Keynote Address.- Science Underlying Radioactive Waste Management: Status and Needs.- Waste Solidification.- Vitrification.- Techniques for High Level Waste Solidification in Europe.- Development of Glass Compositions for Immobilization of Savannah River Plant Waste.- Preparation and Characterization of an Improved High Level Radioactive Waste (Haw) Borosilicate Glass.- Vitrification of High Sodium-Aluminum Wastes: Composition Ranges and Properties.- Non-Radioactive Operation Experience with a Joule Heated Ceramic Melter for Vitrification of High-Level Liquid Waste.- Structure and Properties of Vitreous Waste Forms.- Natural Glasses: Analogues for Radioactive Waste Forms.- Characterization of Glass and Glass Ceramic Nuclear Waste Forms.- Microstructural Characterization of Solidified Simulated Reactor Wasteforms.- Bonding of Metal Oxides in Sodium Silicate Glass.- Helium Formation from ?-Decay and its Significance for Radioactive Waste Glasses.- Thermal, Chemical and Radiation Stability of Vitreous Radioactive Wastes.- Chemistry of Nuclear Waste Glass Reactions: Problems and Potential of Prediction.- Characterization of Leached Surface Layers on Simulated High-Level Waste Glasses by Sputter-Induced Optical Emission.- Leaching Characteristics of Actinides from Simulated Reactor Waste Glass.- Leach Rate Characterization of Solid Radioactive Waste Forms.- Long-Term Elevated Temperature Leaching of Solid Waste Forms.- Calculations of Radioactivity Release Due to Leaching of Vitrified High Level Waste.- Ceramic and Metal Matrix Forms.- Development of Multibarrier Nuclear Waste Forms.- Metal Encapsulation of Ceramic Nuclear Waste.- Cermets for High Level Waste Containment.- Clay-Phosphate Ceramics and Vitromets: Alternatives to Monolithic High Level Waste Glass Products.- Synthetic Rutile Microencapsulation: A Radioactive Waste Solidification System Resulting in an Extremely Stable Product.- Hot Isostatic Pressing for the Consolidation and Containment of Radioactive Waste.- Characterization of a Titanate Based Ceramic for High Level Nuclear Waste Solidification.- Raman Spectra of Cesium Aluminosilicate Waste Forms.- Investigations of the Volatility of Cesium from Aluminosilicates by Mass Spectrometry.- Pollucite and its Alteration in Geological Occurrences and in Deep-Burial Radioactive Waste Disposal.- Waste Isolation.- Direct Emplacement of Wastes in Geomedia.- The Scientific Basis For, and Experience With, Underground Storage of Liquid Radioactive Wastes in the USSR.- Influence of Radiation on the System Liquid Radioactive Wastes-Geologic Formation.- Waste Disposal by Shale Fracturing at ORNL.- The Rock-Melt Approach to Nuclear Waste Disposal in Geological Media.- Interaction of a Glass-Based Nuclear Waste Simulant and Natural Rock.- Containment.- Corrosion Resistance of Canisters for Final Disposal of Spent Nuclear Fuel.- Corrosion Considerations for Nuclear Waste Isolation Canisters.- Preliminary Corrosion Test of a Glass-Ceramic Candidate for a Nuclear Waste Canister.- Thermal, Geochemical and Radiation Interactions Near the Repository.- Application of Physical Chemistry of Fluids in Rock Salt at Elevated Temperature and Pressure to Repositories for Radioactive Waste.- Application of Studies of Fluid Inclusions in Permian Salado Salt, New Mexico, to Problems of Siting the Waste Isolation Pilot Plant.- P-T-X Relations of Anhydrite and Brine and Their Implications for the Suitability of Anhydrite as a Nuclear Waste Repository Medium.- Hydrothermal Reactivity of Simulated Nuclear Waste Forms and Water-Catalysed Waste-Rock Interactions.- Hydrothermal Glass Reactions in Salt Brine.- Long Term Geochemical Interactions of High Active Waste with Crystalline Rock Repository Media.- Radiation Damage Studies on Natural and Synthetic Rock Salt for Waste Disposal Applications.- Interactions, Retention and Migration of Radionuclides in Geomedia.- Thermodynamic Considerations Underlying the Migration of Radionuclides in Geomedia: Oklo and Other Examples.- Measurements of Parameters Essential to Predicting Nuclide Migration.- Interaction of Waste Radionuclides with Geomedia: Program Approach and Progress.- Radionuclide Migration Studies Associated with the WIPP Site in Southern New Mexico.- Migration of Cesium in Dolomite from the Rustler Formation in the Los Medanos Area in Southeastern New Mexico.- Nuclide Transport by Groundwater in Swedish Bedrock.- Analysis of some Tracer Runs in Granite Rock Using a Fissure Model.- Chemistry of Tc-99 and Np-237 in Contact with Unweathered Igneous Rocks.- Interactions of Simulated Waste Radionuclides and Rocks.- Sorption and Migration of Radionuclides in Geologic Media.- Analysis of Pu-Release Consequences on the Environmental Geochemistry.- Variables Affecting Sorption and Transport of Radionuclides in Hanford Subsoils.- The Effect of Retardation Factors on Radionuclide Migration.- Cement and Concrete in Solidification and Isolation.- Studies of Concrete As a Host for Savannah River Plant Radioactive Waste.- The Disposal of Iodine-129.- Role of Admixtures in Preparing Dense Cements for Radioactive Waste Isolation.- Immobilization of Strontium and Cesium in Intermediate-Level Liquid Wastes by Solidification in Cements.- Permeability Measurements on Cementitious Materials for Nuclear Waste Isolation.- Treatment and Isolation of Other Wastes.- The Development of Process and Storage Materials Suitable for Krypton-85 Waste Management.- Confinement of Volatilized Ruthenium Oxides.- Technical Challenges in the Immobilization of Hanford Defense Waste.- Physicochemical Characterization of Solidification Agents Used and Products Formed with Radioactive Wastes at LWR Nuclear Power Plants.- Low-Level Solidified Waste Characterization: the Scientific Basis for Physical and Chemical Testing.- Modeling and Safety Assessment.- An Analysis of the Geological Stability of a Hypothetical Radioactive Waste Repository in a Bedded Salt Formation.- Preliminary Safety Assessment of the WIPP Facility.- Computer Enhanced "Release Scenario" Analysis for a Nuclear Waste Repository.- Methodology for Estimating Accidental Radioactive Releases in Nuclear Waste Management.- Release of Radionuclides from High-Level Waste during Transportation Fires.- Comparison of some Geologic and Ocean Disposal Concepts Regarding Realistic Modeling that Allows Objective Risk Assessment to be Made.- Author Index.