Engineer from Supélec (class of 1993) and phd in particle physics, I have been working at CEA since 1997 in the field of neutronics and nuclear physics (HDR and and CEA Research Director). Advances in knowledge in nuclear physics (theoretical and experimental), materialize for devices applications (nuclear reactors, etc.) by setting up a process called nuclear data evaluation [2]. The simulation of the objects of interest (reactors/vessel/…) and their properties are calculated by simulation tools (Neutronics) using observables from nuclear physics (cross sections, spectra, multiplicities, etc.). The evaluation of these observables is also accompanied by an estimation of their degree of validity: evaluations of the associated uncertainties. My recent research activity has mainly been directed towards the evaluation of uncertainties on these data [1][3], in particular by the development of Bayesian inference methods which proposes an appropriate mathematical framework (2 phd’s supervision in progress). These issues still raise questions of physics (model bias, transposition of uncertainties to the application) and mathematics (use of Bayesian inference and/or artificial intelligence methods). Recent articles: [1] C. De Saint Jean et al., “Evaluation of Neutron-induced Cross Sections and their Related Covariances with Physical Constraints”, Nuclear Data Sheets, Volume 148, pages 383-419 (2018). [2] A. J. M. Plompen, O. Cabellos, C. De Saint Jean, M. Fleming et al., “The joint evaluated fission and fusion nuclear data library, JEFF-3.3”, Eur. Phys. J. A 56, 181 (2020). [3] C. De Saint Jean et al., “Conrad - a code for nuclear data modeling and evaluation”, EPJ Nuclear Sci. Technol. 7 10 (2021).