Austenitic steel AIM1 is considered as benchmark alloy for fuel cladding in fourth-generation lead (RNR-pb) or sodium (RNR-Na) reactors. This alloy is currently undergoing qualification testing. The solution treatment of titanium carbides is a key point to obtaining a microstructure that is resistant to irradiation and, in particular, to the phenomenon of irradiation swelling (condensation of vacancies that form cavities in the material). It depends mainly on the quality of the thermomechanical treatments carried out during industrial manufacturing. New approaches to fine characterization (combining electron microscopy, atom probe tomography (APT), and thermoelectric power (TEP)) make it possible to specify microstructural changes during the manufacturing process.
In this thesis, we propose to study a new criterion for assessing the manufacturing quality of AIM1. The primary objective is to determine to which extent the variations in the material's thermoelectric power (TEP) can contribute to the implementation of an acceptance test that can be applied industrially. We will seek to acquire the knowledge that will enable us to perform a simple measurement to validate the metallurgical state of the tubes by having a precise understanding of the microstructures that produce the TEP signal intensity.
This study, which will combine experimental work and modeling, will enable to acquire skills in transmission electron microscopy, atom probe tomography, behavior under ion irradiation, and cluster dynamics modeling.