Periodic Reporting for period 3 - GENIORS (GEN IV Integrated Oxide fuels recycling strategies)
Período documentado: 2020-06-01 hasta 2021-05-31
The open nuclear fuel cycle utilises less than one percent of the energy contained in natural uranium. Spent fuel recycling (as done e. g. in France) increases fuel efficiency by 20%. Future multi-recycling strategies to be deployed in fast reactors will lead to huge improvement, eventually rendering further uranium mining unnecessary.
In this context and in the continuity of previous EURATOM projects (NEWPART, PARTNEW, EUROPART, ACSEPT, SACSESS), GENIORS carries out research and innovation for developing compatible techniques for dissolution, reprocessing and manufacturing of innovative oxide fuels, potentially containing minor actinides, in a “fuel to fuel” approach, taking into account safety issues under normal and mal-operation. The most promising options were further developed to address the challenges specific to GEN IV.
By implementing a three-step approach (reinforcement of the scientific knowledge — process development and testing — system studies, safety and integration), GENIORS contributes to the provision of more science-based strategies for nuclear fuel management in the EU. It supports nuclear energy to contribute significantly and sustainably to EU energy independence. In the longer term, it will facilitate the management of ultimate radioactive waste by reducing its volume and radiotoxicity.
In this context and in the continuity of previous EURATOM projects (NEWPART, PARTNEW, EUROPART, ACSEPT, SACSESS), GENIORS carries out research and innovation for developing compatible techniques for dissolution, reprocessing and manufacturing of innovative oxide fuels, potentially containing minor actinides, in a “fuel to fuel” approach, taking into account safety issues under normal and mal-operation. The most promising options were further developed to address the challenges specific to GEN IV.
By implementing a three-step approach (reinforcement of the scientific knowledge — process development and testing — system studies, safety and integration), GENIORS contributes to the provision of more science-based strategies for nuclear fuel management in the EU. It supports nuclear energy to contribute significantly and sustainably to EU energy independence. In the longer term, it will facilitate the management of ultimate radioactive waste by reducing its volume and radiotoxicity.
WP1 The new acquired data will feed process simulation codes in order to better design the scrubbing part of the process flowsheets. These data will be use to define recovery processes of potentially valuable elements such as ruthenium, to be developed in the proposal under building on the topic EURATOM 2021-NRT-01.03
WP2 All the results on degradation studies can be used for safety case studies, for improving the stability of molecules and for optimising the washing part of the process flowsheets.
WP3 Distribution data are of paramount importance for defining extraction models and for feeding simulation process codes. In particular, CEA, NNL and KIT who are developing simulation codes will use them. In addition, some results have been used to define the work to be done in PATRICIA on an americium extraction process.
WP4 The better understanding of solid/liquid interface will allow an optimisation of the dissolution processes, in particular by optimising/limiting the use of highly reactive reagents as well as the operating temperature. At the conversion, it helps at understanding the microstructure formation mechanisms. This could improve the performance of the fuel. This work will be useful in the NRT01-03 proposal.
All the work done in WP5/WP6 allows the optimisation of process flow sheets, relying on improved thermodynamics and kinetics data. Relevant pilot experiments can be proposed. An additional work performed in the frame of an I-NERI project together with US national labs (INL, ORNL) allowed the benchmarking of irradiation loops. Now irradiation results can be compared with a higher degree of confidence.
WP7 Dissolution of single phases UxPu1-xO2± exhibiting different Pu content and/or morphologies were carried out to allow establishment of dissolution models describing both morphology and Pu content effects. Determination of solubility modification is being studied and curative option to get rid of organic residues using mediated electrochemical oxidation is tested. Safer minor actinide enriched oxide synthesis routes were tested to produce minor actinide bearing blanket with less dust dissemination increasing safety.
WP8 The main results include a concept design of a Euro-Ganex reprocessing plant, a study comparing different options for solvent extraction, a mapping of different partitioning and transmutation strategies, spent fuel recycling scenarios and a simulation model to illustrate changes in reprocessing plants.
WP9: NNL performed an internal safety review on an end-to-end reprocessing plant utilising the EURO-GANEX flowsheet. This review generated a prioritised list of future R&D recommendations to eliminate, control or mitigate hazards within future plants. No showstoppers have been identified in terms of safety on the reference separation processes. The development of pilot facilities can be done with more confidence.
WP10 A stakeholder event and a clustering event were organized. They intended to provide insight on the current state of the art of partitioning and transmutation and to put this in the context of the nuclear fuel back-end scenarios currently implemented or intended to be implemented in the EU countries and beyond.
WP2 All the results on degradation studies can be used for safety case studies, for improving the stability of molecules and for optimising the washing part of the process flowsheets.
WP3 Distribution data are of paramount importance for defining extraction models and for feeding simulation process codes. In particular, CEA, NNL and KIT who are developing simulation codes will use them. In addition, some results have been used to define the work to be done in PATRICIA on an americium extraction process.
WP4 The better understanding of solid/liquid interface will allow an optimisation of the dissolution processes, in particular by optimising/limiting the use of highly reactive reagents as well as the operating temperature. At the conversion, it helps at understanding the microstructure formation mechanisms. This could improve the performance of the fuel. This work will be useful in the NRT01-03 proposal.
All the work done in WP5/WP6 allows the optimisation of process flow sheets, relying on improved thermodynamics and kinetics data. Relevant pilot experiments can be proposed. An additional work performed in the frame of an I-NERI project together with US national labs (INL, ORNL) allowed the benchmarking of irradiation loops. Now irradiation results can be compared with a higher degree of confidence.
WP7 Dissolution of single phases UxPu1-xO2± exhibiting different Pu content and/or morphologies were carried out to allow establishment of dissolution models describing both morphology and Pu content effects. Determination of solubility modification is being studied and curative option to get rid of organic residues using mediated electrochemical oxidation is tested. Safer minor actinide enriched oxide synthesis routes were tested to produce minor actinide bearing blanket with less dust dissemination increasing safety.
WP8 The main results include a concept design of a Euro-Ganex reprocessing plant, a study comparing different options for solvent extraction, a mapping of different partitioning and transmutation strategies, spent fuel recycling scenarios and a simulation model to illustrate changes in reprocessing plants.
WP9: NNL performed an internal safety review on an end-to-end reprocessing plant utilising the EURO-GANEX flowsheet. This review generated a prioritised list of future R&D recommendations to eliminate, control or mitigate hazards within future plants. No showstoppers have been identified in terms of safety on the reference separation processes. The development of pilot facilities can be done with more confidence.
WP10 A stakeholder event and a clustering event were organized. They intended to provide insight on the current state of the art of partitioning and transmutation and to put this in the context of the nuclear fuel back-end scenarios currently implemented or intended to be implemented in the EU countries and beyond.
Progress was made on fission product behaviour and in particular ruthenium. Conditions for effective fission product masking/ scrubbing were optimized for Tc, Sr, Zr, Mo, Pd from TODGA and mTDDGA solvents, allowing the simplification of the scrubbing section of EURO-GANEX.
Radiolytic damages on the chemical systems can reduce the process performances but also impact the safety of the processes. The thermal stabilities studies of PTD, PTT, PT EtHex, and azide reagents, neither TODGA extractant in contact with nitric acid did not show additional risk of spontaneous decomposition during the synthesis process or the operation.
The stripping solvent based PTD has been extensively studied and its applicability to the i-SANEX and EURO-GANEX processes was demonstrated. Me-TDDGA was tested as an alternative to mTDDGA.
The impact of experimental parameters on the dissolution of U-Ln solid solution samples was investigated and explained on a microscopic level. The hydrothermal synthesis of uranium oxide was optimized.
At process developpement leve, the work confirmed the relevance of the reference system based on PTD + (TODGA-DMDOHEMA), with a possible substitution of (TODGA-DMDOHEMA) by m-TDDGA (showing a higher Pu loading) for EURO-GANEX.
Simplification options of EURO-GANEX and EURO-EXAM were proposed. To improve the links between reprocessing and fabrication (integrated approach), studies were carried out to identify possible issues at the interface of fuel dissolution and separation, and separation and conversion/fabrication. For the conversion of actinides to oxides, the presence of complexing agents in the solution has no affect on conversion performances of actinides to oxides. Concerning MOX fuel fabrication, with innovative techniques, investigations on the synthesis of simulated MOX fuel particles, potentially bearing MAs and blanket materials, were carried out using the sol-gel route via internal gelation.
To better integrate the results of GENIORS in the international context, a study undertook a comparative assessment of the different recycling needs and options considered, and identified the facilities that could integrate the reprocessing options at EU level. Holistic impacts of flowsheet deployment can be assessed using the SimPlant tool.A total of six fuel cycles have been described, bearing in mind that the exact parameters of these cycles will result from further engineering studies.
A safety and environmental hazards review of EURO-GANEX made 20 prioritized recommendations towards full industrialization with a view to elimination or mitigation of the identified hazards.
Utilising the Concept Design, a safety review of the EURO-GANEX process allowed the production of an in-depth criticality review. All the collected information and methods can now be used to develop processes at higher TRL with a high level of confidence both in terms of performance and safety.
Radiolytic damages on the chemical systems can reduce the process performances but also impact the safety of the processes. The thermal stabilities studies of PTD, PTT, PT EtHex, and azide reagents, neither TODGA extractant in contact with nitric acid did not show additional risk of spontaneous decomposition during the synthesis process or the operation.
The stripping solvent based PTD has been extensively studied and its applicability to the i-SANEX and EURO-GANEX processes was demonstrated. Me-TDDGA was tested as an alternative to mTDDGA.
The impact of experimental parameters on the dissolution of U-Ln solid solution samples was investigated and explained on a microscopic level. The hydrothermal synthesis of uranium oxide was optimized.
At process developpement leve, the work confirmed the relevance of the reference system based on PTD + (TODGA-DMDOHEMA), with a possible substitution of (TODGA-DMDOHEMA) by m-TDDGA (showing a higher Pu loading) for EURO-GANEX.
Simplification options of EURO-GANEX and EURO-EXAM were proposed. To improve the links between reprocessing and fabrication (integrated approach), studies were carried out to identify possible issues at the interface of fuel dissolution and separation, and separation and conversion/fabrication. For the conversion of actinides to oxides, the presence of complexing agents in the solution has no affect on conversion performances of actinides to oxides. Concerning MOX fuel fabrication, with innovative techniques, investigations on the synthesis of simulated MOX fuel particles, potentially bearing MAs and blanket materials, were carried out using the sol-gel route via internal gelation.
To better integrate the results of GENIORS in the international context, a study undertook a comparative assessment of the different recycling needs and options considered, and identified the facilities that could integrate the reprocessing options at EU level. Holistic impacts of flowsheet deployment can be assessed using the SimPlant tool.A total of six fuel cycles have been described, bearing in mind that the exact parameters of these cycles will result from further engineering studies.
A safety and environmental hazards review of EURO-GANEX made 20 prioritized recommendations towards full industrialization with a view to elimination or mitigation of the identified hazards.
Utilising the Concept Design, a safety review of the EURO-GANEX process allowed the production of an in-depth criticality review. All the collected information and methods can now be used to develop processes at higher TRL with a high level of confidence both in terms of performance and safety.