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Waste Package Degradation Process Model Report
TDR-WIS-MD-000002 REV 00 ICN 01

Front Matter

Title Page
Disclaimer
Signature Page
Authors
Change History
Executive Summary
Acronyms

TABLE OF CONTENTS

1. INTRODUCTION
 1.1 OBJECTIVES
  1.1.1 Objectives of this Report
  1.1.2 Purpose of the Analysis and Model Reports
 1.2 SCOPE
 1.3 Principal Factors and Other Factors Considered
 1.4 QUALITY ASSURANCE
 1.5 WASTE PACKAGE DEGRADATION PROCESS AND ABSTRACTION MODELS
  1.5.1 Environment on the Surface of Drip Shield and Waste Package Outer Barrier
  1.5.2 Mechanisms for Early Failures and Manufacturing Defects
  1.5.3 Aging and Phase Stability of Waste Package Outer Barrier
  1.5.4 General Corrosion and Localized Corrosion
  1.5.5 Stress Corrosion Cracking
  1.5.6 Hydrogen-Induced Cracking of Drip Shield
 1.6 Screening of Features, Events, and Processes
 1.7 RELATIONSHIP TO OTHER PROCESS MODEL REPORTS AND DOCUMENTS

2. EVOLUTION OF THE PROCESS MODEL
 2.1 BACKGROUND
 2.2 PREVIOUS TREATMENT OF WASTE PACKAGE DEGRADATION MODELING
 2.3 Total System Performance Assessment-Site Recommendation APPROACH
 2.4 Issues Related to Waste Package Degradation

3. Models and ABSTRACTED MODELs
 3.1 Model Descriptions
  3.1.1 Overview of Waste Package and Drip Shield Design
  3.1.2 Manufacturing Defects (Early Failure AMR)
  3.1.3 Environment on the Surface of the Waste Package and Drip Shield
  3.1.4 Phase Stability and Aging
  3.1.5 General Corrosion
  3.1.6 Localized Corrosion
  3.1.7 Stress Corrosion Cracking
  3.1.8 Hydrogen-Induced Cracking
  3.1.9 Model Uncertainties
  3.1.10 Model Validation
  3.1.11 Alternative Approaches or Models
 3.2 INTEGRATED MODEL
  3.2.1 Concept for the Integrated Model
  3.2.2 Abstraction of General Corrosion Models for Waste Package Outer Barrier and Drip Shield
  3.2.3 Abstraction of Localized Corrosion Models for Waste Package Outer Barrier and Drip Shield
  3.2.4 Abstraction of Slip Dissolution Stress Corrosion Cracking Model
  3.2.5 Abstraction of Stress and Stress Intensity Factor Profile in Waste Package Closure Welds
  3.2.6 Abstraction for Manufacturing Defects in Waste Package Closure Welds
  3.2.7 Drip Shield and Waste Package Degradation Analyses

4. Relationship to NRC Issue Resolution Status Reports
 4.1 Summary of the Key Technical Issues
 4.2 RELATION OF THE WASTE PACKAGE PMR TO THE KEY TECHNICAL ISSUES
  4.2.1 Container Life and Source Term
  4.2.2 Total System Performance Assessment and Integration
  4.2.3 Repository Design and Thermal-Mechanical Effects

5. SUMMARY AND CONCLUSIONS

6. REFERENCES
 6.1 DOCUMENTS CITED
 6.2 CODES, STANDARDS, REGULATIONS, AND PROCEDURES
 6.3 SOURCE DATA

FIGURES

1-1. Waste Package
1-2. A View of a Typical In-Drift Placement of Waste Packages
1-3. Model Confidence Foundation
1-4. Schematic Representation of the Elements of Process Models Interrelationships Among the Process Models and the AMRs Containing These Models
3-1. Size Distribution for Indicated Frequency of Occurrence for Outer Surface Breaking Flaws in Waste Package Alloy 22 Shell Welds
3-2. Size Distribution for Indicated Frequency of Occurrence of Outer Surface Breaking Flaws in Waste Package Alloy 22 Lid Welds
3-3. Deliquescence Point for Sodium Nitrate Solutions
3-4. Isothermal Time-Temperature-Transformation Diagram for Alloy 22 Base Metal
3-5. Effect of Thermal Aging at 649°C on the Precipitation of Intermetallic Phases at Grain Boundaries on Alloy 22
3-6. Time to Reach Various Stages of Precipitation in Aged Alloy 22 Base Metal Plotted on a Log Scale as a Function of Reciprocal Temperature
3-7. Graphical Extrapolation of the Curves to Repository-Relevant Temperatures
3-7a. Temperature of the WPOB Surface as a Function of Time for the Hottest Waste Package
3-8. Graphical Extrapolation of the Limited Kinetic Data for Long Range Order in Alloy 22 Base Metal
3-9. Effect of Thermal Aging for 173 Hours at 700°C on the Corrosion Resistance of Alloy 22 in Simulated Acidic Concentrated Water at 90°C
3-10. Effect of Thermal Aging for 173 Hours at 700°C on the Corrosion Resistance of Alloy 22 in Simulated Concentrated Water at 90°C
3-11. Schematic Representation of Model for General Corrosion and Localized Corrosion of Drip Shield and Waste Package Materials
3-12. Schematic Representation Showing Augmentation of Model for General Corrosion and Localized Corrosion to Account for Microbiologically Influenced Corrosion of Drip Shield and Waste Package Materials
3-13. Regression Analysis of Dry Oxidation Rate Data for Titanium
3-14. Range of Observed Penetration Rates for Stainless Steels 304 and 316 Shown as Cumulative Probability Distributions
3-15. Range of Observed Logarithms of Penetration Rates for Stainless Steels 304 and 316 Shown as Cumulative Probability Distributions
3-16. Range of Localized Penetration Rates for Stainless Steels 304 and 316
3-17. Comparison of Observed Penetration Rates for Stainless Steels 304 and 316
3-18. Two-Year General Corrosion Rate Data from Long Term Corrosion Test Facility Based Upon Generic Weight-Loss Samples
3-19. Two-Year General Corrosion Rate Data from Long Term Corrosion Test Facility Based Upon Generic Crevice Samples
3-20. Two-Year General Corrosion Rate Data From Long Term Corrosion Test Facility Based Upon Both Generic Weight-Loss and Crevice Samples, Including Those with Apparent Negative Rates
3-21. Two-Year General Corrosion Rate Data From Long Term Corrosion Test Facility Based Upon Both Generic Weight-Loss and Crevice Samples, Excluding Those with Apparent Negative Rates
3-22. Combination of All General Corrosion Rate Data for Alloy 22 from Long Term Corrosion Test Facility, Including 6-, 12-, and 24-Month Exposures
3-23. Combination of All General Corrosion Rate Data for Alloy 22 from Long Term Corrosion Test Facility, Including 6-, 12-, and 24-Month Exposures with Negative Rates Excluded
3-24. General Corrosion of Titanium Grade 16: 12-Month Weight-Loss Samples from Long Term Corrosion Test Facility
3-25. General Corrosion of Titanium Grade 16: 12-Month Crevice Samples From Long Term Corrosion Test Facility
3-26. Distribution of Positive General Corrosion Rates Based Upon Weight-Loss and Crevice Samples
3-27. Distribution of Positive General Corrosion Rates with Variability Based Upon Weight-Loss and Crevice Samples
3-28. Baseline – Platinum in Simulated Concentrated Water at 90°C
3-29. Type 1–Alloy 22 in Simulated Acidic Concentrated Water at 90°C
3-30. Type 2–Alloy 22 in Simulated Concentrated Water at 90°C
3-31. Type 3–316L in Simulated Saturated Water at 100°C
3-32. Alloy 22 in Various Repository Media – Comparison of Cyclic Polarization Data
3-33. Potentiostatic Polarization of Alloy 22 in Simulated Concentrated Water at 90°C and 200 mV Versus Ag/AgCl
3-34. Cyclic Polarization Curve for Alloy 22 in 110°C Basic Saturated Water – Thermally Aged at 700°C for 10 Hours
3-35. Cyclic Polarization Curve for Alloy 22 in 110°C Basic Saturated Water – Thermally Aged at 700°C for 173 Hours
3-36. Titanium Grade 7 in Simulated Saturated Water at 120°C
3-37. Titanium Grade 7 in Simulated Concentrated Water at 90°C
3-38. Potentials versus Temperature – Stainless Steel 316L in Simulated Acidic Concentrated Water
3-39. Potentials versus Temperature – Stainless Steel 316L in Simulated
Concentrated Water
3-40. Potentials versus Temperature – Stainless Steel 316L in Simulated Saturated Water
3-41. Potentials versus Temperature – Alloy 22 in Simulated Dilute Water
3-42. Potentials versus Temperature – Alloy 22 in Simulated Concentrated Water
3-43. Potentials versus Temperature – Alloy 22 in Simulated Acidic Concentrated Water
3-44. Potentials versus Temperature – Alloy 22 in Simulated Saturated Water
3-45. Corrosion and Threshold Potentials of Titanium Grade 7 in Simulated Saturated Water
3-46. Corrosion and Threshold Potentials for Titanium Grade 7 in Simulated Acidic Concentrated Water
3-47. Corrosion and Threshold Potentials for Titanium Grade 7 in Simulated Concentrated Water
3-48. Corrosion and Threshold Potentials for Titanium Grade 7 in Simulated Dilute Water
3-49. Effect of Molybdenum on the Critical Pitting Temperature of Stainless Steels in Ferric Chloride Solution
3-50. Effect of Pit Resistance Equivalence Number on the Critical Pitting and Crevice Corrosion Temperature of Stainless Steels in Ferric Chloride Solution
3-51. Effect of Hydrogen Peroxide on Corrosion Potential of Alloy 22 in Simulated Acidic Concentrated Water at 25°C
3-52. Effect of Hydrogen Peroxide on Corrosion Potential of Alloy 22 in Simulated Concentrated Water at 25°C
3-53. Effect of Chromium Content in Nickel-Chromium Alloys on Ultimate Crevice pH
3-54. Concentrations of Dissolved Metals in Stainless Steel 304 Crevice Exposed to 0.1 N NaCl
3-55. Stainless Steel 316L, 4M NaCl, 200 mV and 23°C – Crevice pH versus Time
3-56. Alloy 22, 4M NaCl at 23°C – Crevice pH versus Time
3-57. Determination of Crevice pH for Waste Package Materials
3-58. Finite Element Model for the Initial WPOB Design and Selected Cross Sections for Stress Plots (single-lid design)
3-59. Radial Stress - Initial WPOB Outer Lid at 125°C Plots (single-lid design)
3-60. Hoop Stress - Initial WPOB Outer Lid at 125°C Plots (single-lid design)
3-61. Flaw Orientations for Lid Welds
3-62. Stress Intensity Factor for Radial Crack in Initial WPOB Outer Lid (single-lid design)
3-63. Schematic and Dimensions for Dual-Lid WPOB Design
3-64. Measured Hoop Stress with and without Single-Pass Laser Peening Compared to Threshold Stress for SCC
3-65. Calculated Stress Intensity Factor for Hoop Stress with and without Laser Peening
3-66. Schematic of the Dual-Closure-Lid Design for Waste Package Outer Barrier
3-67. Schematic of the Conceptual Model of Stochastic Waste Package Degradation Model (WAPDEG) for TSPA-SR
3-68. Logic Flow for Nominal-Case Model for Waste Package and Drip Shield Degradation Model for TSPA-SR
3-69. Cumulative Distribution Functions for the General Corrosion Rate of Alloy 22 Derived from 6-month, One-Year, and Two-Year Exposure Data
3-70. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 50th Uncertainty Percentile
3-71. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 25th Uncertainty Percentile
3-72. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 75th Uncertainty Percentile
3-73. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 50th Uncertainty Percentile
3-74. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 25th Uncertainty Percentile
3-75. The Variability Cumulative Probability Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 75th Uncertainty Percentile
3-76. Cumulative Probability Distribution Functions for the General Corrosion Rate of Alloy 22 Waste Package Outer Barrier Before (Original) and After (Corrected) Accounting for Bias Due to Possible Silica Scale Deposits
3-77. Cumulative Probability Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield Before (Original) and After (Corrected) Accounting for Bias Due to Possible Silica Scale Deposits
3-78. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 50th Uncertainty Percentile
3-79. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 25th Uncertainty Percentile
3-80. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Alloy 22 Waste Package Outer Barrier with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 75th Uncertainty Percentile
3-81. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 50th Uncertainty Percentile
3-82. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 25th Uncertainty Percentile
3-83. The Variability Cumulative Distribution Functions for the General Corrosion Rate of the Ti-7 Drip Shield with the Silica-Scale Deposit Correction Using 25%-75%, 50%-50%, and 75%-25% Uncertainty and Variability Partitioning Ratios and 75th Uncertainty Percentile
3-84. Plot of ΔE vs. pH for Alloy 22 from Equation (3-39) Showing the ±3σ and ±4σ Confidence Intervals and the CP Experimental Data
3-85. Plot of ΔE vs. pH for Titanium Grade 7 from Equation (3-42) Showing the ±3σ and ±4σ Confidence Intervals and the CP Experimental Data
3-86. Bounding Calculations for the Model Responses for the Time to Failure of the Outer and Inner Closure Lids by SCC Calculated with the Slip Dissolution Model Using the Bounding Values for Parameter n for a Range of the Stress Intensity Factor Values
3-87. Hoop Stress as a Function of Depth in the Alloy 22 Outer-Lid Welds (25-mm thick) at the Reference Location on the Outer-Lid Weld Circumference and the Uncertainty Range
3-88. Stress Intensity Factor as a Function of Radial Crack in the Alloy 22 Outer-Lid Welds (25-mm thick) at the Reference Location on the Outer-Lid Weld Circumference and the Uncertainty Range
3-89. Hoop Stress as a Function of Depth in the Alloy 22 Outer-Lid Welds (25-mm thick) at 0°, 90° and 180° Angles Along the Circumference of the Outer-Lid Weld
3-90. Stress Intensity Factor as a Function of Radial Crack Depth in the Alloy 22 Outer-Lid Welds (25-mm thick) at 0°, 90° and 180° Angles Along the Outer-Lid Weld Circumference
3-91. Hoop Stress as a Function of the Projected Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at the Reference Location on the Inner-Lid Weld Circumference and the Uncertainty Range
3-92. Hoop Stress as a Function of the Projected Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at 0°, 90° and 180° Angles Along the Circumference of the Inner-Lid Weld
3-93. Stress Intensity Factor as a Function of the Projected Radial Crack Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at the Reference Location on the Inner-Lid Weld Circumference and the Uncertainty Range
3-94. Stress Intensity Factor as a Function of the Projected Radial Crack Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at 0°, 90° and 180° Angles Along the Inner-Lid Weld Circumference
3-95. Hoop Stress as a Function of Depth in the Alloy 22 Outer-Lid Welds (25-mm thick) at the Reference Location on the Outer-Lid Weld Circumference using Uncertainty Bounds of ± 10, 15, and 30%
3-96. Stress Intensity as a Function of Depth in the Alloy 22 Outer-Lid Welds (25-mm thick) at the Reference Location on the Outer-Lid Weld Circumference using Uncertainty Bounds of ± 10, 15, and 30%
3-97. Hoop Stress as a Function of Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at the Reference Location on the Outer-Lid Weld Circumference using Uncertainty Bounds of ± 10, 15, and 30%
3-98. Stress Intensity as a Function of Depth in the Alloy 22 Inner-Lid Welds (10-mm thick) at the Reference Location on the Outer-Lid Weld Circumference using Uncertainty Bounds of ± 10, 15, and 30%
3-99. Cumulative Probability for the Occurrence of Defects in the Welds of the Outer (25-mm thick) and Inner (10-mm thick) Lids of Waste Package Outer Barrier (Surface breaking flaws only)
3-100. Conditional Probability Density Functions of Defect Sizes in the Closure Lid Welds for Various Combinations of Values for the Location and Scale Parameters (b & v )
3-101. Cumulative Probability for the Average Number of Defects per Waste Package in the Welds of the Outer (25-mm thick) and Inner (10-mm thick) Lids of Waste Package Outer Barrier Including Surface Breaking and Embedded Defects
3-102. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th and 5th Percentile Confidence Intervals of the First Breach Profile of Waste Packages with Time
3-103. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th, and 5th Percentile Confidence Intervals of the First Breach Profile of Drip Shield with Time
3-104. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th, and 5th Percentile Confidence Intervals of the First Crack Breach Profile of Waste Packages with Time
3-105. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th, and 5th Percentile Confidence Intervals of the First Patch Breach Profile of Waste Packages with Time
3-106. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th, and 5th Percentile Confidence Intervals of the First Breach Profile of Waste Packages with Time
3-107. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th and 5th Percentile Confidence Intervals of the First Breach Profile of Drip Shield with Time
3-108. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th and 5th Percentile Confidence Intervals of the First Crack Breach Profile of Waste Packages with Time
3-109. The Upper and Lower Bounds, Median, Mean, and 95th, 75th, 25th and 5th Percentile Confidence Intervals of the First Patch Breach Profile of Waste Packages with Time

TABLES

1-1. Principal Factors, Other Factors, and the PMRs Where Addressed
1-2. Primary FEP Summary for Waste Package and Drip Shield Degradation
2-1. Key External Issues for the Waste Package Degradation Process Model Report
3-1. Summary of Estimated Probabilities and Performance Consequences for Various Types of Waste Package Defects
3-2. Composition of Standard Test Media Based upon J-13 Well Water
3-3. Initial Basic Saturated Water Solution Recipe
3-4. Modified Basic Saturated Water Solution Recipes
3-5. Intermetallic Phases Observed in Alloy 22 with Transmission Electron Microscopy
3-6. Time Required for Precipitation of Intermetallic and Carbide Particles on the Grain Boundaries of Alloy 22 Base Metal
3-7. Summary of the Distribution of Rates for General Corrosion of Alloy 22 Samples
3-8. Summary of Error Analysis for Corrosion Rates Based Upon Weight Loss of Alloy 22
3-9. Summary of Error Analysis for Corrosion Rates Based Upon Weight Loss of Titanium Grade 16
3-10. Electrochemical Potentials Determined from Cyclic Polarization of Alloy 22 in Basic Saturated Water
3-11. Distribution of Localized Corrosion Rates for Alloy 22
3-12. Distribution of Localized Corrosion Rates for Titanium Grade 7
3-13. Corrosion Model Parameters Evaluated in the Waste Package and Drip Shield Degradation Analysis for Realistic and Alternative Conservative Cases
4-1. Issue Resolution Status Reports, Subissues, Technical Acceptance Criteria, and PMR Approach