About TRANSPARANT
Project summary
The impact of low carbon energy sources in combating rapid climate change underlines the role of nuclear energy as part of a sustainable energy mix. Yet, safety and waste concerns must not be downplayed. For the latter, the main goal should be to recycle used fuel, aiming to close the fuel cycle. This eases ultimate radioactive waste management, enhances proliferation resistance and drastically improves economy and sustainability by better use of fuel resources.
The SNETP deployment plan outlines technical needs for fuel recycling including separation of used fuel, fabrication and characterisation of minor actinide bearing fuel and the development of transmutation systems to recover energy and reduce waste.
TRANSPARANT aligns with the SNETP deployment plan and responds to the call in HORIZON-EURATOM-2023-NRT-01, topic 05 “Partitioning and transmutation of minor actinides towards industrial application”. It focuses on the efficiency of Am (Americium) separation from used fuel, on experimental and fuel performance code development work studying the behaviour of Am bearing fuel under irradiation and on the safety related research supporting the licensing process of MYRRHA in its role as dedicated accelerator driven transmuter demonstrator. This project builds upon the collaborative efforts initiated in the PATRICIA project, bringing together communities working on partitioning, transmutation, and MYRRHA development.
Finally, dedicated work packages deal with education, focusing on pre-and post-graduates, and with dissemination, targeting the specific stakeholders and the public at large. A further task on knowledge management encompasses both foreground data as well as metadata as to ensure that proper quality assessment and validation is possible. The project will employ a combination of experiments, theoretical studies and numerical simulations harnessing the expertise of 21 research centres and universities from eight EU countries, the UK and Switzerland.
Objectives and ambition
The central objective of the TRANSPARANT project is to take the next step towards industrialization required to close the fuel cycle.
Domain 1: Separation of used fuel: Partitioning
The main objective is developing a simple and robust solvent extraction process for direct americium separation from the PUREX raffinate solution. DM1 will also do a quantitative assessment of pyroprocessing as a route for recycling transmuter fuel.
Domain 2: Minor actinide bearing fuel behaviour
The primary objective of Domain 2 is to make significant progress in the qualification procedure of minor actinide bearing driver fuels envisaged for homogeneous transmutation of minor actinides (MA), particularly Am and Np.
Domain 3: Transmuter safety
In the field of thermal-hydraulics the specific objective is to describe the state-of-the-art and define a current best fit approach for thermal hydraulic analysis of important heavy liquid metal cooled (HLM) reactor components and systems, namely the fuel bundle, the heat exchangers, and the primary cooling system at large.
The second goal is to analyse coolability of a fuel debris bed postulated to have settled at the bottom of the reactor after a severe accident scenario with core damage. The third main objective in this domain, which is addressed in WP8, deals with radiological release where the objective is to study all individual steps on radionuclide migration.
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Lead beneficiary: CEA
Objectives:
The current CHON AmSel system (using TODGA and PrOH-BPTD) has a Cm/Am selectivity of approx. 2.
This is basically sufficient to develop a separation process. However, increasing the selectivity is desirable to improve the Technology Readiness Level (TRL), the safety and the economics of such a process.
WP1 aims to optimise the AmSel system with respect to improved selectivity. This involves synthesis, focusing on robust, scalable routes allowing that allow future scale-up) and screening of new extracting and complexing agents. The most promising system(s) will be studied in more detail, determining thermodynamic data, and assessing their chemical and radiolytic stability.
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Lead beneficiary: NNL
Objectives:
In WP2, an improved AmSel System identified in WP1 will be advanced towards a lab-scale process demonstration. This is a prerequisite for scale-up towards industrialisation, achieving a higher TRL, safety level and economic feasibility.
WP2 involves collecting all required thermodynamic and kinetic data and calculating a flowsheet, to be tested using (a) a spiked feed solution and (b) a feed solution containing nominal concentrations of Am(III). Furthermore, routes to scale up synthesis of complexing agents will be sought. Finally, possible impacts of the water soluble Am(III) stripping agents on the downstream coconversion processes will be investigated.
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Lead beneficiary: SCK CEN
Objectives:
In WP3, the current state-of-the-art of pyroprocessing technology, with specific focus on Am separations will be assessed.
SNF composition of MA bearing fuel irradiated in an ADS transmuter will be calculated for various scenarios. This characterisation will be the input for the feed envelope of a future pyroprocessing plant. Based on this information a reference flowsheet for MA bearing spent fuel will be defined. A flowsheet model will be used to calculate the Am recoveries and prove that pyroprocessing can recover Am efficiently or provide a usable final product stream for manufacturing of second-generation MA bearing fuel and irradiation in consecutive ADS cycles.
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Lead beneficiary: POLIMI
Objectives:
Improvement of models used in European fuel performances codes for MAbearing fuels, especially for high burnups and transients, the implementation of these models in a European FPC and the validation of the updated version of the code. The activities will include the coupling of a thermochemistry module with FPC, as well as development of improved models for gas behaviour and for the gap conductance.
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Lead beneficiary: BANGOR
Objectives:
Obtaining thermal and thermal-chemical data and further understanding of the mechanisms underlying the behaviour of MA-bearing fuels during fabrication and irradiation in reactor for the improvement of the models for FPC: In particular, phase diagram data on U-Pu-Am-Np-O system and thermal-chemical properties of compounds of the “Joint-Oxyde-Gaine” and “Reaction Oxyde-Gaine” are needed. This data will be obtained using separate effect investigations combining experimental characterizations and multiscale modelling.
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Lead beneficiary: CEA
Objectives:
Obtaining data on the behaviour of MA-bearing fuels under irradiation by performing post examination examinations of samples irradiated in the SPHERE experiments and to design an irradiation of MA-bearing fuels in transient conditions. Behaviour of the fuels will be simulated using European Fuel performance codes to support the interpretation of the PIEs and the design of the irradiation.
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Lead beneficiary: NRG
Objectives:
In WP7, Task 7.1: Evaluation of data for thermal hydraulic analysis of HLM cooled systems: Deeper analysis and interpretation of existing experimental and numerical data on fuel bundle, the heat exchanger and the primary pool system, and corresponding numerical analysis approaches with regard to FoM and acceptable uncertainties.
In Task 7.2: Fuel debris bed cooling Comparison of porous-medium debris bed simulations against newly generated reference data from explicit models of small-size reference fuel debris beds Parametric study of full-scale fuel debris cooling in postulated severe accident scenarios to define enveloping conditions for vessel failure.
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Lead beneficiary: PSI
Objectives:
Understanding the kinetics of polonium release by evaporation experiments with oxygen and H2O control (PSI, SCK CEN) and by Calculations on stability of PoOxHy molecules using DFT, quantum chemistry and AI (UGent), Study fission products release rates, source term and transport by measuring the iodine evaporation rate from liquid metal by transpiration (SCK CEN), KEMS studies on fission product evaporation kinetics and speciation (JRC), Development of source term predictive capabilities in the open source SCIANTIX code (POLIMI), Numerical assessment of radioactivity transport in the containment building of a reactor (KTH), Experiments on volatilization of radioactive isotopes from molten liquid metal as well as their interaction with containment materials (Chalmers).
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Lead beneficiary: SCK CEN
Objectives:
As a follow-up of the PATRICIA project (GA945077), this task aims at studying internal (undetected) flow blockages in a fuel bundle, arising from chemical processes in LBE that might occur during abnormal operating conditions and/or accidents:
- PbO deposition/accumulation will be assessed by measuring pressure loss (and temperature) time evolutions across a heated bundle mock-up, installed in the MEXICO loop, as a function of different relevant boundary conditions.
- To help understanding the mechanisms leading to chemical blockages, and in particular to isolate the effect of flow paths peculiar of wire wrapped fuel assemblies on particle accumulation, a water mock-up experiment will be performed at VKI.
- Parametric CFD simulations will be performed to support the analyses of the MEXICO loop produced data. For example, parameters such as roughness and hydraulic diameter will allow to map the effects of the main deposition characteristics on the increased measured pressure loss Test the UT NDT inspection on a realistic geometry and in realistic wetting conditions.
- Measure the impact of wetting on the measurement results.
- Compare the results of measurements in different conditions with the results of UT simulations.
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Lead beneficiary: VKI
Objectives:
- Dissemination and exploitation of project results,
- Data management during the project,
- Education and training,
- General communication with the public and stakeholders.
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Lead beneficiary: SCK CEN
Objectives:
Ensuring efficient project management including financial and legal aspects, internal coherence and timing.