IRSN conducts research projects to acquire knowledge and skills, required for safety assessment of the CIGEO project developed by ANDRA (deep geological disposal facility for IL/ILW radioactive waste). It is particularly aimed at understanding and modelling physico-chemical phenomena that are important for the future facility safety. As a significant production of hydrogen is expected inside the future geological repository, this gaseous phase could modify the flows and mechanical conditions of the rock and engineered material. IRSN works on different transfers and perturbations occurring in a disposal and its host-rock, by developing and using a variety of direct simulation codes at several scales. A pore scale Hydro-Mechanical-gas code has been developed, based on Smoothed Particle Hydrodynamics, to study water-gas migration accounting for drying within a deformable solid (elastic with thermodynamical damage model). Within EURAD1 project (2019-2024), approaches to investigate separately the impact of physical processes (mass transfer between phases: drying and condensation, hydromechanical coupling …) involved in gas migration in host rock at the mesoscopic scale were developed.

In the frame of EURAD 2 project (2024-2028),we want to implement the coupling between the different physical (THMC) processes involved in gas migration and to upscale results into the continuum scale, to be able to use them for modelling of laboratory experiments from EURAD1. For upscaling process, the work will be conducted within a dedicated work-package HERMES, that will put forward several approaches and make them interoperate. IRSN, in collaboration with GeoRessources (Univ. of Lorraine), proposes to study the THMC couplings in the near- and far-field at the micro and meso scale (order of tens of pores) based on microstructural information obtained from 3D imaging approaches (XRay µtomography, FIB-SEM, …) within EURAD1. In particular, the SPH code will be used to extensively study coupling of water-gas flow with deformation of elasto-damageable solid matrix in in-situ oriented conditions with consideration of temperature dependency of multiphase flow parameters (to be implemented). Taking advantage from increasing capabilities of modern GPUs, we will be able to simulate bigger domains and thus to compute effective properties (e.g., saturation curve, relative permeability, poromechanical properties) and their evolution with time so that an upscaled model could be derived. Dynamics data integration though unified EURAD2 HERMES interface will be implemented as well to simulate small scale experiments and deliver data for code comparisons.

Such comparison of our computationally expensive microscale models with macroscale approaches will be used to explore the consequences of usual simplifications and will provide benchmarking and training data for predictive surrogate models.

ADDED VALUE FOR CANDIDATE :

uncommon simulation method (SPH) used in astrophysics and computer games, international project EURAD2 with plenty of networking opportunities, high performance computing

PhD in numerical fluid and/or solid mechanics

Modelling of two-phase flow in porous media, poromechanics, hydro-mechanical coupling, upscaling, Physics Informed Neural Networks (PINNs)

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Whatever the differences, we aim to attract, integrate and retain our candidates and employees within an inclusive working environment.
IRSN has for many years pursued an active policy in favor of equal opportunities in the workplace and the employment of disabled people. If you have a disability, please let us know if you have any specific needs that we can take into account.