How fuels work in the next generation of reactors

News - 17 March 2022 - Communication TNW

In order for Europe to have a safe and sustainable energy supply in the future, a better understanding is needed of fuel performance in next-generation nuclear reactors. In the INSPYRE project, the TU Delft Reactor Institute, together with 13 partners throughout Europe, have now significantly increased the knowledge of how nuclear fuels work in such Generation IV reactors.

The current generation of nuclear reactors (Gen II‐III) guarantees a stable supply of nuclear energy for the next 2‐3 decades, but to increase sustainability and safety of nuclear energy in Europe, additional development of nuclear technology is necessary. The aim of the INSPYRE project was to investigate the fast reactor Mixed Oxide (MOX) fuel to support the development and qualification of the fuels for the future generation of reactors, the so-called Generation IV reactors such as the Sodium-cooled Fast Reactor (SFR) or Lead-cooled Fast Reactor (LFR).

Nuclear fuel

Researcher Anna Smith from RID, who worked on the project: “One main challenge for the development and commercialisation of nuclear reactors is a thorough understanding and modelling of the nuclear fuel physico-chemical properties since the fuel is at the heart of the energy production process. The reference fuel in Europe for SFRs and LFRs is (U,Pu)O2 with 15-30% of Pu. During reactor operation, numerous fission products will be generated with different chemical and physical properties, which makes the chemistry of irradiated fast reactor fuel very complex. At the TU Delft, we investigated the chemistry of key fission products in those types of fuel, coupling experimental investigations and thermodynamic modelling assessments.   

Digital twins of nuclear reactors

In conclusion of the INSPYRE project, scientists now have a better fundamental understanding of thermochemical and –mechanical behaviour of these MOX nuclear fuels, the way fission gasses behave and diffuse in these fuels, and improved codes to simulate fuel performance. Marjorie Bertolus, project coordinator from CEA (France): “The next step for us will be that fuel designers and manufacturers as well as electricity producers will be now able to use a more physics-based approach in their fuel development and licensing processes. INSPYRE has laid the path for the next generation of scientists to build digital twins of nuclear fuel elements and eventually of nuclear reactors.


The INSPYRE partners have prepared a video explaining the objectives and results of the project on the nuclear fuel research to the nuclear community and to the general public. This project was conducted within the framework of the European INSPYRE project.

More information on the INSPYRE project

The website of the INSPYRE project

The website of Cordis: factsheet, reporting, and results


If you have any questions on this subject please contact Anna Smith, who took part in this Horizon 2020 project and takes part as work package leader in a new Joint Programme on Nuclear Materials (JPNM) pilot project called  Research on Oxide fuels for Data to improvE cOdes (RODEO).

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