The overall objective of the work is to quantify the defects created by irradiation in Zr cladding, to determine their nature, how they evolve with time and how the can be annealed out by increasing temperature. The result is used to evaluate the macroscopic consequences on the cladding: growth and variations in ductility.
Zirconium alloys are used to clad the nuclear fuel where the fission reaction occurs. They are corroding, creeping and subjected to intense neutron irradiation. This high flux creates numerous point defect in the metal (vacancies, interstitials, clusters) which evolves with time and temperature. In zirconium alloys they cluster in dislocation loops which in turn impact greatly the mechanical properties as well as the dimensions of the cladding.
EDF has long been working to enhance its knowledge of irradiation defects in Zr claddings since it is of prime importance to get assess the state of the cladding in the various conditions encountered by a fuel rod (normal operation but also transportation or storage) or which must be taken into account in the safety file (design basis accident such as Loss Of Coolant Accident).
The work proposed is based on modelling. The student will have to cope with density functional modelling, Monte Carlo modelling which will be used to calculate how a defect distribution evolve with time. The work does not start from scratch as it will build upon 20 years of experience in such a modelling.
The work will be part of MIDAS, a UK project funded by EPSRC and led by Manchester University. As such, the student will spend part of his PhD time at Manchester (tentitatively 6 months) where he will help to model the impact of these irradiation defects on diffraction pattern and TEM images. His/her knowledge in the details of atomic positions around the defects gained during the first part of the work will be required.
Most of his/her time will be spent at EDF Labs Les Renardières. The student will graduate from Université de Lille. The work is funded by EDF and a CIFRES grant from the ANRT.
The work can start at any time during the year after completion of the ANRT file for the CIFRES grant. It is better to start in fall to synchronize the work with the academic year.
Ideal candidate profile
The student should have no fear of coding nor using computers. Fluency in English is mandatory. Training in material science is appreciated. Good communication skills, initiative, working proficiency and enthusiasm are warmly welcomed.