Publications (YM) Yucca Mountain 5-2007 Geochemical modeling of solubility and speciation of uranium, neptunium, and plutonium Zhongbo Yu Yuyu Lin Karen Johannesson Amy J. Smiecinski University of Nevada, Las Vegas, [email protected] Klaus J. Stetzenbach University of Nevada, Las Vegas, [email protected] Follow this and additional works at: https://digitalscholarship.unlv.edu/yucca_mtn_pubs Part of the Geochemistry Commons Repository Citation Yu, Z., Lin, Y., Johannesson, K., Smiecinski, A. J., Stetzenbach, K. J. (2007). Geochemical modeling of solubility and speciation of uranium, neptunium, and plutonium. Available at: https://digitalscholarship.unlv.edu/yucca_mtn_pubs/66 This Technical Report is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Technical Report in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Technical Report has been accepted for inclusion in Publications (YM) by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. Conceptual Model Mathenutical Model Process Model C] Ahslrdon Modd Systeun Model Intended use of Model lnput to Calculation ' lnput to another Model 0 lnput to Technical Documont lnput to other Technclol Product. Descritm use: This model is used to evaluate the sensitivity of the current models to solubility data and to predict the impad of actinide speciation data on the behavior and mobility of actinide species. 7 (0)Principal Investigator Klaus J. Stebenbach k/~dddr~~~~ (10) Remarks: // MODEL REVISION HISTORY Complete only applicable items (1) Page 1 of 1 (2) Model Title: Geochemical Modeling of Solubility and Speciation of Uranium, Neptunium, and Plutonium (3) Document Identifier (including Revision No.): MOD-06-001 REV 00 (4) (5) Description of Revision 0 Initial Issue ACRONYMS ACC Yucca Mountain Project Records Accession Number AMR Analysis Model Report DIRS Document Input Reference System DOE U.S. Department of Energy DTN Data Tracking Number ESF Exploratory Studies Facility NRC U.S. Nuclear Regulatory Commission NCEWDP Nye County Early Warning Drilling Program NTS Nevada Test Site OCRWM Office of Civilian Radioactive Waste Management Q Qualified QA Quality Assurance QAP Quality Assurance Procedure RW Radionuclide Wastes RWP Radionuclide Wastes Package SZ Saturated Zone UQ Unqualified USGS U.S. Geological Survey UZ Unsaturated Zone YM Yucca Mountain TABLE OF CONTENTS LIST OF TABLES............................................................................................................. iv LIST OF FIGURES ............................................................................................................ v 1. PURPOSE.................................................................................................................... 1 2. QUALITY ASSURANCE........................................................................................... 2 3. COMPUTER SOFTWARE AND MODEL USAGE.................................................. 2 4. INPUTS........................................................................................................................ 3 4.1 DATA AND PARAMETERS .................................................................................. 3 4.1.1 Direct Inputs....................................................................................................... 3 4.1.2 Indirect Inputs .................................................................................................... 4 4.2 CRITERIA ................................................................................................................ 5 4.3 CODES AND STANDARDS................................................................................... 5 5. ASSUMPTIONS.......................................................................................................... 6 6. MODEL ....................................................................................................................... 7 6.1 MODEL OBJECTIVES............................................................................................ 7 6.2 OVERVIEW OF THE MODEL ............................................................................... 7 6.3 TECHNICAL ISSUES IN SOLUBILITY EVALUATION..................................... 7 6.3.1 The Definition of Solid Solubility ..................................................................... 8 6.3.2 Uranium Solubility............................................................................................. 8 6.3.3 Neptunium Solubility....................................................................................... 10 6.3.4 Plutonium Solubility ........................................................................................ 10 6.4 TECHNICAL ISSUES IN SPECIATION EVALUATION................................... 11 6.4.1 The Definition of Aqueous Speciation ............................................................ 11 6.4.2 Uranium Aqueous Speciation .......................................................................... 11 6.4.3 Neptunium Aqueous Speciation ...................................................................... 11 6.4.4 Plutonium Aqueous Speciation........................................................................ 12 6.5 TREATMENT OF VARIATION AND UNCERTAINTY.................................... 13 6.6 MODEL CONFIGURATION ................................................................................ 13 6.6.1 Temperature ..................................................................................................... 13 6.6.2 pH..................................................................................................................... 14 6.6.3 CO2 Fugacity................................................................................................... 14 6.6.4 Oxidation Potential .......................................................................................... 14 6.7 URANIUM SOLUBILITY AND SPECIATION RESULTS................................. 14 6.7.1 Solubility Results............................................................................................. 14 6.7.2 Speciation Results............................................................................................ 18 6.8 NEPTUNIUM SOLUBILITY AND SPECIATION RESULTS ............................ 20 6.8.1 Solubility Results............................................................................................. 20 6.8.2 Speciation Results............................................................................................ 23 6.9 PLUTONIUM SOLUBILITY AND SPECIATION .............................................. 23 6.9.1 Solubility Results............................................................................................. 23 6.9.2 Speciation Results............................................................................................ 26 6.10 MODEL VALIDATION .......................................................................................... 26 6.10.1 Validation Criteria ............................................................................................. 26 6.10.2 Testing and Comparison .................................................................................... 28 7. CONCLUSIONS........................................................................................................ 31 ii 7.1 MODEL OUTPUT.................................................................................................. 31 7.2 OUTPUT UNCERTAINTY ................................................................................... 31 7.3 RESTRICTIONS .................................................................................................... 31 8. INPUTS AND REFERENCES................................................................................ 33 9. ATTACHMENTS.................................................................................................... 37 APPENDIX A TRANSPORT MODEL DISCUSSION................................................... 37 A.1 OVERVIEW OF THE TRANSPORT MODEL.................................................... 37 A.2 URANIUM TRANSPORT MODEL..................................................................... 39 A.3 NEPTUNIUM AND PLUTONIUM TRANSPORT MODEL .............................. 42 iii LIST OF TABLES Table 4-1 Input Data Source and Data Tracking Number for Solubility and Speciation Model. ............................................................................................................... 4 Table 4-2 Chemical Compositions of Solution Used in Solubility and Speciation Models............................................................................................................... 4 Table 4-3 Summary of Indirect Inputs .............................................................................. 5 Table 6-1 Dissolution Equations of Principal Alteration Phases of Uranium, Neptunium, and Plutonium at 25ºC. ................................................. 9 Table 6-2 Calculated Uranium Solubility Controlled by Secondary Minerals (mol/L).. 16 Table 6-3 Calculated Neptunium Solubility Controlled by Np2O5 (mol/L)...................