Ebook: Actinide Speciation in High Ionic Strength Media: Experimental and Modeling Approaches to Predicting Actinide Speciation and Migration in the Subsurface

The management and disposal of radioactive wastes are key international issues requiring a sound, fundamental scientific basis to insure public and environmental protection. Large quantities of existing nuclear waste must be treated to encapsulate the radioactivity in a form suitable for disposal. The treatment of this waste, due to its extreme diversity, presents tremendous engineering and scientific challenges. Geologic isolation of transuranic waste is the approach currently proposed by all nuclear countries for its final disposal. To be successful in this endeavor, it is necessary to understand the behavior of plutonium and the other actinides in relevant environmental media. Conceptual models for stored high level waste and waste repository systems present many sCientific difficulties due to their complexity and non-ideality. For example, much of the high level nuclear waste in the US is stored as alkaline concentrated electrolyte materials, where the chemistry of the actinides under such conditions is not well understood. This lack of understanding limits the successful separation and treatment of these wastes. Also, countries such as the US and Germany plan to dispose of actinide­ bearing wastes in geologic salt deposits. In this case, understanding the speciation and transport properties of actinides in brines is critical for confidence in repository performance and risk assessment activities. Many deep groundwaters underlying existing contaminated sites are also high in ionic strength. Until recently, the scientific basis for describing actinide chemistry in such systems was extremely limited.

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This proceedings, based on an American Chemical Society symposium entitled `Experimental and Modeling Studies of Actinide Speciation in Non-Ideal Systems', deals with the management and disposal of radioactive waste. More specifically, it concerns modeling and experimental approaches for actinide chemistry in high ionic strength media, including general aspects of actinide chemistry in high-level nuclear waste and environmental systems, and the special problems of actinide behavior in concentrated electrolytes and/or alkaline conditions.

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This proceedings, based on an American Chemical Society symposium entitled `Experimental and Modeling Studies of Actinide Speciation in Non-Ideal Systems', deals with the management and disposal of radioactive waste. More specifically, it concerns modeling and experimental approaches for actinide chemistry in high ionic strength media, including general aspects of actinide chemistry in high-level nuclear waste and environmental systems, and the special problems of actinide behavior in concentrated electrolytes and/or alkaline conditions.
Content:
Front Matter....Pages i-x
Front Matter....Pages 1-1
Near Field and Far Field Interactions and Data Needs For Geologic Disposal of Nuclear Waste....Pages 3-10
Modern Speciation Techniques Applied to Environmental Systems....Pages 11-38
Modeling the Effect of Ionic Interactions on Radionuclides in Natural Waters....Pages 39-61
Use of Dissolved and Colloidal Actinide Parameters within the 1996 Waste Isolation Pilot Plant Compliance Certification Application....Pages 63-82
Chemical Species of Plutonium in Hanford Site Radioactive Tank Wastes....Pages 83-110
Front Matter....Pages 111-111
Dissociation Constants of Carboxylic Acids at High Ionic Strengths....Pages 113-124
Correlation of Equilibrium Constants with Ionic Strength by Sit, Pitzer and Parabolic Models....Pages 125-139
Actinyl(VI) Carbonates in Concentrated Sodium Chloride Solutions: Characterization, Solubility, and Stability....Pages 141-151
Solubility of NaNd(CO3)2.6H2O(c) in Mixed Electrolyte (Na-Cl-CO3-HCO3) and Synthetic Brine Solutions....Pages 153-169
Plutonium (VI) Solubility Studies in Savannah River Site High-Level Waste....Pages 171-176
UO2 2+ and NpO2 + Complexation with Citrate in Brine Solutions....Pages 177-185
Complexation and Ion Interactions in Am(III)/EDTA/NaCl Ternary System....Pages 187-197
Interaction of Uranyl with Humic and Fulvic Acids at High Ionic Strength....Pages 199-211
Front Matter....Pages 213-213
Retardation of Colloidal Actinides Through Filtration in Intrusion Borehole Backfill at the Waste Isolation Pilot Plant (WIPP)....Pages 215-225
Contribution of Mineral-Fragment Type Pseudo-Colloids to the Mobile Actinide Source Term of the Waste Isolation Pilot Plant (WIPP)....Pages 227-237
Laboratory Evaluation of Colloidal Actinide Transport at the Waste Isolation Pilot Plant (WIPP): 1. Crushed-Dolomite Column Flow Experiments....Pages 239-251
Laboratory Evaluation of Colloid Transport Under Simulated Subsurface Conditions at the Waste Isolation Pilot Plant (WIPP): 2. Large-Scale-Intact-Core Column Flow Experiments....Pages 253-260
Toxicity of Actinides to Bacterial Strains Isolated from the Waste Isolation Pilot Plant (WIPP) Environment....Pages 261-268
Back Matter....Pages 269-271

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This proceedings, based on an American Chemical Society symposium entitled `Experimental and Modeling Studies of Actinide Speciation in Non-Ideal Systems', deals with the management and disposal of radioactive waste. More specifically, it concerns modeling and experimental approaches for actinide chemistry in high ionic strength media, including general aspects of actinide chemistry in high-level nuclear waste and environmental systems, and the special problems of actinide behavior in concentrated electrolytes and/or alkaline conditions.
Content:
Front Matter....Pages i-x
Front Matter....Pages 1-1
Near Field and Far Field Interactions and Data Needs For Geologic Disposal of Nuclear Waste....Pages 3-10
Modern Speciation Techniques Applied to Environmental Systems....Pages 11-38
Modeling the Effect of Ionic Interactions on Radionuclides in Natural Waters....Pages 39-61
Use of Dissolved and Colloidal Actinide Parameters within the 1996 Waste Isolation Pilot Plant Compliance Certification Application....Pages 63-82
Chemical Species of Plutonium in Hanford Site Radioactive Tank Wastes....Pages 83-110
Front Matter....Pages 111-111
Dissociation Constants of Carboxylic Acids at High Ionic Strengths....Pages 113-124
Correlation of Equilibrium Constants with Ionic Strength by Sit, Pitzer and Parabolic Models....Pages 125-139
Actinyl(VI) Carbonates in Concentrated Sodium Chloride Solutions: Characterization, Solubility, and Stability....Pages 141-151
Solubility of NaNd(CO3)2.6H2O(c) in Mixed Electrolyte (Na-Cl-CO3-HCO3) and Synthetic Brine Solutions....Pages 153-169
Plutonium (VI) Solubility Studies in Savannah River Site High-Level Waste....Pages 171-176
UO2 2+ and NpO2 + Complexation with Citrate in Brine Solutions....Pages 177-185
Complexation and Ion Interactions in Am(III)/EDTA/NaCl Ternary System....Pages 187-197
Interaction of Uranyl with Humic and Fulvic Acids at High Ionic Strength....Pages 199-211
Front Matter....Pages 213-213
Retardation of Colloidal Actinides Through Filtration in Intrusion Borehole Backfill at the Waste Isolation Pilot Plant (WIPP)....Pages 215-225
Contribution of Mineral-Fragment Type Pseudo-Colloids to the Mobile Actinide Source Term of the Waste Isolation Pilot Plant (WIPP)....Pages 227-237
Laboratory Evaluation of Colloidal Actinide Transport at the Waste Isolation Pilot Plant (WIPP): 1. Crushed-Dolomite Column Flow Experiments....Pages 239-251
Laboratory Evaluation of Colloid Transport Under Simulated Subsurface Conditions at the Waste Isolation Pilot Plant (WIPP): 2. Large-Scale-Intact-Core Column Flow Experiments....Pages 253-260
Toxicity of Actinides to Bacterial Strains Isolated from the Waste Isolation Pilot Plant (WIPP) Environment....Pages 261-268
Back Matter....Pages 269-271
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