OperaHPC project

OPEn HPC theRmomechanical tools for the development of eAtf fuels

In a nutshell

Electrification of the energy sector will be a key step for its transition to climate-neutrality. In order to achieve it by 2050, it will be necessary to maintain and even extend the production capacity of current nuclear reactors, while taking into account the evolving electricity mix and increasing requirements regarding the safety assessment of nuclear reactors. 

On these points, the question of nuclear fuel behaviour is essential because it sets the main constraints to be satisfied for safe operation of nuclear reactors and defines the source term for accidental conditions.



Generation II and III reactor fuels in Europe take advantage of a large experimental feedback with a continuous evolution of fuel element design and materials, which allows maintaining high safety standards while adapting to the evolution of the operating conditions.
Fuel performance codes, which enable the simulation of the behaviour of the fuel elements in reactor, are now an essential component of the design, licensing and safety assessment of nuclear fuels.
The licensing of innovative fuel materials and design requires an extension of the current fuel performance codes to meet safety authority’s requirements, in particular regarding the Verification, Validation and Uncertainties Quantification processes.
Opera HPC will work on four aspects to improve the approach and computational tools used by the nuclear research community and industry.

Basic research on the mechanical behaviour of fuel under irradiation Code development Industrial application Education and training and dissemination of the project’s results
Obtain missing data, identify elementary mechanisms and develop physics-based models of the non-linear mechanical behaviour of fuel and fuel elements Open source 3D HPC simulation tools with parallel computing capabilities at the microstructure and fuel element scales, as well as a meshless prototype tool Improved industrial models and application to the simulation of the thermo-mechanical behaviour  of enhanced accident tolerant fuel elements in normal and accidental conditions Transfer of approach, tools and results through open-access publications, workshops and exchanges with industrial end-users and training of a new generation of researchers

Work packages

To reach its objectives, the project is organised in 9 work package.


Multiscale modelling and characterization of non-linear mechanical behaviour of irradiated fuel

Get further insight into the creep and rupture behaviour of irradiated UO2 fuel using a basic research approach coupling multiscale modelling and experimental tests and characterizations.

Development of multiscale mechanical models for fuel elements

Develop improved rheological non-linear mechanical models of the fuel pellet and the cladding needed for the simulation of innovative fuel elements



Calculation of input data and boundary conditions using state-ofthe-art fuel performance codes

Produce high-fidelity input data and associated tools for the simulation of fuel element thermomechanical behaviour of innovative fuel elements.



Development of 3D HPC simulation tools for the thermo‐mechanical behaviour under irradiation

Develop open-source 3D high-fidelity simulation tools for the thermomechanical behaviour of nuclear fuel rods under irradiation.

  • The MMM tools for simulation at the microstructure scale 
  • the OFFBEAT code for simulations of the fuel elements. 
  • A prototype tool using a novel multiscale meshless methodology to help addressing some limitations of MMM and OFFBEAT.
Verification and Validation, Uncertainty and Sensitivity Analyses

Perform Verification, Validation, and Uncertainty and Sensitivity analyses for the MMM and OFFBEAT codes before their application on innovative fuels and fuel elements

Development of improved models for industrial fuel performancecodes

Develop improved models for industrial fuel performance codes using machine learning and model order reduction techniques, as well as reference 3D simulation results yielded by the MMM and OFFBEAT codes.


Simulation of fuel element behaviour in operating and accidental transient conditions

Using the 3D advanced tools and improved industrial fuel performance codes developed in the project, provide a detailed assessment of the behaviour of innovative fuel elements in PWR and VVER reactors in nominal steady state conditions as well as transient ones due to flexible operation and accidental conditions.

Education and training, exploitation, dissemination and communication

Disseminate and communicate on the Project’s activities and results through inter alia publications, organization of workshops and exchanges with the end-user group

Organize education and training activities in the field of the Project: develop a MOOC, enable mobility of the young scientists involved in the project between the partners of the projects and co-organize summer schools


Project management

Monitor the activities and finances of the project and ensure timely delivery of the expected results of the projects.

News AND Events

The Project kick off meeting will be held on
Nov 23-24° 2022 in Aix en Provence