PUREX

Abstract: A generic transurantc (TRU) element extraction/recovery process was developed based on the use of octyl(phenyl)-N,N-diiso-butylcarbamoylmetliylphosphine oxide, 0φD(iB)CMPO, dissolved in PUREX process solvent (tribntyl phosphate, TBP, in normal paraffluic hydrocarbon, NPH). The process (called TRUEX) is capable of reducing the TRU concentration by many orders of magnitude In waste solutions containing a wide range of nitric acid, salt, and fission product concentrations. A major feature of the process is that it is readily adaptable for waste processing in existing fuel reprocessing facilities.

Abstract: Contributor contact details Woodhead Publishing Series in Energy Preface Part I: Fundamentals of radioactive materials separations processes: chemistry, engineering and safeguards Chapter 1: Chemistry of radioactive materials in the nuclear fuel cycle Abstract: 1.1 Introduction 1.2 Chemical features of important fission products and actinides 1.3 Relevant actinide chemistry in the nuclear fuel cycle 1.4 Essential features of solvent extraction separations in the nuclear fuel cycle 1.5 Behavior in molten salts/molten metals/ionic liquids/alternative media 1.6 Interactions at interfaces significant to the nuclear fuel cycle 1.7 Future trends Chapter 2: Physical and chemical properties of actinides in nuclear fuel reprocessing Abstract: 2.1 Introduction 2.2 Thermodynamic properties of compounds 2.3 Speciation, complexation and reactivity in solution of actinides 2.4 Irradiation effects 2.5 Future trends 2.6 Sources of further information and advice Chapter 3: Chemical engineering for advanced aqueous radioactive materials separations Abstract: 3.1 Introduction 3.2 Containment concepts 3.3 Separations equipment 3.4 Equipment materials considerations 3.5 Future trends 3.6 Sources of further information and advice Chapter 4: Spectroscopic on-line monitoring for process control and safeguarding of radiochemical streams in nuclear fuel reprocessing facilities Abstract: 4.1 Introduction 4.2 Static spectroscopic measurements 4.3 Demonstration of spectroscopic methods 4.4 Conclusions 4.5 Acknowledgments 4.7 Appendix: acronyms Chapter 5: Safeguards technology for radioactive materials processing and nuclear fuel reprocessing facilities Abstract: 5.1 Introduction 5.2 Requirements 5.3 Safeguards technology 5.4 Safeguards applications for aqueous separations 5.5 Safeguards applications for pyrochemical separations 5.6 Acknowledgement Part II: Separation and extraction processes for nuclear fuel reprocessing and radioactive waste treatment Chapter 6: Standard and advanced separation: PUREX processes for nuclear fuel reprocessing Abstract: 6.1 Introduction 6.2 Process chemistry 6.3 Current industrial application of PUREX 6.4 Future industrial uses of PUREX 6.5 Conclusions Chapter 7: Alternative separation and extraction: UREX+ processes for actinide and targeted fission product recovery Abstract: 7.1 Introduction 7.2 Separation strategy 7.3 UREX + LWR SNF GNEP application: separation strategy 7.4 Benefits of using models to design flowsheets 7.5 Advantages and disadvantages of techniques 7.6 Future trends Chapter 8: Advanced reprocessing for fission product separation and extraction Abstract: 8.1 Introduction 8.2 Separation methods, advantages/disadvantages, and future trends 8.3 Conclusions and future trends Chapter 9: Combined processes for high level radioactive waste separations: UNEX and other extraction processes Abstract: 9.1 Introduction to universal extraction process (UNEX) and other processes 9.2 Universal processes for recovery of long-lived radionuclides 9.3 Development and testing of the universal extraction (UNEX) process and its modifications 9.4 Conclusions Part III: Emerging and innovative techniques in nuclear fuel reprocessing and radioactive waste treatment Chapter 10: Nuclear engineering for pyrochemical treatment of spent nuclear fuels Abstract: 10.1 Introduction 10.2 Process chemistry and flowsheet of pyrochemical processing 10.3 Design and installation of process equipment 10.4 Materials behaviour and interactions 10.5 Developments in monitoring and control for pyrochemical processing 10.6 Techniques for safe and effective interoperation of equipment 10.7 Future trends 10.8 Sources of further information and advice Chapter 11: Development of highly selective compounds for solvent extraction processes: partitioning and transmutation of long-lived radionuclides from spent nuclear fuels Abstract: 11.1 Introduction 11.2 Which long-lived radionuclides to partition and why? 11.3 How to develop selective ligands and extractants? 11.4 Examples of development of highly selective compounds in European partitioning and transmutation (P&T) strategy 11.5 Future trends 11.6 Conclusions 11.7 Sources of further information and advice 11.8 Acknowledgment Chapter 12: Developments in the partitioning and transmutation of radioactive waste Abstract: 12.1 Introduction to transmutation 12.2 Modelling transmutation processes and effects 12.3 Systems for transmutation: design and safety 12.4 Transmutation fuel development 12.5 Future trends Chapter 13: Solid-phase extraction technology for actinide and lanthanide separations in nuclear fuel reprocessing Abstract: 13.1 Introduction 13.2 Basic methodology of solid-phase extraction 13.3 Solid-phase extraction sorbents for actinides and lanthnides 13.4 Modeling of solid-phase extraction systems 13.5 Advantages and disadvantages of solid-phase extraction in treatment processes for nuclear fuel reprocessing streams 13.6 Future trends in solid-phase extraction technology for nuclear fuel reprocessing applications 13.7 Sources of further information and advice 13.8 Acknowledgment Chapter 14: Emerging separation techniques: supercritical fluid and ionic liquid extraction techniques for nuclear fuel reprocessing and radioactive waste treatment Abstract: 14.1 Introduction 14.2 Supercritical fluid extraction of lanthanides and actinides 14.3 Direct dissolution of uranium oxides in supercritical carbon dioxide 14.4 Current industrial demonstrations of supercritical fluid extraction technology for nuclear waste treatment and for reprocessing spent fuel 14.5 Ionic liquid and supercritical fluid coupled extraction of lanthanides and actinides 14.6 Future trends Chapter 15: Development of biological treatment processes for the separation and recovery of radioactive wastes Abstract: 15.1 Introduction 15.2 Classification of waste 15.3 Waste from high temperature fast reactors 15.4 Treatment options 15.5 Biological removal of metal oxyions 15.6 Biosorption and recovery 15.7 Biofilm processes 15.8 Future trends 15.11 Engineering dimensions (units) Index

Abstract: After a brief description of the PUREX process as a starting point, this paper aims to point out some of its most recent developments, always from the viewpoint of the chemistry involved in the solvent extraction methods. In addition to PUREX, other well-known technological approaches devoted to the reprocessing of irradiated uranium and thorium nuclear fuels and general radioactive wastes — TRUEX, DIAMEX, TRPO, DIDPA and UNEX — are also presented and discussed.

Abstract: Current status on the chemical aspects of nuclear fuel reprocessing is presented with special emphasis on the Purex process which continues to be the process of choice for the last four decades. Better decontamination from fission products, new methods for uraniumplutonium partitioning and removal of actinides from high active waste are challenging areas in process chemistry. The development work on TRUEX and DIAMEX process for treating high active waste is briefly described. An overview of pyrochemical processes, which are important for Integral Fast Reactor Concept, is presented.