-02

0

* 1.0E-03

0

0- 1.OE-04 0

(UM

. 1.OE-05

0.

= 1.0E-06 0

'S 1.OE-07

3 1.OE-08 0

E

< 1.OE-09

* A kAo * At

A A

0

a

U

-- O

I

A Cu

* CaSiO3

A Ca2Mg5Si8O22(OH)2

or i2SiO4

)K SiO2

* NaAISi308

o Fe3SiO4010(0H)2

o Ca3FeSiO3012

* ZO.Fe203

COt

0.1 I 10 100 1000

Time (h)

Figure 4-3. Calculated Amount, in Mol, of Predicted Solid Phases Formed As a

Function of Time, in Hours, in 0.259 M [2,800 ppm] Borated Alkaline Containment

Water at 60 °C [140 OF]

4-6
100.0%

Co

CUQ

C o

.: 10.0%

0

1.0%

C

* 9

* * X4 *.. A A____

A

A

AAA

A Cu

* CaSiO3

A Ca2Mg5Si8O22(OH)2

oZn2SiO4

)K SiO2

* NaAISi308

o Fe3SiO4010(0H)2

o Ca3FeSiO3012

* ZrO. Fe2O3

.1 1 10

Time (h)

100 1000

Figure 4-4. Calculated Percent Predicted Solid Phases Formed As a Function of

Time in 0.259 M j[2,800 ppm] Boron in Borated Alkaline Containment Water at pH 10

at 60 °C [140 OF]

Table 4-6. Percent of Potentially Amorphous Solid Phases at 60 °C [140 OF],

101 kPa [1 atm], pH 10

NaAISi 308 Ca2MgSi,0,2 2 (OH)2 CaSiO3 Sio 2 Zn2SiO4

Time (h) (Percent) (Percent) (Percent) (Percent) (Percent)

0.5 90.2 8.7 0 0 0.36

4 87.0 11.3 0 0 0.74

32 55.6 7.4 35.6 0 0.49

72 44.4 5.9 37.0 12.3 0.39

148 26.0 3.5 22.7 47.8 0.23

240 32.0 3.7 24.3 40.0 0.32

360 48.4 4.3 29.0 17.6 0.56

4-7

Co3
.III

Table 4-7. Percent Element Distribution in Potentially Amorphous Solid Phases at 60 0C [140 IF],

101 kPa [1 atm] pH 10

Major Contributors Minor Contributors

Time Magnesium Aluminum Silicon Calcium Zinc Iron

(Hour) (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

0.5 100 100 35 8 63 75

4 100 100 44 19 98 96

32 100 100 53 76 100 100

72 100 100 59 94 100 NA*

148 100 100 76 98 100 NA

240 100 100 79 98 100 NA

360 100 100 80 98 100 NA

*NA-not applicable.

The speciations of corrosion products based on corrosion rates from literature at 60 *C [140 OF]

are presented in Appendix C. The dominant potentially amorphous solid phases formed in the

borated containment water at pH 10 after 360 hours were SiO2, CaSiO3, NaAlSi308,

Ca2Mg5Si8022(OH)2, Ca3Fe2Si30,2, and a minor quantity of Zn2SiO4. Comparison of data

presented in Appendix C, Figure 3-2, indicates formation of similar phases in a 360-hour

simulation at 60 0C [140 0F] with the exception of the iron phases. As indicated in Section 4.1,

the absence of iron bearing silicate phases is attributed to the extremely low corrosion rate for

carbon steel determined in this study. The formation of iron-bearing solid silicate phases was

replaced by calcium magnesium silicate.

Both silicon- and calcium-bearing soluble phases were also observed in the borated

containment water at pH 10. At 0.5 hour, approximately 68 mol percent of silicon and

92 mol percent calcium were distributed within various soluble silicates. Figures 4-5 and 4-6

show the concentrations of sodium and boron and concentrations of silicon and calcium,

respectively, in soluble phases as a function of time at 60 'C [140 0F]. The dominant

silicon-bearing soluble phases were Si0 2 (aqueous), H3SiO4-', and NaHSiO3. The dominant

calcium-bearing soluble phase was CaH 2BO3

1

. It should be noted that while the concentrations

of silicon and calcium in solid phases continue to increase with time (Table 4-7), the total

amount of debris components also continues to increase with time (Figure 4-3). A net increase

in the amount of debris components results in an increase in the soluble concentration of the

elements shown in Figures 4-5 and 4-6. Results also indicate that the boron and sodium

concentrations increase with time. Silicon, calcium, sodium, and boron are released from

Nukon5 low-density fiber insulation. Contributions for silicon and calcium could also come

from concrete.

4-8
0.28

-J

o 0.26

E

0

:= 0.24 co

4.2

C.

r_ 0.22

0

0.2

-

.s M

I * U

Uw

UF

l I l l*Na

0 50 100 150 200 250 300 350 400

Time (h)

Figure 4-5. Calculated Sodium and Boron Concentrations, in mol/L, in Aqueous Phase

As a Function of Time in 0.259 M [2,800 ppm] Borated Alkaline Containment Water in

pH 10 at 60 °C [140 °F]

aj

0

0

L-.

C.

0

C.

1.OOE-01

1.OOE-02

1.OOE-03

1.OOE-04

U

I I*II S I

I I I , a 1.OOE-05

0 50 100 150 200 250 300 350 400

Time (h)

Figure 4-6. Calculated Calcium and Silicon Concentrations, mol/L, in Aqueous Phase

As a Function of Time in 0.259 M [2,800 ppm] Borated Alkaline Containment Water in

pH 10 at 60 °C [140 °F]

4-9

CO(A
all

The increase in silicon and calcium concentrations as a function of time, along with the

increased boron and sodium concentrations, could be used to estimate and monitor ongoing

corrosion in the system.

It should be noted that input for the simulations excludes organics to model the formation of

complexes due to organic binder retained in fiber insulation after heat treatment. While

simulations examine complex interactions between metals and inorganic materials such as fiber

insulation and aluminum, the inputs are based on the corrosion or leaching rates of individual

components. Experimental studies to examine interactions between debris components were

not conducted. If leaching of fiber insulation or concrete is restricted due to a formation of a

coating on the surface, simulations will result in significantly different results. For example, the

Pourbaix diagram (Figure 4-7) for aluminum in a pH 10 alkaline borated water at 60 0C [140 OF]

indicates that at a pH 10 or higher aluminum is predominantly present as a soluble AI(OH)4

complex. Results are in contrast to simulations in the presence of dissolution products from

fiber insulation and concrete where aluminum is predominantly present in a solid phase as

NaAISi3O, (Table 4-6). The Pourbaix diagram (Figure 4-8) for aluminum in a pH 10 alkaline

borated water containing silica at 60 0C [140 OF] indicates that the NaAISi 308 solid phase is

dominant up to a pH of 12.

The comparison of the results using measured corrosion rates with the results presented in

Appendix C using literature data indicates formation of similar dominant solid phases with the

exception of iron silicates such as Fe3Si205(OH)4 and Ca3Fe2Si3O,2. The absence of

iron-bearing silicate phases in calculations using measured corrosion rates was attributed to an

extremely low corrosion rate measured for carbon steel at pH 10 compared to the corrosion rate

assumed in Appendix C calculations.

Higher measured dissolution rates for NukonO fiber insulation and concrete result in higher

concentration of solid phases. Solid phases, however, are similar in composition. It should be

noted that despite a higher measured dissolution rate for concrete, Appendix C calculations are

overly conservative, because the Appendix C analyses assumed concrete particulates to

contribute at the same rate without an end-point at which particulates would be considered

completely dissolved. In this analysis, because of the lack of a good estimate on the particulate

surface area, the entire inventory of concrete particulates (22.43 g/M3 [0.0014 lbm/ft3'} was

assumed to go through dissolution instantly. Despite this conservative assumption, the

contribution from concrete particulates was significantly lower than the contributions from

Nukon' fiber insulation.

This report provides insight to and is useful in understanding the evolution of solution chemistry

and the formation of solid phases in integrated chemical effects tests at the University of

New Mexico.

4-10
0 2 4 6 8 10 12 14

2 2

1.2 1.2

i

0. 4 _ 04

w

-0.4 -0A

-1.2 -1.2

-2 -2

0 2 4 6 8 10 12 14

pH

Figure 4-7. Pourbaix Diagram for Aluminum in a pH 10 Borated Alkaline Solution

at 60 0

C [140 OF]

4-11

CD5
a 2 4 6 8 10 12 14

2

1.2.

0.4.

w

-0.4

-1.2

4

-2 _III10

0 2 4 6 8 10 12 14

pH

Figure 4-8. Pourbaix Diagram for Aluminum in a pH 10 Borated Alkaline Water

Containing Silica at 60 0C [140 OF]

4-12

cQG&

Be.....I. . ... - _1 I I ........................
5 SUMMARY

Corrosions of galvanized steel, copper, aluminum, and carbon steel were measured using

ASTM G59-97 (ASTM International, 2004a), and corrosion rates were calculated using

ASTM G102-89 (ASTM International, 2004b) at 60, 90, and 110 'C [140, 194, and 230 0FJ in

borated {0.259 M [2,800 ppm] B} alkaline containment water at pH 10. Results indicate

the following:

* Except for the corrosion rate of carbon steel, the corrosion rates of aluminum, copper, and

galvanized steel increase with increase in temperature.

* The measured corrosion rates for aluminum, galvanized steel, and copper were lower than

the corrosion rate values assumed in Appendix C, Chapter 2.

* A significant difference was observed between the measured carbon steel corrosion rate and

the value assumed in Appendix C, Chapter 2. Carbon steel at pH 10 in borated alkaline

containment water showed a passive behavior with a low corrosion rate. The measured

corrosion rate in pH 7 borated trisodium phosphate containment water was approximately an

order of magnitude higher than the corrosion rate in pH 10 borated alkaline containment

water.

The dissolution rate for Nukono glass was determined using ASTM C1220-98 (ASTM

International, 2002) at 60, 90, and 110 0C [140, 194, and 230 OF] in borated {0.259 M

[2,800 ppm] B} alkaline containment water at pH 10 and in borated {0.259 M [2,800 ppm] B}

containment water at pH 7. A pH 10 was adjusted by the addition of sodium hydroxide and a

pH 7 was adjusted by the addition of trisodium phosphate. Results indicate the following:

* The corrosion rate data showed a strong dependence on temperature. The corrosion rate

increased with the increase in the temperature.

* The corrosion rate was higher than the value assumed in Appendix C, Chapter 2. The

Nukono low-density fiber insulation corrosion rate at pH 7 was lower compared to the

corrosion rate at pH 10.

The dissolution rate for concrete was also determined using ASTM C1220-98 (ASTM

International, 2002). Results indicate the following:

* The corrosion rate data showed a strong dependence on temperature. The corrosion rate

increased with the increase in the temperature.

* The measured corrosion rate for concrete was higher than the value assumed in Appendix C,

Chapter 2.

The thermodynamic simulations documented in this report were made using a thermodynamic

simulator developed by OLI Systems, Inc. (2002b) for evaluating aqueous chemical processes

in industrial and environmental applications. Computational thermodynamic simulation

calculations were conducted using StreamAnalyzer° Version 1.2 (2002a). Key chemical

components involved in speciation simulation were copper, carbon steel, galvanized steel,

aluminum, Nukon' low-density fiber insulation, and concrete. The amount of corroded product

5-1
III

was determined based on the surface areas exposed as discussed in the NRC test plan, (NRC,

2005), and the experimentally determined corrosion rates. Thermodynamic simulations were

conducted at 60, 90, and 110 0C [140, 194, and 230 OF]. At 90 and 110 0C [194 and 230 OF],

simulations were based on corrosion of components for 30 minutes. At 60 0C [140 OF],

simulations were based on corrosion of components from 30 minutes to 360 hours. The results

of the corrosion rate measurements and estimate of corrosion amounts indicate the following:

* The comparison of corrosion amounts indicate that Nukono low-density fiber insulation is two

to three orders of magnitude higher compared to corrosion products from carbon steel,

galvanized steel, and copper. Corrosion amounts associated with these metals, can be

neglected in simulations.

* Based on the corrosion rate for Nukono low-density fiber insulation at 60 0C [140 OF], an

average 7-pm [0.28-mil]-diameter Nukono low-density fiber would corrode in approximately

182 hours.

* The contributions of calcium, aluminum, and sulfur from Nukono low-density fiber insulation

are approximately 10,000 times more than the contribution from concrete walls. In this study,

concrete particulates were assumed to be released instantly.

Analysis of the simulation data at 60, 90, and 110 *C [140,194, and 230 'F] for 30 minutes in

borated alkaline containment water at pH 10 indicates the following:

* The formation of potentially amorphous solid phases was predicted to be dominated by

silicates. Sodium aluminum silicate (NaAISi 308) and calcium magnesium silicate

[Ca2MgSi8022(OH)2j constituted approximately 99 percent of the solid phases.

* Smaller quantities of calcium iron silicate (Ca3Fe2Si30,2), zinc-iron oxide (ZnO Fe203), and

zinc silicate (Zn2SiO4) were observed. Simulation results indicate no phase change for

copper. Contributions from metals were dominated by aluminum.

* A comparison with the simulation data presented in Appendix C, Figure 3-1, indicates the

formation of similar dominant potentially amorphous solid phases with the exception of iron

silicates such as Fe3Si205(OH)4 and Ca3Fe2Si30,2 The absence of iron-bearing silicate

phases was attributed to the fact that the measured carbon steel corrosion rate at pH 10 was

extremely low compared to the corrosion rate assumed in Appendix C. In both cases, the

solid phases were dominated by the formation of silicates. These results support the

conclusion reached in Appendix C that there is no need for a pressurized test loop.

Analysis of simulation data at 60 0C [230 OF] from 30 minutes to 360 hours in borated alkaline

containment water at pH 10 indicates the following:

* At 0.5 hour, dominant solid phases consisted of 90 mol percent NaAlSi308 and 9 mol percent

Ca2Mg5Si8022(OH)2 The formation of calcium silicate (CaSiO 3) initiated at 32 hours and silica

(Si0 2) at 72 hours. NaAlSi308 continued to be a dominant potentially amorphous solid phase

as a function of time. The formation of CaSiO3 and SiO2 resulted in redistribution of solid

phases. Beyond 72 hours, dominant solid phases consist of NaAlSi 308, CaSiO3 and Si0 2

with a smaller quantity of Ca2Mg9Si8022(OH)2. Irrespective of time at 60 0C [140 OF], the

formation of solid phases is dominated by silicates and silica.

5-2
* A comparison of data presented in Appendix C indicates formation of similar phases in a

360-hour simulation at 60 CC [140 OF] with the exception of iron phases.

* Both silicon- and calcium-bearing soluble phases were observed in borated alkaline

containment water. Dominant silicon-bearing soluble phases were Si02 (aqueous), H3Si04

1, and NaHSiO3, and dominant calcium-bearing soluble phase was CaH 2BO3+'. Furthermore,

concentrations of boron and sodium in the solution increased with time.

* The increases in silicon and calcium concentrations, along with the increase in the boron and

sodium concentrations, in the aqueous phase as a function of time could be used to estimate

and monitor ongoing corrosion in the system.

Simulations provide insight to and is useful in understanding the evolution of solution chemistry

and the formation of solid phases in integrated chemical effects tests at the University of New

Mexico. The simulation results can be used to corroborate the evolution of solution chemistry

and the formation of solid phases on the surfaces of the corroding components observed. It

should be noted that while simulations were based on the measured corrosion rates, input for

the simulation excludes organics to model formation of complexes due to organic binder

retained in fiber insulation after heat treatment. While simulations examine complex interactions

between metals and inorganic materials such as fiber insulation and aluminum, the inputs are

based on the corrosion or leaching rates of individual components. Experimental studies to

examine interactions between debris components were not conducted.

5-3
6 CONCLUSIONS

Based on the measured corrosion rates, estimated exposed surface area, and exposure time,

the thermodynamic simulations indicate that formation of dominant solid phases is controlled by

the presence of Nukono low-density fiber insulation, aluminum, and concrete. The dominant

potentially amorphous solid phases consisted of silicate phases such as NaAISi308,

Ca2Mg5Si8022(OH)2, CaSiO3, and Si02. Although some of these constituents decreased

proportionally with increasing time, the solid NaAlSi 308 phase continued to be a dominant solid

phase as a function of time. The calculations are based on the solid phases in the OLI

database. The formation of actual solid phases may be different depending on the reaction

kinetics. The formation of NaAISi308 coupled with the presence of alkaline solutions could lead

to gel formation, resulting in clogging of the containment area sump pump suction strainers.

Thermodynamic simulations confirm that no significant differences in corrosion product

formation are expected in alkaline simulated containment water at pH 10 as the

high-temperature and pressure conditions during the initial stages of a LOCA event approach

steady-state conditions.

This study also provides, based on thermodynamic simulations, an evolution of soluble species

in borated alkaline containment water at 60 0C [140 °F]. Both silicon- and calcium-bearing

soluble phases were observed in borated alkaline containment water. The dominant siliconbearing soluble phases were Si0 2 (aqueous), H3SiO4 ', and NaHSiO3, and the dominant

calcium-bearing soluble phase was CaH 2BO3+

1. Furthermore, the concentrations of boron and

sodium increased with time. The increase in silicon and calcium concentrations, along with the

increase in boron and sodium concentrations, in aqueous phase as a function of time could be

used to estimate and monitor ongoing corrosion in the system.

Simulations provide insights to and is useful in understanding the evolution of solution chemistry

and the formation of solid phases in integrated chemical effects tests at the University of

New Mexico.

It should be noted that while simulations were based on measured corrosion rates, input for the

simulation excludes organics to model formation of complexes due to organic binder retained in

fiber insulation after heat treatment. While simulations examines complex interactions between

metals and inorganic materials such as fiber insulation and aluminum, the inputs are based on

the corrosion or leaching rates of individual components. Experimental studies to examine

interactions between debris components were not conducted.

6-1
7 REFERENCES

ASTM International. "Metals Test Methods and Analytical Procedures." ASTM G59-97

(Reapproved 2003): Standard Test Method for Conducting Potentiodynamic Polarization

Resistance Measurement. Volume 3.02: Wearand Erosion-Metal Corrosion. Published on

CD ROM. West Conshohocken, Pennsylvania: ASTM International. 2004a.

. "Metals Test Methods and Analytical Procedures." ASTM G102-89 (1999): Standard

Practice for Calculation of Corrosion Rates and Related Information from Electrochemical

Measurements. Volume 3.02: WearandErosion-Metal Corrosion. Published on CD ROM.

West Conshohocken, Pennsylvania: ASTM International. 2004b.

. "Nuclear, Solar, and Geothermal Energy." ASTM C1220-98: Standard Test Method for

Static Leaching of Monolithic Waste Forms for the Disposal of Radioactive Waste.

Volume 12.01: Nuclear Energy (I). Published on CD ROM. West Conshohocken,

Pennsylvania: ASTM International. 2002.

Griess, J.C. and A.L. Bacarella. 'Design Consideration of Reactor Containment Spray Systems

-Part Ill: The Corrosion of Materials in Spray Solutions." ORNL-TM-2412, Part l1l. Oak

Ridge, Tennessee: Oak Ridge National Laboratory. 1969.

Hall, J.F. "Corrosion of Low Alloy Steel Fastener Materials Exposed to Borated Water."

Proceedings of the Third International Symposium on Environmental Degradation of Materials in

Nuclear Power Systems-Water Reactors. G.J. Theus and J.R. Weeks, eds. La Grange Park,

Illinois: American Nuclear Society. pp. 711-722. 1988.

Hermannson, H.P. and S. Erixon. "Chemical Environment for Strainers at Loss of Coolant

Conditions in a PWR." SKI Report 98:12. Stockholm, Sweden: Swedish Nuclear Power

Inspectorate. 1997.

Jantzen, C.M. "Radioactive Waste-Portland Cement Systems II: Leaching Characteristics."

Journal of American Ceramic Society. Vol. 67, No. 10. pp. 674-678. 1984.

Johns, R.C., B.C. Letellier, K.J. Howe, and A.K. Ghosh. "Small-Scale Experiments: Effects of

Chemical Reactions on Debris-Bed Head Loss." LA-UR-03-6415. Los Alamos, New Mexico:

Los Alamos National Laboratory. 2003.

NRC. "Test Plan: Characterization of Chemical and Corrosion Effects Potentially Occurring

During a Pressurized Water Reactor LOCA." Rev. 12b. ML050450478. Washington, DC:

NRC. 2005. <www.nrc.gov/reading-rm/ adams.html>

. NUREG/CR-6808, "Knowledge Base for the Effect of Debris on Pressurized Water

Reactor Emergency Core Cooling Sump Performance." Washington, DC: NRC.

February 2003.

OLI Systems, Inc. "StreamAnalyzer* Version 1.2." Morris Plains, New Jersey: OLI

Systems, Inc. 2002a.

7-1
al

-. Environmental Simulation' Program Version 6.6." Morris Plains, New Jersey:

OLI Systems, Inc. 2002b.

Piippo, J., T. Laitinen, and P. Sirkai. 'Corrosion Behavior of Zinc and Aluminum in Simulated

Nuclear Accident Environments." STUK-YTO-TR 123. Helsinki, Finland: Finnish Center for

Radiation and Nuclear Safety. 1997.

7-2
APPENDIX A
APPENDIX A

CORROSION RATE MEASUREMENT METHODS FOR METALS

The corrosion rates for aluminum, copper, zinc on galvanized steel surface, and carbon steel

samples were determined in borated alkaline water at pH 10 at 60, 90, and 110 'C [140, 194,

and 230 OF]. The corrosion rate for carbon steel was also determined in a borated trisodium

phosphate solution at pH 7 at 60, 90, and 110 0C [140,194, and 230 F]. Borated alkaline

containment water contained 0.259 M [2,800 ppm] boron, and the pH was adjusted by the

addition of NaOH. Borated containment water {0.259 M [2,800 ppm] boron) at pH 7 was

obtained by the addition of Na3PO4. The following two electrochemical methods were used for

corrosion measurements:

* Polarization resistance method in accordance with ASTM G59-97 (ASTM International,

2004a), Standard Test Method for Conducting Potentiodynamic Polarization Resistance

Measurements

* Alternate current impedance method according to ASTM G1 06-89 (ASTM International,

2004b), Standard Practice for Verification of Algorithm and Equipment for Electrochemical

Impedance Measurements

The corrosion rates were calculated in accordance with ASTM G102-89 (ASTM International,

2004c), Standard Practice for Calculation of Corrosion Rates and Related Information from

Electrochemical Measurements.

In practice, the corrosion rate measurements using electrochemical methods are determined in

deaerated solution to avoid interference of the oxygen reduction reaction, especially for a

passive system in which the passive current density is low. Because the measured or net

current is the sum of the anodic current contributed from metal corrosion and the cathodic

current contributed from oxygen reduction, the net current can be substantially reduced or even

become cathodic when the dissolved oxygen concentration is large. For an active system in

which the anodic current is high, the relative error caused by oxygen reduction is low.

A.1 Basis of the Electrochemical Methods

A.1.1 Polarization Resistance Method

The polarization resistance method is an electrochemical method that determines the amount of

current density, I, obtained by polarizing the metal or alloy test specimen a few millivolts, E, from

the corrosion potential, Ebon.

A-1
aI

The polarization resistance, Rp, of the corroding test specimen is defined as the slope of the

E versus I curve at the Em, and the resistance is related to the corrosion current density, /c,

through Eq. (A-1)

R dE (A-1)

di Ecor,dEO - 2.303 (fla +flc,~(Ai

dt

where

Da and p - anodic and cathodic Tafel slopes in units of V/decade of current

dE/dt - potential scan rate

After /, is obtained, the corrosion rate, CR, based on Faraday's law, is calculated according to

Eq. (A-2)

CR=K IcorrEW (A-2)

Up

where

K - constant with values depending on the units of other parameters in the equation

EW - equivalent weight of the corroding metal or alloy test specimen

p - density of the test specimen

In this method, the potential scan is performed within a few millivolts of the corrosion potential to

avoid perturbing the system too much, which can alter the kinetics of the corrosion process and

change the surface oxide film for passive metals. To avoid capacitive charging, the scan rate is

sufficiently slow. A scan rate of 0.001 mV/s is usually used for passive metals, but a faster scan

rate can be used for active metals.

A.1.2 Basis of Electrochemical Impedance Spectroscopy and Anodic

Passive Current Density Methods

In principle, the electrochemical impedance spectroscopy and anodic polarization methods are

also useful in the determination of the corrosion rate.

The electrochemical impedance spectra are usually obtained by applying a small amplitude

potential (or current) perturbation to the working electrode at varying frequencies and

subsequently measuring the resulting current (or potential). By scanning a wide range of

frequencies, the polarization resistance of the metal can be determined by fitting the spectra to

an equivalent electrical circuit model. After Rp is obtained, the corrosion rate can be calculated

using Eqs. (A-1) and (A-2) as described previously. However, the data obtained by fitting to an

equivalent circuit must be treated with caution, because there are no unique equivalent circuit

and set of parameter values that describe the spectra. More details on this technique can be

found in the literature (Scully, 1995; Cottis and Turgoos, 1999; Bard and Faulkner, 2001).

The corrosion current in Eq. (A-2) also can be estimated from the steady-state anodic

current density measured in deaerated solution by polarizing the potential away from the

corrosion potential.

A-2
A.2 Experimental

A.2.1 Metal Samples Preparation

The test specimens with dimensions of approximately 25 mm [1 in] (length), 25 mm [1 in]

(width), and the thickness of the as-received material were cut from the as-received plates. The

thickness of the as-received plates is 1.59 mm [0.0625 in]. Before measurement, the aluminum,

copper, and carbon steel specimens were polished on successive grades of silicon carbide

papers (320, 400, and 600 grit) and cleaned in deionized water and in acetone. The galvanized

steel was cleaned only in deionized water and acetone without polishing, and all edges of the

specimens were coated with microstop' to avoid exposure of steel to solution.

A.2.2 Electrochemical Cell

The measurements were conducted in a three-electrode electrochemical cell in N2-deaerated

solutions. The three electrodes consist of a test specimen (or working electrode), a reference

electrode, and a counter electrode.

The measurements at 60 and 90 'C [140 and 194 OF] were conducted in 250-mL [0.067-gal]

glass cells with Teflon lids. For tests at 60 and 90 *C [140 and 194 OF], an Alloy 825 wire, which

was thermally sealed in glass tubing with an outer diameter of 9.52 mm [0.375 in], was

connected to the specimen for electrical conduction. Test cells were fitted with a water-cooled

condenser to minimize solution loss at elevated temperatures. A saturated calomel electrode

was used as a reference electrode, and it was connected to the solution through a water-cooled

Luggin probe with a porous silica tip to maintain the reference electrode at room temperature. A

platinum flag was used as the counter electrode.

At 110 'C [230 OF], a stainless steel autoclave lined with Teflon was used as the test cell. The

solution was deaerated with N2 at least 1 hour before setting the temperature to 100 'C [212 OF].

The test specimen was held in solution using an Alloy 22 specimen holder, which was

connected to an Alloy 22 rod shrunk in Teflon for electrical conduction. The specimen holder

and the contact area between the Alloy 22 rod, specimen holder, and specimen were wrapped

with Teflon tape to avoid contact with solution. A custom tungsten-tungsten oxide electrode

was used as the reference electrode. Platinum was also used as the counter electrode in this

test cell. The potentials of the tungsten-tungsten oxide in the same pH 10 solution used in the

tests were measured at 25, 60, and 90 'C [77, 140, and 194 OF] to be -0.293, -0.443, and

-0.536 V against a saturated calomel electrode maintained at room temperature. At 110 OC

[230 OF], the potential was estimated to be -0.623 VSCE by extrapolating to that temperature. At

pH 7, the potential was calculated to be -0.445 VSCE according to the Nernst equation for

tungsten-tungsten oxide electrode and the potential in a pH 10 solution. Accordingly, all the

applied potentials at 110 *C [230 OF] were adjusted against saturated calomel electrode, which

is 0.241 V against standard hydrogen electrode at 25 0C [77 OF].

IStop-off lacquer. Tolber Chemical, Hope, Arkansas 71801.

A-3
al

A.2.3 Polarization Resistance and Cyclic Potentiodynamic Polarization

Polarization resistance measurements were conducted by measuring the current density while

scanning the potential of the test specimens in the anodic direction for the range -10 to +10 mV

or -20 to +10 mV, with respect to the corrosion potential. The scan rate used was 0.01 mV/s.

The specimens were immersed in solution for 1 hour prior to the start of the tests. The value of

the polarization resistance, Rp, was obtained by fitting a straight line to the data in the range of

-5 to +5 mV with respect to the corrosion potential. The corrosion current density was

calculated using Eq. (A-3)

= 0.12

CoO 2 x 2303 Rp (A-3)

which was derived from Eq. (A-1), assuming values of 0.120 V/decade for the anodic and

cathodic Tafel slopes, 6e and 4 (Shoesmith, 1987).

After this small linear polarization, potentiodynamic polarization was performed on the same

electrode. The potential was scanned from 100 mV below the open circuit potential toward the

more noble direction at a scan rate of 0.167 mV/s to 900 mV with respect to the reference

electrode. Subsequently, the scanning was reversed until the potential reached -600 mV with

respect to the reference electrode.

The potential and the resulting current were monitored using a computer-controlled potentiostat

(Multichannel Solartron 1480).

A.2.4 Electrochemical Impedance Spectroscopy

The impedance measurements were conducted at the open-circuit potential with an alternate

amplitude of ±10 mV during the frequency range from 20 kHz to 1 mHz with 10 points per

decade (Scully, 1995). The acquisition time per impedance spectrum is near 1.5 hours.

A.3 Results

A.3.1 Corrosion Rates from Polarization

Figures A-1, A-2, A-3, and A-A show the potential versus current density plots for all four

metals at 60, 90, and 110 'C [140,194, and 230 OF] in a borated {0.259 M [2,800 ppm] boron}

alkaline containment water at pH 10. From Figures A-1 and A-3, the polarization resistances

for aluminum and copper were determined by linear fit to the data near the corrosion potential.

For carbon steel and zinc, there was significant scatter in the polarization data (not shown here)

during the range from - 10 to 10 mV with respect to the corrosion potential. The scatter may be

caused by the interference of electrical noise and the agitation of N2 gas. Alternatively, the

passive current densities from the potentiodynamic polarization curves shown in Figures A-2

and A-4 were used to determine the corrosion current. The data points chosen were indicated

in the curves as a, b, and c. To be conservative, as indicated in point c, the larger current

density in Figure A-2 was chosen as the corrosion current for carbon steel at 110 0C [230 OF].

Equations (A-2) and (A-3) were used to calculate the corrosion rates, which are summarized in

A-4
Table A-1. Measured Corrosion Rates for Aluminum, Carbon Steel, Copper, and

Galvanized Steel (Zinc) in Borated Deaerated Alkaline Water at pH 10

Corrosion Rate [gIm2-h (mil/yr)]

Temperature Temperature Temperature

Metals 60 0C [140 0F] 90 0C [194 0F] 110 0C [230 0F]

Aluminum

Density 2.70 g9cm3 0.986 [126] 1.89 [241] 2.20 [281]

Equivalent weight 9.66 g/mol

Carbon Steel -2

Density 7.84 g/cm3 1.35 x l0-2 [0.594] 2.95 x 102 (1.30] 8.21 x 10 [3.61]

Equivalent weight 27.9 g/mol

Copper

Density 8.96 g/cm3 4.78 x 10-3 [0.184] 5.19 x 10 -2 [2.00] 9.91 x 10-2 [3.82]

Equivalent weight 63.5 g/mol

Galvanized Steel (Zinc)

Density 7.13 gfcm3 3.57 x 1 -

2 [1.73] 4.05 x 10-2 [1.96] 2.34 x 10-1 [11.4]

Equivalent weight 32.7 g/mol I

Measured Corrosion Rates for Carbon Steel in Borated Water at pH 7

Carbon Steel 1.27 x 10-1 [5.59] 9.36 x 10-2 [4.12] 2.14 x 10-2 [0.944]

Table A-1. The density and the equivalent weight for each metal used in the calculation also

are included in Table A-1.

A similar method was used to determine the corrosion rate for carbon steel at 60, 90, and

110 0 C [140, 194, and 230 OF1 in a borated containment water {0.259 M [2,800 ppm] boron, and

0.17 M Na3PO4I at pH 7. The potential versus current density is plotted in Figure A-5. It is

unclear what caused the significant open circuit potential increase by approximately 500 mV as

the temperature increased from 90 to 110 °C [194 to 230 OF]. Similar results were obtained as

the test at 110 °C [230 °F] was repeated. The most possible reason is attributed to oxide film

property change as temperature increased to 110 °C (230 °F]. The polarization resistance was

determined by linear fit to experimental data. The calculated corrosion rates are included in

Table A-1 for comparison.

In a pH 7 solution, the corrosion rate of carbon steel is lower than the rate in pH 10 solution,

which is consistent with that observed from the Pourbaix diagram (Macdonald and

Cragnolino, 1989). The slightly alkaline solution is beneficial for carbon steel to maintain

its passivity.

A.3.2 Comparison of Polarization in Aerated and Deaerated Solution

Figure A-6 shows a comparison of the potentiodynamic polarization curves for all four metals at

60 °C [140 °F] in air aerated and nitrogen deaerated borated {0.236 M [2,550 ppm] boron}

A-5
L11

alkaline containment water at pH 10. This solution had approximately 9-percent lower boron

concentration, attributed to the presence of moisture in boric acid. However, the lower boron

concentration is not expected to change the comparison between aerated and deaerated

solutions. Except for aluminum, the addition of oxygen increased the corrosion potentials by

approximately 500 mV for carbon steel, copper, and zinc. This increase is expected because

oxygen is a stronger oxidant than water. However, the polarization curves in aerated and

deaerated solutions had a similar shape. The passive current densities for aluminum, carbon

steel, and copper in aerated solutions, as shown in Figure A-6, were similar or slightly lower

than the passive current densities in the deaerated solution. Table A-2 lists the calculated

corrosion rate values in aerated and deaerated solutions. To keep consistency with data values

in Table A-1, the corrosion rates for carbon steel and zinc were calculated from the

potentiodynamic polarization curves (Figure A-6), whereas the corrosion rates for aluminum

and copper were determined by linear fit to the data near the corrosion potential (not shown

here). For zinc, the corrosion rate measured in aerated solution is slightly higher than the

corrosion measured in the deaerated solution.

In summary, these metals have similar behavior in aerated and deaerated solutions at 60 OC

[140 OF]. The corrosion rates measured in deaerated solution are representative for that

measured in aerated solution.

A.3.3 Electrochemical Impedance Spectroscopy

Figures A-7, A-8, A-9, and A-1 0 are the impedance spectra for all four metals at 60, 90, and

110 0C [140, 194, and 230 OF] in a {0.236 M [2,550 ppm] boron) borated alkaline containment

water at pH 10. The simplest model for a corroding metal consists of a solution resistance, Rs,

a polarization resistance, Rp, and a double-layer capacitance, Cd,, in parallel (Schueller and

Taylor, 1993). The impedance spectra obtained for the four metals in Figures A-7, A-8, A-9,

and A-10 indicate that the behavior of the four metals cannot be described simply by using the

simple circuit. The presence of two time constants in aluminum, the high passivity of carbon

steel, the diffusion process in copper and zinc, and the signal noise in the low-frequency region

resulted in significant uncertainty in the estimation of Rp and the metal corrosion rates. The

spectra for copper, carbon steel, and zinc were fitted with this simple circuit by excluding some

Table A-2. Comparison of Measured Corrosion Rates for Aluminum, Carbon Steel,

Copper, and Galvanized Steel (Zinc) in Aerated and Deaerated pH 10 Alkaline Water at

60 CC [140 OF]

Corrosion Rate [glm2-h (mil/yr)]

Metals Nitrogen Deaerated Air Aerated

Aluminum 1.01 [128] 4.59 x 10-1 [58.7]

Carbon Steel 1.15 x 10-2 [0.508] 9.88 x 10-3 [0.435]

Copper 4.64 x 10-3 [0.179] NA*

Zinc 4.21 x 10-2 [2.04] 6.69 x 10-2 [3.24]

*Not applicable-data are too noisy to fit, but the corrosion rate is small.

A-6
noisy data points in the low-frequency range, whereas the spectra for aluminum were fitted with

a two-time constants circuit model. Table A-3 summarizes the corrosion rates determined by

preliminarily fitting the spectra to the simple circuit. There are discrepancies from that

measured using the direct current polarization method, Table A-1. The main reason is because

of the high uncertainty in fitting the impedance spectra to the equivalent circuit.

Table A-3. Measured Corrosion Rates from Impedance Spectra for Aluminum, Carbon

Steel, Copper, and Galvanized Steel (Zinc) In Deaerated Borated Alkaline Water at

pH 10

Corrosion Rate [g/m2 -h (mil/yr)]

Temperature 60 IC Temperature 90 0C Temperature 110 0C

Metals [140 IF] [194 OF] [230 0

F]

Aluminum 1.22 [157] 3.50 [448] 7.04 [901]

Extremely high 1.60 x1- 3.47 x 10-3

Carbon Steel uncertainty in fitting.0 3 x 10 [1.53 x 10-1]

caused by high passivity 1

Copper 1.93 x 10-2 [0.742] 4.48 x 10-2 [1.721 8.68 x 10-2 [3.35]

Zinc 3.42 x 10-2 [1.66] 3.76 x 10-2 [1.82] 2.85 x 10-2 [1.38]

A.4 References

ASTM International. 'Metals Test Methods and Analytical Procedures." ASTM G59-97

(Reapproved 2003): Standard Test Method for Conducting Potentiodynamic Polarization

Resistance Measurements. Volume 3.02: Wear and Erosion-Metal Corrosion. Published on

CD ROM. West Conshohocken, Pennsylvania: ASTM International. 2004a.

. Metals Test Methods and Analytical Procedures." ASTM G106-89 (1999): Standard

Practice for Verification of Algorithm and Equipment for Electrochemical Impedance

Measurements. Volume 3.02: Wear and Erosion-Metal Corrosion. Published on CD ROM.

West Conshohocken, Pennsylvania: ASTM International. 2004b.

-. "Metals Test Methods and Analytical Procedures." ASTM G102-89 (1999): Standard

Practice for Calculation of Corrosion Rates and Related Information from Electrochemical

Measurements. Volume 3.02: Wearand Erosion-Metal Corrosion. Published on CD ROM.

West Conshohocken, Pennsylvania: ASTM International. 2004c.

Bard, A.J. and L.R. Faulkner, eds. Electrochemical Methods, Fundamentals andApplications.

2nd Edition. New York City, New York: John Wiley & Sons, Inc. pp. 368-416. 2001.

Cottis, R. and S. Turgoos. Electrochemical Impedance and Noise. Houston, Texas: NACE

International. 1999.

A-7
"l

Macdonald, D.D. and G.A. Cragnolino. "Corrosion of Steam Cycle Materials." The ASME

Handbook on Water Technology for Thermal Power Systems. P. Cohen, ed. New York City,

New York: ASME. pp. 659-1,031. 1989.

Schueller, G.R.T. and S.R. Taylor. "Equivalent Circuit Modeling of Aluminum/Polymer

Laminates Using Electrochemical Impedance Spectroscopy." ASTM STP-1 188:

Electrochemical Impedance-Analysis and Interpretation. J.R. Scully, D.C. Silverman, and

M.W. Kendig, eds. Philadelphia, Pennsylvania: ASTM International. pp. 328-343. 1993.

Scully, J.R. Electrochemical Corrosion Tests and Standards: Application and Interpretation.

R. Boboian, ed. Philadelphia, Pennsylvania: ASTM International. pp. 75-90. 1995.

Shoesmith, D.W. "Kinetics of Aqueous Corrosion." Metals Handbook. 9!h Edition. Vol. 13.

Metals Park, Ohio: ASM International. pp. 29-36. 1987.

A-8
I 1A- -1.14U -

Aluminum

-1.145 Borated pH 10 solution

N2 deaerated, 60 °C

0 -1.150 Rp = 95.2 Ohms.cm 2 A

> R2 of the best fit line = 0.996

-i -1.155

o -1.160

IL _

-1.165

-1.170 I . . . . . .

-1.5E-04 -1.0E-04 -5.OE-05 0.OE+00

11,110'

5.0E-05

Current density, A/cm2

-1.220

-1.225

W

o -1.230

M -1.235

9 -1.240

-.

-1.245

Aluminum

Borated pH 10 solution

N2 deaerated, 90 °C

Rp = 49.7 Ohms.cr 2

R2 of the best fit line = 0.

-1.250 1-

-4.OE-04 -2.OE-04 O.OE+00

Current denity, A/cm2

2.OE-04

-1.040

-1.140 -

LU

> -1.240-

a -1.340- 0

a.

-1.440-

Aluminum

Borated pH 10 solution I

N2 deaerated, 110 °C

RP = 42.7 Ohms.cm 2 .i

R2 of the best fit line = 0.982

...-

-1.540 _--

-8.OE-03 -4.0E-03 O.OE+00 4.OE-03

Current density, A/cm2

Figure A-1. Polarization Resistance Determined from Potential Versus Current Density for Aluminum in Deaerated pH 10 Sodium Hydroxide with 0.259 M [2,800 ppm] Boron at

60, 90, and 110 ° C [140, 194, and 230 OF] Obtained Using a Scan Rate of 0.01 mVIs.

Only Points within 5 mV or Less of the Corrosion Potential Were Used to Determine

Polarization Resistance.

A-9

QO l
1.50 - _..__

Carbon steel polarization at 60 0C

Carbon steel polarization at 90 0C

1.00 - Carbon steel polarization at 110 0C

Q 0.50

,, 0.00

-0.50 11000

900C

-1 .00 , , ,,,,' I ,7TI , ,, I I I -1, ............ I . I

1.OE-10 1.OE-08 1.OE-06 1.OE-04 1.OE-02

Current density, A/cm2

Figure A-2. Potentiodynamic Polarization Curves for Carbon Steel in Deaerated pH 10

Sodium Hydroxide with 0.259 M [2,800 ppm] Boron at 60, 90, and 110 0C [140,194, and

230 OF] Obtained Using a Scan Rate of 0.167 mV/s. The Current Density Values at Three

Data Points, a, b and c, As Indicated in the Curves Were Chosen for Calculating

Corrosion Rates.

A-10

CQt

.... 

- .. ........... ......... ....I ........ .- - :. _ .. ~ ......... -.-.......................
-0.31

Copper

-0.32 Borated pH 10 solution

LU N2 deaerated, 60 °C

o -0.32 RP=1.29X10 5Ohms.cm2

033 R2 of the best fit line =0.969

-0.33 -

0 -0.33-

IL

-0.34 .

-0.34

-2.0E-07 -1.OE-07 O.OE+00 1.OE-07

Current density, AIcm2

-0.340 -

-0.345 Copper

Borated pH 10 solution ,, -0.350 - N2 deaerated,90 °C 0

co -035 > -0.355 - Rp = 1.19 X 104 Ohms .cm2

2 -0.360 - R2 of the best fit line = 0.955

o -0.365

0

IL -0.370

-0.375

-0.380

-1.3E-06 -9.OE-07 -5.OE-07 -1.OE-07 3.OE-07

Current density, A/cm2

-0.322 Copper

Borated pH 10 solution

,, -0.330 N2 deaerated, 110 C

> R =6.23X10 3 Ohms.cm2

-0.338 -R2ofthe best fit line 0.930

_ -0.346 - 4-W

0

-0.354

-0.362

-2.0E-06 -1.OE-06 0.0E+00 1.OE-06

Current density, A/cm2

Figure A-3. Polarization Resistance Determined from Potential Versus Current

Density for Copper in Deaerated pH 10 Sodium Hydroxide with 2,800 ppm Boron at

60, 90, and 110 °C [140, 194, and 230 °F] Obtained Using a Scan Rate of 0.01 mV/s.

Only Points within 5 mV or Less of the Corrosion Potential Were Used to

Determine Polarization Resistance.

A-11
1.50 -_.__ _

Zn polarization at 60 0C

- Zn polarization at 90 0C

-DZn polarization at 110 0C

0.50

21 0.00

5 ,C a 

06

-0.50

-1.00

-1.50 I ~ ~ I II~

1.OE-09 1.OE-08 1.OE-07 1.OE-06 1.OE-05 1.OE-04

Current density, Acm2

Figure A-4. Potentiodynamic Polarization Curves for Galvanized Steel (Zinc) in

Deaerated pH 10 Sodium Hydroxide with 0.259 M [2,800 ppm] Boron at 60, 90, and

110 0C [140,194, and 230 OF] Obtained Using a Scan Rate of 0.167 mV/s. The Current

Density Values at Three Data Points, a, b and c, As Indicated in the Curves Were

Chosen for Calculating Corrosion Rates. The Dips and Recoveries in the Curves Could

Be Attributed to Temperature Fluctuations During Measurements.

A-12

.... ... . . ... ... .... ... ... ... ... .... .. ... ..... .... ... ... ... ...
-0.700

ow -0.710

>

4-

AS -0.720

0

I. -0.730

Carbon steel

Borated pH 7 solution

N2 deaerated, 60 °C __

Rp=2.14X103 Ohms.crn2

R2 of the best fit line = 0.977

. ... _

-0.740 , . . . . . . . . . . . . .

-8.OE-06 -4.OE-06 O.OE+00 4.0E-06 8.OE-06

Current density, A/cm2

0

C

0

0

-0.714

-0.724

-0.734

-0.744

-8.C

Carbon steel

Borated pH 7 solution

N2 deaerated, 90 IC

- RP = 2.90 X 103 Ohms.cm2

R2 of the best fit line = 0.933

/-*

. . I I . . . . I

IE-06 -4.OE-06 O.OE+00

Current density, Alcmr

4.OE-06

w0

Co

C

0

0

9.

-0.202

-0.212

Carbon steel

Borated pH 7 solution

N2 deaerated, 110 °C

RP = 1.27 X 104 Ohms.cm 2

R2 of the best fit line = 0.653/

-0.222 - '

-4.OE-06

m , . . . . . .

-2.OE-06 O.OE+00

Current density, A/cm2

Figure A-5. Polarization Resistance Determined from Potential Versus Current

Density for Carbon Steel in Deaerated pH 7 Trisodium Phosphate Solution with 0.259 M

[2,800 ppm] Boron at 60, 90, and 110 °C [140, 194, and 230 0

F] Obtained Using a Scan

Rate of 0.01 mV/s. Only Points within 5 mV of the Corrosion Potential Were Used to

Determine Polarization Resistance.

A-13
non u.o'J -

0.40 [ w 0.00

. -0.40

60

a. -0.80

-1.20

-1.60

1.OE-06

-Al deaerated at 60 TC

-Al aerated at 60 °C

1.40

1.00 -

u 0.60:

M 0.20

sa -0.20 -

-0.60

.4 1 II . . .1 . I . 1- I I - .1 -1 .00

1.OE-05 1.OE-04 1.OE-03 1.OE-02 1.0E-10

Current density, A/cm2

, ...... ..... . . . ...... ..... . . ....... ....... . . .....

1.OE-08 1.OE-06 1.OE-04 1.OE-02

Current density, A/cm2

1.20

0.80

> 0.40

0 .W

CL

I

-0.40-1.10

-0.80 -, ,"' l . , , , , , ...' - ....... ' I , -1.60 .. I I ---I , I I.

1.0E08 1.0E-07 1.0E-06 1.0E-05 1.0E 04 1.OE-03 1.OE-08 1.OE-07 1.OE-06 1.OE-05 1.0E-0

Current density, Afcm2 Current density, A/cm2

Figure A-6. Potentiodynamic Polarization Curves for Aluminum, Carbon Steel, Copper,

and Zinc in Aerated and Nitrogen Deaerated pH 10 Sodium Hydroxide Solution with

0.236 M [2,550 ppm] Boron at 60 °C [140 OF]

4

A-14

' I l, .....I... ... ...-.- - ...I.. .... ............. I -- - -- -- . - - - e u is -.
- A irmedance at 60 C - Alimpedanceat90 C - Alimnpedanceat110 C

-25

60

25

0 25 50 75 100 125

Z, Ohn..crr2

102 N 3

lo I 11l ,,,, 111,;,,f,7j,,j, jjl- j;j,,,, 10 gr1-2 lor' A1 101 10n 1a 104 1CP

Frequency (Hz)

'10 } a N'y

0

10 gggIgggI . ...... 10a 10-2 1orl 102 101 102 102 104 105

Frequency (Hz)

Figure A-7. Electrochemical Impedance Spectra Recorded from Potential Versus

Current Density for Aluminum in Deaerated pH 10 Sodium Hydroxide with 0.236 M

[2,550 ppm] Boron at 60, 90, and 110 'C [140, 194, and 230 *F]. The Spectra

Indicate That the Polarization Resistance Decreases with the Increasing

Temperature. Two Time Constants Equivalent Circuit Was Used to Fit

the Spectra.

A-15
- Carbon steel impedance at60 °C

- Carbon steel impedance at9O0 C

Carbon steel impedance at 110 0c

N

100000

0 100000 20000

Z', Ohms.crn2

300000 400000

103

N 104

i 1o2p

i0'3 10-2 10.1 1F qc e 101 ) 1(Hz 104 

Frequency (Hz)

100

-75:

-50

CM-25 -, co k 2 10-2 10.1 1lo o1, 102

Frequency (Hz)

103 104 103

Figure A-8. Electrochemical Impedance Spectra Recorded from Potential Versus

Current Density for Carbon Steel in Deaerated pH 10 Sodium Hydroxide with 0.236 M

[2,550 ppm] Boron at 60, 90, and 110 °C [140, 194, and 230 °F]. The Spectra Suggest

That Carbon Steel Retains High Passivity at 60 °C [140 OF].

A-16 .

:

-

. 

:

CJ t- -

_ 
Cu impedance at 60 'C ___u impedance at 90 'C

__Cu irpedance at 110 0

-100000 C

6

NF~

-5W0 I

I I

0 50000 100000

Z, hrms.cn9

150000

id'

~1o3

N 102

Frequency (Hz)

-75

E 0L 103 10 1i0° 101 102 10C 104 1C

Frequency (Hz)

Figure A-9. Electrochemical Impedance Spectra Recorded from Potential Versus

Current Density for Copper in Deaerated pH 10 Sodium Hydroxide with 0.236 M

[2,550 ppm] Boron at 60, 90, and 110 0

C [140,194, and 230 'F]. The Spectra Show a

Diffusion Process in the Low-Frequency Region.

A-17
- Zn impedance at 60 TC

- Zn impedance at 90 'C

-- Zn impedance at 110 'C

-20000

6

N

-10000

0

10000

0 10000 20000 30000

Z, Ohms.cm2

40000 50000

6- 102

N

10 L'

10-3 10-2 1cr' 10° 101 102

Frequency (Hz)

103 104 10i

Frequency (Hz)

Figure A-10. Electrochemical Impedance Spectra Recorded from Potential

Versus Current Density for Zinc in Deaerated pH 10 Sodium Hydroxide with

0.236 M [2,550 ppm] Boron at 60, 90, and 110 'C [140, 194, and 230 0

F]. The Data

in the Low-Frequency Region Are Noisy.

A-18

C I P

........ .................................

kk..

I.. -- .jjE .......... - .__ ............... -~. ....... ....-E .....-.................................. ............. __~ a- B ......... -
APPENDIX B
APPENDIX B

CORROSION RATE MEASUREMENTS FOR FIBER INSULATION GLASS

AND CONCRETE

The corrosion rates were determined in borated containment waters (pH 7 and 10) containing

0.259 M [2,800 ppm B] as H3BO3 addition at 60, 90, and 110 0C [140, 194, and 230 'F]. The

pH 7 borated solution was obtained by adjusting the solution pH using trisodium phosphate in

the form of Na3PO4*12H2O, whereas the pH 10 solution was adjusted by the addition of NaOH.

The corrosion rates for fiber insulation glass were measured in both pH 7 and 10 borated

containment waters. Only the pH 10 borated containment water was used for concrete

corrosion rate measurements.

B.1 Experimental Methods

Bulk glass samples, provided by Owens Corning' for producing Nukon' low-density fiber

insulation, were used in this study. These glass samples are referred hereafter as Nukonh

glass. The composition of the Nukone glass analyzed by inductively coupled plasma atomic

emission spectrometry, as listed in Table 2-6 of this report, is similar to the composition of the

low-density fiber insulation (Appendix C, Table 2-7) installed in a large number of containment

buildings. A concrete block, cast with a cement/sand/aggregate ratio of 1:1.7:2.6 (by weight)

and a water/cement ratio of 0.45:1 (by weight), was provided by the Electric Power Research

Institute. The cement is mainly composed of 52 percent 3CaO SiO2, 20 percent 2CaO-SiO2,

7 percent 3CaO-A120 3, and 11 percent 4CaO-Al 2O3 Fe2O3. The oxide composition of the cement

is provided in Table 2-4 of this report. Figure B-1 shows the as-received Nukon" glass and

concrete block samples.

The corrosion rates for Nukono glass and concrete were determined using the static leaching

method provided in ASTM Standard C-1220 (ASTM International, 2002). This method provides

determination of corrosion rates without the influence of feedback effects from corrosion

products. Static leaching tests for Nukon' glass and concrete were conducted in 60-ml [2.0 oz]

polytetrafluoroethylene vessels using monolithic specimens. The representative Nukon' glass

and concrete test specimens are displayed in Figure B-2. The test vessels were cleaned and

checked for pH and fluoride release to meet the requirements specified in the test method. In

all tests, a monolithic test specimen was placed in a 50-mL [1.7-oz] test solution with a

geometric surface area of the specimen-to-solution volume ratio of approximately 10.0 m'1. Test vessels were placed in ovens held at various temperatures and withdrawn at time intervals

of 1, 3, 5, 7, and 14 days. In addition, one blank control test that did not contain a test sample

in solution was carried out for 14 days for each solution-temperature combination. At the end

of each test period, the vessels were removed from the ovens and allowed to cool. A small

portion of the leachate was used to measure pH using a standard glass electrode and a

calibrated pH meter. The leachate was then filtered with a 0.45-pm [0.018-mill syringe filter for

cation analysis using inductively coupled plasma atomic emission spectrometry.

The aforementioned leaching tests for concrete indicate that the leachate attains saturation

within 1 day. Additional concrete leaching tests were conducted under low surface

area-to-volume ratio conditions. In these tests, a small specimen was placed in a 125-mL

[4.23-oz] test solution, resulting in a surface area of the specimen-to-solution volume ratio of

B-1
al

approximately 1.2 m-1. The tests were performed at 60, 90, and 110 OC [140, 194, and 230 OF]

for 1, 4, 8, and 24 hours.

For Nukon' glass release, the normalized elemental mass release, NR,, based on the leached

component i from the sample, was calculated using Eq. (B-1)

NRj (C- B,) xV B

F. xSA (B-i)

where

NRj - normalized elemental mass release, in units of g/m2

Cj - concentration of element i in solution, in units of g/m3

B, - concentration of element i in the blank solution, in units of gim3

F; - mass fraction of element i in the unleached specimen (dimensionless)

V - volume of solution in test vessel, in units of m3

SA - surface area of test specimen, in units of m2

The leaching rates were determined from the slopes of the normalized elemental mass release

versus time plots.

In practice, normalization of elemental mass release using the mass fraction factor is not

applicable for heterogeneous materials with different release rates for various components,

such as concrete. The elemental mass release from concrete was calculated from the leaching

solution concentration divided by the surface area-to-volume ratio. The leaching rates for

various elements for concrete were determined from the slopes of the elemental mass release

versus time curves.

B.2 Leaching Results

B.2.1 Nukon5 Glass

The normalized release from Nukon® glass as a function of time at temperatures of 60, 90, and

110 'C [140, 194, and 230 OF], based on the matrix dissolution of silicon, is shown in Figure B-3

for the tests in borated containment water at pH 7 and in Figure B-4 for the pH 10 borated

containment water. As evident in Figures B-3 and B-4, the silicon release from the Nukong

glass increases with increasing time, but it deviates from a linear trend for longer times. This

nonlinear behavior was observed for the 110 0

C [230 OF] tests in the pH 7 borated containment

water and also for all tests in the pH borated containment water as a result of the extended

diffusion path. The slope of the best-fit line between normalized release and time provides the

leaching rate. Linear fit was obtained by using the linear portion of the curve as shown in

Figures B-3 and B4. The calculated leaching rates are given in Table B-1. It is apparent that

leaching rate increases with increasing temperature in both solutions. Solution pH also has a

strong influence on the leaching of Nukon5 glass. At 110 OC [230 OF], a factor of 2.2 increase in

leaching rate was measured in the borated containment water at pH 10, compared to the

borated containment water at pH 7. This factor increases to 4.8 at a temperature of 60 0C

[140 OF]. High leaching of Nukon' glass at alkaline pH is attributed to dissolution of the glass

network. Because glass leaching is a thermally activated process, activation energy can be

regressed from the experimental data by plotting in leaching rate versus 1/T as shown in

B-2
Table B-1. Measured Corrosion Rate for Nukon' Glass

Borated Containment Water Borated Containment Water

at pH 7 at pH 10

Temperature (gIm 2-h) [millyr] (gIm2-h) [millyr]

60 CC [140 0F] 1.09 x 10-2 [1.50] 4.86 x 10-2 [6.71]

90 0C [194 0F] 7.56 x 10-2 [10.4] 2.32 x 10-1 [32.0]

110 0C [230 OF] 1.43 x 10-' [19.7] 4.53 x 10-' [62.6]

Figures B-3 and B-4. The activation energy values for Nukonh glass in the borated

containment waters at pH 7 and 10 are 76.4 and 55.8 kJ/mol [18.2 and 13.3 kcal/mol],

respectively. These values are consistent with the reported activation energies for dissolution of

different glasses at various pH levels in the range of 54-84 kJ/mol [13-20 kcallmol] (Perera, et

al., 1991; Perera and Doremus, 1991).

The leached Nukon' glass samples were characterized to determine their morphology and

chemical composition using optical microscopy and energy-dispersive x-ray spectroscopy.

Figure B-5 shows changes in the surface conditions of the Nukone glass after leaching for

1 day and 7 days in the pH 10 borated containment water. It is noted in Figure B-5 that while

numerous small pits were observed on the glass surface immersed for one day, enhanced

dissolution occurred in the sample tested for 7 days. This progressive leaching process is in

agreement with the measured leaching solution concentrations. The chemical composition

analysis from the near-surface regions of the corresponding glass conditions indicates the glass

surface composition remained essentially unchanged after leaching in the borated containment

water at pH 10. This result suggests that the extent of the leached glass surface is limited. In

addition, as shown in Figure B-6, a white deposit rich in calcium and phosphorous was

observed on the glass sample after leaching in the pH 7 borated containment water containing

trisodium phosphate. The presence of the surface deposit which decreases the exposed

surface area, may result in reduction in glass release. The significance of the deposit needs

further evaluation.

To correlate the leaching behavior between bulk glass and fiber, the surfaces of the NukonO

fiberglass insulation, before and after leaching in the pH 10 borated containment water for

7 days, were examined by scanning electron microscopy. As shown in Figure B-7, although the

surface of the starting fiberglass was smooth and clean, the leaching process caused severe

damage to the fiberglass. Even though different modes of chemical attack as a result of

leaching were observed, the leaching rates for the bulk Nukono glass and the Nukonh lowdensity fiber insulation are expected to be similar because both materials have almost the

identical composition (see Figure B-8), and glass composition is the primary determinant of

glass dissolution.

B.2.2 Concrete

Figure B-9 shows the elemental release for aluminum, calcium, and silicon as a function of time

for the concrete sample in the pH 10 borated containment water at various temperatures. As

shown in Figure B-9, dissolution of calcium ions from the cement component was found to

B-3
[l

predominate in concrete release for all temperatures. Many experiments have shown

preferential leaching of calcium in the dissolution of cements as discussed by Harris, et al.

(2002). The leaching results are consistent with the observed change in surface condition of

the leached concrete sample, as displayed in Figure B-10. The concrete surface before

leaching is shown in Figure B-1. The leaching rates from linear fits between elemental release

and time for various elements and temperatures are provided in Table B-2. As temperature

increases, the leaching rate for each element was observed to increase. It is apparent that

corrosion of the concrete is dominated by the release of calcium. An activation energy of

22.6 kJ/mol [5.4 kcal/moll can be obtained for the concrete material in the borated containment

water at pH 10.

Table B-2. Measured Corrosion Rate for Various Elements for Concrete

in Borated Containment Water at pH 10

60 0C [140 0F] 90 0C [194 0F] 110 C [230 0F]

Element (glm 2-h) (glm 2 h) (glm2 -h)

Aluminum 2.95 x 10-2 5.93 x 10-2 8.94 x 10-2

Calcium 7.29 x 10-' 1.18 2.20

Silicon 3.79 x 10-2 1.12 x 10-' 1.54x 10-'

B.3 References

ASTM International. 'Nuclear, Solar, and Geothermal Energy." ASTM C1220-98: Standard

Test Method for Static Leaching of Monolithic Waste Forms for the Disposal of Radioactive

Waste. Volume 12.01: Nuclear Energy (I). Published on CD ROM. West Conshohocken,

Pennsylvania: ASTM International. 2002.

Harris, A.W., M.C. Manning, W.M. Tearle, and C.J. Tweed. "Testing of Models of the

Dissolution of Cements-Leaching of Synthetic CSH Gels." Cement and Concrete Research.

Vol. 32. pp. 731-746. 2002.

Perera, G. and R.H. Doremus. "Dissolution Rates of Commercial Soda-Lime and Pyrex

Borosilicate Glasses: Influence of Solution pH." Journal of American Ceramic Society. Vol. 74.

pp. 1,554-1,558. 1991.

Perera, G., R.H. Doremus, and W. Lanford. 'Dissolution Rates of Silicate Glasses in Water at

pH 7." Journal of American Ceramic Society. Vol. 74. pp. 1,269-1,274. 1991.

B-4
_;___ k

N

Figure B-1. Photograph Showing the As-Received

Concrete Block (Left) and NukonO Glass (Right)

Samples. Scale in Inches.

Figure B-2. Photograph Showing the Representative

Nukone Glass (Right) and Concrete (Left)

Test Samples. Scale In Inches.

B-5
16

14 -

,;- 12 -

-s 10 -

0

' 8- 01

i 6-

34

2-

0

4,

Al

A11 0 A N

* . I

E

.- -2

I

-4-

y=-6701.9x+ 15.68

I

-5 -

0.0025

1. , . . - . .

0 20 40 60 80 100 120

Time (h)

0.0026 0.0027 0.0028 0.0029 0.003 0.0031

I/Temperatur (19

Figure B-3. Nukone Glass Release Based on the Normalized Release for Silicon Versus

Time (Left) and Linear Regression of Normalized Release Rate Versus Temperature (Right) in Borated Containment Water at pH 7

50

E

'a

01

:1

= -1 .

E

.° -2

. -3

i 4 'U1 -

Y=-5762.3x+14.317

0 20 40 60

Time (h)

80 100 120 0.0525 0.0026 0.0027 0.0028 0.0029 Q0030 0.0031

lITemperalure (19

Figure B-4. Nukono Glass Release Based on the Normalized Release for Silicon Versus

Time (Left) and Linear Regression of Normalized Release Rate Versus Temperature (Right) in Borated Containment Water at pH 10

B-6

C1l- U-
Figure B-5. Optical Microscopic Photographs Showing Changes in the Surface

Conditions of the Nukon' Glass After Leaching in Borated Containment Water at pH 10 at

110 'C [230 'F] for I Day (Left) and 7 Days (Right)

_ WW dhlp

A0 -r _

Figure B-6. Optical Microscopic Photograph Showing Surface Deposit on the NukonO

Glass After Leaching in the pH 7 Borated Containment Water Containing Trisodium

Phosphate at 110 0C [230 'F] (Left) and the Energy-Dispersive X-Ray Spectrum on the

Deposit (Right)

B-7

U
Figure B-7. Scanning Electron Micrographs of Nukon' Fiberglass Before Leaching (Left)

and After Leaching in the pH 10 Borated Containment Water at 110 0C [230 OF] for

7 Days (Right)

jc td*Alsmp 

U-.

hOo.dd fdibe

0 ...

_-0

e. I - -w

Figure B-8. Energy-Dispersive X-Ray Spectra on the Pristine Nukon' Glass (Left) and

Fiberglass (Right)

B-8
10

,E8

a

S06

01

20

a4

a 12 .2

M

0

I 1 6

.4

0

0 4 8 12

Time (h)

16 20 24

0 4 8 12

Time (h)

16 20 24

24

A4- 20

0 16

& 12 w

ec 8 aE

w 4

0

0 4 8 12

Time (h)

16 20 24

Figure B-9. Concrete Release Based on the Elemental Release Versus Time in the pH 10

Borated Containment Water at 60 *C [140 'F] (Top), 90 'C [194 'F] (Middle), and 110 'C

[230 OF] (Bottom)

B-9

CUZo

U-
VZ4.

Figure B-10. Optical Microscopic Photograph Showing Change in the Surface Condition

of the Concrete Sample After Leaching in the pH 10 Borated Containment Water at 110 lC

[230 OF] for 24 Hours

B-1 0

C-Z'
APPENDIX C
Appendix C includes a report that provides a summary of plausible reaction products in coolant

waters after a post LOCA event. Thermodynamic simulations were used to identify critical

variables from a large number of components present during and subsequent to a LOCA event

in the containment system. In this study, chemical speciation of plausible reaction products in

sump water after a post LOCA event was modeled to (i) determine the need for a pressurized

test loop and (ii) assess whether gelatinous products could form in the typical

time-temperature-pressure-chemistry-pH regime following a LOCA event. The corrosion rates

were based on conservative values between pH 7 and pH 10 in borated water, selected from

the values published in the literature. The study provided input to parameters for the

development and operation of a circulating water test loop at the University of New Mexico to

study experimentally the chemical reactions from metal and insulation corrosion and to examine

the formation of precipitation products including gelatinous products. This report was prepared

to document work performed by the Center for Nuclear Waste Regulatory Analyses (CNWRA)

for the U.S. Nuclear Regulatory Commission (NRC) under Contract No. NRC-DR-04-04-070.

C-1
CWNRA 2004-07

Revision I

CHEMICAL SPECIATION, USING THERMODYNAMIC

MODELING, DURING A REPRESENTATIVE

LOSS-OF-COOLANT ACCIDENT EVENT

Prepared for

U.S. Nuclear

Contract

Regulatory Commission

NRC-DR-04-04-070

Center for Nuclear Waste Regulatory Analyses

San Antonio, Texas
CWNRA 2004-07

Revision 1

CHEMICAL SPECIATION, USING THERMODYNAMIC

MODELING, DURING A REPRESENTATIVE

LOSS-OF COOLANT ACCIDENT EVENT

Prepared for

U.S. Nuclear Regulatory Commission

Contract NRC-DR-04-04-070

Prepared by

V. Jain

L. Yang

K. Chiang

Center for Nuclear Waste Regulatory Analyses

San Antonio, Texas

July 2004
CONTENTS

Section Page

FIGURES . ......................................................... v

TABLES . ......................................................... vii

ACKNOWLEDGMENTS ....................................................... ix

EXECUTIVE SUMMARY ...................................................... xi

1 INTRODUCTION ........................................................ 1-1

2 CORROSION OF DEBRIS COMPONENTS ......... .......................... 2-1

2.1 Zinc ......... I.I.III.IIII.IIIII.IIIIIIIII.III..I.I......... 2-1

2.2 Aluminum ......................................................... 2-3

2.3 Carbon Steel ....................................................... 2-5

2.4 Copper ......................................................... 2-6

2.5 Concrete ....................................................... 2-7

2.6 Fiber Insulation ...................................................... 2-8

3 FORMATION OF SOLID PHASES DUE TO CORROSION OF COMPONENTS IN ALKALINE

CONTAINMENT WATER .................................................. 3-1

3.1 Sensitivity Analyses .................................................. 3-7

3.1.1 Behavior of Zinc Metal in the Simulated Containment Water ..... ........ 3-7

3.1.2 Behavior of Aluminum Metal in Simulated Containment Water .... ....... 3-9

3.1.3 Behavior of Carbon Steel in Simulated Containment Water ..... ........ 3-10

3.1.4 Behavior of Concrete in Simulated Containment Water ..... ........... 3-10

3.1.5 Behavior of Fiber Insulation in Simulated Containment Water .... ....... 3-13

4 FORMATION OF SOLID PHASES DUE TO CORROSION OF COMPONENTS IN Na3PO4

CONTAINMENT WATER .................................................. 4-1

4.1 Sensitivity Analyses ............................... ................ 4-4

4.1.1 Behavior of Zinc Metal in the Simulated Containment Water ..... ........ 4-5

4.1.2 Behavior of Aluminum Metal in Simulated Containment Water .... ....... 4-5

4.1.3 Behavior of Carbon Steel in Simulated Containment Water ..... ......... 4-8

4.1.4 Behavior of Concrete in Simulated Containment Water ..... ............ 4-8

4.1.5 Behavior of Fiber Insulation in Simulated Containment Water .... ....... 4-10

5 EVALUATION OF A NEED TO CONDUCT EXPERIMENTS AT HIGH TEMPERATURE AND

PRESSURE SYSTEM .................................................... 5-1

5.1 Need to Conduct Experiments at High Temperature and Pressure

System in an Alkaline Simulated Containment Water ...... .................. 5-1

5.2 Need to Conduct Experimental Analysis in a High-Temperature

High-Pressure System in Simulated Containment Water Containing

Trisodium Phosphate .................................................. 5-3

iii
CONTENTS (continued)

Section Page

6 EVALUATION OF POTENTIAL FOR GEL FORMATION ...... .................... 6-1

7 SUMMARY AND CONCLUSIONS ............ ............................... 7-1

7.1 Conclusions ........................................................ 7-2

8 FUTURE WORK ......................................................... 8-1

9 REFERENCES ......................................................... 9-1

APPENDIX A SOFTWARE VALIDATION AND SIMULATION METHODS .... ....... A-1

APPENDIX B TYPICAL OLI SIMULATION OUTPUT ........................... B-1

iv
FIGURES

Figure Page

2-1 Surface Area Versus Diameter for Various Graphite Powders and

Tokamak Dusts .................................................. 2-9

3-1 Concentration, in mol/L, of Dominant Solid Phases As a Function of Temperature

and Pressure in 0.26 M [2,800 ppm] Boron in an Alkaline Simulated Containment

Water at pH 10 ......... 3-3

3-2 Concentration, in mol/L, of Dominant Solid Phases at 150 0C [302OF],

507 kPa [5 atm] for 0.5 Hour at 60 OC [140 OF] for 15 Days in [2,800 ppm] Boron

Alkaline Simulated Containment Water at pH 10 ............................ 3-5

3-3 Dominant Solid Phases at 60 OC [140 OF], 101 kPa [1 atm] As a

Function of pH ........ 3-6

3-4 Dominant Solid Phases at 130 0C [266 OF], 304 kPa [3 atm] As a

Function of pH ........ 3-6

3-5 Dominant Solid Phases at 60°C [140 OF], 101 kPa [1 atm] As a Function of Zinc

in Simulated Containment Water at pH 10 ............................. 3-8

3-6 Dominant Solid Phases at 130 0C [266 F

0 , 101 kPa [1 atm] As a Function of Zinc

in Simulated Containment Water at pH 10 ............................. 3-8

3-7 Dominant Solid Phases at 60 °C 1140 °F], 101 kPa [1 atm] As a Function of

Aluminum Metal in Simulated Containment Water at pH 10 ...... ............. 3-11

3-8 Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As a Function of

Aluminum Metal in Simulated Containment Water at pH 10 ...... ............. 3-11

3-9 Dominant Solid Phases at 60 °C [140 OF], 101 kPa [1 atm] As a Function of

Iron in Simulated Containment Water at pH 10 ............................ 3-12

3-10 Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As a Function of

Iron in Simulated Containment Water at pH 10 ............................ 3-12

3-11 Dominant Solid Phases at 60°C [140 OF], 101 kPa [1 atm] As a Function of

Ca2SiO4 in Simulated Containment Water at pH 10 ........... .............. 3-14

3-12 Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As a Function of

Ca2SiO4 in Simulated Containment Water at pH 10 .......... ............... 3-14

3-13 Dominant Solid Phases at 60 °C [140 OF], 101 kPa [1 atm] at Different Fiber

Insulation Concentrations in Simulated Containment Water at pH 10 ..... ...... 3-15

3-14 Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] at Different Fiber

Insulation Concentrations in Simulated Containment Water at pH 10 ..... ...... 3-15

4-1 Concentration, in mol/L, of Dominant Solid Phases As a Function of Temperature

and Pressure in 0.26 M [2,800 ppm] Boron in Na3PO4 Simulated Containment

Water at pH 7 ........ 4-2

4-2 Concentration, in mol/L, of Dominant Solid Phases at 150 °C [302 °F], 507 kPa

[5 atm] for 0.5 Hour at 60 °C [140 °F3 for 15 Days in a 0.26 M [2,800 ppm] Boron,

Na3PO4 Simulated Containment Water at pH 7 ............................. 4-4

4-3 Dominant Solid Phases at 60 °C [140 °F], 101 kPa [1 atm] As a Function of

Zinc in Simulated Containment Water at pH 7 .............................. 4-6

4-4 Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As a Function of

Zinc in Simulated Containment Water at pH 7 .............................. 4-6

v
LII

FIGURES (continued)

Figure Page

4-5 Dominant Solid Phases at 60 0C [140 OF], 101 kPa [1 atm] As a Function of

Aluminum in Simulated Containment Water at pH 7 ....... .................. 4-7

4-6 Dominant Solid Phases at 130 OC [266 OF], 304 kPa [3 atm] As a Function of

Aluminum Concentration in Simulated Containment Water at pH 7 ..... ......... 4-7

4-7 Dominant Solid Phases at 60 0C [140 0F], 101 kPa [1 atm] As a Function of

Iron Concentration in Simulated Containment Water at pH 7 ...... ............ 4-9

4-8 Dominant Solid Phases at 130 0C [266 OF], 304 kPa [3 atm] As a Function of

Iron Concentration in Simulated Containment Water at pH 7 ...... ............. 4-9

4-9 Dominant Solid Phases at 60 0C [140 OF], 101 kPa [1 atm] As a Function of

Ca2SiO4 in Simulated Containment Water at pH 7 ............. ............. 4-11

4-10 Dominant Solid Phases at 130 0C [266 OF], 304 kPa [3 atm] As a Function of

Ca2SiO4 in Simulated Containment Water at pH 7 ............. ............. 4-11

4-11 Dominant Solid Phases at 60 °C [140 OF], 101 kPa [1 atm] at Different Fiber

Insulation Concentrations in Simulated Containment Water Containing Na3PO4 ... 4-12

4-12 Dominant Solid Phases at 130 °C [266 OF], 101 kPa [1 atm] at Different Fiber

Insulation Concentrations in Simulated Containment Water Containing Na3PO4 ... 4-13

6-1 Silicon and Aluminum Tetrahedra Units .6-2

6-2 A Basic Alkali Aluminosilicate Structural Unit .6-2

6-3 A Polymeric Poly(Sialate-Siloxo) Unit .6-2

6-4 A Polymeric Poly(Sialate-Disiloxo) Unit .6-2

vi
TABLES

Table Page

1-1 Sources of Debris on the Sump Screen and Strainers ........................ 1-2

1-2 Solids from Bottom Containment Water ................................... 1-3

2-1 Summary of Corrosion Rate Data for Zinc and Galvanized Zinc ..... ........... 2-2

2-2 Estimation of Zinc in Simulated Containment Water ......................... 2-3

2-3 Summary of Corrosion Rate Data for Aluminum ............................ 2-4

2-4 Estimation of Aluminum in Simulated Containment Water ..... ................ 2-5

2-5 Summary of Corrosion Rate Data for Carbon Steel .......................... 2-6

2-6 Estimation of Carbon Steel in Simulated Containment Water ..... ............. 2-7

2-7 Summary of Corrosion Rate Data for Copper ............................... 2-7

2-8 Estimation of Copper in Simulated Containment Water ....................... 2-8

2-9 Estimation of Concrete (Non-Particulate) in Simulated

Containment Water . .................................................. 2-9

2-10 Estimation of Concrete (Particulate) in Simulated Containment Water .... ...... 2-10

2-11 Chemical Composition of Nukono Fiber Insulation .......................... 2-10

2-12 Estimation of Fiber Insulation in Simulated Containment Water ..... ........... 2-11

2-13 Estimation of Fiber Glass in the Nukono Insulation in Simulated

Containment Water . .................................................. 2-11

3-1 Input Values Per Liter of Solution for Simulations ........................... 3-1

3-2 pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water ..... ....... 3-2

3-3 Percent Element Distribution in Solid Phases at pH 10 ....................... 3-3

3-4 Percent Solid Phases at pH 10 ........... ............................... 3-4

4-1 pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water .... ........ 4-1

4-2 Percent Element Distribution in Solid Phase at pH 7 ......................... 4-2

4-3 Percent Solid Phases at pH 7 ............ ............................... 4-3

7-1 Comparison of Constituents in pH = 7 and pH = 10 Containment Solutions .... ... 7-5

vii
ACKNOWLEDGMENTS

This report was prepared to document work performed by the Center for Nuclear Waste

Regulatory Analyses (CNWRA) for the U.S. Nuclear Regulatory Commission (NRC) under

Contract No. NRC-DR-04-04-070. The activities reported here were performed on behalf of the

NRC Office of Nuclear Regulatory Research, Division of Engineering Technology. This report is

an independent product of CNWRA and does not necessarily reflect the views or regulatory

position of NRC.

The authors gratefully acknowledge the technical reviews of Y.-M. Pan and D. Dunn, editorial

reviews by P. Mackin and J. Pryor, and the programmatic review of B. Sagar. Appreciation is

due J. Gonzalez for assistance in preparing this report.

QUALITY OF DATA: Sources of data are referenced in each chapter. CNWRA-generated

data contained in this report meet quality assurance requirements described in the CNWRA

Quality Assurance Manual. Data from other sources, however, are freely used. The respective

sources of non-CNWRA data should be consulted for determining levels of quality assurance.

Experimental data have been recorded in CNWRA scientific notebook number 642.

ANALYSES AND CODES: StreamAnalyzer Version 1.2@ (2002a) and Environmental

Simulation Program (ESP) Version 6.60 (OLI Systems, Inc., 2002b) were used for the

thermodynamic simulations. These codes are controlled according to the requirements of

CNWRA Technical Operating Procedure (CNWRA, 2003). Detailed calculations can be found in

scientific notebook numbers 652E and 572.

References

CNWRA. "Development and Control of Scientific and Engineering Software." Technical

Operating Procedure-TOP-018. Rev. 8, Change 2. San Antonio, Texas: CNWRA. 2003.

OLI Systems, Inc. "StreamAnalyzer Version 1.2." Morris Plains, New Jersey: OLI Systems,

Inc. 2002a.

. Environmental Simulation Program Version 6.6." Morris Plains, New Jersey: OLI

Systems, Inc. 2002b.

ix
EXECUTIVE SUMMARY

A loss-of-coolant accident (LOCA) event results in rapid changes in the time-temperaturepressure-chemistry-pH conditions in the containment environment of nuclear reactors. Changes

in the coolant chemistry are further complicated because of the interactions of the materials

present inside the containment. These complex interactions require a large number of

experiments to obtain sufficient data to analyze the potential impact on a sump screen blockage

caused by chemical precipitation. Thermodynamic simulations, using thermodynamic

simulation software allow the identification of critical variables and their ranges from a large

number of constituents present, during, and following a LOCA event in the containment system.

This study modeled chemical speciation of plausible reaction products in containment water

after a representative LOCA event to (i) determine the need for a pressurized test loop,

(ii) assess whether gelatinous products could form in the typical time-temperature-pressurechemistry-pH regime following a LOCA event, and (iii) validate OLI Systems, Inc. software

(OLI Systems, Inc., 2002a,b) for speciation in borated waters.

Computational thermodynamics simulation calculations were conducted using Environmental

Simulation Program (ESP) Version 6.6' (OLI Systems, Inc., 2002a) and StreamAnalyzer

Version 1.20(OLI Systems, Inc., 2002b).

Key components in chemical speciation simulation were copper, carbon steel, zinc, aluminum,

fiber insulation, and concrete in 0.26 M [2,800 ppm] boron solution. The surface areas exposed

during a LOCA event for these components were provided by the U.S. Nuclear Regulatory

Commission, and corrosion rates for these components from literature data were used to

estimate amounts of corrosion.

The influence of pressure, temperature, and pH on chemical speciation was studied by

speciating a fixed amount of each component based on its corrosion rate. These amounts were

speciated at 150 0C [302 OF] at 507 kPa [5 atm], 130 'C [266 0F] at 304 kPa [3 atm], and 90 'C

[194 'F1 and 60 'C [140 0F] at 101 kPa [1 atm]. The formation of solid phases as a function of

temperature and pressure was examined at pH 10 and 7. A pH of 10 was obtained by the

addition of 0.23 mol/L sodium hydroxide [5,300 ppm sodium], and a pH of 7 was obtained by the

addition of 8.4 x 10-3 mol/L Na3PO4 [630 ppm sodium]. The corrosion rate was selected based

on conservative values obtained between pH 7 and 10 in borated water. The temperaturedependent data were not available in most cases. Therefore, the sensitivity analysis was

conducted over a wide range of amounts of each component to evaluate the effect of

temperature on speciation. Furthermore, uncertainties exist in the estimation of the surface

area for concrete particulates. The NRC Test Plan, Revision 12b (NRC, 2005), provides the

amount of concrete particulates per unit volume but the information on the size and size

distribution is not available to estimate exposed surface area. While relevant data could

improve prediction of solid phases, the simulations presented in this study demonstrate the

potential of solid phase corrosion products covering a wide range of components present in a

containment system.

In alkaline solutions silicates are major corrosion products. A strong influence of pH and

temperature was observed in the formation of the dominant solid phases in the simulated

containment water. A review of the simulation data and the associated sensitivity analysis in

alkaline simulated containment water at pH 10 indicates NaAISi308, Ca3Fe2Si3O,2, and

Fe3Si205(OH)4 are dominant solid phases that contribute to more than 90 percent of the solid

xi
M~

phases formed between 150 'C [302 'FJ, 507 kPa [5 atm], and 60 0C [140 *F], 101 kPa [1 atm].

Despite iron phase changes, most of the iron remained a solid. Based on the simulations, it can

be inferred that minimal changes in the solid phase formation are expected as high temperature

and pressure conditions during the initial stages of a LOCA event approach

steady-state conditions. Therefore, testing under high temperature and pressure conditions is

not necessary.

A review of the simulation data and the associated sensitivity analyses in Na3PO4 simulated

containment water at pH 7 indicates significant differences in the solid phase formation in

Na3PO4 simulated containment water at pH 10. At pH 7, Ca5(OH)(PO4)3 was the dominant solid

phase, containing approximately 100 percent of calcium; while at pH 10, calcium was

approximately 1 percent insoluble at 60 0C (140 'F). Irrespective of temperature and pressure,

more than 90 percent of the solids precipitated as Ca,(OH)(PO4)3 and NaAISi308. Both iron and

zinc showed a decrease in solid phase concentration with a decrease in temperature and

pressure. The contribution of zinc was below 2 percent and iron below 9 percent compared to

the total solid phases. Based on these simulations, it can be inferred that minimal changes in

solid phase formation are expected as high temperature and pressure conditions during the

initial stages of a LOCA event approach steady-state conditions.

A review of the literature about geopolymers and glass indicates that, in alkaline solutions,

aluminosilicate unit can react with an alkali silicate unit to form polysialate (-Si-O-AI-O-),

poly(sialate-siloxo) (-Si-O-AI-O-Si-O-), or poly(sialate-disiloxo) (-O-Si-O-AI-O-Si-O-Si-O-)

polymers. These polysialates condense as gels similar to organic polymers at temperatures

below 100 0C [212 'F]. Gel formation, a precursor to polymerization, occurs in an alkaline

solution when silicon, aluminum, and alkali ions are present. Gelling, however, requires an

alkaline pH. Therefore, gel is likely to form in alkaline simulated containment water.

OLI Systems, Inc. software was validated by comparing simulation results with data on borated

water published in the literature and with results of solubility type experiments using borated

water containing CaCO3 or ZnCO3 in the temperature range of 25°C [770F] to 1300C [266°F].

Data showed a good agreement between published literature and OLI Systems, Inc. simulation.

Except for ZnCO3 at 130°C [266°F], the experimentally measured solubility data agreed with the

OLI Systems, Inc. simulation results for the dominant solid or soluble phases, including aqueous

H3603, aqueous NaOH, and solid CaCO 3 or solid ZnCO3. A large variation was observed for

soluble phases of zinc and calcium and was attributed to the variation and uncertainty in

published data used in OLI Systems, Inc. software database.

Suggestions for future work include deriving a better understanding of corrosion rates.

REFERENCES

NRC. "Test Plan: Characterization of Chemical and Corrosion Effects Potentially Occurring

During a Pressurized Water Reactor LOCA." Rev. 12b. ML050450478. Washington, DC:

NRC. 2004.

OLI Systems, Inc. "Environmental Simulation Program Version 6.6." Morris Plains, New

Jersey: OLI Systems, Inc. 2002a.

"StreamAnalyzer Version 1.2." Morris Plains, New Jersey: OLI Systems, Inc. 2002b.

xii
I INTRODUCTION

On March 29, 1979, the activation of the emergency core cooling system (ECCS) at the

Three-Mile Island nuclear reactor resulting from the pressure-operated relief valve being stuck

in the open position led to a release of 2,158 m3 [570,000 gal] of water, including 712 m3

[188,000 gal], of Susquehanna River water, into the reactor building basement. One-hundred

fifty-three days after this loss-of-coolant-accident event (LOCA), a green gelatinous precipitate

material was observed on the floors and walls of the containment building. The July 28, 1992,

LOCA at Barseback-2 nuclear power plant led to ECCS failure due to plugging of the sump

pump. Consequently, the U.S. Nuclear Regulatory Commission (NRC) examined the strainer

performance of U.S. boiling water reactors. The NRC required boiling water reactor licensees to

install suction strainers with larger surface areas and, for pressurized water reactors, NRC

issued Generic Safety Issue (GSI)-191, Assessment of Debris Accumulation on Pressurized

Water Reactor Sump Performance.

During a potential LOCA event within the containment of a light-water reactor, materials in the

vicinity of a pipe break could dislodge, react chemically, and be transported to the containment

floor. Typical materials in these areas include fiber insulation, concrete, paints, galvanized

steel, scaffolding, and insulation jackets. Some of this debris could eventually accumulate on

the recirculation-sump screens or strainers and challenge the ECCS and containment spray

system pumps. Table 1-1 shows the sources of various debris material and associated

corrosion products.

Using laboratory tests, Johns, et al. (2003) studied the conditions that could lead to formation of

a gelatinous material similar to that observed on the Three Mile Island nuclear reactor floor and

walls. This study, however, did not examine elements such as copper, nickel, magnesium,

sulfur, and chromium that were found in the gelatinous phase. Table 1-2 shows the

composition of the solids found at the bottom of the containment building at the Three-Mile

Island nuclear reactor. The high copper content is speculated to originate from the river water.

Copper concentration in the Susquehanna River water, however, is three to five orders of

magnitude lower than the concentration found in the containment system. Uncertainties

associated with the corrosion rates of materials shown in Table 1-1 and the composition of

solids found in the containment building shown in Table 1-2 make it difficult to define the origin

of the gelatinous material.

The primary objective of this project is to thermodynamically model the chemical speciation of

plausible reaction products in coolant waters after a representative LOCA event to (i) determine

if an experimental pressurized loop test is needed to evaluate precipitation behavior during

initial LOCA conditions (Chapter 5); (ii) assess whether gelatinous products could form in the

typical time-temperature-pressure-chemistry-pH regime following a LOCA event (Chapter 6);

and (iii) validate OLI Systems, Inc. software (OLI Systems, Inc, 2002a,b) for speciation in

borated waters (Appendix A). The formation of gelatinous material is inferred from the solids

observed in the thermodynamic calculations.

This study also provides input to parameters for the development and operation of a circulating

water test loop. The test loop is being constructed at the University of New Mexico to study

experimentally chemical reactions from metal corrosion and insulation leaching, and examine

the formation of precipitation products including gelatinous products.

1-1
I'll'

Table 1-1. Sources of Debris on the Sump Screen and Strainers

Sources Corrosion/Erosion Products

Scaffold/insulation jackets Aluminum, zinc

Insulation fibers Silicon, aluminum, calcium,

magnesium, boron, alkalis

Steel Iron, nickel, sulfur

Galvanized steel Zinc, iron

Concrete Calcium, silicon

Cooling water Boron, lithium

River water Organics

pH adjusters Trisodium phosphate, hydrochloric

acid, sodium hydroxide

Heat exchangers, fan coolers, Copper

instrument-air lines

1-2
Table 1-2. Solids from Bottom Containment WaterThree Mile Island

(Parts Per Million on Total Volume of Bottom Sample)*

Silver 8.0

Aluminum 8.0

Boron 3.0

Calcium 2.0

Cadmium < 0.5

Cobalt < 0.1

Chromium 2.0

Cesium < 0.5

Copper:. : - .:. -**i . -.54.0 . -:

Iron 10.0

Iodine 0.7

Indium 0.3

Potassium 1.0

Lithium < 0.3

Magnesium 7.0

Manganese 1.0

Molybdenum <1.0

Sodium < 1.0

Nickel 10.0

Phosphorus 0.4

Rubidium < 0.3

Sulfur 5.0

Strontium < 0.2

Tellurium < 0.2

Titanium 0.5

Zinc 2.0

Uranium 0.106

Plutonium 0.00016

*NRC RFP No. RS-RES-04-070

1-3
2 CORROSION OF DEBRIS COMPONENTS

Table 1-1 lists source of various debris material and associated corrosion products. In this

section, corrosion rates and their expected corrosion product accumulations are estimated

based on the surface area exposed as defined in the NRC Test Plan, Revision 12b:

Characterization of Chemical and Corrosion Effects Potentially Occurring During a Pressurized

Water Reactor LOCA (NRC, 2005).

2.1 Zinc

In a containment building, zinc is present in galvanized steel and zinc based protective coatings.

Zinc coatings are top coated with a design basis accident qualified epoxy or a modified

phenolic-epoxy. These top-coated zinc paints do not readily participate in chemical reactions.

However, a small fraction of noncoated zinc paints could release zinc into solution.

Griess and Bacarella (1969), Niyogi, et al. (1982), Piippo, et al. (1997), and Johns, et al. (2003)

have examined the corrosion rate of zinc. Griess and Bacarella (1969) measured corrosion rate

of galvanized steel and zinc metal in 0.28 M [3,000 ppm] boron with 0.15 M sodium hydroxide

[3,450 ppm sodium] solution between 55 and 140 'C [131 and 284 OF]. Both galvanized steel

and zinc metal showed negligible corrosion. Some samples showed a slight weight gain with

many small blisters of zinc oxide. Griess and Bacarella (1969) concluded, based on these

observations, that corrosion damage to a galvanized surface is insignificant.

Piippo, et al. (1997) examined zinc corrosion from 50 to 170 'C [122 and 388 OF] in

environments ranging from reducing (nitrogen) to oxidizing (air), and in borated (pH 9.2)

solutions. The highest corrosion rate for zinc was 11.27 g/m2-h [545 mil/yr] at 170 0C [338 OF].

At 90 0C [194 OF], zinc corrosion rate varied from 0.04 gIm2-h [1.9 mil/yr] in borated solution at a

pH of 9.2 to 0.163 g/m2-h [7.9 millyr] in aerated solution at pH 8. A higher than one order of

magnitude increase in zinc corrosion rate was observed in borated solution when the

temperature was increased from 90 to lC 110 [194 to 230 F]. Niyogi, et al. (1982) estimated a

zinc corrosion rate of 0.23 g/m2-h [11.4 mil/yr] at 91 °C [196 °F] using an empirical corrosion rate

relationship. Recently, Johns, et al. (2003), using the weight loss method, examined corrosion

rate of zinc in 0.033-M boric acid [360-ppm boron] and 2.0 x 10-4 M lithium hydroxide

[1.4 ppm lithium] solution. Tests were conducted between 22 and 80 °C [72 and 176 'F] at a pH

of 7 or 9. The pH was adjusted by the addition of sodium hydroxide or hydrochloric acid. A

maximum weight loss was obtained at room temperature for an immersed sample indicating a

corrosion rate of 0.012 g/m2 h [0.58 mil/yr]. This rate could result in reprecipitation of soluble

phases on the surface of zinc to compromise measurements so that the sample would exhibit

weight gain rather than weight loss. The measured zinc corrosion rates could have been

compromised by using glass bottles that could leach silica and alkalis at higher temperatures.

Table 2-1 provides a summary of corrosion rate data for zinc and galvanized steel.

Using a maximum immersed surface area and a minimum volume of available containment

water {-1,893 m3 [-500,000 gal]), zinc surface to containment volume ratio is estimated as

26.2 m2/m3 [8.0 ftWft 2 3] for galvanized steel (see Table 2-2). Because the immersed fraction for

galvanized zinc is estimated as 0.05, the total immersed surface area-to-containment volume

reduces to 1.31 rn2 m3 [0.4 ft2/ft3]. The non-top coated zinc paint is neglected in the simulations.

2-1
'LII'

Table 2-1. Summary of Corrosion Rate Data for Zinc and Galvanized Zinc

Reference Solution Temperature Corrosion Rate

Griess & Bacarella (1969) 0.28 M [3,000 ppm] 55 to 140 0C Negligible

boron [131 to 284 OF]

+ 0.15 M sodium

hydroxide

[3,450 ppm sodium]

Niyogi, et al. (1982) Not described 91 0C [196 OF] 0.23 g/m2 -h [11.4 miVyr]

Pippo, et al. (1997) pH = 8.0 & 9.2 50 to 170 0C 0.04 g/m2-h [1.9 mil/yr]

borated solutions [122 to 388 OF] at pH = 9.2 in borated

solution and

0.163 g/m2-h [7.9 mil/yr]

in aerated solution at

90 0C [194 OF]; an order

of magnitude increase

in rates at 110 0C; and

11.27 g/m2-h

[545 milfyr] at 170 °C

[338 OF]

Johns, et al. (2003) 0.033 M [360 ppm] 22 to 80 0C 0.012 g/m2-h

boron + 2.0 x 10-4 M [72 to 176 OF] [0.58 mil/yr]

[1.4 ppm] lithium

References

Griess, J.C. and A.L. Bacarella. 'Design Consideration of Reactor Containment Spray Systems -Part IlIl: The

Corrosion of Materials in Spray Solutions." ORNL-TM-2412, Part l1l. Oak Ridge, Tennessee: Oak Ridge

National Laboratory. 1969.

Niyogi, K.K., R.R. Lunt, and J.S. Mackenzie. NUREG/CP-0038, 'Corrosion of Aluminum and Zinc in Containment

Following a LOCA and Potential for Precipitation of Corrosion Products in the Sump." Proceedings of the Second

Intemational Conference on the Impact of Hydrogen on Water Reactor Safety, Albuquerque, New Mexico,

October 3-7,1982. Rockville, Maryland: NRC. pp. 410-423. October 1982.

Piippo, J., T. Laitinen, and P. Sirkai. 'Corrosion Behavior of Zinc and Aluminum in Simulated Nuclear Accident

Environments." STUK-YTO-TR 123. Helsinki, Finland: Finnish Center for Radiation and Nuclear Safety. 1997.

Johns, R.C., B.C. Letellier, K.J. Howe, and A.K. Ghosh. 'Small-Scale Experiments: Effects of Chemical

Reactions on Debris-Bed Head Loss." LA-UR-03-6415. Los Alamos, New Mexico: Los Alamos National

Laboratory. 2003.

2-2
Table 2-2. Estimation of Zinc in Simulated Containment Water

Immersed Corrosion

Surface Surface Rate Amount Released

Area/Volume Immersed AreaNolume g/m2 h Time Per Liter

m'/m' [ft2lft] Fraction m21m [31ftI ] [milyr6 (hour) g [mol]

1.1 X io26.2 [8.0] 0.05 1.31 [0.4] 0.163 [7.9] 1/2 [1.6 x 10-6]

In this study, a zinc corrosion rate of 0.163 gfm 2-h [7.9 mil/yr] at 90 'C [194 'F] in aerated

solution at pH 8 was used for basecase simulation, because this value provided a conservative

estimate. The basecase simulations were conducted at 60 and 90 0C [140 and 194 0F] at

101 kPa [1 atm], 130 'C [266 'F] at 304 kPa [3 atm] pressure, and 150 0C [302 0F] at 507 kPa

[5 atm] pressure. The effect of temperature and corrosion rate on the formation of solid phases

was evaluated by conducting sensitivity analysis at 60 0C [140 'F], 101 kPa [1 atm]; and 130 0C

[266 °F], 304 kPa [3 atm]. Table 2-2 shows the amount of zinc released in grams and in mole

per liter of simulated containment solution, in 0.5 hour using a corrosion rate of 0.163 g/m2-h

[7.9 millyr]. Based on temperature-time profiles for postulated LOCA event, 30 minutes

represents maximum time containment solution remains above 90 °C [194 F:].

2.2 Aluminum

In a containment building, aluminum may be present in scaffolding. Additional aluminum may

come from fiber insulation in oxide form.

Piippo, et al. (1997), Griess and Bacarella (1969), and Niyogi, et al. (1982) have examined the

corrosion rate of aluminum. Griess and Bacarella (1969) measured corrosion rates of several

aluminum alloys in 0.20 M [3,000 ppm] boron with 0.15 M sodium hydroxide [3,450 ppm sodium]

solution between 55 and 140 °C [131 and 284 °F]. The corrosion rate for sprayed samples was

higher than for submerged samples. For aluminum alloys at 55 °C [131 °F], spray corrosion

rates ranged from 1.0 to 1.5 g/m2-h [130 to 190 mil/yr], and submerged corrosion rates ranged

from 0.35 to 0.61 g/m2-h [45 to 78 mil/yr]. At 100 0C [212 *F], spray corrosion rates ranged from

9.4 to 33.4 g/m2-h [1,200 to 4,300 mil/yr], and submerged corrosion rates ranged from 14.0 to

18.0 g/m2-h [1,800 to 2,300 millyr]. The aluminum alloys 1100, 3003, and 6061 corroded at very

high rates, with sprayed samples showing higher attack than submerged samples. While the

submerged samples showed uniform corrosion, extensive pitting was observed in samples

subjected to spray. Niyogi, et al. (1982) estimated an aluminum corrosion rate of 23.9 g/m2-h

[3060 millyr] at 90 °C [194 °F] using an empirical relationship. However, Niyogi, et al. (1982)

suggested a long-term aluminum corrosion rate of 1.6 g/m2-h [200 mil/yr]. Piippo, et al. (1997)

examined aluminum corrosion from 50 to 130 0C [122 to 266 0F] in environments ranging from

reducing (nitrogen) to oxidizing (air), and in buffered borated solution at a pH of 9.2. Aluminum

in buffered borated water showed the highest corrosion rate. At 90 0C [194 °F], Piippo, et al.

(1997) measured corrosion rates of 0.012 g/m2-h [1.5 mil/yr] in aerated solution at pH 10 and

1.45 g/m2-h [186 millyr] in borated water. Corrosion rates measured for immersed samples by

Griess and Bacarella (1969) are a factor of 10 higher than these measured by Piippo, et al.

(1997). Table 2-3 provides a summary of corrosion rate data for aluminum.

2-3
"'il

Table 2-3. Summary of Corrosion Rate Data for Aluminum

Reference Solution Temperature Corrosion Rate

Griess & Bacarella 0.28 M 55 to 140 0C At 55 0C [131 OF], spray

(1969) [3,000 ppm] boron [131 to 284 0F] corrosion rates ranged from

+ 0.15 M sodium 1.0 to 1.5 g/m2-h [130 to

hydroxide 190 millyr], and submerged

[3,450 ppm corrosion rates ranged from

sodium] 0.35 to 0.61 g/m2-h [45 to

78 mil/yr].

At 100 0C [212 OF], spray

corrosion rates ranged from

9.4 to 33.4 g/m2-h [1,200 to

4,300 mil/yr], and submerged

corrosion rates ranged from

14.0 to 18.0 g/m2-h [1,800 to

2,300 mil/yr].

Nyogi, et al. (1982) Not described 90 0C [194 OF] 23.9 g/m2-h [3060 mil/yr]

Pippo, et al. (1997) pH = 9.2 borated 50 to 130 0C At 90 0C [194 OF], corrosion

solutions, pH = 10 [122 to 266 OF] rates were 0.012 gIm2 h

aerated solution [1.5 mil/yr] in aerated solution

at pH 10 and 1.45 g/m2 -h

[186 mil/yr] in borated water.

References

Griess, J.C. and A.L. Bacarella. 'Design Consideration of Reactor Containment Spray Systems -Part IlIl: The

Corrosion of Materials, in Spray Solutions. ORNL-TM-2412, Part IlIl. Oak Ridge, Tennessee: Oak Ridge

National Laboratory. 1969.

Niyogi, K.K., R.R. Lunt, and J.S. Mackenzie. NUREGICP-0038, 'Corrosion of Aluminum and Zinc in Containment

Following a LOCA and Potential for Precipitation of Corrosion Products in the Sump." Proceedings of the Second

International Conference on the Impact of Hydrogen on Water Reactor Safety, Albuquerque, New Mexico,

October 3-7,1982. Rockville, Maryland: NRC. pp. 410-423. October 1982.

Piippo, J., T. Laitinen, and P. Sirkai. 'Corrosion Behavior of Zinc and Aluminum in Simulated Nuclear Accident

Environments." STUK-YTO-TR 123. Helsinki, Finland: Finnish Center for Radiation and Nuclear Safety. 1997.

Using a maximum immersed surface area and a minimum volume of available containment

water, an aluminum metal surface area-to-volume ratio is estimated as 11.5 m2/m3 [3.5 f2ef] as

shown in Table 2-4. Because the immersed fraction for aluminum is 0.05, the total immersed

surface area-to-containment volume reduces to 0.57 m2/m3 [0.17 ft2/ft3i.

Basecase simulations for aluminum were conducted using a corrosion rate of 1.45 glM2-h

[186 mil/yr] at 90 °C [194 OF] (Piippo, et al., 1997). The effects of temperature and corrosion

rate on the formation of solid phases was evaluated by conducting sensitivity analysis at 60 °C

1140 OF], 101 kPa [1 atm]; and 130 °C [266 OF], 304 kPa [3 atm]. Table 2-4 also shows the

amount of aluminum released in grams and in mole per liter of simulated containment solution in

0.5 hour using a corrosion rate of 1.45 g/m2 h [186 mil/yr].

2-4
Table 2-4. Estimation of Aluminum in Simulated Containment Water

Immersed Amount

Surface Surface Corrosion Released Per

AreaNolume Immersed Area/Volume Rate Time Liter

m21m 3 [ft2/ft3] Fraction m2/m3 [ft2lft3] gI/M -h [millyr] (hour) g [mo]]

4.2 x 1-

11.5 [3.51 0.34 0.57 [0.17] 1.45 [186] 1/2 [1.5 x 10-9]

2.3 Carbon Steel

Carbon steel is present as structural steel in the containment building. However, most of the

carbon steel is protected by design basis accident qualified coatings or is encased in insulation.

Estimates are that the unprotected carbon steel surface area is small.

Griess and Bacarella (1969) and Hall (1988) have examined the corrosion rate of carbon steels

in borated water. Griess and Bacarella (1969) measured the corrosion rate of A-108 and A-210

carbon steels in 0.15 M sodium hydroxide [3,450 ppm sodium] solution between 55 and 140 'C

[131 and 284 OF]. The corrosion rate for sprayed samples was higher than for submerged

samples. Results showed a negligible attack on carbon steels in alkaline borated water

regardless of the test conditions. Hall (1988) measured corrosion of SA-193 Grade B7, SA-540

Grade B23, and SA-540 Grade B24 carbon steels {0.092 M [1,000 ppm] boron} borated water

from 79 to 204 OC [175 to 400 OF]. At 79 0C [175 OF], a maximum corrosion rate of 19.0 g/m2-h

[833 mil/yr], and an average corrosion rate of 14.6 g/m2-h [639 millyr], was observed for SA-193

B7 carbon steel. Average corrosion rates at 79 0C [175 OF] for SA-540 Grade B23 and SA-540

Grade B24 were 16.7 g/m2-h [731 mil/yr] and 6.0 g/m2-h [265 mil/yr], respectively. At 177 OC

[350 OF), average corrosion rates for SA-193 Grade B7, SA-540 Garde B23, and SA-540

Grade B24 carbon steels were 4.3 g/m2-h [190 mil/yr], 14.8 g/m2-h [650 mil/yr], and 11.3 g/m2-h

[495 mil/yr], respectively. Table 2-5 provides a summary of corrosion rate data for carbon steel.

The corrosion rates at 177 'C [350 OF] were lower for SA-193 Grade B7, and SA-540 Grade B23

at higher temperatures while for SA-540 Grade B24 the corrosion rate was higher at higher

temperatures. Therefore, based from the work of Hall (1988) and Griess and Bacarella (1969),

in alkaline solutions, carbon steel behaves as a passive material.

Using a maximum immersed surface area and a minimum volume of available water, a carbon

steel surface area-to-volume ratio is estimated as 0.49 m21m3 [0.15 ft2/ft3

] as shown in Table 2-6.

Because the immersed fraction for carbon steel is 0.34, the total immersed surface area-tocontainment volume reduces to 0.17 m2/m3 [0.05 ft2/ft3].

Basecase simulations for carbon steel were conducted using a corrosion rate of 19.0 g/m2 h

[833 mil/yr] at 90 °C [194 OF]. The effect of the temperature and corrosion rate on the formation

of solid phases was evaluated by conducting sensitivity analysis at 60 °C [140 OF, 101 kPa

[1 atm]; and 130 °C [266 OF], 304 kPa [3 atm]. Table 2-6 also shows the amount of carbon steel

released in grams and in mole per liter of simulated containment solution in 0.5 hour using a

corrosion rate of 19.0 g/m2-h [833 mil/yr].

2-5
ILIE

Table 2-5. Summary of Corrosion Rate Data for Carbon Steel

Reference Solution Temperature Corrosion Rate

Griess & Bacarella 0.28 M [3,000 ppm] 55 to 140 0C Negligible

(1969) boron [131 to

+ 0.15 M sodium 284 0F]

hydroxide

[3,450 ppm

sodium]

Hall (1988) 0.092 M 79 to 204 0C At 79 0C [175 OF], a maximum

[1,000-ppm] boron [175 to 400 *F] corrosion rate of 19.0 g/m2-h

[833 mil/yr], and an average

corrosion rate of 14.6 g/m2-h

[639 mil/yr], for SA-193 B7

carbon steel.

Average corrosion rates at 79 0C

[175 0F] for SA-540 Grade B23

and SA-540 Grade B24 were

16.7 g/m2-h [731 mil/yrj and

6.0 g/M2 -h [265 mil/yr]. At

177 *C [350 0F], average

corrosion rates for SA-1 93

Grade B7, SA-540 Garde B23,

and SA-540 Grade B24 carbon

steels were 4.3 g/m2-h

[190 mil/yr],

14.8 g/m2-h [650 mil/yr], and

11.3 g/m 2 h [495 mil/yr].

References

Griess, J.C. and A.L. Bacarella. 'Design Consideration of Reactor Containment Spray Systems -Part III: The

Corrosion of Materials in Spray Solutions.' ORNL-TM-2412, Part Ill. Oak Ridge, Tennessee: Oak Ridge

National Laboratory. 1969.

Hall, J.F. 'Corrosion of Low Alloy Steel Fastener Materials Exposed to Borated Water.' Proceedings of the Third

International Symposium on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors.

G.J. Theus and J.R. Weeks. eds. La Grange Park, Illinois: American Nuclear Society. pp. 711-722. 1988.

2.4 Copper

In a containment building, copper is present in fan coolers with small contributions from

instrument air lines.

Griess and Bacarella (1969) examined the corrosion rate of copper and copper alloys in borated

water. Griess and Bacarella (1969) also measured the corrosion rate of copper in 0.15 M

sodium hydroxide [3,450-ppm sodium] solution between 55 and 140 0C [131 and 284 °F]. The

corrosion rates for sprayed samples were higher than for submerged samples. For copper at

2-6
Table 2-6. Estimation of Carbon Steel In Simulated Containment Water

Immersed

Surface Surface Corrosion Amount Released

AreaNolume Immersed AreaNolume Rate Time Per Liter

m21m3 [ft 2/ft3] Fraction m2/m3 [ft2

Ift3] g/m2-h [mil/yr] (hour) g [mol]

1.6x 10-4

0.49 [0.15] 0.05 0.17 [0.05] 19.0 [833] 1/2 [2.8 x 0-5]

Table 2-7. Summary of Corrosion Rate Data for Copper

Reference Solution Temperature Corrosion Rate

Griess & Bacarella 0.28 M [3,000 ppm] 55 to 140 'C At 100 'C [212 0F], the

(1969)* boron [131 to average spray corrosion rate

+ 0.15 M sodium 284 0F] was 0.043 gJm2-h [1.7 mil/yr],

hydroxide and the average submerged

[3,450 ppm sodium] corrosion rate was

0.013 g/m2 -h [0.51 mil/yr].

*Griess, J.C. and A.L. Bacarella. 'Design Consideration of Reactor Containment Spray Systems -Part IlIl: The

Corrosion of Materials in Spray Solutions.' ORNL-TM-2412, Part IlIl. Oak Ridge, Tennessee: Oak Ridge

National Laboratory. 1969.

100 0C [212 0F], the average spray corrosion rate was 0.043 g/m2-h [1.7 mil/yr], and the average

submerged corrosion rate was 0.013 g/m2-h [0.51 mil/yr]. Table 2-7 provides a summary of

corrosion rate data for copper.

Using a maximum immersed surface area and a minimum volume of available containment

water, a copper surface area-to-volume ratio is estimated as 19.7 m2/m3 [6.0 ft2/ft3] as shown in

Table 2-8. Since the immersed fraction for copper is 0.25, the total immersed surface area-tocontainment volume reduces to 4.9 m2/m3 [1.5 ft2

/ft3].

Basecase simulations were conducted using a corrosion rate of 0.03 g/m2-hr [1.2 mil/yr] at 90 °C

[194 *F]. The effect of the temperature and corrosion rate on the formation of solid phases was

evaluated by conducting sensitivity analysis at 60 °C [140 OF], 101 kPa [1 atm]; and 130 °C

[266 'F], 304 kPa [3 atm]. Table 2-8 also shows the amount of copper released in grams and

mole per liter of simulated containment solution, in 0.5 hour using a corrosion rate of

0.03 g/m2-hr [1.2 mil/yr].

2.5 Concrete

Concrete contribution comes from the erosion of concrete surfaces due to the impact of the

water stream around the LOCA location. While a protective paint is applied to concrete

surfaces, a small portion of the concrete is expected to be uncoated during the LOCA event.

Using a maximum immersed surface area and a minimum volume of available containment

water, a concrete surface area-to-containment volume ratio is estimated as 0.15 m2/m3

2-7
11 MI

Table 2-8. Estimation of Copper in Simulated Containment Water

Immersed Corrosion

Surface Surface Rate Amount Released

AreaNolume Immersed Area[Volume g/m2'h Time Per Liter

m2lm3 fl2 ftlJ Fraction m21m3 [ft2

Ift3] [mil/yr] (hour) g [MOl]

7.6 x 1-

19.7 (6.01 0.25 4.9 [1.51 0.03 (1.21 1/2 (1.2 x 10-61

[0.045 ft2/ft3] as shown in Table 2-9. Since the immersed fraction for concrete is 0.34, the total

immersed surface area-to-volume reduces to 0.05 m2/m3 [0.015 ft2/ft3]. The total amount of

concrete particulate is estimated as 22.25 g/m3 [0.0014 Ibm/ft3I. Carmack, et al. (1998)

determined the dust particle size and surface area associated with graphite powders and

compared it with Tokamaks (General Atomics Dlll-D, MIT's Alcator CMOD, and Princeton's

TFTR) dusts as shown in Figure 2-1. For 10-1 5-pm [0.39-0.59-mil]-diameter graphite particles,

the specific surface area was approximately 15 m2/g [7.3 x 104 ft2/lbm]. This specific surface

area was used to estimate the amount of concrete particulate as shown in Table 2-10.

Concrete or cement is a mixture of tricalcium silicate, dicalcium silicate, and tricalcium

aluminate. To simplify the simulation, cement was represented by dicalcium silicate. The

corrosion rate of typical Portland cement was based on Jantzen (1984). Jantzen (1984)

examined the release of calcium from cast cement, cold-pressed cement, warm-pressed

cement, formed under elevated temperatures and pressures, and clinkered cement. Based on

28-day tests at 60 'C [140 OF], the average release of calcium ions into the solution was

0.13 g/m2-hr [14.7 mil/yr]. Tables 2-9 and 2-10 indicate that the contributions from concrete

floors and walls are negligible compared to the contribution from concrete particulates.

Therefore, only concrete particulates were included in the simulation.

Basecase simulations were conducted using a dissolution rate of 0.13 g/m2 h [14.7 mil/yr]. The

effect of temperature and dissolution rate on the formation of solid phases was evaluated by

conducting sensitivity analysis at 60 OC [140 OF], 101 kPa [1 atm]; and 130 OC [266 OF], 304 kPa

[3 atm]. Tables 2-9 and 2-10 also show the amount of concrete dissolved in grams and moles

per liter of simulated containment solution in 0.5 hour using a dissolution rate of 0.13 g/m2-h

[14.7 mil/yr].

2.6 Fiber Insulation

Fiber insulation is primarily made of glass fiber wool. The diameter of glass fiber wool ranges

from 3 to 10pm [0.12 to 0.39 mil with a mean diameter of 7.0 pm [0.28 mil]. Binders of as

much as 25-percent weight are added to hold the insulation together. Typically, these binders

are phenol formaldehyde resin based. The binders are applied immediately after fiberization.

These binders accumulate as droplets, which upon curing at an elevated temperature, flatten on

the fiber surface. During curing, phenol formaldehyde converts to an insoluble polymer. Most

of the fiber wool compositions are not designed for aggressive acid or alkaline conditions. A

significant difference in fiber insulation dissolution rates is not expected among different fiber

insulation brands because most of the manufacturers use a similar glass composition. An

average Nukon' fiber insulation composition is shown in Table 2-11. A surface area to volume

ratio of fiber glass in the fiber insulation is approximately 4.33 x 105 m2/m3 [1.32 x 105 ft2/ft3l.

2-8
Table 2-9. Estimation of Concrete (Non-Particulate) in Simulated Containment Water

Immersed Amount

Surface Surface Released per

Area/Volume Immersed Area/Volume Corrosion Rate Time Liter

m2/m3 [ft2/ft3] Fraction m21m3 [ft2/ft3

] g/m2 -h [mIl/yr] (hour) g [MO]]

3.3 x 10-,

0.15 [0.045] 0.34 0.05 [0.015] 0.131[14.7] 1/2 [1.9 x 10-8]

1

'e 10

cm

E

a)

CZ

U)

0

Dn 0.1

0.)

0.01

DMVS (gm)

Figure 2-1. Surface Area Versus Diameter for Various Graphite Powders

and Tokamak Dusts (Carmack, et al., 1998)

2-9
____________________________________________________________________________________IL'

Table 2-10. Estimation of Concrete (Particulate) in Simulated ContainmentWater

Immersed Corrosion Amount

Specific Surface Rate Released Per

Amount/Volume Surface Area Area/Volume g/m2-hr Time Liter

g/m3 [Ibm/ft3] m2 Ig [ftW/lbm] m21m3 [ft2/ft3l (mil/yr] (hour) g [moll

1.0 x 10-2

22.25 [0.0014] 15 [7.3 x 104] 333 [101] 0.13 [14.7] 1/2 [1.3 x 10-

Table 2-11. Chemical Composition of Nukono Fiber Insulation

Component Weight Percent Molecular Weight Mole Fraction

SiO2 62.5 60 0.637

A120 3 3.6 102 0.022

CaO 8.2 56 0.090

MgO 3.45 40 0.053

Na2O 15.8 62 0.156

B203 5.0 70 0.044

Fiber insulation is widely used as pipe insulation in containment buildings. The amount of fiber

insulation depends on the specific plant design. Nukon', an Owens-Coming brand, is installed

in a large number of containment buildings.

Using a maximum immersed volume of fiber insulation and a minimum volume of available

containment water and assuming an immersed Nukon fiber fraction of 0.75, the ratio of the

surface area of glass fibers in Nukon insulation to the volume of containment water is estimated

at 7.8 x 102 m21m3 [2.4 x 102 ft2

/fel as shown in Table 2-12.

Most of the dissolution studies about fiber insulation materials used simulated lung solution for

toxicity studies. Corrosion, however, is an important parameter for the disposal of radioactive

waste in glass, and a large volume of literature is devoted to the subject. Because the fiber

insulation and typical nuclear waste glasses have similar compositions (in fact, fiber insulation

glasses have better chemical durability than nuclear waste glasses because of the higher

concentration of silica), a corrosion rate of 0.025 g/m2-h [3.4 mil/yr], determined by Pan, et

al. (2003) for surrogate nuclear waste glasses at 90 0C [194 OF], is used in the simulations.

Assuming the density of glass is 2,500 kg/iM3 [157 lbm/ft3], an average corrosion rate can be

expressed as 0.24 pm/day [3.4 mil/yr]. For a radius of 3.5 pm [0.14 mil], fiber would dissolve in

approximately 14.6 days. The glass corrosion rate, however, would decrease with time

because of the formation of secondary layers on the surface of the glass. The corrosion rate

used in the simulations represents a conservative estimate for fiber insulation corrosion.

Basecase simulations were conducted using a fiber insulation dissolution rate of 0.025 g/m2-h

[3.4 mil/yr] at 90 OC [194 OF]. The effect of temperature and corrosion rate on the formation of

2-10
Table 2-12. Estimation of Fiber Insulation in Simulated Containment Water

Parameter Value

Volume of NukonNolume of Water, m31r3 [ft WftV] 3 0.137 [0.137]

Immersed Fraction 0.75

Immersed Volume of Nukon/Volume of Water, m3/m3 [ft3/ft3

] 0.103 [0.103]

Density of Nukon, kg/rM3 [Ibf/ft3] 38.1 [2.4]

Weight of NukoneNolume of Water, kg/rM3 [lbf/ft3] 3.9 [0.25]

Density of Fiber Glass, kg/M3 [Ibf/ft3] 2,500 [157]

Surface AreaNolume Ratio of Glass Fiber, m2/m3 [ft2/ft3j 4.3 x 105 [1.3 x IO']

Surface Area of Fiber GlassNolume of Water, m2/m3 [ft2/ft3] 678 [207]

Corrosion Rate, gfm2-h [mil/yr] 0.025 [3.4]

Time, hour 1/2

Amount of Glass Fiber in Insulation, g/1 [mol/l] 8.5 x 10-3 [1.4 x 10-4]

Table 2-13. Estimation of Fiber Glass In the Nukon' Insulation in Simulated

Containment Water

Component Amount Per Liter of Solution (mol)

SiO2 9.0 x 10-5

A1203 3.0 x 10-6

CaO 1.3 x 10-5

MgO 7.4 x 10-6

Na2O 2.2 x 10-5

B203 6.2 x 10-6

solid phases was evaluated by conducting a sensitivity analysis at 60 'C [140 0F], 101 kPa

[1 atm]; and 130 0C [266 'F], 304 kPa [3 atm]. Table 2-13 shows the amount of fiber insulation

released in grams and moles per liter of simulated containment solution in 0.5 hour using a

corrosion rate of 0.025 g/m2-h [3.4 mil/yr].

2-11
3 FORMATION OF SOLID PHASES DUE TO CORROSION OF

COMPONENTS IN ALKALINE CONTAINMENT WATER

This chapter uses the software validated in Appendix A to examine the potential and nature of

any solid corrosion products that might form in the environment surrounding a LOCA event.

Simulations presented in this chapter assumed a pressure of 507 kPa [5 atm] and 150 'C

[302 OFJ as the peak temperature of the containment water immediately following a LOCA event.

The influence of pressure, temperature, and pH on chemical speciation was studied by

speciating a fixed amount of each component based on its corrosion rate. Speciation

simulations were conducted at 150 OC [302 OF] at 507 kPa [5 atm], 130 0C [266 OF] at 304 kPa

[3 atm], and 90 'C [194 'F] and 60 CC [140 0F] at 101 kPa [1 atm]. The amount of each

component was estimated based on the corrosion rate at 90 *C [194 OF] for 0.5 hour. Given the

significant uncertainties in corrosion rates in borated water as a function of temperature and to

provide a comparative assessment on the effects of temperature and pressure, a fixed amount

of each component was used as input for simulations. Input values for the simulations are

shown in Table 3-1. The basis for selecting these values was discussed in Chapter 2.

Simulations were conducted at pH 10, and the formation of solid phases as a function of

temperature and pressure was examined. Appendix B shows a typical simulation output. A pH

of 10 was obtained by adding 0.23 molIL [5,300 ppm Na] NaOH. The precipitation of phases

during the 15-day operation for the containment system at 60 °C [140 OF] was estimated by

multiplying the hourly corrosion amount of each component by 720. Additional 0.24 M H3B03

Table 3-1. Input Values Per Liter of Solution for Simulations

Amount Released/

Corrosion Rate Liter in 0.5 Hour

Component g/m2-h [millyr] g [moll

NukonO Fiber 0.025 [3.4] 8.5 x 10-3 [1.4 x 10-4]

SiO2 _ 5.4 x 10-3 [9.0 x 10-5]

A1203 _ 3.1 x 10-4 [3.0 x 10-r

MgO _ 3.0 x 10-4 [7.4 x 10-6]

Na2O _ 1.4 x 10-3 [2.2 x 10-5]

B203 _ 4.3 x 10-4 [6.2 x 10-6]

CaO 7.1 x 10-4 [7.3 x 10-5]

Concrete (Ca2SiO4) 0.13 [14.7] 1.0 x 10-2 [1.3 x 10-41

Aluminum metal 1.45 [186] 4.2 x 10-4 [1.5 x 10-5j

Zinc metal 0.163 [7.9] 1.1 x 10-4 [1.6 x 10-61

Iron metal 19.0 [833] 1.6 x 10-4 [2.8 x 10-]

Copper metal 0.03 [1.2] 7.6 x 10-5 [1.2 x 10-6]

B(OH)3 N/A 16.1 [0.26]

NaOH N/A 9.2 [0.23]

3-1
1 aIII

was needed to maintain pH at 10. An increase in pH was observed as the concentration of

corrosion components increased in the simulation. This increase in pH was attributed to the

hydrolysis reactions associated with the fiber insulation. Corrosion rates of the components at

90 OC [194 OF] were used in the simulations to estimate the amount of each component. Use of

such rates leads to conservative assessment of long-term corrosion because corrosion rates of

components are expected to be lower at 60 CC [140 OF] which is expected to be the temperature

of the containment water during steady-state operations.

Table 3-2 shows the calculated pH and redox potential at different temperatures and pressures

in borated water with 0.26-M [2,800-ppm] boron and 0.23-M [5,300-ppm Na] NaOH. At 60 0C

(140 OF), pH in alkaline borated water with 0.26-M [2,800-ppm] boron was 10. A slight decrease

in pH was observed with the increase in the temperature and pressure. Similarly, redox

potential at 60 0C [140 OF] was approximately -0.6 V versus the standard hydrogen

electrode (VSHE).

Table 3-2. pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water with

0.26 M [2,800 ppm B] and 0.23 M [5,300 ppm Na] NaOH

Test Conditions pH Eh (VSHE)

60 °C [140 OF] at 101 kPa [1 atm] 10.0 -0.60

90 °C [194 OF] at 101 kPa [1 atm] 9.7 -0.62

130 °C [266 OF] at 304 kPa [3 atm] 9.5 -0.64

150 °C [302 OF] at 507 kPa [5 atm] 9.4 -0.65

Figure 3-1 shows the concentrations of solid phases at pH 10. The dominating solid phases in

the simulated containment water were sodium aluminum silicate (NaAISi308), calcium iron

silicate (Ca3Fe2Si3O12), iron silicate [Fe3Si2O5(OH)4], and Fe304. In addition, calcium magnesium

silicate [Ca2Mg5Si8022(OH) 2], ZnO-Fe203, and copper were observed in smaller quantities.

Table 3-3 shows the solid phase percentage for each element present in the simulated

containment water. Table 3-4 provides a percent distribution of solid phases for compounds at

different temperatures and pressures. Table 3-4 demonstrates that, even though silicon was

not present as S102 solid phase, more than 90 percent of the solid phases observed at pH 10

are silicates. Simulation results indicate no phase change for copper. Most of the copper

added as copper metal in the simulation remained as copper metal. The concentration of

Ca2Mg5Si8022(OH)2 did not change from 150 °C [302 °F], 507 kPa [5 atm] to 60 °C [140 OF],

101 kPa [1 atm], and 100 percent of the magnesium was incorporated in the solid phase. Zinc

was present as ZnO-Fe203, and the solid phase concentration increased with decrease in

temperature. At 60 °C [140 °F], 101 kPa [1 atm], 100 percent of zinc was present as

Zn&-Fe203, while at 150 °C [302 °F], 507 kPa [5 atm], zinc was completely soluble as Zn(OH)3-'

phase. Aluminum was present in NaAISi 308 phase and the solid phase concentration increased

with decrease in temperature. At 60 °C [140 OF]. 101 kPa [1 atm], 100 percent of aluminum was

present as NaAISi308, while at 150 °C [302 OF], 507 kPa [5 atm], aluminum was completely

soluble as AI(OH) 4 ' phase. Iron metal was associated with the formation of several solid

phases. The concentration of Ca3Fe2Si3012 decreased with decrease in temperature. At 90 °C

3-2
1 .OOE-04

1.00E-05

o 1.OOE-06 - - -- __ _ _ _ _

EE E E t E E ES E EcE 0= o _ o '° n =D 0 a) to 0_ F

Cu NaA Ca2Mg5 Ca3Fe2 ZnO Fe3O4 Fe3

S1308 S18022 S13012 Fe2O3 Si2O5

(OH)2 (OH)4

Phases

Figure 3-1. Concentration, in mol/L, of Dominant Solid Phases As a

Function of Temperature and Pressure in 0.26 M [2,800 ppm] Boron in

an Alkaline Simulated Containment Water at pH 10

Table 3-3. Percent Element Distribution in Solid Phases at pH 10

Temperature Magnesium Iron Aluminum Zinc Silicon Calcium

and Pressure (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

150°C[302°F], 100 100 0 0 25 17

507 kPa [5 atm] |

130°C[266°F], 100 100 39 66 35 16

304 kPa [3 atm]

90 °C [194 -F], 100 100 100 98 43 8

101 kPa [1 atm] I I II__

60 °C[140°F], 100 100 100 98 42 1

101 kPa [1 atm] I II I I

3-3
- - _111

Table 3-4. Percent of Solid Phases at pH 10

Ca2Mg 5Si8 Ca3Fe2Si3 ZnO&Fe 2

Temperature NaAISi3 0, 022(OH)2 Fe3Si205(OH) 4 012 03 Fe304

and Pressure (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

150 0C [302 0 F], 0 10 90 0

507 kPa [5 atm]

130 0C [266 0 F], 35 6 54 4 -

304 kPa [3 atm]

90 0 C [194 0 F], 61 4 - 17 5 12

101 kPa [1 atm]

60 -C [140 0 FJ, 65 5 26 - 5 _

101 kPa [1 atm] I I

[194 OF], iron was present as Ca3Fe2Si3O12, ZnO Fe2O3, and Fe3O4. At 60 OC [140 OFJ, iron was

present as Fe3Si2O5(OH)4 and ZnO-Fe2O3. Even though new iron bearing phases were formed

as the temperature decreased from 150 °C [302 °F], 507 kPa [5 atm] to 60 °C [140 OF],

100 percent of the iron remained in solid phase.

Table 3-3 shows the percent of distribution for elements at different temperatures and

pressures. The Ca3Fe2Si3O,2 solid phase concentration decreased from 1.4 x 10-5 to 0 mollL

when the temperature dropped from 150 °C [302 OF], 507 kPa [5 atm] to 60 °C [140 OF],

indicating retrograde solubility of calcium with temperature as shown in Figure 3-1. As calcium

dissolves, the solid phase of Fe3O4 changes at 90 °C [194 OF] to Fe3Si4O10(OH)2 at 60 °C

[140 OF], 101 kPa [1 atm]. Both soluble and insoluble silicon bearing phases were observed in

the simulated containment water. At 150 °C [302 °F], 507 kPa [5 atm], 25 percent of silicon was

distributed within various solid silicates, while at 60 °C [140 °F], 42 percent of silicon bearing

phases were distributed in solid phases. The dominant silicon bearing soluble phases were

SiO2 (aqueous), H3SiO3 ', and NaHSiO3. The increase in silicon bearing solid phases is

attributed to the formation of NaAISi3O8 Only 17 percent of calcium was present in calcium

bearing solid phases at 150 °C [302 OF], 507 kPa [5 atm], while 1 percent of calcium was

present in calcium bearing solid phases at 60 °C [140 OF].

A major difference observed at 130 °C [266 OF], 304 kPa [3 atm] and 60 °C [140 °F] was a

redistribution of iron phases. However, despite redistribution, 100 percent of the iron remained

in the solid form. Results also indicate that the solubility of ZnO-Fe2O3 and NaAISi308

decreased with a decrease in temperature and pressure, resulting in a higher concentration of

solids at lower temperatures. As corrosion proceeds, concentration of corroded species

increases with time.

Figure 3-2 compares the observed solid phases at pH 10 after 15 days of corrosion at 60 °C

[140 OF] with solid phases observed at 130 °C [266 OF], 304 kPa [3 atm] in 0.5 hour. Additional

0.24 M H3BO3 was needed to maintain pH at 10. An increase in pH was observed as the

concentration of corrosion components increased in the simulation. This increase in pH was

attributed to hydrolysis reactions associated with the fiber insulation.

3-4
0

E 1.OOE-0 -

0 ff1.0E0E4 -

0 1.00E06-

1.0OE0E8-

co0

Cf Ci) N4 <U N 05 cP N (P

z c N s L.

co) N 0 a U co U..

0) Cf

(U) C

Phases

Figure 3-2. Concentration, in mol/L, of Dominant Solid Phases at 150 0C [302 OF], 507 kPa [5 atm] for 0.5 Hour at 60 OC [140 OF] for

15 Days in a 0.26-M [2,800-ppm] Boron Alkaline Simulated

Containment Water at pH 10

The dominant solid phases formed in the simulated containment water at pH 10 after 15 days were SiO2, CaSiO3, NaAISi 308, Ca2Mg5Si8022(OH)2 Ca3Fe2Si3O,2, and a minor quantity of Zn2SiO4. Simulation results show that the concentrations of solid phases observed at 60 0C [140 OF], pH 10 were much larger than those observed at 130 0C [266 OF], 304 kPa [3 atm] in 0.5 hour. With the exception of ZnO-Fe2 03 observed at 130 0C [266 OF], 304 kPa [3 atm], solid phases formed at pH 10 at 130 0C [266 OF], 304 kPa [3 atm] in a 15-day simulation were similar to the high temperature and high pressure phase results in the simulations. In addition, CaSiO3 solid phase was also observed at 60 0C [140 °F]. The simulations indicate that with the exception of ZnO-Fe203, similar solid phases are formed in the first 0.5 hour of the LOCA event at 150 0C [302 OF], 507 kPa [5 atm] as those from a 15-day or longer simulation test at 60 °C [140 OF].

Figures 3-3 and 3-4 indicate there are major differences in the formation of dominant silicate solid phases at 60 0C [140 OF] and 130 0C [266 OF], 304 kPa [3 atm] as a function of pH. Figure 3-3 shows the speciation of the dominant solid phases as a function of pH in the alkaline

range between pH 7 and 11 at 60 0C [140 OF]. The pH of the solution was adjusted by the addition of NaOH. At 60 °C [140 OF], at pH 7, the dominant solid phases were NaAISi 308 and Fe3Si205(OH)4, while at pH 10, the dominant solid phases were NaAISi 308 and Fe304. At pH

3-5

c-z_.z_
Dominant Solids vs pH at 60 C

MI1

O.0001

D- Ar N.4SIO4 . S.1id I..q: .~ ; Ij 

. N.-0AIS0rn . Solid nooq l

-.j-No F.iSi2O SOlid Imo. I

=

52

E

e

'o

9

*E-- C.3Fo2Si30l2- sOldoilm~ - A

.- *-Co. Solid [ollo \i

; _-caSsao2U5E2tolo. Sold lmb

-U_ - OSFE203. Solid (tool]

A. A-- A .. ''- '-A-- 1S.5

1b7 ,.rt a GI 72 7.8 a4 9 OA 15.2 108 11.4

pH [pH]

12

Figure 3-3. Dominant Solid Phases at 60 °C [140 OF], 101 kPa

[1 atm] As a Function of pH

DominantSolids vs pHat130C,3atm

0.001

~R-a4siO- old

0WN

EO

.52

a

-A * - --- *-- ^-Ax

Uel

J--

* +_ X- ,, ;_ -- .. . .

U- U U U U U U U U

1 0. I . . . . . . . . . . . . . . . .

a °8 72 79 84 9 9J. 102 10. 114

pH [pH)

12

Figure 3-4. Dominant Solid Phases at 130 °C [266 OF], 304 kPa

[3 atm] As a Function of pH

3-6
exceeding 11, Na4SiO4 was a dominant solid phase and its concentration exceeded the

concentration of other solid phases by an order of magnitude.

Figure 34 shows the speciation of the solid phases as a function of pH at 130 OC [266 OF],

304 kPa [3 atm] pressure. At 130 OC [266 OF], 304 kPa [3 atm] and pH 7, the dominant solid

phases were NaAISi308 and Fe3O4, while at pH exceeding 10, the dominant solid phase was

Na4SiO4 The concentration of this phase exceeded the concentration of other solid phases by

an order of magnitude. At pH 9, Fe304 transformed to Ca3Fe2Si3O,2.

The formation of iron phases depends on temperature, pressure, and pH. However,

irrespective of the solid phase formed, 100 percent of the iron was associated with solid phases.

At 60 'C 1140 OF], as the pH increased, the iron phase transformed from Fe3Si205(OH)4 at pH7,

to Fe3O4 at pH 10, and to Ca3Fe2Si3O,2 at pH 10.6. At 130 OC [266 OF], 304 kPa [3 atm], the iron

phase transformed from Fe3O4 at pH 7, to Ca3Fe2Si3O,2 at pH 9, and to CaFe204 at pH 11. The

differences in iron phases are attributed to the availability of silicon. In an alkaline environment,

the solubility of silica increases with increase in pH and temperature. Since silicates are major

corrosion products, pH and temperature have strong influence on the formation of the dominant

solid phases in simulated containment water.

Even though iron phase changes are clearly evident from these simulations, the solubility of iron

in containment solutions remained close to zero.

3.1 Sensitivity Analyses

The simulations are based on corrosion rates at 90 DC [194 °F]. As discussed in Chapter 2,

corrosion rates could vary significantly with temperature. To gain confidence in the results, a

series of simulations was conducted while varying the amount of each component and

analyzing any effects on the formation of solid phases.

3.1.1 Behavior of Zinc Metal in the Simulated Containment Water

The effect of zinc corrosion rate on the formation of solid phases was evaluated by conducting

sensitivity analyses at 60 °C [140 °F] and 130 °C 1266 OF], 304 kPa [3 atm]. The amount of zinc

in the simulated containment solution is directly related to its corrosion rate for a fixed interval of

time. The zinc concentration in the basecase simulation was 2 x 10-6 mol/L. In the sensitivity

analysis, the zinc concentration was varied between 1 x 10-8 and I x 10-4 mol/L. Figures 3-5

and 3-6 show the influence of zinc additions on the formation of solid phases and soluble

Zn(OH)' phase in the simulated containment water at pH 10, 600 C [140 OF] and 130 °C

[266 OF], and 304 kPa [3 atm]. These data show that at 600 C [1400 F], zinc was predominantly

present as a solid ZnO-Fe203 phase. However at 130 °C [266 OF], the difference in'

concentration between solid ZnO-Fe203 and soluble Zn(OH) 3-' was smaller than the difference

at 60 °C [140 OF], while it is predominantly present as a soluble Zn(OH)3;' phase at

concentrations below 3 x 10-8 mol/L at 60 °C [140 OF] and 1 x 10-6 mol/L at 130 °C [266 OF],

304 kPa [3 atm]. Zinc is predominantly present as a mixture of solid Zn2SiO4 and ZnO-Fe203

phases at concentrations higher than 3 x 10-5 mol/L at 60 °C [140 OF] and 130 °C [266 OF],

304 kPa [3 atm]. The formation of Zn2SiO4 occurs by a reduction in Fe3Si2O5(OH)4

concentration at 60 °C [140 OF] and Ca3Fe2Si3O,2 concentration at 130 °C [266 °F], 304 kPa

[3 atm]. Again, the formation of Ca3Fe2Si30,2 at 130 °C [266 OF], 304 kPa [3 atm] and the

3-7
I

Dominant Solids & ZnOH3- vs Zn at 60 C, pH 10

L.i L.UI1

le-5 A ,A- -- A A ,s, h A

.A g p -----------

0

N

i

a

0)

1 e-b

1 e-7

N.SOO- S -i

-*. Nair3OS.SoI1d[molj ='

.js~sFd352w(OiQ4 SOW d[nmoi 4

i -.. Z,2SlO4i- Sffl.id imCti<,0i

* .4-ZOJE20O Solid {moQ

-4-C.2Meg5rnO22(012 -Solid ["' fi . .I_

, a'

Ie9

L

, t , -U-t- --- _ _U_ _

t

1e-9.

1 e-9 1 es8 I e-7 le-6 1e -5 a.-a1

2n ImolJ

Figure 3-5. Dominant Solid Phases at 60 °C [140 °F], 101 kPa

[1 atm] As a Function of Zinc in Simulated Containment Water

at pH 10

Dominant Solids & ZnOH3- vs Zn at 130C,3 atm, pH 10

'E

0

N

.d

(C

0

1es9 1e98 1e-7 1e-6 Ies5

Zn Imoll

0.101

Figure 3-6.

[1 atm] As a

Dominant Solid Phases at 130 "C [266 °F], 101 kPa

Function of Zinc in Simulated Containment Water at

pH 10

3-8
formation of Fe3Si4O10(OH)2 at 60 0C [140 OF] are attributed to the retrograde solubility of

calcium in iron bearing minerals.

The influence of zinc was limited to interactions between solid phases associated with iron and

zinc. Dominant solid phases such as NaAISi 308 and Ca2Mg5Si8022(OH)2 are not influenced by

the presence of zinc-containing phases in the simulated containment water. The soluble

Zn(OH) 3' phase is present in the simulated containment water only at low concentrations of

zinc. The formation of solid Zn2SiO4 is also consistent with a 15-day simulation test where solid

Zn2SiO4 was a predominant solid species.

The increase in zinc concentration increases the concentrations of ZnO Fe2O3 and Zn2SiO4 by

incorporating iron and silicon present in Fe3Si2O5(OH) 4 at 60 0C [140 'F] and Ca3Fe2Si3012 at

130 0C (266 OF], 304 kPa [3 atm]. This exchange does not influence other solid phases that

were formed in the simulated containment water after a LOCA event.

3.1.2 Behavior of Aluminum Metal in Simulated Containment Water

The source of aluminum is aluminum metal and fiber insulation. The effect of aluminum metal

concentration on the formation of solid phases was evaluated by conducting a sensitivity

analysis at 60 0C [140 OF] and 130 0C [266 IF], 304 kPa [3 atm]. The aluminum metal

concentration in the basecase simulation was 1.5 x 10-5 mol/L. In the sensitivity analysis, the

aluminum metal concentration was varied between 1 x 10-7 and 1 x 10-3 mol/L.

Figures 3-7 and 3-8 show the influence of aluminum metal additions on the formation of solid

phases in the simulated containment water at 60 IC [140 OF] and 130 0C [266 OF], 304 kPa

[3 atm] and pH 10. These data show that at 600 C [1400 F], aluminum was predominantly

present as a solid NaAISi 308 phase. However, at 130 0C [266 °F], 304 kPa [3 atm], aluminum

was predominantly present as Al(OH) 4 ' soluble phase.

At 60 0C [140 °F], dominant solid phases were Fe3Si2O5(OH) 4 and NaAISi 3O8. The

concentration of NaAISi3O, phase increased with increase in the aluminum concentration in the

simulated containment water. However, for aluminum concentrations higher than

3 x 10-5 mol/L, formation of NaAISi 308 was followed by the transformation of Fe3Si4O10(OH)2 to

Fe304 and dissolution of Ca2Mg5Si 8022(OH)2 phase. In addition, when aluminum concentration

exceeded 2 x 10-4 mol/L, AI(OH)3 was the dominant solid phase along with solid NaAISi 308 and

soluble AI(OH) 4-' phases.

At 130 0C [266 OF], 304 kPa [3 atm], dominant solid phases were Ca3Fe2Si30,2 and NaAISi308. However, the majority of the aluminum was present as AI(OH)4; soluble species at 130 °C

[266 OF], 304 kPa [3 atm]. For aluminum concentration higher than 3 x 1 0-6 mol/L, the

concentration of the NaAISi 30, phase increased with the increase in the aluminum

concentration in the simulated containment water. In addition, for aluminum concentrations

higher than 1 x 10-4 mol/L, the formation of NaAISi308 was followed by the transformation of

Ca3Fe2Si30,2 to Fe304, and for aluminum concentrations higher than 3 x 1O5 moVL, dissolution

of Ca2Mg5Si8022(OH)2 phase was observed. In addition, when aluminum concentration

exceeded 2 x 10-4 mol/L, solid NaAISi 308 and Fe3O4 were the dominant solid phases. Again

formation of Ca3Fe2Si3O,2 at 130 0C [266 °F], 304 kPa [3 atm] and formation of Fe3Si4O10(OH)2

at 60 0C [140 °F] are attributed to the retrograde solubility of calcium in iron bearing minerals.

3-9
Figures 3-7 and 3-8 demonstrate that the addition of aluminum metal increases the

concentration of NaAISi3O8 solid phase. However, the influence of aluminum metal was only

observable when the concentration of aluminum metal was comparable to the aluminum

concentration from the fiber insulation.

The increase in aluminum concentration increased the concentration of NaAISi308 solid phase

by incorporating silicon present in Fe3Si205(OH)4 at 60 *C [140 OF] and in Ca3Fe2Si3O,2 at

130 0C [266 0F], 304 kPa [3 atm]. In addition, for aluminum concentrations higher than

3 x 10-5 mol/L, dissolution of Ca2Mg5Si802(OH)2 phase was observed. In addition, formation of

AI(OH) 3 occurs for aluminum concentrations exceeding 2 x 1 mol/L at 60 0C [140 OF].

3.1.3 Behavior of Carbon Steel in Simulated Containment Water

The source of iron is carbon steel. The effect of iron metal concentration on the formation of

solid phases was evaluated by conducting a sensitivity analysis at 60 0C [140 OF] and 130 0C

[266 OF], 304 kPa [3 atm]. The iron concentration in the basecase simulation was 2.8 x 10-5

mol/L. In the sensitivity analysis, the iron concentration was varied between 1 x 10-7 and

1 x 10-3 mol/L. Figures 3-9 and 3-10 show the influence of iron additions on the formation of

solid phases in the simulated containment water at a pH of approximately 10 at 60 0C [140 0F]

and 130 'C [266 OF], 304 kPa [3 atm]. The data show that, irrespective of temperature and

pressure, iron present in solid phases increased with an increase in iron concentration.

However, the nature of iron bearing solid phases is different at different iron concentrations

and temperatures.

At 60 °C [140 OF], the dominant solid phase was NaAISi308. For iron concentrations below

1 x IO-5 mol/L, iron was predominantly present as ZnO-Fe203, and above 1 x 10-5 mol/L, iron

was predominantly present as Fe3Si205(OH)4. Formation of Fe304 was observed at 1 x 10-3

mol/L. For iron concentrations higher than 1 x 10-4 mol/L, dissolution of Ca2Mg5Si8022(OH)2

phase was observed.

At 130 °C [266 °F], 304 kPa [3 atm], the dominant solid phase was NaAISi 308. For iron

concentrations below 1 x 1 O6 mol/L iron was predominantly present as ZnO-Fe203. Between

1 X 10-6 and 7 x 10-5 mol/L, iron was predominantly present as Ca3Fe2Si3012; and above

7 x 10-5 mollL, iron was predominantly present as Fe304 The dissolution of Ca2MgSi8022(OH)2

solid phase was not observed. For iron concentrations exceeding 5 x 10-6 mol/L, NaAISi308 the

solid phase was consumed by the formation of Ca3Fe2Si3O12.

Again, formation of Ca3Fe2Si3O12 at 130 °C [266 °F], 304 kPa [3 atm] and formation of

Fe3Si205(OH)4 at 60 °C [140 OF] are attributed to the retrograde solubility of calcium in iron

bearing minerals. Despite these phase changes, all iron present was in the solid phase.

3.1.4 Behavior of Concrete in Simulated Containment Water

CaO and SiO2 are the main contributors from concrete (assuming Ca2SiO4 is the primary

concrete constituent). Both CaO and SiO2 are also present in fiber insulation. The contribution

of CaO from concrete is 1.3 x 10-4 mol/L, while the contribution of CaO from fiber insulation is

1.3 x 1 0- mol/L. The calcium contribution from concrete is about 10 times larger than that from

fiber insulation. The effect of concrete concentration on the formation of solid phases was

evaluated by conducting a sensitivity analysis at 60 °C [140 OF] and 130 0C [266 OF], 304 kPa

3-10
Dominant Solids vs Al at 60 C, pH 10

U.WI

.fl.Aitlii13.5o1idjoflmo ...... 0:.

--- HoAiSHAO. Solid [o-ol.

. .3S1205(OH)5 N Solid (0M.01

* O..F.3-0 Solid . rmon O.WO1 LO...LLO- lO-OI~~

9

IE

ciE

a

1 s-S

-4--C.2M95Si0o22*oH12. Solid Inoq

A. ,.- A - -* * 

I ' I I, ±4 1'....~..... .... 1i-6 .

1iS7 . .

lia 1i-i7 1i-6 1i-5 o.0KJ1 0o001

Ai (moll

Figure 3-7. Dominant Solid Phases at 60 °C [140 °F], 101 kPa

[1 atm] As a Function of Aluminum Metal in Simulated

Containment Water at pH 10

Dominant Solids vs Al at 130C,3 atm, pH 10

0.001

FE/

ci /

i .--. 4.

Al Imoll

Figure 3-8. Dominant Solid Phases at 130 'C [266 °F], 304 kPa

[3 atm] As a Function of Aluminum Metal in the Simulated

Containment Water at pH 10

3-11

C-Z
Fe60CpHl1 0- Dominant Solids vs Fe

O.Mal

c

,.

._

.,

,3

1e-S

1 seA4 .

***A '* I

5 1 .g .1 . 3 R

A A* ha14- Soi~d 11i - ;

* -A-.Fo3S5(i9i>14 S-iidmi' bl '

.C .2Mg4SM022(SOM SPlid 101.11

U-C.- SF2d0 , l , 1e-7

ie.-BIs-1

_zo2s04 Slid i lnlo F -

1e-7 Ies- 1 -5 0.0001 0.001

Fe (moll

Figure 3-9. Dominant Solid Phases at 60 °C [140 °F], 101 kPa

[1 atm] As a Function of Iron in Simulated Containment Water at

pH 10

Fe130CpH10 - DominantSolidsvs Fe

0.0001

1 e-5

E

.S

E

E

l3~0F2 soii /'s

j * * 8 *_ 1 .1

U

: ,.

1 e-B

1s-7

i-.R

1es- 1s-7 1eb- 1se5 0.0001 0.101

Fe Imoll

Figure 3-10. Dominant Solid Phases at 130 °C [266 OF], 304 kPa

[3 atm] As a Function of Iron in Simulated Containment Water at

pH 10

3-12

0.: 2 4~ 

- -.................................................-......................... _ -....... ... .............-.......
[3 atm]. The sensitivity analysis was conducted by varying the amount of Ca2SiO4 in the

simulated containment water. The concrete concentration in the basecase simulation was

1.3 x 10-4 mol/L. In the sensitivity analysis, the Ca2SiO4 concentration was varied between

1 x 10-6 and 1 x 10-2 mol/L. The CaO and SiO2 contributions from fiber insulation were fixed

while conducting the sensitivity analysis. Figures 3-11 and 3-12 show the influence of Ca2SiO4

additions on the formation of solid phases in the simulated containment water at pH 10 at 60 0C

[140 OF] and 130 0C [266 F], 304 kPa [3 atm].

At 60 0C [140 °F], the dominant solid phase was NaAISi308. For Ca2SiO4 concentrations below

3 x 10-5 mol/L, iron was predominantly present as Fe3O4. Between 3 x 10-5 mol/L and

3 x 1 mol/L Ca2SiO4 concentration, iron was present as Fe3Si4O10(OH)2. Above 3 x 10- mol/L

Ca2SiO4 concentration, iron was predominantly present as Ca3Fe2Si3O,2. As the concentration of

calcium and silicon increases, the iron phase changes from oxide iron silicate to calcium iron

silicate. For Ca2SiO4, concentrations exceeding 1 x 10-3 mol/L higher, CaSiO3 was the

dominant solid phase. Other solid phases were in insignificant concentrations. CaSiO3 was

also the dominant phase observed in a 15-day simulation.

At 130 °C [266 °F], 304 kPa [3 atm], the iron bearing phase was the dominant solid phase. The

NaAISi308 solid phase was observed between 1 x 10-4 and 3 x 10-3 mol/L Ca2SiO4

concentration. Aluminum is fairly soluble at 130 °C [266 oF, 304 kPa [3 atm]. For Ca2SiO4

concentration below 3 x 10-5 mol/L, iron was predominantly present as Fe3O4 and above

3 x 10-4 mol/L Ca2SiO4 concentration, iron was predominantly present as Ca3Fe2Si3O,2. For

Ca2SiO4 concentrations exceeding I x 10-3 mol/L higher, CaSiO3 was the dominant solid phase.

Other solid phases were in insignificant concentration. In addition, for Ca2SiO4 concentrations

exceeding 3 x 10-3 mol/L, Ca2B205 solid phase was also observed.

Based on thermodynamic simulations in the presence of Ca2SiO4 exceeding 1 x 10-3 mol/L,

irrespective of the temperature and pressure, the concentration of CaSiO3 increased with an

increase of concrete concentration. The dominant solid phases below 1 x 10-3 mol/L Ca2SiO4

concentration were a series of iron bearing phases with almost all iron remaining in a solid

phase along with NaAISi 308. At 60 °C [140 °F], NaAISi 308 was a dominant solid phase. At

130 °C [266 F], 304 kPa [3 atm], aluminum is significantly soluble, and NaAISi308 solid phase

occurred in a narrow range of Ca2SiO4 concentration.

3.1.5 Behavior of Fiber Insulation in Simulated Containment Water

Insulation consists of several components as shown in Table 2-11. Both CaO and SiO2 are also

present in concrete. The effect of fiber insulation concentration on the formation of solid phases

was evaluated by conducting a sensitivity analysis at 60 °C [140 °F] and 130 °C [266 °F],

304 kPa [3 atm]. In the sensitivity analysis, the insulation concentration was varied from

1 x 10-3 mol/L tol0 times the basecase fiber insulation concentration. The CaO and SiO2

contributions from concrete were fixed while conducting the sensitivity analysis for

fiber insulation.

Figures 3-13 and 3-14 show the influence of fiber insulation on the formation of dominant solid

phases in the simulated containment water at a pH of 10 at 60 °C [140 OF] and 130 °C [266 °F],

304 kPa [3 atm]. At 60 °C [140 °F], 101 kPa [1 atm] in a 10 times the basecase concentration of

fiber insulation in the simulated containment water, dominant solid phases were NaAISi308,

Ca2Mg5Si8O22(OH)2, Ca3Fe2Si3O12, and Zn2SiO4. As the amount of silicon reduced on

3-13
I

Dominant Solids vs Ca2SiO4 at 60 C, pH 10

0.01

0.001

-~A--iSi i3- Sold [tooI3 . -~N.NJSO08 Soli Fooll

.U--CiFo.2iS012 Solid ".0Q

-4--F340 WSlid llooq

-O--Ce. Solid lmoq :

-i-. FoSO2OM(H)4- Solid jool

vI

E

0E

0

n nnn U.1

A

A A A A I

.U1 .- '

.- * * * A ... - ----- ..a.-.- - Ile5 * ------- - *----- ---*- ------- *

I ... . . -- - - - . -- - -- - , -- - --- , 7 ,t 7 -7: - -, ,-- - ': : 7 ;,* -- ;;-;;,-- - -- * - ;- - ;- ----- * - --- - A

1 e-7 1 e-6 1 e-5 0.0001 0.001 0.01

Ca2Sii4 [moll

Figure 3-11. Dominant Solid Phases at 60 °C [140 °F], 101 kPa

[1 atm] As a Function of Ca2SiO4 in Simulated Containment

Water at pH 10

Dominant Solids vs Ca2SiC4 at 130 C, 3 atm, pH 10

0.01 j

r 11~ Soi lon

P.30 Si[oo

a

I

E

o

i o.orj

b

le-5k ,.. I 0. . . - -- --- *

-- -- -I

1- . . . .......... .... i - * .- . . . . .............. . . .. .4 I GiED ................. . ................ . s . .

l.7i 1e-6 1e-S 0.0001 0.001 0.01

Ca2SiO4 [moll

Figure 3-12. Dominant Solid Phases at 130 *C [266 OF], 304 kPa

[3 atm] As a Function of Ca2SiO4 in Simulated Containment

Water at pH 10

3-14
IEiO.OX m0iX OBasecase 3 lox

-J

0

0

'U

'U

E

0

1.OE-04 i

1.OE-06

1 .OE-0O3-,

cCO

cooet C -

lase °40 5~

Ph,----

Figure 3-13. Dominant Solid Phases at 60 °C [140 OF], 101 kPa

[1 atm] at Different Fiber Insulation Concentrations in Simulated

Containment Water at pH 10

2T

0

E

0

v

0

U

0 01 C*) C\ 0 C\ 5CN _ a) U) 0 M 7C Li CM~ Cl)

w m 0 ° C 65 Z4 N 0 N

Z N 0 O

CU 0

() U)

Phases A

0

Figure 3-14. Dominant Solid Phases at 130 °C [266 OF], 304 kPa

[3 atm] at Different Fiber Insulation Concentrations in Simulated

Containment Water at pH 10

3-15

U
- - - llls .11

decreasing the concentration of insulation fiber, the silicate phases formed at 60 'C [140 OF],

underwent transformation. As the 10 times the basecase concentration is reduced to basecase

fiber insulation concentration, Zn2SiO4 changed to ZnO-Fe203. At further reduction in fiber

insulation concentration, Ca3Fe2Si3O,2 converted to Fe304. In addition, the concentration of

Ca2Mg5Si8022(OH)2 continued to decrease as the concentration of fiber insulation was reduced.

The formation of Ca2Mg5Si.O22(OH)2 was limited by the amount of magnesium from the fiber

insulation. At 1 x 10-3 times the basecase fiber insulation concentration, 100 percent of

magnesium was soluble in the simulated containment water.

At 130 0C [266 OF], 304 kPa [3 atm], in a 10 times the basecase concentration of fiber insulation,

dominant solid phases were the same as at 60 0C [140 OF]. Similar to the phase changes

observed at 60 'C [140 OF], the silicate phases undergo transformation as the amount of silicon

is reduced with decreasing concentration of insulation fiber. As 10 times the basecase

concentration is reduced to the basecase fiber insulation concentration, Zn2SiO4 changed to

ZnO Fe203. In addition, the concentration of Ca2MgSi8022(OH)2 continued to decrease as the

concentration of fiber insulation was reduced. The formation of Ca2Mg5Si8022(OH)2 was limited

by the amount of magnesium from the fiber insulation. At 1 x 10-3 times the basecase fiber

insulation concentration, 100 percent of magnesium was soluble in the simulated containment

water. However, no change in Ca3Fe2Si3O,2 phase was observed in simulations at 130 0F

[266 OF] and 304 kPa [3 atm].

Irrespective of the temperature and pressure, the formation of silicate phases continued even at

1/1000 of the basecase concentration but the number of phases and their concentration

reduced as the concentration of fiber insulation reduced. At 60 °C [140 OF], iron phase

distribution underwent a significant change. At lower fiber concentration, iron was

predominantly present as Fe304. However, as the concentration increases, iron combined with

zinc to form Ca3Fe2Si3O,2. At 130 °C [266 °F], 304 kPa [3 atm], iron was present exclusively as

Ca 3 Fe 2 Si 3O1 2 -

This fiber insulation sensitivity analysis at pH 10 indicated no significant impact on the formation

of solid phases over a wide fiber insulation concentration range in simulated containment water

after a LOCA event.

3-16
4 FORMATION OF SOLID PHASES DUE TO CORROSION OF

COMPONENTS IN Na3PO4 CONTAINMENT WATER

This chapter is similar to Chapter 3 but substitutes the chemical environment with Na3PO4

containment water, resulting in a pH - 7.

Simulations presented in this chapter assume a pressure of 507 kPa [5 atm] and 150 'C

[302 OF] as the peak temperature for the containment water immediately following a LOCA

event. The influence of pressure, temperature, and pH was studied by speciating a fixed

amount of each component based on its corrosion rate. Simulations were conducted at 150 0C

[302 OF] at 507 kPa [5 atm], 130 0C [266 OF] at 304 kPa [3 atm], and 90 0C [194 OF] and 60 OC

[140 OF] at 101 kPa [1 atm]. The amount of each component was estimated based on corrosion

at 90 OC [1940] for 0.5 hour. Given the significant uncertainties in the corrosion rates in borated

water as a function of temperature and to provide a comparative assessment of the effect of

temperature and pressure, a fixed amount of components was used as an input for the

simulations. Input values used in the simulations are shown in Table 3-1. The basis for

selecting these values was discussed in Chapter 2. The boron concentration was fixed at

0.26 M [2,800 ppm]. Simulations were conducted at a pH of 7, and the formation of solid

phases as a function of temperature and pressure was examined. A pH of 7 was obtained by

the addition of 8.4 x 10-3 mol/L of Na3PO4. The precipitation of phases during a 15-day

operation of the containment system at 60 °C [140 °F] was estimated by multiplying the hourly

corrosion rate of each component by 720. An additional amount of 1.5 M H3B03 was needed to

maintain a pH 7. An increase in pH was observed as the concentration of corrosion

components increased in the simulation. This increase in pH was attributed to the hydrolysis

reactions associated with the fiber insulation. Corrosion rates of the components at 90 °C

[194 °F] were used for simulation at different temperatures. These estimates lead to a

conservative assessment of long-term corrosion. Corrosion rates of components are expected

to be lower at 60 °C [140 °F] which is the likely temperature of the containment water during

steady-state.

Table 4-1 shows the calculated pH and Eh at quantity of temperatures and pressures in borated

water with 0.26-M [2,800-ppm] boron and 8.4 x 10-3 mol/L Na3PO4. At 60 °C [140 OF], pH in

8.4 x 10-3 mol/L of Na3PO4 borated water with 0.26-M [2,800-ppm] boron was 7. A slight

decrease in pH was observed with the increase in the temperature and pressure. Similarly,

redox potential at 60 °C [140 °F] was approximately -0.4 V versus the standard hydrogen

electrode (VSHE). Figure 4-1 shows the concentration of solid phases at a pH of 7. Table 4-2

provides a percent solid phase for each element present in the simulated containment water.

Table 4-1. pH and Redox Potential [Eh (VSHE)] of Simulated Containment Water with

0.26-M (2,800-ppm] Boron and 8.4 x 10-3 mol/L of Na3PO4

Test Conditions pH Eh (VSHE)

60 °C [140 °F] at 101 kPa [1 atm] 7.0 -0.40

90 °C [194 °F] at 101 kPa [1 atm] 7.0 -0.42

130 °C [266 OF] at 304 kPa [3 atm] 7.0 -0.44

150 °C [302 OF] at 507 kPa [5 atm] 7.0 -0.45

4-1
- -

1 .OE -04

-J

0

:70

0

U

C

0

U

1 .O E -06 -

UI U

1 .OE -08

'11UUU

Cu

i, ,11V

NaAI

S 1308

:f!0

Ca 5(O H)

(P04)3

Fe30 4 Fe3S i2

0 5(0 H )4

Pha e

ZnO Zn3 Fe3

F e2 03 (P 04)2 (P 04)2

2H20 8H20

Figure 4-1. Concentration, in mollL, of Dominant Solid Phases As a Function of

Temperature and Pressure In 0.26-M [2,800-ppm] Boron in Na3PO4 Simulated

Containment Water at pH 7

Table 4-2. Percent Element Distribution in Solid Phases at pH 7

Temperature Magnesium Iron Aluminum Zinc Silicon Calcium

and Pressure (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

150 C [302 °F], 0 91 100 90 35 100

507 kPa [5 atm]

130 °C [266 °F], 0 96 100 72 29 99

304 kPa [3 atm] .

90 °C [194 °F], 0 82 100 22 36 99

101 kPa [1 atm]

60 °C [140 0 F], 0 38 100 0 29 96

101 kPa [1 atm] .

4-2
Table 4-3 provides a percent distribution of solid phases for compounds observed at different

temperatures and pressures. Table 4-3 shows that over 90 percent of the solids precipitated

come from Ca5(OH)(PO4)3 and NaAISi 308 phases at pH 7. The contributions from other solid

phases is around 10 percent. The other phases include Fe3Si4O10(OH)2, Fe3(PO4)2j8H2O,

Fe3 04, ZnO-Fe203, and Zn3(OH)(PO4)3-2H20. The contribution of zinc containing phases was

less than 2 percent. The Ca5(OH)(PO4)3 solid phase concentration remained the same from

150 0C [302 OF], 507 kPa [5 atm] to 60 *C [140 OF], and contained almost 100 percent of the

calcium present in the simulated containment water. There was no phase change observed for

copper. Most of the copper added in the simulation remained as copper metal. Aluminum is

present as aluminum metal and fiber insulation. All the aluminum was in NaAlSi308 and no

change in concentration was observed in the simulation temperature range. A redistribution of

iron phases similar to the iron behavior in pH 10 was observed. However, different phases were

formed. At temperatures above 130 OC [266 OF], 304 kPa [3 atm], iron was present as Fe304

and ZnO-Fe203. Greater than 90-percent of the iron was associated with these two solid

phases. ZnO-Fe203 phase contained 90-percent zinc at 150 OC [302 OF], 507 kPa [5 atm] and

72 percent zinc at 130 0C [266 OF], 304 kPa [3 atm]. At 90 OC [194 OF], 101 kPa [1 atm], zinc

was present as Zn3(OH)(PO4)3-2H2O which incorporated about 22-percent zinc, and iron was

present as Fe3Si4O10(OH)2 which incorporated 82-percent iron. At 60 °C [140 OF], 100 percent

of zinc was present as a ZnHPO4 soluble phase, while 38 percent of the iron was present as

Fe3(PO4)2-8H20. Magnesium that was released from fiber insulation was 100-percent soluble.

Between 150 °C [302 °F], 507 kPa [5 atm] and 60 °C [140 OF], 29 to 36-percent of the silicon

was distributed within various solid silicates. No significant change in silicon distribution

was observed.

Simulations indicated no significant changes in the precipitation of dominant solid phases

resulting from silicon, aluminum, calcium, and magnesium as the temperature decreased from

150 to 60 °C [302 to 140 °F] and the pressure dropped from 5 to 101 kPa [1 atm]. Significant

phase changes and redistribution of iron and zinc phases were observed as shown in

Figure 4-1. In addition, the elemental concentration for both iron and zinc in solid phase

reduced significantly as shown in Table 4-2. While reduction in the amount of solid phases at a

lower temperature would assist in unclogging the sump pump, it is important to analyze the

formation of phases during steady-state operations. As corrosion proceeds, the concentration

of corroded species increases with time. Figure 4-2 compares the observed solid phases at

I Table 4-3. Percent Solid Phases at pH 7

Ca5(OH) Fe3S14O10 Fe3(PO4)2- ZnOTemperature and NaAISI30, (P04 )3 (OH)2 81120 Fe 2O3 Fe304

Pressure (Percent) (Percent) (Percent) (Percent) (Percent) (Percent)

150 °C [302 °F], 25 63 - _ 2 10

507 kPa [5 atm]

130 °C [266 F1], 25 63 1 _ 4 10

304 kPa [3 atm]

90 °C [194 °F], 26 64 9 - -

101 kPa [1 atm]

60 °C [140 °F], 28 67

101 kPa [1 atm]

4-3
I

0

0

° I. E-088

M 0

0 00

Fiue42 ocnrton-nmlL fDmnn So.li Phse a

z 1 0 6 aC U- - c N 6

15Dy na02 M C,0 p]BrnNuO iuae Cotimn

LO 0)

0j) UI

LO

Phases

Figure 4-2. Concentration, in mnolIL, of Dominant Solid Phases at

150 0

C [302 0F], 507 kPa [5 atm] for 0.5 Hour at 60 0

C [140 OF] for

15 Days in a 0.26 M [2,800 ppm] Boron, Na3PO 4 Simulated Containment

Water at pH 7

pH 7 after a 15-day corrosion test at 60 0

C [140 OF] with 0.5 hour corrosion at 130 0C [266 OF], 304 kPa [3 atm]. The dominant solid phases formed at pH 7 after 15 days were Ca5(OH)(PO4)3 , NaAISi3 08, Ca2Mg5Si8022(OH)2, Fe3Si4O10(OH)2, and SiO2 with a minor quantity of Zn2SiO4 in the

simulated containment water. While Ca5(OH)(PO4)3 and NaAISi 308 concentrations were similar

to the high-temperature high-pressure phases, CaSiO 3, Ca2Mg5Si8022(OH)2, Fe3Si4O10(OH)2, and Zn2SiO4 were not observed at high-temperature and pressure for pH 7 at 130 °C [266 °F], 304 kPa [3 atm].

This simulation indicates that solid phases formed in the first 0.5 hour of a LOCA event at

130 °C [266 OF], 304 kPa [3 atm] may not be found in a 15-day or longer simulation test at 60 °C

[140 OF].

4.1 Sensitivity Analyses

The above simulations in Na3PO4 containment water at pH 7 are based on corrosion rates at

90 0C [194 OF]. As discussed in Chapter 2, corrosion rates could vary significantly with

4-4

UM
temperature. To gain confidence in simulations, a series of simulations was conducted by

varying the amount of each component and analyzing its influence on the formation of

solid phases.

4.1.1 Behavior of Zinc Metal in the Simulated Containment Water

The effect of zinc corrosion rate on the formation of solid phases was evaluated by conducting a

sensitivity analysis at 60 0C [140 OF] and 130 'C [266 OF], 304 kPa [3 atm]. The zinc

concentration in the basecase simulation was 2 x 10- mol/L. In the sensitivity analysis the zinc

concentration was varied between 1 x 10-8 and 1 x 10-4 mol/L. Figures 4-3 and 4-4 show the

influence of zinc additions on the formation of solid phases in the simulated containment water

at pH 7; 60 0C [140 OF]; and 130 CC [266 OF]; 304 kPa [3 atm]. Also shown in the figures are

soluble Zn(OH)" and Zn 2 phases.

The data show that at 60 'C [140 OF], zinc was predominantly present as a soluble phase

consisting of Zn(OH)+' and Zn" 2 below 2.5 x 10-6 mol/L concentration of zinc, while at 130 *C

[266 'F], 304 kPa [3 atm] a zinc-based soluble phase was formed below 1 x 10-6 mol/L zinc

concentration. At 60 °C [140 °F] and zinc concentration exceeding 2.5 x 10-6 mol/L, zinc was

predominantly present as Zn3(OH)(PO4)3-2H20 solid phase. At 60 °C [140 OF], dominant phases

such as Ca5(OH)(PO4)3 and NaAISi308, were not influenced by zinc additions as shown in

Figure 4-3. However, at 130 °C [266 OF], 304 kPa [3 atm] and zinc concentrations exceeding

I x 10-6 moUL, zinc was present as ZnO*Fe2O3 up to 2 x 10-5 moltL and as Zn3(OH)(PO4)3-2H 20

at concentrations exceeding 2 x 10-5 mol/L. In addition, a reduction in Fe3O4 concentration was

observed due to incorporation of iron in ZnO-Fe2O3. At 130 °C [266 OF], 304 kPa [3 atm],

dominant phases such as Ca5(OH)(PO4)3 and NaAISi308, were not influenced by zinc additions

as shown in Figure 4-4.

The influence of zinc was limited to interactions between solid phases associated with iron and

zinc. Dominant solid phases such as NaAISi 3O8 and Ca5(OH)(PO4)3 were not influenced by the

presence of zinc-containing phases in the simulated containment water. The formation of solid

Zn2SiO4 occurred in a 15-day simulation test where solid Zn2SiO4 was a predominant solid

species. The increase in zinc concentration increased the concentrations of

Zn3(OH)(PO4)3-2H20 at 60 °C [140 OF], and Zn3(OH)(PO4)3 2H20 and ZnO-Fe2O3 at 130 °C

[266 °F], 304 kPa [3 atm].

4.1.2 Behavior of Aluminum Metal in Simulated Containment Water

The source for aluminum is aluminum metal and fiber insulation. The effect of aluminum metal

concentration on the formation of solid phases was evaluated by conducting a sensitivity

analysis at 60 °C [140 OF], and 130 °C [266 °F], 304 kPa [3 atm]. The aluminum concentration

in the basecase simulation was 1.5 x 10-5 mol/L. In the sensitivity analysis, the aluminum

concentration was varied between 1 x 10-7 and 1 x 10-3 mol/L. Figures 4-5 and 4-6 show the

influence of aluminum additions on the formation of solid phases in the simulated containment

water at pH 7 at 60 °C [140 OF] and 130 °C [266 °F], 304 kPa [3 atm]. These data show that in

the simulated containment water at pH 7 at 60 °C [140 °F], aluminum was predominantly

present as NaAISi308. However, for aluminum concentrations exceeding 1.0 x 10-4 mol/L,

formation of Al(OH)3 occurred at 60 °C [140 OF], and AIO(OH) forms at 130 °C [266 °F], 304 kPa

[3 atm]. However, in a 15-day simulation, aluminum was exclusively present as NaAISi308. At

both temperatures, Ca5(OH)(PO4)3 was an additional dominant solid phase. Other solid phases

4-5
Dominant Solids & ZnOH+, Zn2+ vs Zn at 60 C, pH 7

p p p

1e-6 k

+

N

+

0

N

od

.j

0

1 e-6

1 e-7

1 e-8

U

A A A A A A A

A A A------

/ -E-Zo2 [nMI]

A -~~-.ZnO it.1 m

* A *NaASI308 ~lidIMAWn~

1 e-9

lw q''-Cu'Solld jM0'Q , - lz"''s" I D'M -MM'

1-in'

1 e-9 1 e-8 1e-7 1e-6 1e-5 0.0001

Zn [mol]

Figure 4-3. Dominant Solid Phases at 60 'C [140 OF], 101 kPa [1 atm] As a

Function of Zinc in Simulated Containment Water at pH 7

Dominant Solids & ZnOH+, vs Zn at 130 C, 3 atm, pH 7

O.DO01

& A A & &

1e-5

E

+

0

N

E

0

1e9-

1 e-7

_ _ _ _ _ _ _ U

* , * .. *.*,, //

.. A- -' A..

. A

1 e-9

1e-9.

1e-9 Ie-8 1 e-7 1e-5 1e-5 0.0001

Zn Imoll

Figure 4-4. Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As

a Function of Zinc in Simulated Containment Water at pH 7

4-6
Dominant Solids vs Al at 60 C, pH 7

0.001

_ -AKOHl3 - Solid Imoll

-*-C-(OiHXi4-3. Solid Imoq

- -N.AISi3085 Solid [n.ol]

-:-- F.3P04.8 [B20 teQo:

-*---Cu Selid lmnQ S

0.0001 --&-Fo35i4010(Ol2 . Solid Imaq

(D l e-6

Is- ' 5 * * *

l e-7 ............

le-9 le-7 le-6 le-S 0.0001 0.001

Al [moll

Figure 4-5. Dominant Solid Phases at 60 'C [140 °F], 101 kPa [1 atm] As

a Function of Aluminum in Simulated Containment Water at pH 7

Dominant Solids vs Al at 130 C, 3 atm, pH 7

0.001

CoS .il [meou

0.0001 _

in 1e-5

E

1 e-S

1 e-7

Is- le-7 Ile-6 le-5 0.0001 0.001

Al [moll

Figure 4-6. Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm] As

a Function of Aluminum Concentration in Simulated Containment Water

at pH 7

4-7

CS3
11 nl -11 V

were at least an order of magnitude lower in concentration. Even though at 60 0C [140 OF],

Fe3S14O10(OH)2 transformed to Fe3(P04)2-8H2O, the concentration of iron containing solid phase

remained well below that of the dominant Ca5(OH)(PO4)3 phase.

The influence of aluminum was limited to increasing the concentration of NaAISi30 and

formation of AI(OH) 3 that occurred at 60 CC [140 OF], and AIO(OH) at 130 0C [266 OF], 304 kPa

[3 atm]. NaAISi308 and Ca,(OH)(PO4)3 remained dominant solid phases. For aluminum

concentrations exceeding 3.0 x 10-4 mol/L, the dominant phase was AI(OH) 3 at 60 0C [140 0F],

and AIO(OH) at 130 0C [266 OF], 304 kPa [3 atm]. However, in a 15-day simulation, aluminum

was exclusively present as NaAlSi 308.

4.1.3 Behavior of Carbon Steel in Simulated Containment Water

The contribution for iron comes from carbon steel. The effect of iron metal concentration on the

formation of solid phases was evaluated by conducting sensitivity analysis at 60 0C [140 0F] and

130 0C [266 OF], 304 kPa [3 atm]. The iron concentration in the basecase simulation was

2.8 x 10-5 mol/L. In the sensitivity analysis, the iron concentration was varied between 1 x 10-7

and 1 x 10-3 mol/L. Figures 4-7 and 4-8 show the influence of iron additions on the formation of

solid phases in the simulated containment water at a pH of 7 at 60 0C [140 OF] and 130 °C

[266 °F], 304 kPa [3 atm].

The data show that at 60 0C [140 °F] and below 7x 10-4 mol/L iron concentration, iron was

predominantly present as a soluble Fe+2 phase, while at 130 0C [266 °F], 304 kPa [3 atm], an

iron-based soluble phase was formed below I x 10-6 mol/L iron concentration. At 60 °C

[140 OF] and iron concentration exceeding 7 x 10-4 mol/L, iron was predominantly present as

Fe3(PO4)2 8H2O solid phase. At 60 0C [140 °F], dominant phases were Ca5(OH)(PO4)3 and

NaAISi308, and were not influenced by iron additions as shown in Figure 4-7. However, at

130 0C [266 OF], 304 kPa [3 atm] and iron concentrations exceeding 1 x 10-6 mol/L, iron was

present as ZnO-Fe203 up to 1 x 10-5 mol/L, and as Fe304 from 1 x 10-5 mol/L and in

combination with Fe3Si2O5(OH)4 for concentrations exceeding 3 x 10-4 mol/L iron. The

contribution of iron phases below 3 x 10-5 mol/L iron concentration was insignificant compared

to other dominant phases.

The influence of iron was limited to increasing the concentration of Fe3(PO4)2 8H20 at 60 0C

[140 °F], and the concentration of Fe304 and Fe3Si2O(OH)4 at 130 0C [266 °F], 304 kPa [3 atm].

Iron had no influence on NaAISi 308 and Ca5(OH)(PO4)3 which were the dominant solid phases.

The influence of iron was not expected below 3 x 10-4 mol/L concentration of iron.

4.1.4 Behavior of Concrete in Simulated Containment Water

CaO and SiO2 are the main contributors from concrete (assuming Ca2SiO4 is the primary

concrete constituent). Both CaO and SiO2 are also present in fiber insulation. The contribution

of CaO from concrete is 2 x 10' mol/L while the contribution of CaO from insulation is

8.3 x 10-4 mol/L. The effect of concrete concentration on the formation of solid phases was

evaluated by conducting a sensitivity analysis at 60 0C [140 °F] and 130 °C [266 °F], 304 kPa

[3 atm]. The analysis was conducted by varying the amount of Ca2SiO4 in the simulated

containment solution. The concrete concentration in the basecase simulation was

1.3 x 10-4 mol/L. In the sensitivity analysis, the Ca2SiO4 concentration varied between 1 x 10-6

4-8
I

Fe60C pH7 - Dominant Solids & Fe2+ vs Fe

0.001

0.0001

e

E

0

1e-5

1ieU

A A A A A I A

A

A

U

A

*-..-..---,,-4.4 4 4 -4 A

e2(mci]

A - --Ca5(OHXpO-Sclld (mcli

.N.AlsI3O8 -SQIid (mcli -*--Cc- Solid (mcli

1 e-7

l e-8 1 e-7 1 e-S 1 e-5 0.0001 0.001

Fe [mol]

Figure 4-7. Dominant Solid Phases at 60 0

C [140 OF], 101 kPa [1 atm] As a

Function of Iron Concentration in the Simulated Containment Water at pH 7

Fe130C, 3 atm pH7 - Dominant Solids & Fe+2 vs Fe

0.001 e

0.0001

* * * * * * 0 1i --- -- l--

A A* A A

I

U.-

-e

0

1 e-S

1i-

*- -. - -

09

S--- - - -4 .-- - - -I4. . . . .

.

Ie-7

A

-s-8 1 e-7 I - 1 e-5 0.0001 0.001

Fe [moll

Figure 4-8. Dominant Solid Phases at 130 0

C [266 OF], 304 kPa [3 atm] As

a Function of Iron Concentration in Simulated Containment Water at pH 7

4-9
-

and 1 x 1 0-2 mol/L. The CaO and SiO2 contributions from fiber insulation were fixed while

conducting the sensitivity analysis for concrete.

Figures 4-9 and 4-10 show the influence of concrete additions on the formation of dominant

phases in the simulated containment water at a pH of 7 at 60 0C [140 OF] and 130 0C [266 OF],

304 kPa [3 atm]. These data show that concrete was predominantly present as Ca,(OH)(PO4)3,

and its concentration increased with the concrete concentration. For concrete concentration

exceeding 1 x 10-4 mol/L at 60 0C [140 OF] and 3 x 10-4 mol/L at 130 0C [266 OF), 304 kPa

[3 atm], SiO2 was observed as a dominant solid phase along with Ca5(OH)(PO4)3. One other

dominant solid phase included NaAISi3O8 for which concentration did not change with

temperature or pressure. A conversion of Fe3(PO4)2-8H20 to Fe3Si4O10(OH)2 at concrete

concentration of 1 x 10-4 moVL at 60 0C [140 OF]. At 130 0C [266 OF), 304 kPa [3 atm], Fe3O4

converted to Fe3Si4010(OH)2 at about 1 x 10-4 mol/L and to Ca3Fe2Si3012 at 1 x 10-3 mol/L. At

3.5 x 10-4 mol/L and 600 C [1400 F] concentration of concrete, ZnO-Fe2O3 converted to solid

Zn2SiO4. At 130 0C [266 OF], 304 kPa [3 atm], zinc was soluble below 3 x 10-3 mol/L concrete

concentration. However, the concentration of zinc-based solid phases was insignificant

compared to the dominant solid phases.

The influence of concrete was limited to increasing the concentration of Ca5(OH)(PO4)3 at 60 0C

[140 OF], and 130 0C [266 OF], 304 kPa [3 atm]. At concrete concentrations exceeding

1 X 10-3 mol/L, SiO2 was observed as an additional dominating solid phase. While

transformation of the zinc phase was insignificant, the transformation of iron phases could be

important below 1 x 10-4 mol/L. Concrete concentration had no influence on NaAISi308 which

was the dominant solid phase.

4.1.5 Behavior of Fiber Insulation in Simulated Containment Water

Fiber insulation is contained in several components as shown in Table 2-7. Both CaO and SiO2

are also present in concrete. The effect of fiber insulation concentration on the formation of

solid phases was evaluated by conducting a sensitivity analysis at 60 0C [140 OF] and 130 0C

[266 OF3, 304 kPa [3 atm]. In the sensitivity analysis, the fiber insulation concentration was

varied from 1 x 10-3 to 10 times the basecase concentration. The CaO and SiO2 contributions

from concrete were fixed while conducting the sensitivity analysis for fiber insulation.

Figures 4-11 and 4-12 show the influence of fiber insulation on the formation of dominant solid

phases in the simulated containment water at pH of 7 at 60 °C [140 OF] and 130 0C [266 OF],

304 kPa [3 atm].

At 60 0C [140 0F], in a 10 times the basecase concentration of fiber insulation the dominant solid

phases were Ca5(OH)(PO4)3, NaAISi308, and Fe3Si4O10(OH)2. Both Ca5(OH)(PO4)3 and

NaAISi 308 were present as dominant solid species for all concentrations evaluated. As the

amount of silicon was reduced due to decreasing the concentration of insulation fiber, the

Fe3Si4O10(OH)2 phase formed at 60 0C [140 OF] converted to Fe3(PO4)28H 20. In addition, the

concentration of NaAISi308 continued to decrease as the concentration of fiber insulation

was reduced.

4-10
Dominant Solids vs Ca2SiO4 at 60 C. pH 7

0.01

0.ojo

0*5S02- Soiid fmooll

-4-C.S(0HP04Z- Solidlv omo

iS1 Solid [molf -

.Ap .F,.3Sl401~0Cit. Selid (nmel

4*_FaTP04)2.H201mq/:

---- Cu- Solid InolA--Zn2SiO4- Solid U loN

I

Vi

EX

0ES

0.0001

18s5 A~ .r I A A A A

A- -- -X -A --- - . - ...

- a.......... . .. .. *.. ....... * ..

1e-6

1e-7.1 e-7 1e-6 1 e-5 0.0001

Ca2Si04 [moll

0.001 0.01

Figure 4-9. Dominant Solid Phases at 60 'C [140 °F], 101 kPa [1 atm] As

a Function of Ca2SiO4 in Simulated Containment Water at pH 7

Dominant Solids vs Ca2SiO4 at 130C.3 atm, pH7

0.01

0.011

,g o.0xih

I

E

E 1 e-5

0

I

4 A A- A

* * -- - - - ---- ----

I --------- 

A

A

* * 4 4

- - - -* . ... a. .... 1s-6

1e-7 .

1 e-7 1 e-6 1e-5 0.0001

Ca2SiO4 [moll

0.001 0.01

Figure 4-10. Dominant Solid Phases at 130 °C [266 OF], 304 kPa [3 atm]

As a Function of Ca2SiO4 in Simulated Containment Water at pH 7

4-11
E

0

- 1.lE-06l

(U

1.OE0E 8D-loo

4-

iC C

CC

0

Ul) !i Q

LL a) LL. Rums

Figure 4-11. Dominant Solid Phases at 60 'C [140 OF], 101

kPa [1 atm] at Different Fiber Insulation Concentrations in

Simulated Containment Water Containing Na3PO4

At 130 0C [266 0F], 304 kPa [3 atm], in a 10 times the basecase concentration of fiber insulation

in the simulated containment water, dominant solid phases were the same as a 60 0C [140 OF].

As the amount of silicon was reduced due to decreasing the concentration of insulation fiber,

the Fe3Si4O10(OH)2 phase transformed to Fe304 and ZnO-Fe203. In addition, the concentration

of NaAISi 308 continues to decrease as the concentration of fiber insulation was reduced.

Except for iron phase redistribution, no significant changes were observed as fiber insulation

corroded. The fiber insulation sensitivity analysis at pH 7 indicated no significant impact on the

formation of solid phases over a wide fiber insulation concentration range in simulated

containment water after a LOCA event.

4-12

C?*L
E10.01X EQ X OBasecase O1OX -.- l . = : .......... .- I... =-.. 1 .OE-04 i- I

0

E

. 1.0E-06 -

0

U 000 M1|l1

1 .OE08 -,_i

0 0- cr, 2 c0 VN I 0

IL _ U

0 Q L- °O N °

TV)

UPhases

Figure 4-12. Dominant Solid Phases at 130 'C [266 OF],

101 kPa [1 atm] at Different Fiber Insulation Concentrations in

Simulated Containment Water Containing Na3PO4

4-13

U-
5 EVALUATION OF A NEED TO CONDUCT EXPERIMENTS AT HIGH

TEMPERATURE AND PRESSURE SYSTEM

An evaluation of the need to conduct integrated chemical effects tests (planned at the University

of New Mexico) at high temperature and pressure to simulate initial stages of a LOCA event has

been performed. This requires an assessment of solid phases that exclusively occur either at

high temperature and pressure or at steady-state operating conditions. In addition, the

distribution of an element within solid and liquid phases at any given temperature and pressure

is important. If 100 percent of an element is present in a solid phase but the composition of the

solid phase changes, the effect on sump clogging could be minimal. However, if element

solubility changes, the effect on sump clogging can be significant. The concentrations of solid

phases through a range of temperatures and pressures are also important. Concentration of

phases is a product of corrosion rate and time. Typically, the higher the temperature, the higher

the corrosion rate. A higher corrosion rate at higher temperature can be simulated as corrosion

at lower temperature but for longer times. For example, the corrosion in 0.5 hour at 130 0C

[266 OF], 304 kPa [3 atm], is equivalent to corrosion for 50 hours at 60 0C [140 OF] if the

corrosion rate is 100 times lower, or that for 500 hours at 60 OC [140 OF] if the corrosion rate is

1,000 times lower.

The simulations presented in this report (Chapters 3 and 4) are based on corrosion rate data

from literature. The selection of corrosion rates was based on conservative values for pH

between 7 and 10 in borated water. In some cases, (e.g., fiber insulation corrosion), no data

were available for borated water. In these cases, a best estimate based on other closely related

(e.g., nuclear waste glasses for fiber insulation) environment was used. Corrosion rates are

highly dependent on temperature. However, temperature-dependent data were often not

available. Therefore, sensitivity analysis was conducted over a wide range of amounts for each

component to evaluate the effect of temperature change. Furthermore, uncertainties exist in

estimation of the surface area for concrete particulates. The NRC Test Plan, Revision 12b

(NRC, 2005), provides the amount of concrete particulates per unit volume, but the information

on the size and size distribution is not available to estimate exposed surface area. While

relevant data could improve prediction of solid phase formation more accurately, the simulations

presented in this study provide a reasonable assessment of solid phase corrosion product

formation covering a wide range of components present in a containment system.

5.1 Need to Conduct Experiments at High Temperature and Pressure

System in an Alkaline Simulated Containment Water

A review of simulation data and associated sensitivity analysis (Chapter 3) for an alkaline

simulated containment water at pH 10 indicates that

(i) NaAISi308, Ca3Fe2Si3O12, and Fe3Si2O5(OH)4 were dominant solid phases that

contributed to over 90 percent of the solid phases formed between at 150 OC [302 OF],

507 kPa [5 atm] and 60 OC [140 OF]. The Ca3Fe2Si30,2 solid phase was formed at

150 0C [302 OF], 507 kPa [5 atm] while Fe3Si2O5(OH)4 was formed at 60 OC [140 OF] and

is attributed to the retrograde solubility of calcium in iron bearing minerals. Despite

these phase changes, all the iron was always present in the solid phase (Figure 3-1).

5-1
a - -

.11

(ii) Copper had no influence on the precipitation of solid phases. No corrosion of copper

is expected (Figure 3-1).

(iii) Zinc contribution was below 5 percent to the total solid phases. Zinc was dominantly

present as ZnO-Fe203 for which solubility decreased with the decrease in temperature

(Table 3-4). At 60 0C [140 OF], 98 percent of zinc was present in solid phase (Table 3-3).

Zinc was predominantly present as a mixture of solid Zn2SiO4 and ZnO Fe2O3 phases at

concentrations higher than 3 x 10-5 mol/L at 60 0C [140 OF] and 130 0C [266 IF],

304 kPa [3 atm] or at 10 times the basecase concentration of fiber insulation

(Figures 3-5 and 3-6).

(iv) Aluminum metal has always associated with NaAISi 308 for which solubility decreased

with decrease in temperature (Table 3-1). At 60 OC [140 OF], 100 percent of aluminum

was present in the solid phase (Table 3-3). An increase in the aluminum concentration

increased the concentration of NaAISi308 solid phase. In addition, formation of AI(OH)3

occurred for aluminum concentrations exceeding 3 x 10-4 mol/L at 60 0C [140 'F]. The

formation of AI(OH) 3 was not observed at 130 0C [266 F], 304 kPa [3 atm] (Figures 3-7

and 3-8).

(v) Calcium-containing components showed higher solubility at lower temperatures.

Concrete and fiber insulation were the key sources for calcium. At 130 0C [266 OF],

304 kPa [3 atm], 17 percent of calcium was associated with calcium-bearing solid

phases, while at 60 0C [140 OF], only 1 percent was associated with calcium-bearing

solid phases (Table 3-3). The calcium phases formed at higher temperatures tended to

solubilize at lower temperatures, and thereby, could assist in unclogging pump strainers.

Irrespective of the temperature and pressure, for Ca2SiO4 exceeding 1 x 10-3 mol/L, the

concentration of CaSiO3 increased with an increase in concrete concentration

(Figures 3-11 and 3-12).

(vi) The concentration of silicon in the solid phase increased with decrease in temperature.

At 130 0C [266 °F], 304 kPa [3 atm], 25 percent of silicon was associated with solid

silicate phases, while at 60 0C [140 OF], 42 percent of silicon was associated with solid

silicate phases (Table 3-3). In a 15-day simulation at 60 0C [140 OF], all components

(except copper) present in the simulated containment water were present as solid

silicates (Figure 3-2). As silicon concentration was reduced, the concentration of silicate

phases reduced also (Figures 3-13 and .3-14).

(vii) At 60 0C [140 OF], for iron concentrations below 1 x 10' mol/L, iron was predominantly

present as ZnO-Fe203, and above 1 x 10-5 mol/L iron was predominantly present as

Fe3Si205(OH)4 (Figures 3-9 and 3-10). Formation of Fe3O4 was observed at 1 x 10-3

mol/L. At 130 0C [266 OF], 304 kPa [3 atm], for iron concentration below 1 x 10' mol/L

iron was predominantly present as ZnO-Fe203. Between 1 x 10-6 and 7 x 10-5 mol/L iron

was predominantly present as Ca3Fe2Si30,2, and above 7 x 10-5, iron was predominantly

present as Fe304 Again formation of Ca3Fe2Si30,2 at 130 0C [266 OF], 304 kPa [3 atm]

and formation of Fe3Si205(OH)4 at 60 0C [140 OF] are attributed to the retrograde

solubility of calcium in iron-bearing minerals. Despite these phase changes, all iron was

in the solid phase. At lower fiber insulation concentrations and pH 10, iron was

predominantly present as Fe304. As the concentration of fiber insulation increased, iron

was present as Ca3Fe2Si30,2. In a 15-day simulation, iron was exclusively present as

5-2
Ca3Fe2Si3O12 (Figures 3-13 and 3-14). In all cases, most of the iron was associated with

the solid phases (Figure 3-2).

These simulations indicated, irrespective of temperature and pressure, that silicates of iron and

aluminum contribute 90 percent of the solid phases formed in an alkaline solution at pH 10.

While the distribution and formation of these silicate phases could change based on

temperature, pressure, or concentration, the total percentage of solid phases in simulated

containment water remains around 90 percent. The contributions of other solid phases are less

than 10 percent. Based on these simulations, we conclude that minimal changes are expected

as the high-temperature and pressure conditions that exist during the initial stages of a LOCA

event approach steady-state conditions.

5.2 Need to Conduct Experimental Analysis in a High-Temperature HighPressure System in Simulated Containment Water Containing

Trisodium Phosphate

A review of simulation data and associated sensitivity analysis (Chapter 4) for a trisodium

phosphate simulated containment water at pH 7 indicates that

(i) There were significant differences in solid phase formation in Na3PO4 containing

simulated containment water at pH 7 compared to alkaline simulated containment water

at pH 10. At pH 7, Ca5(OH)(PO4)3 was the dominant solid phase, containing almost

100 percent of the calcium, while at pH 10, calcium was approximately 1 percent soluble

at 60 0C [140 OF]. A significantly higher quantity of solid phases was formed in solutions

containing Na3PO4 compared to alkaline containment water (Figures 3-1 and 4-1).

(ii) Irrespective of temperature and pressure, over 90 percent of the solids precipitated

originate from Ca 5(OH)(PO4)3 and NaAISi 308 at pH 7 (Table 4-3).

(iii) Ca,(OH)(PO4)3 was the dominant solid phase and increased with an increase in concrete

concentration. For concentration of concrete exceeding 3 x 10-4 mol/L, Ca5(OH)(PO4)3

coexisted with solid SiO2 phase. The concentrations of these two phases far exceed

contributions from other solid phases (Figures 4-7 and 4-8).

(iv) Copper had no influence on the precipitation of solid phases (Figure 4-1).

(v) Aluminum metal was always associated with NaAISi3O8, and the concentration of

NaAISi308 increased with an increase in aluminum concentration. However, formation of

Al(OH)3 and AIO(OH) was observed for aluminum concentrations exceeding

3 x 10-4 mol/L at 60 0C [140 'F] and 130 0C [266 OF], 304 kPa [3 atm], respectively

(Figures 4-5 and 4-6). In a 15-day simulation, aluminum was present exclusively as

NaAISi308 (Figure 4-2).

(vi) Both iron and zinc showed a decrease in solid phase concentration with decrease in

temperature and pressure. The solid phase concentration of zinc reduced from

90 percent solid phase at 150 0C [302 OF] to a fully soluble phase at 60 0C [140 OF]

(Table 4-1). The solid phase concentration of iron reduced from 91 percent at 150 °C

[302 OF] to 38 percent at 60 0C [140 °F] (Table 4-1). However, this decrease in solid

5-3
aI

phase concentration was accompanied by changes in the composition of the solid

phase. At 150 0C [302 OF], 507 kPa [5 atm], and 130 0C [266 OF], 304 kPa [3 atm], iron

and zinc were present as Fe3O4 and ZnO Fe2O3 (Table 4-2). However, at 90 0C [194 OF],

zinc was present as Zn3(PO4)2 -2H20 and iron was present as Fe3Si4010(OH)2. When the

temperature was reduced to 60 OC [140 OF], zinc was completely soluble, and iron was

present as Fe3(PO4 )2j8H2O. The formation of these phases was limited to interaction

between zinc and iron. Dominant phases such as Ca,(OH)(PO4)3 and NaAiSi308 were

not influenced by zinc and iron.

(vii) As the amount of silicon was reduced due to a reduction in fiber insulation concentration,

Fe3Si4010(OH)2 converted to Fe3(PO4)2-8H 2O at 130 0C [266 OF], 304 kPa [3 atm] as a

mixture of Fe3O4 and ZnO-Fe2O3. Other than reorganization of iron phases, no

significant changes were observed (Figures 5-11 and 5-12).

(viii) The dominant solid phases formed after 15 days were Ca5(OH)(PO4)3 and NaAISi308,

with minor quantities of Ca2Mg5Si8022(OH)2, Fe3Si4O10(OH) 2, SiO2, and Zn2SiO4

(Figure 5-2). While Ca,(OH)(PO4)3 and NaAISi 308were present at high-temperature,

high-pressure phases, Fe3Si4010(OH)2, SiO2, Ca2Mg5Si8 022(OH)2, and Zn2SiO4 were not

observed at high temperature and pressure at pH 7 at 130 °C [266 OF], 507 kPa [5 atm].

Conversion of Fe304 and ZnO-Fe2O3 to Fe3Si4010(OH)2 and Zn2SiO4 was observed.

These simulations indicated that both iron and zinc have increased solubility as temperature

was reduced from 150 0C [302 OF] to 60 0C [140 OF]. Irrespective of temperature and pressure,

Ca,(OH)(PO4)3 and NaAISi308 contribute over 90 percent of the solid phases formed in a

Na3PO4, pH 7 solution. The distribution of these two phases did not significantly change as a

function of temperature and pressure. Based on these simulations, we conclude that minimal

chemical changes are expected as the high-temperature and pressure conditions that exist

during the initial stages of a LOCA event approach steady-state conditions. Therefore, the

integrated chemical effects tests planned at the University of New Mexico can be performed at

atmospheric pressure and 60 0 [140 °F]. There is no need for a pressurized test loop.

5-4
6 EVALUATION OF POTENTIAL FOR GEL FORMATION

This section provides an analysis of the potential for formation of a precipitate gel that could

clog containment room pump straining after a LOCA event.

S102 is marginally soluble in water as shown by Eq. (6-1).

SiO2 (solid)+ 2H20 = Si(OH) 4 (6-1)

However, in alkaline solutions, the reactions shown by Eqs. (6-2) and (6-3) occur.

Si(OH)4 + OH- = (HSiO3 ) + H2 0 (6-2)

(HSiO3 ) + OH- = (SiO4 )2- + H20 (6-3)

The formation of silicate ions (SiO4)

2- occurs at pH exceeding 10. A typical silicate tetrahedra

structural unit is shown in Figure 6-1. A silica tetrahedra unit consists of a silicon atom

surrounded by four oxygen atoms. In solutions containing NaOH, silicate ion reacts to form

sodium trisilicate. This is commonly referred to as water glass and is widely used as an

adhesive. Insoluble metal silicates, when precipitated from aqueous solution, are usually a

gelatinous, amorphous mass. In dilute solutions, precipitation occurs at pH below which metal

hydroxide would precipitate. Often, hydroxides are precipitated along with silica by mutual

coagulation when a solution of polyvalent metal salt is mixed with a solution of soluble alkali

metal silicate (ller,1955).

In the presence of aluminum ions, silicon ions are replaced in the tetrahedra structure as shown

in Figure 6-1. The charge is balanced by a monovalent alkali ion or a divalent alkaline earth ion.

The structural units shown in Figure 6-1 for silicon and aluminum combine to form alkali

aluminosilicate or polysialate structural units as shown in Figure 6-2. The structure consists of

SiO4 -4 and MAI04 -4 tetrahedras linked alternately by mutual sharing of oxygen atoms as

shown in Figure 6-2. The charge is balanced by positive ions (M) such as alkalis (lithium,

sodium, potassium, cesium) or alkaline earths (calcium, magnesium).

In alkaline solutions, the aluminosilicate unit can react with an alkali silicate unit to form

polysialate (-Si-O-AI-O-), poly(sialate-siloxo) (-Si-O-Al-O-Si-O-), or poly(sialate-disiloxo) (-O-SiO-AI-O-Si-O-Si-O-) polymers as shown in Figures 6-3 and 64. These polysialates condense to

a gel similar to organic polymers at temperatures below 100 °C [212 OF].

This brief analysis indicates that gelling, a precursor to polymerization, could occur in alkaline

solutions when silicon, aluminum, and alkali ions are present. Therefore, gel formation is likely

in alkaline simulated containment water because gelling requires a higher pH.

6-1
- l l

0

i

-o -Si- 0-

0

0

M+ I

-O -Al- 0-

0

Figure 6-1. Silicon and Aluminum Tetrahedra Units

I I

0 0

I M+ 0

-o _Si-o _ Al- o_

0 0

Figure 6-2. A Basic Alkali Aluminosilicate Structural Unit. This Is also Referred to As

Polysialate (-Si-O-AI-O-) Unit.

0 0 0

I M+ i I

-0 -Si-O -Al- 0- Si-o -

I II

0 0 0

Figure 6-3. A Polymeric Poly(Sialate-Siloxo) Unit

I I I I

0 0 0 0

1 M+ I I I

-0 -Si-o -Al-_ 0o - i-o -Si- o- I I I I

0 0 0 0

Figure 6-4. A Polymeric Poly(Sialate-Disiloxo) Unit

6-2
7 SUMMARY AND CONCLUSIONS

A LOCA event causes rapid changes in the time-temperature-pressure-chemistry-pH conditions

in the containment environment. Changes in the coolant chemistry are further complicated

because of the interactions among the materials typically present. These complex interactions

will require extensive experimentation for an adequate analysis of the potential for sump

blockage caused by chemical precipitation. Thermodynamic simulations allow identification of

critical variables and their ranges considering the large number of components present in the

containment system during and subsequent to a LOCA event. This study modeled chemical

speciation of plausible chemical reaction products in containment water after a representative

LOCA event using thermodynamic simulation software. This report: (i) concludes that there is

no need for a pressurized test loop, (ii) assesses the formation of gelatinous products in the

typical time-temperature-pressure-chemistry-pH regime following a LOCA event, and

(iii) validates OLI Systems, Inc. software for speciation in borated waters.

The calculations documented in this report were made using a thermodynamic simulator

developed by OLI Systems, Inc. for evaluating aqueous chemical processes in industrial and

environmental applications. The simulations varied the amount of key components, pH

moderators (i.e., sodium hydroxide versus trisodium phosphate), pH, temperature, and pressure

to determine the need for a pressurized test loop for additional investigation. Computational

thermodynamics simulation calculations were conducted using ESP Version 6.6' and

StreamAnalyzer Version 1.2'. Key chemical components involved in speciation simulation were

copper, carbon steel, zinc, aluminum, fiber insulation, and concrete in 0.26-M [2,800-ppm]

boron solution. The surface areas exposed for these components during a LOCA event were

provided by the U.S. Nuclear Regulatory Commission, and literature data on corrosion rate for

these components were used to estimate amounts of corrosion. Given significant uncertainties

in corrosion rates in borated water as a function of temperature, and to provide a comparative

assessment of the effects of temperature and pressure, a fixed amount of each component was

used as an input for simulations. The amount of each component was estimated based on the

corrosion rate at 90 'C [194 'F] for 0.5 hour.

The influence of pressure, temperature, and pH on chemical speciation was studied by

speciating a fixed amount of each component based on its corrosion rate. In each simulation, a

fixed amount was speciated at 150 °C [302 *FJ at 507 kPa [5 atm], 130 0C [266 0F] at 304 kPa

[3 atm], and 90 0C [194 *F] and 60 0C [140 0F] at 101 kPa [1 atm]. The boron concentration was

fixed at 0.26 M [2,800 ppm]. The formation of solid phases as a function of temperature and

pressure was examined at pH values of 10 and 7. A pH of 10 was obtained by the addition of

0.23 mol/L [5,300 ppm Na] NaOH, and pH 7 was obtained by the addition of 8.4 x 10-3 mol/L of

Na3PO4. The precipitation of phases during a 15-day operation of the containment system at

60 °C [140 OF] was estimated by multiplying the hourly corrosion rate of each component by

720. The pH was adjusted to account for an increase in pH due to the increase in the

concentration of corrosion components. This increase in pH was attributed to hydrolysis

reactions associated with fiber insulation. The estimate for the total amount of corrosion

product was conservatively based on the corrosion rates of the components at 90 °C [194 °F].

Corrosion rates of components are expected to be lower at 60 °C [140 °F] the expected

steady-state temperature.

The need to conduct experiments at high temperature and pressure to simulate initial stages of

a LOCA event requires an assessment of solid phases that exclusively occur at high

7-1
-

temperature and pressure. In addition, distribution of elements in solid and liquid phases at any

given temperature and pressure is important. If 100 percent of an element is present in a solid

phase, but the composition of the solid phase changes, the effect on sump clogging should be

minimal. On the other hand, if the element become soluble, the effect on sump clogging could

be significant. However, the concentration of phases is a product of corrosion rate and time.

Typically, the higher the temperature, the higher the corrosion rate. The effect of a higher

corrosion rate at higher temperature can be simulated by corrosion at a lower temperature for

longer times. For example, the corrosion amount in 0.5 hour at 130 0C [266 OF], 304 kPa

[3 atm] will be equivalent to 50 hours at 60 0C [140 OF] if the corrosion rate is 100 times lower, or

500 hours at 60 0C [140 OF] if the corrosion rate is 1,000 times lower.

The simulations documented in this report are based on corrosion rate data from literature. The

selected corrosion rates were conservative values between pH 7 and 10 in borated water. In

some cases, for example fiber insulation corrosion, no data were available in borated water. In

such cases, a best estimate based on other closely related systems was used. Corrosion rates

are highly dependent on temperature, but temperature-dependent data were not available in

most cases. Therefore, sensitivity analysis was conducted over a wide range to evaluate the

effect of temperature. Furthermore, uncertainties exist in the estimation of the surface area for

concrete particulates. The NRC Test Plan, Revision 12b (NRC, 2005), provides the amount of

concrete particulates per unit volume, but the information on the size and size distribution is not

available to estimate exposed surface area. While better data could improve prediction of solid

phases, the simulations presented in this study reasonably assess the potential for solid phase

corrosion product formation covering a wide range of concentrations for each component

present in a containment system during a LOCA event.

7.1 Conclusions

Review of simulation data and associated sensitivity analyses in alkaline simulated containment

water at pH 10 indicate the following.

* NaAISi308, Ca3Fe2Si3012 and Fe3Si4O10(OH)2 were dominant solid phases that

contributed to over 90 percent of the solid phases formed between 150 0C [302 OF],

507 kPa [5 atm] and 60 0C [140 OF].

* The Ca3Fe2Si3O12, solid phase was formed at 150 0C [302 OF], 507 kPa [5 atm], while

Fe3Si2O5(OH)4 was formed at 60 °C [140 OF]. This transformation was attributed to the

retrograde solubility of calcium in iron bearing minerals. Despite these phase changes,

all the iron was present in the solid phase.

* Copper had no influence on the precipitation of solid phases, and no corrosion of copper

is expected.

* The contribution from zinc was insignificant compared to other solid phases and was

limited to 5 percent to the total quantity of solid phases.

* Sensitivity analyses for aluminum indicated formation of AI(OH)3 for aluminum

concentrations exceeding 2 x 10-4 mol/L at 60 0C [140 OF]. The formation of AI(OH)3

was not observed at 130 °C [266 °F], 304 kPa [3 atm].

7-2
* Sensitivity analyses for concrete indicated, irrespective of the temperature and pressure,

for Ca2SiO4 exceeding 1 x 10' mol/L, the concentration of CaSiO 3 increased with an

increase of concrete concentration.

* In a 15-day simulation at 60 OC [140 OF], all solid phases (except copper) present in the

simulated containment water were solid silicates.

* As silicon concentration was reduced, the concentration of silicate phases reduced also.

In an alkaline environment, the solubility of silica increased with an increase in pH and

temperature. Since silicates were major corrosion products, a strong influence of pH

and temperature was observed on the formation of the dominant solid phases in the

simulated containment water. However, at pH 10, irrespective of the temperature,

pressure, and concentration, silicates of aluminum and iron contribute 90 percent of the

solid phases.

Based on these simulations, we conclude that no significant differences in corrosion product

formation are expected in alkaline simulated containment water at pH 10 as the

high-temperature and pressure conditions during the initial stages of a LOCA event approach

steady-state conditions.

Review of simulation data and associated sensitivity analysis in a trisodium phosphate

simulated containment water at pH 7 indicated that:

* There were significant differences in the solid phase formation in Na3PO4 containing

simulated containment water at pH 7 from that in alkaline simulated containment water

at pH 10.

* At pH 7, Ca,(OH)(PO4)3 was the dominant solid phase containing almost 100 percent of

calcium, while at pH 10, calcium was approximately 1 percent insoluble at 60 OC

[140 OF].

* A significantly larger quantity of solid phases were formed in a solution containing

Na3PO4 compared to alkaline containment water. Ca5(OH)(PO4)3 and NaAISi308

contributed to over 90 percent of the solid phases.

* Sensitivity analyses for concrete indicated increase in the Ca,(OH)(PO4)3 concentration

with a increase in the concrete concentration. For concentrations of concrete exceeding

3 x 10-4 mol/L, Ca5(OH)(PO4)3 coexisted with solid Si0 2 phase. The concentrations of

these two phases far exceeded contributions from other solid phases.

* Copper had no influence on the precipitation of solid phases.

* The sensitivity analyses for aluminum indicated an increase in the concentrations of

NaAlSi308 with an increase in aluminum concentration. Formation of AI(OH) 3 and

AIO(OH) was observed for aluminum concentrations exceeding 3 x 10-4 mol/L at 60 OC

[140 OF] and 130 °C [266 °F], 304 kPa [3 atm], respectively. In a 15-day simulation,

aluminum was present exclusively as NaAlSi308.

7-3
- -

* Both iron and zinc showed a decrease in solid phase concentration with decrease in

temperature and pressure. The contribution of zinc was below 2 percent and that of iron

is below 9 percent compared to the total solid phases. Other than a reorganization of

iron phases, no significant changes were observed.

* The dominant solid phases formed after 15 days were Ca5(OH)(PO4)3 and NaAISi308,

with minor quantities of Ca2Mg5Si8022(OH)2, Fe3Si4O10(OH)2, SiO2, and Zn2SiO4 in the

simulated containment water.

Based on the observations, we conclude that changes in solid phase formation for iron and zinc

are expected as high temperature and pressure conditions during the initial stages of a LOCA

event approach steady-state conditions. However, both iron and zinc showed increased

solubility as temperature was reduced from 150 'C [302 'F] to 60 'C [140 'F]. Irrespective of

temperature and pressure, Ca,(OH)(PO4)3 and NaAISi308 contribute over 90 percent of the solid

phases formed in a Na3PO4, pH 7 solution. The distribution of these two phases did not

significantly change as a function of temperature and pressure. A comparison of the

constituents in pH = 7 and pH = 10 containment solutions is provided in Table 7-1.

In alkaline solutions, aluminosilicate units can react with alkali silicate units to form polysialate

(-Si-O-AI-O-), poly(sialate-siloxo) (-Si-O-AI-O-Si-O-), or poly(sialate-disiloxo) (-O-Si-O-AI-O-SiO-Si-O-) polymers. These polysialates condense as a gel similar to organic polymers at

temperatures below 100 'C [212 'F]. Such polymers are widely used in the manufacture of

geopolymers. Gel formation, a precursor to polymerization, could occur in alkaline solutions

when silicon, aluminum, and alkali ions are present. Therefore, gel formation is likely in alkaline

simulated containment water because gelling requires a high pH. This gel formation could

result in clogging of containment area sump pump suction strainers.

7-4
Table 7-1. Comparison of Constituents In pH = 7 and pH = 10 Containment Solutions

Characteristic pH = 7 (Trisodlum Phosphate pH = 10 (Sodium Hydroxide

Moderator) Moderator)

Dominant Solid Ca5(OH)(PO4)3 and NaAISi 308 NaAlSi308 and Ca2M95Si.O22(OH) 2,

Phases with Fe3(P04)2-8H20 (60 'C with Ca3Fe2Si3O12 (60 'C [140 'F]} [140 'F]}, and Fe3O4 and and Fe3Si4O01 (OH)4 (150 0C

Fe3Si205(OH)4 (150 0C (302 0F]} [302 0F]}

Temperature Redistribution of iron and zinc Redistribution of iron phases

Dependencies phases

Sensitivity-Aluminum Increasing aluminum leads to Increasing aluminum leads to

increasing AI(OH)3 (60 0C increasing AI(OH) 3 {60 0C [140 0F]}

[140 'F]} and AIO(OH) (130 'C and increases NaAISi 308 (130 0C

[266 0F]} [266 F1]}

Sensitivity-Carbon Increasing iron leads to Increasing iron leads to increasing

Steel increasing Fe3(PO4)2 8H20 Fe3Si205(OH)4 {60 °C [140 °F]} and

(60 °C [140 °FJ}, Fe304, and Ca3Fe2Si30,2 (130 °C [266 °F]}

Fe3Si205(OH)4 (130 °C

[266 °F]}

Sensitivity-Zinc Increasing zinc leads to Increasing zinc leads to increasing

increasing Zn3(OH)(PO4)3-2H20 ZnO-Fe2O3 and Zn2SiO4

{60 °C [140 °F]},

Zn3(OH)(PO4)3-2H20, and

ZnO-Fe2O3 {130 °C [266 °F]}

Sensitivity-Copper No corrosion, no influence No corrosion, no influence

Sensitivity-Concrete Increasing concrete leads to Increasing concrete leads to

increasing Ca5(OH)(PO4)3 and increasing CaSiO3

Si02

Sensitivity-Fiber Increasing fiber insulations Increasing fiber insulations leads

Insulation leads to increasing NaAISi308 to increasing NaAISi 3O8 and

Ca 2 MgSi8 022(OH)2

Long-Term Trends Major solid constituents: Major solid constituents:

(time) Ca,(OH)(PO4)3, NaAlSi308, NaAlSi308, Ca2Mg5Si.O22(OH)2, Ca2Mg.Si8022(OH) 2, Ca3Fe2Si30,2, CaSiO 3, and

Fe3Si4O, 0 (OH) 2 , Zn2SiO4

SiO2, and Zn2SiO4

7-5
8 FUTURE WORK

This report is based on corrosion rate data published in the open literature. However, in many

cases, corrosion rate data are not relevant to expected containment water composition and pH.

There are significant uncertainties in the corrosion rates in borated water as a function of

temperature and pH. Laboratory experiments to determine corrosion rate of components in

expected containment water environment would improve simulation results and provide more

confidence for conclusions drawn from the simulations.

8-1
9 REFERENCES

Carmack, W.J., G.R. Smolik, R.A. Anderl, R.J. Paweklo, and P.B. Hembree. 'Takamak Dust

Particle Size and Surface Area Measurement." Log. No. E014. Idaho Falls, Idaho. Idaho

National Engineering and Environmental Laboratory. 1998.

Griess, J.C. and A.L. Bacarella. "Design Consideration of Reactor Containment Spray Systems

-Part IlIl: The Corrosion of Materials in Spray Solutions." ORNL-TM-2412, Part Ill. Oak

Ridge, Tennessee: Oak Ridge National Laboratory. 1969.

Hall, J.F. 'Corrosion of Low Alloy Steel Fastener Materials Exposed to Borated Water."

Proceedings of the Third International Symposium on Environmental Degradation of Materials in

Nuclear Power Systems-Water Reactors. G.J. Theus and J.R. Weeks, eds. La Grange Park,

Illinois: American Nuclear Society. pp. 711-722. 1988.

Iler, R.K. The Colloid Chemistry of Silica and Silicates. Ithaca, New York: Cornell University

Press. 1955.

Jantzen, C.M. 'Radioactive Waste-Portland Cement Systems II: Leaching Characteristics."

Journal of American Ceramic Society. Vol. 67, No. 10. pp. 674-678. 1984.

Johns, R.C., B.C. Letellier, K.J. Howe, and A.K. Ghosh. "Small-Scale Experiments: Effects of

Chemical Reactions on Debris-Bed Head Loss." LA-UR-03-6415. Los Alamos, New Mexico:

Los Alamos National Laboratory. 2003.

Niyogi, K.K., R.R. Lunt, and J.S. Mackenzie. NUREG/CP-0038, "Corrosion of Aluminum and

Zinc in Containment Following a LOCA and Potential for Precipitation of Corrosion Products in

the Sump." Proceedings of the Second Intemational Conference on the Impact of Hydrogen on

Water Reactor Safety, Albuquerque, New Mexico, October 3-7, 1982. Rockville, Maryland:

NRC. pp. 410-423. October 1982.

NRC. "Test Plan: Characterization of Chemical and Corrosion Effects Potentially Occurring

During a Pressurized Water Reactor LOCA." Rev. 12b. ML050450478. Washington, DC:

NRC. 2005.

OLI Systems, Inc. "StreamAnalyzer Version 1.2." Morris Plains, New Jersey: OLI Systems,

Inc. 2002a.

. Environmental Simulation Program Version 6.6." Morris Plains, New Jersey: OLI

Systems, Inc. 2002b.

Pan, Y. -M, V. Jain, and 0. Pensado. "Degradation of High-Level Waste Glass Under

Simulated Repository Conditions." Journal of Non-Crystalline Solids. Vol. 319.

pp. 74-88. 2003.

Piippo, J., T. Laitinen, and P. Sirkai. "Corrosion Behavior of Zinc and Aluminum in Simulated

Nuclear Accident Environments." STUK-YTO-TR 123. Helsinki, Finland: Finnish Center for

Radiation and Nuclear Safety. 1997.

9-1
APPENDIX A

SOFTWARE VALIDATION AND SIMULATION METHODS

A LOCA event involves rapid changes in the time-temperature-pressure-chemistry-pH

conditions. Changes in the coolant chemistry are further complicated because of interactions

among the materials present in the vicinity of the LOCA event (see Table 1-1). These

potentially complex interactions necessitate a large number of experiments to obtain sufficient

data to analyze the potential for sump blockage caused by chemical precipitation.

Thermodynamic simulations allow identification of critical variables and their ranges from a large

number of components present in the containment system during and subsequent to a

LOCA event.

The calculations in this project were made using a thermodynamic simulator developed by

OLI Systems, Inc. (OLI Systems, Inc., 2002a,b) for evaluating aqueous chemical processes in

industrial and environmental applications. The OLI Systems, Inc. data bank contains proprietary

coefficients for predicting thermodynamic, transport, and physical properties for 80 elements of

the periodic table and their associated aqueous inorganic species, as well as more than

5,000 organic species. The thermodynamic framework used by the OLI Systems, Inc. code

(OLI Systems, Inc., 2002a,b) predicts behavior of multicomponent aqueous systems including

aqueous liquid, vapor, organic liquid, and multiple solid phases for the general ranges of 0 to

30 molal, -50 to 300 'C [-58 to 572 'F], and 0-150 MPa [0-1,480 atm].

The simulations conducted for this study varied the amounts of key components, pH moderators

(i.e., sodium hydroxide versus trisodium phosphate), pH, temperature, and pressure to

determine the need for a pressurized test loop to better characterize system response.

Computational thermodynamics simulation calculations were conducted using Environmental

Simulation Program (ESP) Version 6.6' and StreamAnalyzer Version 1.2' developed by

OLI Systems, Inc. Following simulations and sensitivity analyses of key variables including

corrosion products, species that have a potential for causing sump head loss were ranked.

A.1 OLI Systems Software Validation

A.1.1 OLI Simulation Packages

The ESP Version 6.6' and StreamAnalyzer Version 1.20 are two packages of the simulation

software developed by OLI Systems, Inc. (2002a,b). ESP Version 6.60 is for evaluating the

thermodynamic properties of a group of streams that are connected to various chemical reaction

units in a chemical process in industrial and environmental applications. StreamAnalyzer

Version 1.2' is designed to simulate the thermodynamic properties of a single stream. The two

packages share the same thermodynamic frame work-OLI engine. StreamAnalyzer Version

6.6' is a more recent product and provides user-friendly graphical user-interaction interfaces.

Because ESP Version 6.6' is based on earlier designs, it does not support the graphical

user-interfaces.

ESP Version 6.6' and StreamAnalyzer Version 1.2t were validated for applications in the

high-level waste project (Yang, 2003). However, the previous validation tests did not include

the systems that are related to the primary coolant of the pressurized nuclear reactors.

A-1
_11

Validation tests to verify if these OLI Systems, Inc. software packages can be used for the

boron-containing solutions were conducted according to the contract requirements. This

chapter documents the validation results for both ESP Version 6.60 and StreamAnalyzer

Version 1.2' packages in the solutions containing boric acid and borates.

A.1.2 OLI Engine

The OLI Systems, Inc. engine has a large database of thermodynamic parameters and

represents standard-state properties using the Helgeson, et al. (1981) equation-of-state and

represents excess properties using the aqueous activity coefficient expressions developed by

Bromley (1972) and Pitzer (1973, 1991).

For stream simulations, if the temperature, pressure, and composition are specified,

ESP Version 6.60 and StreamAnalyzer Version 1.29 packages can calculate the following

thermodynamic properties:

* Concentration of ionic species in liquid phase (speciation)

* Solid/liquid equilibrium

* Vapor/liquid equilibrium

* Vapor/liquid equilibrium

* Vapor/liquid/solid equilibrium (including deliquescence processes at a mutual

deliquescence point)

For process simulations, if the input streams are fully defined, ESP Version 6.60 allows the

calculations of the thermodynamic properties of all process streams if the operating parameters

such as reaction temperature, pressure, and the fraction distilled for an evaporator

are specified.

A.1.3 OLI Systems, Inc. ESP Version 6.6' Application Example

Figure A-1 shows an example evaporation process that was simulated using ESP Version 6.6P

for a high-level waste stream. The input stream was a brine solution containing salts that can

hydrolyze and produce acidic gases when heated. The calculation was started after the

following parameters were specified:

(i) Input stream temperature, pressure, and brine composition

(ii) Operation mode of evaporator Unit A (dew point, for example), pressure for the dew

point calculation, and the amount of the incoming stream to be evaporated (90 percent,

for example)

(iii) Operation mode of Evaporator Unit B (dew point, for example), pressure for the dew

point calculation, and the amount of the incoming stream, L1, to be evaporated

(90 percent, for example)

(iv) Temperature of Condenser Unit C

(v) Temperature of Condenser Unit D

A-2
S-1

Cond-2

Input

(Brine) 250C

L-2 (Liquid)

Cond-l

250C

Figure A-1. Application Example of OLI Systems, Inc. ESP

Version 6.6; Simulation of Acid Production by Concentrated Brine in

Staged Evaporation Processes (Note: 'F = 1.8 x 'C + 32).

After the calculation, the temperatures of the evaporators, the concentrations of the ionic

species, and the pH in each stream of the process were available. The pH in the Cond-1

stream was the room temperature pH of the condensate collected after 90 percent of the

incoming brine was evaporated, and the pH in the Cond-2 stream was the pH of the condensate

collected upon further evaporation after 90 percent of the incoming brine had been evaporated,

respectively. The former was called the cumulative pH, and the later was called the interval pH.

Figure A-2 shows the calculated cumulative and interval pH values. Both the cumulative and

the interval pH decreased with the increase in the degree of distillation. In addition, the interval

pH was lower than the cumulative pH, which implies most of the acid was produced in the later

stages of evaporation.

A.2 Validation Results

A.2.1 Test Case 1-Solubility of Boric Acid in Water

The test case described in this section includes the calculations of the total dissolved boron in a

boric acid solution in the temperature range of 20 to 94 0C [68 to 201 OF] to obtain the solubility

of boric acid. The calculation was conducted using a mixer reactor, which is a continuously

stirred tank reactor. This calculation was to verify if the ESP Version 6.60 and StreamAnalyzer

Version 1.2w software packages can be used to accurately predict the thermodynamic

properties in a boron-containing solution at different temperature conditions.

A-3
6-

5-

:43-

MA

0; .-.

i1i

0 :

0

* Cumulative pH

o Interval pH

--------------------~----r-4-- I a.

0

Figure A-2. Application Example of OLI Systems, Inc. ESP Version 6.6W; Simulation Results for Acid Production by a Concentrated Brine Solution

in Staged Evaporation Processes

A.2.1.1 Test Input

Input temperatures were 20, 40, 60, 75, and 94 0C [68, 104, 140, 167, and 201 'F]. The input

pressure was 101 kPa [1 atm].

A.2.1.2 Test Procedure

The test was run by specifying the calculation type as a constant pressure isotherm. The input stream contains 8 mol [494.5 gJ of boric acid [B(OH)3] and 55.508 mol [1 kg] of water.

A.2.1.3 Test Results

The calculations with ESP Version 6.6@ provided the following parameters for each phase (aqueous, solid, and vapor) of the input and output streams:

* List of all chemical species and their quantities * Temperature

* Pressure

* pH

* Total molar flow

A-4
* Total mass flow

* Total volume

* Enthalpy

* Density

* Vapor fraction

* Solid fraction

* Organic fraction

* Osmotic pressure

* Redox potential

* Electrical specific conductivity

* Electrical molar conductivity

* Absolute viscosity

* Relative viscosity

* Ionic strength

The calculations with StreamAnalyzer Version 1.20 provided the following parameters:

* List of all chemical species and their quantities

* Temperature

* Pressure

* pH

* Ionic strength

* Osmotic pressure

* Water H20 activity

* Electrical specific conductivity

* Electrical molar conductivity

* Absolute viscosity

* Relative viscosity

* Density

* Enthalpy

* Total molar amount in aqueous phase

* Total molar amount in vapor phase

* Total molar amount in solid phase

* Total mass amount in aqueous phase

* Total mass amount in vapor phase

* Total mass amount in solid phase

* Total volume in aqueous phase

* Total volume in vapor phase

* List of species scaling tendencies

* List of species activity coefficients in liquid phase

* List of species equilibrium constants

* List of species ionic mobilities

* List of species self diffusivities

Partial lists of the parameters calculated with the ESP Version 6.6' and StreamAnalyzer 1.2@

are provided in Tables A-1 and A-2. The comparisons of the calculated solubilities of boric

acid in water with the experimental data obtained by Nies and Hulbert (1967) are also given in

the corresponding tables, and plotted in Figure A-3. The deviations between the calculated

A-5
Table A-1. ESP Version 6.60 Speclation Results and Comparison of the Calculated Boric Acid Solubilities with the Experimental Values at

Different Temperatures

Temperature

°C [OF] 20 [681 40 [104] 60 [140] 75 [167] 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

pH 3.63 - 3.32 - 3.04 _ 2.85 - 2.62 -

Flow Units mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr

H20 55.51 - 55.51 - 55.51 - 55.51 - 55.51 -

B(OH)3 0.81 7.19 1.45 6.55 2.38 5.61 3.37 4.62 5.16 2.83

OH 3.0 x 1011 - 6.2 x 10.11 - 1.1 x 1010 - 1.5 x 10.0 1.9 x 1010 -

B303(OH)4- 2.3 x 104 - 4.8 x 10-4 - 9.2 x 10-4 - 1.4 x 10'3 2.5 x 10-3 -

B405(OH)4 8.0 x 10 - 6.3 x 109 - 6.2 x 109 - 6.9 x 10-9 9.1 x 10-9 -

B(OH)4 1.8 x 106 - 2.4 x 10.6 - 2.9 x 10.6 - 3.2 x 10.6 3.5 x 10.6 -

H+ 2.4 x 104 - 4.9 x 10-4 9.4 x 10-4 - 1.5 x 10-3 2.6 x 103 -

B20(OH)5 2.0 x 10.6 - 5.5 x 10 - 1.2 x 10- - 2.1 x 10-5 3.7 x 10-5 -

Total, g/hr 1,050.3 444.4 1,089.5 405.2 1,147.6 347.1 1,208.9 285.8 1,319.6 175.0

Volume, Uhr 1.03 - 1.07 - 1.11 - 1.16 - 1.25 -

Enthalpy,

cal/hr -4.0 x 106 -1.9 x 106 -4.1 x 106 -1.7 x 106 _4.4 x 106 -1.5 x 106 -4.6 x 106 -1.2 x 101 -5.0 x 106 -7.4 x 105

Density, g/L 1,016.48 - 1,022.64 - 1,030.60 - 1,038.65 - 1,053.20 -

0)
Table A-1. ESP Version 6.6 Speclation Results and Comparison of the Calculated Boric Acid Solubilities with the Experimental Values at

Different Temperatures (continued)

Temperature

C [

0F] 20 [68] 40 [1041 60 [1401 75 [167] 94 [201]

Phase Aqueous Solid Solid Aqueous Solid Aqueous Solid Au o Solid

Solubilities of Boric Acid in Water

Calc. B (M) 0.79 | 1.36 - 2.14 2.90 - 4.13 -

Exp. B (M)* 0.78 1.32 2.14 2.98 4.24 -

Deviation (%) 1.37 2.72 0.28 -2.73 -2.60

Input parameters: H20: 55.508 mol; B(OH)3: 8 mol.

*Nies, N.P. and R.W. Hulbert. 'Solubility Isotherms in the System Sodium Oxide-Boric Oxide-Water." Journal of Chemical Engineering Data. Vol. 12,

No. 3. pp. 303-313. 1967.

I"
Table A-2. StreamAnalyzer Version 1.2@ Speciatlon Results and Comparison of the Calculated Boric Acid Solubilities with the Experimental

Values at Different Temperatures

Temperature

°C [OF] 20 [68] 40 [1041 60 [140] 75 [167] 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

Unit mol - mol - mol - mol - mol

H20 55.508 0 55.509 0 55.51 0 55.511 - - -

B(OH)3 0.81 7.19 1.45 6.55 2.38 5.61 3.37 - - -

B(OH)4, 1.82 x 10.6 0 2.4 x 10.6 0 2.93 x 10.6 0 3.24 x 10.6 - - -

B2O(OH)5 1.96 x 10 0 5.48 x 10.8 0 1.24 x 10-5 0 2.07 x 105 - - -

B303(OH)4 2.34 x 10'4 0 4.84 x 10 0 9.21 x 104 0 1.45 x 10-3 - - -

B405(OH)4 7.99 x 10-9 0 6.31 x 10'9 0 6.19 x 10-9 0 6.90 x 10-9 - - -

H#1 2.37 x 10i4 0 4.92 x 10-4 0 9.36 x 10-4 0 1.47 x 10-3 - - -

OH 3.01 x 10-11 0 6.19 x 1011 0 1.08 x 10-10 0 1.48 x 10.10

Total Mole, mol 56.3 0 57.0 0 57.9 0 58.9 - - -

Total Volume, L 1.03 1.07 - 1.11 1.16

Total Mass, g 1,050.3 1,089.5 - 1,147.6 1,208.9

Density, g/L 1,016.5 = 1,022.7 - 1,030.6 1,038.7

Solubilities of Boric Acid in Water

Calc. B, M 7.87 - 1.36 - | 2.14 - J 2.90 -

Exp. B203* I 1 T I r _ (wt%) 2.66 - 4.50 - 7.22 - 10.00 - 14.00 -

I

W
Table A-2. StreamAnalyzer Version 1.2e Speciation Results and Comparison of the Calculated Boric Acid Solubilities with the Experimental

Values at Different Temperatures (continued)

Temperature

OC [

0F] 20 [68] 40 [104] 60 [140] 75 [1671 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

Exp. B, M 0.78 - 1.32 - 2.14 - 2.98 - 4.24 -

Deviation, % 1.38 - 2.74 - 0.29 - -2.72 -

Input parameters: H20: 55.508 mol; B(OH)3: 8 mol.

*Nies, N.P. and R.W. Hulbert. 'Solubility Isotherms in the System Sodium Oxide-Boric Oxide-Water." Journal of Chemical Engineering Data. Vol. 12,

No. 3. pp. 303-313. 1967.

c6
5.00 _ _ _ _ _ _ _ _ _

5 Caic. B, ESP

4.50 - Expl. B

4.00 x CaIc. B, StreamA. ---

3.50-

_ 2.50-

.0

o 2.00-

C,)

1.50-

0. 50-

0.00 I I I

0 20 40 60 80 100

Temperature (0C)

Figure A-3. Comparison of the Calculated Boric Acid Solubilities Using ESP Version 6.60 and StreamAnalyzer Version 1.29 with the Experimental Values at

Different Temperatures (Note: OF = 1.8 x 0C + 32).

solubilities and the experimentally obtained solubilities are within ±3 percent. Therefore, the

calculated solubilities for boric acid in water are in good agreement with the experimentally measured solubilities by Nies and Hulbert (1967) in the temperature range between 20 and

94 'C [68 and 201 OF] for ESP Version 6.6' and between 20 and 75 0

C [68 and 167 OF] for

StreamAnalyzer Version 1.2'. The results from ESP Version 6.69 are essentially the same as

those from StreamAnalyzer Version 1.20.

A.2.2 Test Case 2-Solubility of Borax in Water

This test case calculates the total dissolved boron and sodium in borax-water systems in the

temperature range of 20 to 94 0C [68 to 201 OF]. The calculations were conducted using a

mixer reactor (a continuously stirred tank reactor). The objective of this test was to verify if the

ESP Version6.61 and StreamAnalyzer Version 1.20 software packages can be used to

adequately predict the thermodynamic properties in a boron- and sodium-containing solution at

varying temperatures.

A-10

C37
A.2.2.1 Test Input

Input temperatures were 20, 40, 60, 75, and 94 'C [68, 104, 140,167, and 201.2 0F]. The input

pressure was 101 kPa [1 atm].

A.2.2.2 Test Procedure

The test was run by specifying the calculation type as constant pressure isotherm. The input

stream contains 2 mol [201.2g] of borax (Na2B407) and 55.508 mol [1 kg] of water.

A.2.2.3 Test Results

Tables A-3 and A-4 present the speciation results calculated with ESP Version 6.60 and

StreamAnalyzer Version 1.2e, respectively. For the boric acid case, these tables list the

temperature and pressure used in the calculation, the resulting ionic strength, and the

calculated concentrations of ionic species, including boron- and sodium-containing species.

Tables A-3 and A-4 also list the calculated total dissolved boron and sodium concentrations

and show comparisons with the experimental data given by Nies and Hulbert (1967). The

calculated solubility results in Tables A-3 and A-4 are also presented in Figure A-4. The

deviations of the calculated results from the experimental data are within ±3.5 percent for both

ESP Version 6.6 and StreamAnalyzer Version 1.2@ at temperatures between 20 and 40 °C

[68 and 104 'F]. The deviations are within ±10 percent in the temperature range from 60 to

94 0C [140 to 201 OF] for ESP Version 6.60 and from 60 to 75 0C [140 to 167 OF] for

StreamAnalyzer Version 1.2'. The results from ESP Version 6.6® are consistent with those

from StreamAnalyzer Version 1.2®.

A.2.3 Test Case 3-Dissociation Constant of Boric Acid in a Concentrated

Sodium Chloride Solution

The test cases described in this section calculate the speciation and dissociation of boric acid in

a concentrated sodium chloride solution in the temperature range of 25 to 90 'C [77 to 194 'F]

to obtain the dissociation equilibrium constant for boric acid in a brine solution. The calculation

was conducted using a mixer reactor. This calculation was to verify if the ESP Version 6.6e

software can be used to accurately predict the thermodynamic behavior of boron containing

species in concentrated brine solutions at different temperatures. As StreamAnalyzer

Version 1.2@ shares the same OLI Systems, Inc. engine with ESP Version 6.6' and the two

previous cases have shown that the results from ESP Version 6.60 are close to the results from

StreamAnalyzer Version 1.20, no calculation was performed with StreamAnalyzer Version 1.20

for this test case.

A.2.3.1 Test Input

Input temperatures were 25, 40, 58, and 90 °C [77, 104, 136, and 194 °F]. The input pressure

was 101 kPa [1 atm].

A-11
Table A-3. ESP Version 6.6e Speciation Results and Comparison of the Calculated Borax Solubilities with the Experimental Values at

Different Temperatures

Temperature

QC [OF] 20 [68] 40 [104] 60 [140] 75 (167] 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

pH 9.30 9.16 = 9.08 = 9.01 8.95

Flow Units mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr mol/hr

H20 36.09 - 36.97 - 48.44 - 48.70 - 49.58 -

B(OH) 3 0.03 - 0.05 - 0.08 - 0.09 - 0.10 -

NaB(OH)4 3.2 x 10- - 1.2 x 10.2 - 6.0 x 10-2 9.0 x 10-2 - 1.5

OH 1.2 x 10-5 - 4.1 x 10-5 - 1.5 x 10-4 - 2.8 x 10-4 - 5.6 x 10-4 -

B303(OH)4 1.8 x 10-2 - 5.4 x 10-2 - 1.8 - 2.5 - 3.5

B405(OH)4- 5.3 x 10-2 - 1.3 - 5.4 - 6.9 - 1.2

B(OH)4 4.3 x 10-2 - 8.8 x 10-2 - 2.0 - 2.5 - 3.0 _

H+ 4.8 x 10`o - 7.5 x 10-1 - 1.4 x 10-9 - 1.6 x 10-9 - 2.0 x 10 -

Na' 0.17 - 0.41 - 1.52 - 1.96 - 3.13 -

B20(OH)5 0.00 - 0.01 - 0.05 - 0.09 - 0.16 -

Na2B4OI 10H2O 1.91 1.79 - - - -

Na2B40 4H2O - - 1.21 - 0.97 - 0.36

Total, g/hr 672 730 721 682 1,072 331 1,136 266 1,304 99

Volume, Uhr 0.65 0.43 0.68 0.40 0.91 0.24 0.93 0.19 0.97 0.07

I~

ha
Table A-3. ESP Version 6.6 Speclatlon Results and Comparison of the Calculated Borax Solubilities with the Experimental Values at

Different Temperatures (continued)

Temperature

°C [

0F] 20 [68] 40 [104] 60 [140] 75 [167] 94 [201]

Enthalpy, -2.56 x -2.89 x -2.73 x -2.69 -4.07 x -1.32 -4.31 x -1.06 -4.95 x -3.94 x

cal/hr 106 106 108 x 106 1O, x 106 lo, X1O6 106 105

Density, g/L 1,030 1,712 1,067 1,712 1,184 1,366 1,228 1,366 1,341 1,366

Solubilities In Borax In Water

CaIc. Na (M) 0.26 - 0.61 - 1.68 - 2.12 - 3.22 -

Calc. B (M) 0.52 - 1.22 - 3.37 - 4.25 - 6.41 -

Expl* Na (M)t 0.25 - 0.63 - 1.84 - 2.23 - 3.52 -

Expi B (M)t 0.51 - 1.26 - 3.70 - 4.47 - 7.08 -

Deviation, Na

(%) 1.66 - -2.43 - -9.04 - -4.85 - -8.72 -

Deviation, B (%) 1.85 - -2.57 -8.98 = -4.97 -9.40

Experimentally Identified Solid Phases*

Na2B407 10H2O - Yes Yes I - I - |

Na2B40 74H 2O Yes Yes Yes

Input parameters: H20: 55.508 mol; Na2B407: 2 mol.

*Expl - experimental.

tNies, N.P. and R.W. Hulbert. 'Solubility Isotherms In the System Sodium Oxide-Boric Oxide-Water. Journal of Chemical Engineering Data. Vol. 12, No. 3. pp.

303-313. 1967.

C,
Table A-4. StreamAnalyzer Version 1.2e Speciation Results and Comparison of the Calculated Borax Solubilities with the Experimental

Values at Different Temperatures

Temperature

C rF] 20 [68] 40 [104) 60 [140] 75 [167] 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

pH 9.30 9.16 9.08 - 9.01 =

Unit mol mol mol mol mol mol mol mol mol mol

H20 36.09 - 36.97 - 48.44 - 48.70 - -

B(OH) 3 0.03 - 0.05 - 0.08 - 0.09 - - -

Na2B407,10H 2O 0.00 1.91 0.00 1.79 0.00 0.00 0.00 0.00 0.00 0.00

Na 2B40,4H2O 0.00 0.00 0.00 0.00 0.00 1.21 0.00 0.97 0.00 0.00

NaB(OH) 4 3.2 x 10-3 - 1.2 x 10-2 - 6.0 x 10.2 - 8.97 x 10-2 - -

B(OH)4 4.26 x 10-2 - 8.8 x 10-2 - 2.03 - 2.51 - - -

B2O(OH)5 - 2.69 x 10-3 - 1.17 x 10-2 - 5.21 x 10-2 - 8.82 x 10.2 - -

B303(OH)4 1.76 x 10.2 - 5.36 x 10-2 - 1.81 - 2.47 - - -

B40 5 (OH) 4 5.29 x 10-2 - 1.30 - 5.41 - 6.89 - - -

Ht 4.79 x 10-10 - 7.48 x 10-1 - 1.35 x 10 - 1.63 x 10-9 - -

Nat 1.69 - 4.13 - 1.52 - 1.96 - - -

OH 1.23 x 10 - 4.13 x 10-5 1.48 x 10-4 - 2.77 x 10-4 - -

Total Mole, mol 36.4 - 37.7 - 51.1 - 52.1 - - -

Total Volume, L 0.65 - 0.68 - 0.91 - 0.93 - - -
Table A-4. StreamAnalyzer Version 1.2 Speciation Results and Comparison of the Calculated Borax Solubilities with the Experimental Values at Different Temperatures (continued)

Temperature

0C [OF] 20 [68] 40 [104] 60 [140] 75 [1671 94 [201]

Phase Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid Aqueous Solid

Total Mass, g 672.46 720.75 1,071.60 - 1,136.50

Density, g/L 1,029.85 1,066.48 1,183.57 - 1,228.28

Solubilities In Borax in Water

Calc. Na (M) 0.26 - 0.63 - 1.74 - 2.22 - | _

Calc. B (M) 0.53 1.26 3.49 - 4.44 _

Exp. Na (M)* 0.25 - 0.63 - 1.84 - 2.23 - 3.52

Exp. B (M)* 0.51 - 1.26 3.70 - 4.47 - 7.08

Deviation, Na

(%) 3.56 - 0.47 -5.45 - -0.51 -

Deviation, B (%) 3.45 - 0.16 -5.87 - -0.71 -

Experimentally Identified Solid Phases*

Na2B4O,1OH2O - IYes - Yes - | I - I - I - Na2B4O7,4H 2O - 1- - - | Yes I - | Yes _- Yes

Input parameters: H20: 55.508 mol; Na2B4O7: 2 mol.

en

*Nies, N.P. and R.W. Hulbert. 'Solubility Isotherms in the System Sodium Oxide-Boric Oxide-Water." Journal of Chemical Engineering Data. Vol. 12, No. 3. pp. 303-313. 1967.
10.00 - __

OCalc. Na, ESP

9.00 - Calc. B, ESP

o Expi. Na

8.00 - Expl B

7.00 x Calc. Na, StreamA. -

+ Calc. B, StreamA.

6 6.00---

5.00 -

6 4.00--------------------------

2.00 - -

1 .0 0 - - - - - - - - - - - - - - - - - - - - - - - - -

0.00

0 20 40 60 80 100

Temperature (

0

C)

Figure A-4. Comparison of the Calculated Solubilities of Sodium and

Boron in Borax-Water Systems Using ESP Version 6.6 and

StreamAnalyzer Version 1.2@ with the Experimental Values at

Different Temperatures (Note: 'F = 1.8 x 'C + 32).

A.2.3.2 Test Procedure

The test was run by specifying the calculation as constant pressure isotherm. The input stream

contains 0.5 mol [30.9 g] of boric acid [B(OH)3] and 55.508 mol [1 kg] of water, 3 mol [175.3 g] of

NaCI, and an appropriate amount of NaOH to adjust the pH of the solution to the neutral range.

A.2.3.3 Test Results

The calculations with ESP Version 6.6@ provides a full range of parameters similar to those

discussed in Test Case 1. A partial list of these parameters is given in Table A-5. The

calculated dissociation constants of boric acid in the 3-M [175.3g] sodium chloride solution are

slightly lower than those experimentally measured by Spessard (1970). The differences of

[log K,(calc)-logK1(exp)] are -0.46 at 25 0C [77 OF] and -0.22 at 90 OC [194 OF].

A- 16
Table A-5. ESP Version 6.6' Speclation Results and Comparison of the Calculated

Equilibrium Constant for Dissociation of Boric Acid in Concentrated NaCI Solution at

Different Temperatures

Temperature, °C [OF] 25 [77] 40 [104] 58 [136] 90 [194]

pH 5.86 5.94 6.01 6.09

Flow Units molality molality molality molality

H20 55.51 55.51 55.51 55.51

HCI 1.01 x 10-12 2.11 x 10-12 5.05 x 10-12 2.12 x 10.11

NaB(OH)4 1.91 x 10-4 3.09 x 10-4 4.92 x 10-4 8.79 x 10-4

B(OH) 3 3.54 x 10-1 3.54 x 10-' 3.55 x 10.' 3.59 x 10-1

OH- 6.19 x 10-9 2.41 x 10i 9.44 x 10-8 6.32 x 10-7

B303(OH)4 4.56 x 10-2 4.58 x 10-2 4.51 x 10-2 4.24 x 10-2

B305(OH)4- 1.62 x 10-3 1.14 x 10-3 8.59 x 10-4 6.98 x 10-4

B(OH)4- 3.18 x 10-4 5.33 x 10-4 8.68 x 10-4 1.59 x 10-3

2.99 2.99 2.99 2.99

H 1.04 x 10-6 9.05 x 10-7 8.14 x 10-7 7.51 x 10-7

Na+ 3.04 3.04 3.04 3.04

B20(OH)5 4.95 x 10-4 9.38 x 10-4 1.70 x 10-3 3.59 x 10-3

Dissociation Constant for B(OH)3 + H20 = H+ + B(OH)4 -

log K, (Calc) -9.03 -8.87 -8.70 -8.48

log K, (Expl)*t -8.56 } -8.47 -8.47 -8.26

Difference -0.46 -0.39 -0.23 -0.22

*Expl - experimental.

tSpessard, J.E. 'Investigation of Borate Equilibria In Neutral Salt Solutions.' Journal of Inorganic and Nuclear

Chemistry. Vol. 32. p. 2,607. 1970.

A-17
_il

A.3 Experimental Validation Tests and Analyses

Three sets of experiments were performed to support validation of the OLI Systems, Inc.

software for borated water. The validation tests involved determination of solubility of

compounds by mixing 0.259 mol H3B03, 0.17 mol NaOH, and 0.01 mol ZnCO3 or CaCO 3 in

1,000 mL water. The validation test matrix is shown in Table A-6.

A.3.1 Validation Test Method

The 25 and 60 OC [77 and 140 OF] tests were performed in open polytetrafluoroethylene beakers.

The 90 0C [194 OF] tests were performed in a sealed glass cell to avoid excessive evaporation.

The water-solid mixtures were stirred for 4 hours and held for another 4 hours to allow the solid

to settle at the bottom of the polytetrafluoroethylene beakers or the glass cell. At the end of the

4-hour hold, samples were taken from the upper section of the beaker or glass cell using a

syringe through a 0.45-pm [1.77 x 10-5-in] filter to prevent the suspended solid particles from

entering the sample. Because of the high water pressure of the solid-water mixture, the 130 OC

[266 OF] tests were conducted in a polytetrafluoroethylene-lined autoclave composed of a

nickel-based alloy that allowed the mixing by a polytetrafluoroethylene-sheathed magnetic stir

bar. At the end of the 4-hour hold, approximately 80 mL [2.7 oz] of liquid were siphoned from the

upper section of the autoclave to a beaker through a 3.18-mm [0.125-in]-diameter stainless steel

tubing. The tubing was slightly cooled so that the liquid temperature exiting the tubing was lower

than 100 CC [212 OF] to avoid evaporation. A syringe was used to take the sample from the

beaker, while the liquid was still hot, through a 0.45-pm [1.77 x 10-5-in] filter to prevent the

suspended solid particle from entering the sample.

Two types of analyses were performed in supporting validation of the OLI Systems, Inc.

software for borated water. The primary method was inductively coupled plasma emission

spectrophotometry analysis, and the second method was atomic absorption spectrophotometry

analysis. Brief descriptions of the analysis methods are given in the following paragraphs.

The inductively coupled plasma spectrophotometer utilizes plasma to excite elemental electrons

that produce photons unique to each element (Vela, et al.,1993; Winge, 1985). Advantages of

using inductively coupled plasma include its ability to identify and quantify all metallic and

Table A-6. Validation Test Matrix

Temperature (°C) [IF]

Solution 25 [77] 60 £140] 90 [1941 130 [266]

Test 1 1,000 mL H20, 0.259 mol -

H3B13, 0.17 mol NaOH X X X

Test 2 1,000 mL H20, 0.259 mol

H3B03, 0.17 mol NaOH, X X X X

0.01 mol ZnCO3

Test 3 1,000 mL H20, 0.259 mol X X X X

H3B03, 0.17 mol NaOH,

0.01 mol CaCO 3

A-18
---

nonmetallic elements in an aqueous solution with the exception of argon. In this method,

elements entering the hot plasma are vaporized and excited, resulting in the emission of

characteristic wavelengths of the element. The intensity of that emission can be used to quantify

the amount of the element. Two inductively coupled plasmas were utilized, a Thermo Jarrell Ash

Inductively Coupled Plasma Spectrometer Model ICAP 61 Trace Analyzer and a Spectro

Inductively Coupled Plasma Spectrometer Model FME-05. The instruments were calibrated

daily using traceable standards from the National Institute of Standards and Technology. The

detection limit by inductively coupled plasma is 2.5 x 10-1 mol [0.1 ppm] for calcium and

1.5 x 10-1 mol [0.01 ppm] for zinc.

Atomic-absorption spectroscopy was employed on selected samples to verify the zinc and

calcium results from inductively coupled plasma. The method uses the absorption of light to

measure the concentration of gas-phase atoms in a sample solution (Elwell and Gidley, 1966;

Perkin-Elmer Corporation, 1971). Concentrations are determined from a working curve after

calibrating the instrument with standards of known concentrations. The calcium and zinc

contents of the 25 'C [77 'F] samples were analyzed using a Perkin-Elmer Model 3100 Atomic

Absorption Spectrophotometer. Calcium and zinc elements were analyzed independently.

Calcium analyses were performed with a copper-iron-manganese-zinc hollow cathode lamp at a

422.7-nm [16.64 x 10-6-in] wavelength using an air-acetylene flame. The detection limits are

5.0 x 1 0-6 mol [0.2 ppm] for calcium and 7.6 x IO-" mol [0.05 ppm] for zinc. Zinc analyses were

performed using a calcium-magnesium hollow cathode lamp at 213.9-nm [8.42 x 10-6-in]

wavelength, using an air-acetylene flame. Five absorbency measurements were recorded for

each sample, and the average values were reported.

Table A-7 compares the measured values from inductively coupled plasma and atomic

absorption analyses on two calcium-containing solutions and one zinc-containing solution. For

the calcium-containing solutions, samples were taken after 4 hours and after 360 hours hold

times. Identical solutions were submitted for atomic absorption and inductively coupled plasma

analysis for comparison. For the 4-hour samples, the atomic absorption and inductively coupled

plasma measurements yield an identical value of 8.03 x 10-4 mol. For the 360-hour samples, the

Table A-7. Comparison of Atomic Absorption and Inductively Coupled

Plasma Measurements

Inductively

Atomic Coupled

Test Solution In Absorption Plasma Percent

1,000 mL Water Measurement Measurement Difference

at 25 0C [77 0F] Component (mol) (mol) (%)

0.259 mol H3B03, 8.03 x 10-4* 8.03 x 10-4* 0

0.17 mol NaOH, Calcium

0.01 mol CaCO 3 8.33 x 1 8.08 x 10 4 t 3.0

0.259 mol H3B03,

0.17 mol NaOH, Zinc 4.89 x 10-6t 4.6 x 10-6t 5.9

0.01 mol ZnCO3

*Samples taken after 4 hours.

tSamples taken after 360 hours.

A-19
-

inductively coupled plasma measurement yields 8.08 x 10-4 mol while the atomic absorption

measurement yields 8.33 x 10-4 mol, a difference of approximately 3 percent. For the

zinc-containing solution, samples were taken after the solution was settled for 360 hours. The

inductively coupled plasma measurement yields a zinc content of 4.6 x 10-6 mol, while the

atomic absorption yields a measurement of 4.89 x 10-6 mol. The measurement difference from

the two methods is approximately 6 percent. The results show that the zinc and calcium

measurements by inductively coupled plasma and atomic absorption are consistent.

A.3.2 Comparison of OLI Systems, Inc. Simulation with

Experimental Results

Inductively coupled plasma analyses were performed on all solutions listed in Table A-6 to

support validation of the OLI Systems, Inc. software. The OLI simulation results for the soluble

and insoluble phases for sodium and boron in zinc- and calcium-containing solutions are

presented in Tables A-8, A-9, A-10, and A-11 for 25, 60, 90, and 130 0C [77, 140, 194, and

266 OF] tests. The inductively coupled plasma analysis results are also shown in the

corresponding tables for comparisons. In the tables, the amount of solid phase for calcium and

zinc was obtained as a difference between the amount added to the solution and its

soluble component.

The results show good agreement between OLI Systems, Inc. simulations and experimental data

for sodium and boron in borated water containing zinc or calcium. Except for 130 0C [266 OF],

the results also show a good agreement for the insoluble phases of CaCO 3 and ZnCO3. The

amount of insoluble phase was estimated by subtracting the amount of soluble phase from the

total amount added to the test solution. However, significant variance was observed between

OLI Systems, Inc. simulations and experimental data for the soluble phases of CaCO 3 and

ZnCO3. The variance observed for the soluble phases of CaCO3 is attributed to the large

degree of variation in the published solubility data used in the OLI database. For example, the

solubility of CaCO 3 in water at about 16 'C [60 OF] was 0.9991 x 1 0' mol/kg-water from one

published source and 1.449 x 10-4 mol/kg-water from another published source.2 The variance

observed for the soluble ZnCO3 is probably also due to the variations in the published data used

in the OLI database. The calculated results for the soluble phases of CaCO3 and ZnCO3 are

approximately the same orders of magnitude as the measured results except for ZnCO3 at

130 0C [266 OFJ. At 130 0C [266 OF], the measured amount of soluble ZnCO3 was two orders of

magnitude lower than that predicted by the OLI Systems, Inc simulation. Detailed analysis of the

simulation indicated that the insoluble phase was present as Zn(OH)2 below 105 0C [221 °F] and

as ZnCO3above105 °C [221 OF]. This discrepancy may be due to error(s) in the ZnCO 3

database or the uncertainty of the ZnCO3 thermodynamic data at temperatures above 105 0C

[221 °F]. The results also show that the calculated trends for the dependence of the solubilities

of both CaCO 3 and ZnCO3 on temperature are the same as the measured trends.

It should be noted, however, that the estimation of insoluble phases by the subtraction of the

soluble phases from added amounts of CaCO 3 and ZnCO3 shows a good agreement between

OLI Systems, Inc simulation and experimental data. This indicates that despite large variance in

the soluble phase, both CaCO 3 and ZnCO3 are expected to have low solubility.

2Personal communication with Andre Anderko, OLI Systems, Inc., July 2004.

A-20
Table A-8. Distribution of Soluble and Insoluble Phases In Boric Acid and Sodium Hydroxide Solutions Containing Zinc

and Calcium at 25 OC [77 OF]

OLI Systems, Inc. Inductively Coupled

Simulation Plasma Analyses

Test Solution in (mol) (mol) Percent Difference

1,000 mL Water Amount Soluble Insoluble Soluble Insoluble Soluble Insoluble

at 25 0C [77 'F] Element (mol) Phase Phase Phase Phase* Phase Phase

0.259 mol H3B03 , Boron 0.259 0.259 0 0.239 - 7.7

0.17 mol NaOH Sodium 0.17 0.17 0 0.147 - 13.5

0.259 mol H3B03 , Boron 0.259 0.259 0 0.247 - 4.6

0.17 mol NaOH,

0.01 mol ZnCO3 Sodium 0.17 0.17 0 0.151 11.2

Zinc 0.01 9.8 x 10-6 9.99 x 10-3 1.85 x 10-6t 9.99 x 10-3 81.1 0

0.259 mol H3B03 , Boron 0.259 0.259 0 0.249 _ 3.9

0.17 mol NaOH,

0.01 mol CaCO 3 Sodium 0.17 0.17 _ 0 0.15 11.8

Calcium 0.01 5.2 x 10-4 9.48 x 10-3 8.0 x 10-4 9.2 x 10-3 -53.8 -3

*Estimated from the analysis of soluble species.

tNumber close to detection limit, indicating extremely low solubility.

r
Table A-9. Distribution of Soluble and Insoluble Phases in Boric Acid and Sodium Hydroxide Solutions Containing Zinc

and Calcium at 60 °C [140 0

F]

OLI Systems, Inc. Inductively Coupled

Simulation Plasma Analyses Test (mol) (mol) Percent Difference

Solution in__ _ _ _ _ _ _ _ _

1,000 mL Water Amount Soluble Insoluble Soluble Insoluble Soluble Insoluble

at 60 'C [140 'F] Element (mol) Phase Phase Phase Phase* Phase Phase

0.259 mol H3B0 3 Boron 0.259 0.259 0 0.229 - 11.6 _

0.17 mcI NaOH Sodium 0.17 0.17 0 0.141 - 17.1

0.259 mol H3B 3, Boron 0.259 0.259 0 0.287 - -10.8

0.01 mol ZnCO3 Sodium 0.17 0.17 0 0.174 - -2.4 _

Zinc 0.01 2.4 x 10-5 9.98 x 10-3 6.0 x 10-6t 9.99 x 10-3 -74.0 -0.1

0.259 moI H3B13 , Boron 0.259 0.259 0 0.292 _ -12.7

0.17 mol NaOH,

0.01 mol CaCO3 Sodium 0.17 0.17 _ 0 0.169 0.6

Calcium 0.01 4.5 x 10- 9.55 x 10-3 8.3 x 10-4 9.2 x 10-3 -84.4 4.0

*Estimated from the analysis of soluble species.

tNumber close to detection limit, indicating extremely low solubility.

13

N)
Table A-10. Distribution of Soluble and Insoluble Phases in Boric Acid and Sodium Hydroxide Solutions Containing Zinc

and Calcium at 90 0

C [194 IF]

OLI Systems, Inc. Inductively Coupled

Simulation Plasma Analyses

Solution in (mol) (mol) Percent Difference

1,000 mL Water Amount Soluble Insoluble Soluble Insoluble Soluble Insoluble

at 90 tC [194 OF] Element (mol) Phase Phase Phase Phase* Phase Phase

0.259 mol H3B0 3 Boron 0.259 0.259 0 0.240 - 7.3

0.17 mol NaOH

Sodium 0.17 0.17 0 0.147 - 13.5

0.259 mol H3BO3, Boron 0.259 0.259 0 0.257 - 0.8

0.17 mol NaOH,

0.01 mol ZnCO3 Sodium 0.17 0.17 0 0.161 - 5.3

Zinc 0.01 3.07 x 10-5 9.97 x 10-3 1.76x 10-5 9.98 x 10-3 43.7 -0.1

0.259 mol H3B13 , Boron 0.259 0.259 0 0.259 0

0.17 mol NaOH,

0.01 mol CaCO 3 Sodium 0.17 0.17 0 0.16 5.9

Calcium 0.01 3.72 x 10-4 9.63 x 10-3 5.36 x 10-4 9.46 x 10-3 -44.1 1.8

*Estimated from the analysis of soluble species.

r,.3
Table A-11. Distribution of Soluble and Insoluble Phases in Boric Acid and Sodium Hydroxide Solutions Containing Zinc

and Calcium at 130 0C [266 'F]

OLI Systems, Inc. Inductively Coupled

Test Simulation Plasma Analyses

Solution in (mOl) (mol) Percent Difference

1,000 mL Water Amount Soluble Insoluble Soluble Insoluble Soluble Insoluble

at 130 0C [266 'F] Element (mol) Phase Phase Phase Phase* Phase Phase

0.259 mol H3BO3, Boron 0.259 0.259 0 0.226 _ 12.7

0.17 mol NaOH,

0.01 mol ZnCO3 Sodium 0.17 0.17 003 0.14 17.6

Zinc 0.01 4.21 x 10-3 5.79 x 10-3 2.54 x 10-5 9.97 x 10V 99.4 72.2

0.259 mol H3B0 3, Boron 0.259 0.259 0 0.241 _ 6.9

0.17 mol NaOH,

0.01 mol CaCO 3 Sodium 0.17 0.17 0 0.148 _ 12.9

Calcium 0.01 2.88 x 10-4 9.71 x 10-3 3.34 x 10-4 9.67 x 10-3 -16.0 0.4

*Estimated from the analysis of soluble species.

L
A.4 Summary

Computational thermodynamics simulation calculations were conducted using Environmental

Simulation Program (ESP) Version 6.61 (OLI Systems, Inc., 2002a) and StreamAnalyzer Version

1.28 (OLI Systems, Inc., 2002b). OLI Systems, Inc. software was validated by comparing

simulation results with data on borated water published in the literature and with results of

solubility type experiments using borated water containing CaCO 3 or ZnCO3 in the temperature

range of 250C [770F] to 1300C [266011. Data showed a good agreement between published

literature and OLI Systems, Inc. simulation. Except for ZnCO3 at 1300C [266011, the

experimentally measured solubility data agreed with the OLI Systems, Inc. simulation results for

the dominant solid or soluble phases, including aqueous H3BO3, aqueous NaOH, and solid

CaCO 3 or solid ZnCO3. A large variation was observed for soluble phases of zinc and calcium

and was attributed to variation and uncertainty in published data used in OLI Systems, Inc.

software database.

A.5 References

Bromley, L.A. "Approximate Individual Ion Values of J (or B) in Extended Debye-Huckel Theory

for Uni-Univalent Aqueous Solutions at 298.15 K." Journal of Chemical Thermodynamics.

Vol. 4. p. 669. 1972.

Elwell, W.T. and J.A.F. Gidley. Atomic Absorption Spectrophotometry. 2nd Edition. New York

City, New York: Pergamon Press. 1966.

Helgeson, H.C., D.H. Kirkham, and G.C. Flowers. "Theoretical Prediction of the Thermodynamic

Behavior of Aqueous Electrolytes at High Pressures and Temperatures IV Calculation of Activity

Coefficients, Osmotic Coefficients, and Apparent Molal and Standard and Relative Partial Molal

Properties to 600 'C and 5 Kb." American Journal of Science. Vol. 281. p. 1,249. 1981.

Nies, N.P. and R.W. Hulbert. "Solubility Isotherms in the System Sodium Oxide-Boric

Oxide-Water," Journal of Chemical Engineering Data. Vol. 12, No. 3. pp. 303-313. 1967.

OLI Systems, Inc. "StreamAnalyzer Version 1.2." Morris Plains, New Jersey: OLI Systems, Inc.

2002a.

. Environmental Simulation Program Version 6.6." Morris Plains, New Jersey: OLI

Systems, Inc. 2002b.

Perkin-Elmer Corporation. 'Analytical Method for Atomic Absorption Spectrophotometry."

Norwalk, Connecticut: Perkin-Elmer Corporation. 1971.

Pitzer, K.S. Activity Coefficients in Electrolyte Solutions. K.S. Pitzer, ed. 2nd Edition. Boston,

Massachusetts: Chemical Rubber Company, CRC Press. pp. 75-153. 1991.

. Thermodynamics of Electrolytes 1: Theoretical Basis and General Equations." Journal

of Physics and Chemistry. Vol. 77. p. 268. 1973.

A-25
-_____________ U'

Spessard, J.E. 'Investigation of Borate Equilibria in Neutral Salt Solutions." Journal of Inorganic

and Nuclear Chemistry. Vol. 32. p. 2,607. 1970.

Vela, N.P., L.K. Olson, and J.A. Caruso. 'Elemental Speciation with Plasma Mass

Spectrometry." Analytical Chemistry. Vol. 65, No. 13. pp. 584A-597A. 1993.

Winge, R.K. Inductively Coupled Plasma-Emission Spectroscopy: An Atlas of Spectral

Information. New York City, New York: John Wiley and Sons. 1985.

Yang, L. 'Software Validation Report for Environmental Simulation Program (ESP) Version 6.6,

Corrosion Simulation Program (CSP) Version 2.3, Environmental Simulation Program for

Concentrated Brines (ESPCB) Version 7.0 Alfa, and Stream Analyzer Version 1.2." San Antonio,

Texas: Center for Nuclear Waste Regulatory Analyses. 2003.

A-26
APPENDIX B

TYPICAL OLI SIMULATION OUTPUT

Calculation Summary

T60C Calculation for WorkW

Automatic Chemistry Model

Databanks:

Corrosion

Geochemical

Public

Redox selected

Unit Set: Default

W isothermal Calculation

Temperature 60.000 C

Pressure 1.0000 atm

Stream Inflows

H20 55.508 mol

Zn 1.6000e-6 mol

Al 1.5000e-5 mol

Cu 1.2000e-6 mol

Fe 2.8000e-5 mol

B(OH)3 0.20000 mol

NaOH 0.0 mol

Ca2S104 1.00OOe-4 mol

SiO2 5.9000e-3 mol

A1203 2.00OOe-4 mol

MgO 8.3000e-4 mol

Na2O 1.4400e-3 mol

CaB204 4.00OOe-4 mol

CaO 7.9000e-4 mol
Speciation Summary

Total number of species: 402

User

Inflows

H20

Zn

Al

Cu

Fe

B(OH)3

NaOH

Ca2SiO4

SiO2

A1203

MgO

Na2O

CaB204

CaO

W

Related

Inflows

12CaO.7A1203

AI(OH)3

Al2Si205(OH)4

Al2Si205(OH)4

Al2Si401 0(OH)2

A12SiO5

A12SiO5

Al2SiO5

Al2SiO5(OH)4

A14Fe5Si6022(OH)2

AIO(OH)

AIO(OH)

Ca(AI2Si4O1 2).2H20

Ca(A12Si5014).5H20

Ca(A12Si601 6).5H20

Ca(OH)2

CaO .165A12.33

Si3.67010(OH)2

Ca12A114033

Ca2A12Si301 O(OH)2

Ca2AI2SiO7

Ca2A12SiO7

Ca2A13Si3O1 2(OH)

Ca2AI3Si3O1 2(OH)

Ca2AI4Si8024 .7H20

Ca2B205

Ca2Fe2O5

Ca2Fe5Si8O22(OH )2

Ca2Mg5Si8O22(OH )2

Ca2MgSi2O7

Ca2Si3O7(OH)2 .1 .5H20

Ca2SiO3(OH)2 .0.17H20

Ca2SiO4

Ca3(B03)2

Ca3A12(SiO4)3

Ca3AI206

Ca3Fe2Si3Ol2

Aqueous

Species

H20

Al(OH)2+1

Al(OH)3 

- Aq

AI(OH)4-1

Al+3

AIOH+2

B(OH)3 

- Aq

B(OH)4-1

B20(OH)5-1

B303(OH)4-1

B405(OH)4-2

Ca+2

CaH2B03+1

CaHSiO3+1

CaOH+1

CaSiO2(OH)2 

- Aq

Cu(OH)2 

- Aq

Vapor

Species

H20 

- Vap

H2 

- Vap

02 

- Vap

Solid

Species

12CaO.7A1203

Al

AI(OH)3

A1203

A12Si205(OH)4

Al2Si401 0(OH)2

A12SiO5

AI2SiO5

Al2SiO5

A1O(OH)

AiO(OH)

B(OH)3

Ca(AI2Si4O12).2H20

Ca(OH)2

CaO.165A12.33Si3.670 10(OH)2

Ca12AI14033

Ca2A12Si301O(OH)2

Second

Liquid Species

Cu(OH)3-1

Cu(OH)4-2

Cu+1

Cu+2

CuOH+1

Fe(OH)2 

- Aq

Fe(OH)2+1

Fe(OH)3 

- Aq

Fe(OH)3-1

Fe(OH)4-1

Fe(OH)4-2

Fe+2

Fe+3

Fe2(OH)2+4

FeO4-2

FeOH+1

FeOH+2

H+1

H2 

- Aq

Ca2AI2SiO7

Ca2AI2SiO7

Ca2AI3Si3012(0H)

Ca2A13Si301 2(0H)

Ca2B205

Ca2Fe2O5

Ca2Mg5Si8O22(OH )2

Ca2MgSi2O7

Ca2Si3O7(OH)2 .1 .5H20

Ca2SiO3(OH)2 .0.17H20

Ca2SiO4

Ca2SiO4

Ca3(B03)2

Ca3A12(SiO4)3

Ca3A1206

Ca3Fe2Si3Ol2

Ca3MgSi208

Ca3Si2O4(OH)6

Ca3Si207

1
0w

Ca3MgSI208

Ca3Si204(OH)6

Ca3Si207

Ca3SiO5

Ca4AI2Fe201

Ca4Si309(OH)2 .0.5H20

Ca5Si6H1 1022.5

CaSSi6H21027.5

Ca5Si6H6020

Ca6Si6Ol 7(OH)2

CaAI2(AI2Si201 O)(OH)2

CaAI204

CaAI2Si2O7(OH)2

CaAI2Si2O7(OH)2.1H20

CaAI2Si2O8

CaAI2Si301 O.3H20

CaAI2Si4O02

CaA12SI4012

CaA12SI4012.4H20

CaA12SI401 2.6H20

CaAI2Si7O18.6H20

CaAI2SiO6

CaB407

CaFe2O4

CaFeSi206

CaMgSI206

CaMgSI206

CaMgSiO4

CaSi2O4(OH)2 .H20

CaSiO2(OH)2

CaSiO3

CaSiO3

Cu(OH)2

Cu2O

CuO

CuOH

Fe(OH)2

Fe(OH)3

FeO.9470

Fe2AI2SI05(OH)4

Fe2AI9Si4023(OH)

Fe2Fe(FeSiO5)(OH )4

Fe203

H2SiO4-2

H3Si04-1

Mg+2

MgHSiO3+1

MgOH+1

MgSIO2(OH)2 

- Aq

Na+1

NaB(OH)4 

- Aq

NaHSiO3 

- Aq

02 

- Aq

OH-1

S102 

- Aq

Zn(OH)2 

- Aq

Zn(OH)3-1

Zn(OH)4-2

Zn+2

ZnOH+1

Ca3SiO5

Ca4AI2Fe2O10

Ca4Si309(OH)2 .0.5H20

Ca5SI6H11022.5

Ca5Si6H21027.5

Ca5Si6H6020

Ca6Si6Ol7(OH)2

CaAI2(AI2Si201 O)(OH)2

CaAI204

CaAI2Si2O7(OH)2 .1 H20

CaAI2Si208

CaAI2Si3O0 O.3H20

CaA12SI401 2.4H20

CaAI2SiO6

CaB204

CaB407

CaFe2O4

CaFeSI206

CaMgSi206

CaMgSiO4

CaO

CaSi2O4(OH)2 .H20

CaSiO3

CaSiO3

Cu

Cu(OH)2

Cu2O

CuO

Fe

Fe(OH)2

Fe(OH)3

FeO.9470

Fe2AI2SiO5(OH)4

Fe203

Fe2SiO4

Fe304

Fe3Si2O5(OH)4

Fe3Si4OlO(OH)2

FeAI204

FeO

FeO

FeO(OH)

FeSiO3
Fe2SiO4

Fe3AI2Si3O12

Fe3O4

Fe3Si2O5(OH)4

Fe3Si4010(OH)2

Fe3Si4OlO(OH)2

Fe5A12Si3O1Q(oH )8

Fe7Si8O22(OH)2

FeA1204

FeA12SiO5(OH)2

FeNaSi206

FeO

FeO

FeO(OH)

FeSiO3

HO.33AI2.33Si3.6701O(0H)2

HO .33Fe2A10.33Si3.6 7010(OH)2

HO .33Mg3A1O.33Si3.67010(0H)2

H2

H2FeO4

H4SiO4

Mg(OH)2

MgO.165AI2.33Si3.670 1O(OH)2

MgO .495A11 .67Si401 O(OH)2

Mg2AI2SiO5(OH)4

Mg2AI3(AISi5o1 8)

Mg2AI3(AISi5o1 8)

Mg2A13(AJSi5O18).1 H20

Mg2AI4Si5O18.H20

Mg2SiO4

Mg2SiO4

Mg3 .165A1O.33Si3.67010(0H)2

Mg3AI2Si301 2

Mg3Si2O5(OH)4

Mg3Si2O5(OH)4

Mg3Si4O1O(OH)2

Mg4jSi6Ol5(OH)2(H20)2].3H20

Mg48Si35085(OH)62

Mg4AI4Si2O1o(oH)8

Mg5Al(AISi3O1 O)(OH)8

Mg5AJ[AISi3O1 O(OH )2](OH)6

Mg7Si2O8(OH)2

HO .33A12.33Si3.67010(OH)2

HO .33Fe2A1O.33Si3.6 7010(OH)2

HO .33Mg3A10.33Si3.67010(OH)2

Mg(OH)2

MgO .165AI2.33Si3.670 10(OH)2

MgO .495A11 .67Si401 O(OH)2

Mg2A13(AISi5O1 8)

Mg2A13(AISi5O18).1 H20

Mg2A14Si5O18 .H20

Mg2SiO4

Mg3.165A1O.33Si3.670 10(OH)2

Mg3A12Si3O1 

2

Mg3Si2O5(OH)4

Mg3Si4OlO(OH)2

Mg4[Si6015(OH)2(H20)2].3H20

Mg48Si35085(OH)62

Mg4AI4Si2O1O(OH)8

Mg5Al(AJSi301O)(OH)8

Mg5Al[AISi3O1O(OH )2](OH)6

Mg7Si2O8(OH)2

MgAJ204

MgFe2O4

MgO

MgSiO3

NaO .33AI2.33Si3.6701O(0H)2

Na2A12Si3O10 .2H20

Na2B407

Na2B407.1OH20

Na2B407.4H20

Na2B407.5H20

Na2O

Na2 .AI203.2.5H20

Na2Si2O5

Na2SiO3

Na2SiO3.5H20

Na2SiO3.6H20

Na2SiO3.8H20

Na2SiO3.9H20

Na4SiO4

Na6Si207

NaAI3Si3O1O(OH)2

NaAL02
a)

Mg7Si8O22(OH)2

MgAI204

MgFe2O4

MgSiO2(OH)2

MgSiO3

MgSiO3

NaO.33AI2.33Si3.6701 O(OH)2

Na2AI2Si301 0.2H20

Na2AI2Si5O14.5H20

Na2B4O7

Na2B407.10H20

Na2B407.4H20

Na2B407.5H20

Na2O.AI203

Na2O.A203.2.5H20

Na2Si2O5

Na2Si5O0 1

Na2SiO3

Na2SiO3.5H20

Na2SIO3.6H20

Na2SiO3.8H20

Na2SiO3.9H20

Na4SIO4

Na6Si2O7

NaAI3Si3O0 O(OH)2

NaAL02

NaAISi2O6

NaAISi2O6

NaAISi206.1 H20

NaAISi3O8

NaAISi3O8

NaAISI308

NaAISi3O8

NaAISi3O8

NaAISiO4

NaB(OH)4

NaB305

NaB508

NaB508.5H20

NaBO2

NaBO2.0.5H20

NABO2.2H20

NaB02.4H20

NaAISi2O6

NaAISI206

NaAISi206.1 H20

NaAISi3O8

NaAISi308

NaAISi3O8

NaAISi308

NaAISi3O8

NaAISiO4

NaB305

NaB508.5H20

NaBO2

NaBO2.0.5H20

NABO2.2H20

NaB02.4H20

NaFeO2

NaFeSi206

NaOH

NaOH.1 H20

SiO2

Si02

SiO2

SiO2

SiO2

Zn

Zn(OH)2

Zn(OH)2

Zn2SiO4

ZnO

ZnO.FE203

ZnSiO3
NaFeO2

NaFeSi2O6

NaH2BO3

NaHSiO3

NaOH.1 H20

02

SiO2

SiO2

SiO2

SiO2

Zn(OH)2

Zn(OH)2

Zn2SiO4

ZnO

ZnO.FE203

ZnSiO3

Stream Parameters

W Stream Amt

I Temperature

Pressure

pH

Ionic Strength

ORP

Osmotic Pressure

Electrical Cond, specific

Electrical Cond, molar

Viscosity, absolute

Viscosity, relative

Total

55.718

60.000

1.0000

6.9771

8.9402e-3

-0.39942

0.10217

1.3289e-3

6.4930

0.46731

1.0017

Aqueous

g/ml

0.98827

Aqueous

cal

-3.8092e6

mol

*C

atm

pH

mol/kg H20

V (SHE)

atm

1/ohm

cm2/ohm-mol

cP

cP/cP H20

Vapor

g/ml

0.0

Vapor

cal

0.0

Density

Solid

g/ml

2.4234

Solid

cal

-1354.3

2nd Liquid

g/ml

0.0

2nd Liquid

cal

0.0

Total

cal

Enthalpy -3.8105e6
Total and Phase Flows (Amounts)

Total Aqueous Vapor Solid 2nd Liquid

mol mol mol mol mol

Mole 55.718 55.713 0.0 4.8162e-3 0.0

Total Aqueous Vapor Solid 2nd Liquid

9 9 9 9 9

Mass 1013.0 1012.6 0.0 0.37692 0.0

Total Aqueous Vapor Solid 2nd Liquid

L L L L L

Volume 1.0248 1.0246 0.0 1.5553e-4 0.0

Scaling Tendencies

solids within temperature range Temperature Range

w Species Output (True Species)

Total Aqueous Vapor Solid 2nd Liquid

mol mol mol mol n/a

H20 55.516 55.516 0.0 0.0 0.0

Cu 1.2000e-6 0.0 0.0 1.2000e-6 0.0

B(OH)3 0.18521 0.18521 0.0 0.0 0.0

S102 3.2483e-4 3.2483e-4 0.0 0.0 0.0

AI(OH)3 7.7473e-15 7.7473e-15 0.0 0.0 0.0

CaSiO2(OH)2 9.1827e-11 9.1827e-11 0.0 0.0 0.0

Cu(OH)2 1.2978e-22 1.2978e-22 0.0 0.0 0.0

Fe(OH)2 1.3646e-10 1.3646e-10 0.0 0.0 0.0

Fe(OH)3 1.2148e-13 1.2148e-13 0.0 0.0 0.0

Fe3Si4010(0 7.2270e-6 0.0 0.0 7.2270e-6 0.0

H)2

H2 5.2100e-5 5.2100e-5 0.0 0.0 0.0

Mg3SI4010( 1.9126e-6 0.0 0.0 1.9126e-6 0.0

OH)2

MgSI02(OH 5.6683e-10 5.6683e-10 0.0 0.0 0.0

)2

NaAiSI308 4.1500e-4 0.0 0.0 4.1500e-4 0.0

NaB(OH)4 2.8294e-6 2.8294e-6 0.0 0.0 0.0

NaHSI03 1.1638e-7 1.1638e-7 0.0 0.0 0.0
02 4.2048e-74 4.2048e-74 0.0 0.0 0.0

SiO2 4.3905e-3 0.0 0.0 4.3905e-3 0.0

Zn(OH)2 7.2373e-9 7.2373e-9 0.0 0.0 0.0

Zn2SiO4 

3 .3908e-7 0.0 0.0 3.3908e-7 0.0

AI(OH)2+1 2.3194e-17 2.3194e-17 0.0 0.0 0.0

AI(OH)4-1 5.9853e-14 5.9853e-14 0.0 0.0 0.0

AI+3 1.8743e-22 1.8743e-22 0.0 0.0 0.0

AIOH+2 1.0088e-19 1.0088e-19 0.0 0.0 0.0

B(OH)4-1 2.0856e-3 2.0856e-3 0.0 0.0 0.0

B20(OH)5-1 6.8893e-4 6.8893e-4 0.0 0.0 0.0

B303(OH)4-1 3.9794e-3 3.9794e-3 0.0 0.0 0.0

B405(OH)4-2 2.2016e-5 2.2016e-5 0.0 0.0 0.0

Ca*2 1.2870e-3 1.2870e-3 0.0 0.0 0.0

CaH2BO3+1 1.0301e-4 1.0301e-4 0.0 0.0 0.0

CaHSiO3+1 2.1910e-8 2.1910e-8 0.0 0.0 0.0

CaOH+1 2.6960e-8 2.6960e-8 0.0 0.0 0.0

Cu(OH)3-1 4.0581e-27 4.0581e-27 0.0 0.0 0.0

Cu(OH)4-2 5.4646e-32 5.4646e-32 0.0 0.0 0.0

Cu+l 1.6469e-14 1.6469e-14 0.0 0.0 0.0

Cu+2 1.2536e-23 1.2536e-23 0.0 0.0 0.0 c CuOH+l 2.4129e-23 2.4129e-23 0.0 0.0 0.0

I Fe(OH)2+1 2.4208e-16 2.4208e-16 0.0 0.0 0.0 co Fe(OH)3-1 1.7902e-13 1.7902e-13 0.0 0.0 0.0

Fe(OH)4-1 3.4405e-15 3.4405e-15 0.0 0.0 0.0

Fe(OH)4-2 3.6573e-20 3.6573e-20 0.0 0.0 0.0

Fe+2 

6 .1804e-6 6.1804e-6 0.0 0.0 0.0

Fe+3 2.3319e-24 2.3319e-24 0.0 0.0 0.0

Fe2(OH)2+4 1.8849e-40 1.8849e-40 0.0 0.0 0.0

FeO4-2 1.0206e-63 1.0206e-63 0.0 0.0 0.0

FeOH+l 1.3855e-7 1.3855e-7 0.0 0.0 0.0

FeOH+2 4.3989e-19 4.3989e-19 0.0 0.0 0.0

H+1 1.1721e-7 1.1721e-7 0.0 0.0 0.0

H2SiO4-2 2.9909e-12 2.9909e-12 0.0 0.0 0.0

H3SiO4-1 2.6300e-6 2.6300e-6 0.0 0.0 0.0

Mg+2 8.2412e-4 8.2412e-4 0.0 0.0 0.0

MgHSiO3+1 2.1532e-8 2.1532e-8 0.0 0.0 0.0

MgOH+1 1.2808e-7 1.2808e-7 0.0 0.0 0.0

Na+1 2.4621e-3 2.4621e-3 0.0 0.0 0.0

OH-1 9.9003e-7 9.9003e-7 0.0 0.0 0.0

Zn(OH)3-1 7.9899e-12 7.9899e-12 0.0 0.0 0.0

Zn(OH)4-2 7.2306e-17 7.2306e-17 0.0 0.0 0.0

Zn+2 6.2688e-7 6.2688e-7 0.0 0.0 0.0

ZnOH+1 2.8772e-7 2.8772e-7 0.0 0.0 0.0
Molecular Output (Apparent Species)

Total Aqueous Vapor Solid 2nd Liquid

mol mol mol mo] n/a

H20 55.534 55.534 0.0 0.0 0.0

Cu 1.2000e-6 0.0 0.0 1.2000e-6 0.0

B(OH)3 0.18291 0.18291 0.0 0.0 0.0

MgO 8.2426e-4 8.2426e-4 0.0 0.0 0.0

CaB407 1.3900e-3 1.3900e-3 0.0 0.0 0.0

Fe2O3 6.2583e-14 6.2583e-14 0.0 0.0 0.0

Fe3SI40IO(O 7.2270e-6 0.0 0.0 7.2270e-6 0.0

H)2

FeO 6.3190e-6 6.3190e-6 0.0 0.0 0.0

H2 5.2100e-5 5.2100e-5 0.0 0.0 0.0

Mg3SI4010( 1.9126e-6 0.0 0.0 1.9126e-6 0.0

OH)2

NaAiSI308 4.1500e-4 0.0 0.0 4.1500e-4 0.0

NaB508 2.4650e-3 2.4650e-3 0.0 0.0 0.0

S102 4.3905e-3 0.0 0.0 4.3905e-3 0.0

S102 3.2762e-4 3.2762e-4 0.0 0.0 0.0

W Zn2S104 3.3908e-7 0.0 0.0 3.3908e-7 0.0

ZnO 9.2183e-7 9.2183e-7 0.0 0.0 0.0 CD

Element Balance

Total Aqueous Vapor Solid 2nd Liquid

mol mol mol mol n/a

AL(+3) 0.0 6.7623e-14 0.0 4.1500e-4 0.0

AL(0) 0.0 0.0 0.0 0.0 0.0

B(+3) 0.0 0.20080 0.0 0.0 0.0

CA(+2) 0.0 1.3900e-3 0.0 0.0 0.0

CU(+1) 0.0 1.6469e-14 0.0 0.0 0.0

CU(+2) 0.0 1.6645e-22 0.0 0.0 0.0

CU(0) 1.2000e-6 0.0 0.0 1.2000e-6 0.0

FE(+2) 0.0 6.3191e-6 0.0 2.1681e-5 0.0

FE(+3) 0.0 1.2517e-13 0.0 0.0 0.0

FE(0) 0.0 0.0 0.0 0.0 0.0

Fe(+6) 0.0 1.0206e-63 0.0 0.0 0.0

H 0.0 1.0420e-4 0.0 0.0 0.0

H(+1) 0.0 111.62 0.0 1.8279e-5 0.0

MG(+2) 0.0 8.2427e-4 0.0 5.7377e-6 0.0

NA(+1) 0.0 2.4650e-3 0.0 4.1500e-4 0.0

0 0.0 8.4095e-74 0.0 0.0 0.0
0(-2) 0.0 56.113 0.0 0.012212 0.0

Sl(+4) 0.0 3.2762e-4 0.0 5.6724e-3 0.0

ZN(+2) 0.0 9.2184e-7 0.0 6.7817e-7 0.0

Zn(O) 0.0 0.0 0.0 0.0 0.0

SDecies Activity Coefficients

H20 0.0 Activity

AI(OH)2+1 0.0 Act-Coef

Ai(OH)3 

- Aq 0.0 Act-Coef

Ai(OH)4-1 0.0 Act-Coef

Ai+3 0.0 Act-Coef

AiOH+2 0.0 Act-Coef

B(OH)3 

- Aq 0.0 Act-Coef

B(OH)4-1 0.0 Act-Coef

B20(OH)5-1 0.0 Act-Coef

B303(OH)4-1 0.0 Act-Coef

B405(OH)4-2 0.0 Act-Coef

Ca+2 0.0 Act-Coef

w CaH2BO3+1 0.0 Act-Coef

1 CaHSiO3+1 0.0 Act-Coef

o CaOH+1 0.0 Act-Coef

CaSIO2(OH)2 

- Aq 0.0 Act-Coef

Cu(OH)2 

- Aq 0.0 Act-Coef

Cu(OH)3-1 0.0 Act-Coef

Cu(OH)4-2 0.0 Act-Coef

Cu+l 0.0 Act-Coef

Cu+2 0.0 Act-Coef

CuOH+1 0.0 Act-Coef

Fe(OH)2 

-Aq 0.0 Act-Coef

Fe(OH)2+1 0.0 Act-Coef

Fe(OH)3 

- Aq 0.0 Act-Coef

Fe(OH)3-1 0.0 Act-Coef

Fe(OH)4-1 0.0 Act-Coef

Fe(OH)4-2 0.0 Act-Coef

Fe+2 0.0 Act-Coef

Fe+3 0.0 Act-Coef

Fe2(OH)2+4 0.0 Act-Coef

FeO4-2 0.0 Act-Coef

FeOH+1 0.0 Act-Coef

FeOHi2 0.0 Act-Coef

H+1 0.0 Act-Coef
H2-Aq 0.0 Act-Coef

H2S104-2 0.0 Act-Coef

H3Si04.1 0.0 Act-Coef

Mg+2 0.0 Act-Coef

MgHSiO3+1 0.0 Act-Coef

MgOH+1 0.0 Act-Coef

MgSiO2(OH)2 

- Aq 0.0 Act-Coef

Na+I 0.0 Act-Coef

NaB(OH)4 

- Aq 0.0 Act-Coef

NaHSiO3 - Aq 0.0 Act-Coef

02 - Aq 0.0 Act-Coef

OH-1 0.0 Act-Coef

SiO2 - Aq 0.0 Act-Coef

Zn(OH)2 - Aq 0.0 Act-Coef

Zn(OH)31 0.0 Act-Coef

Zn(OH)4-2 0.0 Act-Coef

Zn+2 0.0 Act-Coef

ZnOH+1 0.0 Act-Coef

H20 - Vap 0.0 Fug-Coef

H2 - Vap 0.0 Fug-Coef

W 02 

- Vap 0.0 Fug-Coef

Species K(ea)-Values

Species Mobilities

Species Self Diffusivities
NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

(9-2004)

NRCM 3.7 (Assigned by NRC Add Vol. Supp. Rev.

and Addendum Numbers If any.)

BIBLIOGRAPHIC DATA SHEET NUREG/CR-6873

(See lnstructions on the reverse)

2. TITLE AND SUBTITLE 3. DATE REPORT PUBLISHED

Corrosion Rate Measurements and Chemical Speciation of Corrosion MONTH YEAR

Products Using Thermodynamic Modeling of Debris Components to April 2005

Support GSI-191

4. FIN OR GRANT NUMBER

N6061

S. AUTHOR(S) 6. TYPE OF REPORT

B.P. Jain/U.S. Nuclear Regulatory Commission (NRC)

V. Jain, X. He, and Y.-M. Pan/Center for Nuclear Waste Regulatory Analyses (CNWRA)

7. PERIOD COVERED (Incus"'e Cates)

August 2004-April 2005

8. PERFORMING ORGANIZATION -NAME AND ADDRESS (INRCprovide DMsion OfEiceorFlegion U.S. NuclearRegulatoryCommissi on. andrmiling address;iffcontra tor,

provdde name and magiing address.)

Center for Nuclear Waste Regulatory Analyses Southwest Research Institute®

6220 Culebra Road

San Antonio, TX 78228-0510

9. SPONSORING ORGANIZATION- NAMEAND ADDRESS (IfNRCtype 'Samne asabove ;ffcontradorprovideNRCDivision Offrice orRegion US. NuclearRegulatoryCoNTrrisslon

and mailing address)

Division of Engineering Technology

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

10. SUPPLEMENTARY NOTES

B.P. Jain, NRC Project Manager

11. ABSTRACT (200 words orless)

This report documents thermodynamic simulations conducted to determine whether post loss-of-coolant-accident (LOCA) debris

generation and consequent sump screen head loss In a pressurized water reactor containment can be affected by chemical

interactions between the emergency core cooling system/containment spray water and exposed materials. Based on the

measured corrosion rates, estimated exposed surface area, and exposure time, the thermodynamics simulations indicated that

the formation of dominant solid phases was controlled by the presence of Nukone low-density fiber insulation, aluminum, and

concrete. The predicted dominant solid phases consisted of potentially amorphous silicate phases such as sodium aluminum

silicate (NaAlSi 3O8), calcium magnesium silicate [Ca2Mg.SI 82O,(OH)2], calcium silicate (CaSiO3), and silica (SiO2). The results

were based on the solid phases included in the thermodynamic simulation program database. The formation of actual solid

phases may be different depending on the reaction kinetics. Although some constituents decreased proportionally with

increasing time, the solid NaAlSi 30, phase continued to be a dominant solid phase at all times. The formation of NaAlSi3O8 in

the presence of alkaline solutions could lead to gel formation, which could result in clogging of containment area sump pump

suction strainers. Thermodynamic simulations Indicate that in alkaline simulated containment water at pH 10 there is no

significant difference in corrosion product formation as high-temperature and pressure conditions during the initial stages of a

LOCA event approach steady-state atmospheric pressure conditions. This report provides insight to and is useful in

understanding the evolution of solution chemistry and the formation of solid phases in integrated chemical effects tests at the

University of New Mexico.

12. KEY WORDSiDESCRIPTORS ( words orphrases that will assist reseanrher s Iocaing the report) 13. AVAILABILuTY STATEMENT

unlimited

corrosion

thermodynamic modeling 14. SECURITY CLASSIFICATION

LOCA (This Page)

chemical speciation unclassified

fiber insulation (mis Report)

metals unclassified

GSI-191

15. NUMBER OF PAGES

16. PRICE

NRIC FORM 335 (9-200)4) PRINTEDU ON RECQYCLED PAPER
II I

Federal Recycling Program
UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, DC 20555-0001

OFFICIAL BUSINESS