Regeneration of Metal Radioactive Waste from Radiochemical Industries for Metal and Alloy Recycling Purposes

The paper proposes a processing method for metal radioactive waste (high alloyed stainless steel and its alloys) containing transuranic radionuclides. This type of waste is generated during operation and decommissioning of SNF reprocessing equipment at radiochemical production facilities. To ensure the recycling of valuable components, decontamination and conditioning of the regenerated ingots to high-quality metal is arranged in a two-staged process involving MRW remelting: its first stage involves in-depth metal decontamination under a layer of a refining flux, whereas the second stage provides for additional metal treatment to remove radioactive and stable impurities, as well as metal alloying to make up for the "burnt out" valuable components and to level its chemical composition. The process is implemented at an enterprise specialized in RW processing having appropriate infrastructure facilities and licenses authorizing relevant operations with radioactive materials. Metal radioactive waste regeneration results in a grade metal, which in terms of its residual radioactive contamination level can be released from radiation control and admitted to unrestricted use. It has been experimentally demonstrated that ESR, when used for MRW decontamination purposes, allows to obtain high-quality steel suitable for future reuse.

Plutonium (IV) Quantification in Technologically Relevant Media Using Potentiometric Sensor Array

The quantification of plutonium in technological streams during spent nuclear fuel (SNF) reprocessing is an important practical task that has to be solved to ensure the safety of the process. Currently applied methods are tedious, time-consuming and can hardly be implemented in on-line mode. A fast and simple quantitative plutonium (IV) analysis using a potentiometric sensor array based on extracting agents is suggested in this study. The response of the set of specially designed PVC-plasticized membrane sensors can be related to plutonium content in solutions simulating real SNF-reprocessing media through multivariate regression modeling, providing 30% higher precision of plutonium quantification than optical spectroscopy.

Separation of actinides from lanthanides associated with spent nuclear fuel reprocessing in China: current status and future perspectives

Developing necessary reprocessing techniques to meet the remarkable increase of spent nuclear fuels (SNFs) is crucial for the sustainable development of nuclear energy. This review summarizes recent research progresses related to the SNF reprocessing in China, with an emphasis on actinides separation over lanthanides through three different techniques, hydrometallurgical reprocessing, pyrometallurgical processes, and selective crystallization based separation. Some future perspectives with respect to advanced actinide separation are also given.

Toward a Greenish Nuclear Fuel Cycle: Ionic Liquids as Solvents for Spent Nuclear Fuel Reprocessing and Other Decontamination Processes for Contaminated Metal Waste

The final disposition of spent nuclear fuel (SNF) is an area that requires innovative solutions. The use of ionic liquids (ILs) has been examined as one means to remediate SNF in a variety of different chemical environments and with different chemical starting materials. The effectiveness of various ILs for SNF reprocessing, as well as the reaction chemistry that occurs in them, is discussed.

Assessing the Feasibility of Complex Recycling of SNF Reprocessing Waste Using RF Torch Air Plasma

The work studies the implementation of air plasma of radiofrequency torch for the complex recycling of reprocessed SNF waste treated in the form of dispersed aqueous organic compositions (AOCs). The study shows the practicability of magnetic separation for the effective extraction of dispersed solids, including magnetic iron oxide, formed in water suspensions.

Mathematic Simulation of Crystallization Refining Process of Spent Nuclear Fuel Reprocessing Desired Products in Linear Crystallizer

The object of research is crystallization refining process of uranyl nitrate (UN) from nitric acid solution. The process of crystallization refining is a working operation which can provide effective extraction and purification of desired products (fission materials) during spent nuclear fuel (SNF) reprocessing. The purpose of the work is mathematical description of the linear continuous crystallizer operating modes using the example of uranyl nitrate hexahydrate crystals sorting. The mathematical model presented in the work allows describing changes of crystallization process parameters in the active volume of crystallizer and choosing the most effective operating modes in terms of extraction of SNF reprocessing desired products.

Ceramic Immobilisation Options for Technetium

ABSTRACTTechnetium-99 (99Tc) is a fission product produced during the burning of nuclear fuel and is particularly hazardous due to its long half life (210000 years), relatively high content in nuclear fuel (approx. 1 kg per ton of SNF), low sorption, and high mobility in aerobic environments. During spent nuclear fuel (SNF) reprocessing Tc is released either as a separate fraction or in complexes with actinides and zirconium. Although Tc has historically been discharged into the marine environment more stringent regulations mean that the preferred long term option is to immobilise Tc in a highly stable and durable matrix. This study investigated the feasibility of incorporating of Mo (as a Tc analogue) in a crystalline host matrix, synthesis by solid state synthesis under different atmospheres. Samples have been characterised with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray absorption spectroscopy (XAS).