ME Seminar on "Structural materials in nuclear environments: A challenge and driving force for new techniques and materials concepts."
Title: "Structural materials in nuclear environments: A challenge and driving force for new techniques and materials concepts."
Speaker: Prof. Peter Hosemann, Department for Nuclear Engineering , University of California Berkeley
Abstract: Advanced nuclear reactors will minimize the nuclear waste and provide more inherently safe and reliable power without CO2 emission. As is almost always the case for advanced technologies, materials are the limiting factor in making new designs feasible. Radiation damage caused by the neutrons and coolant corrosion-compatibility present unique challenges. In this presentation detailed microstructural characterisation after high dose reactor and ion beam irradiation utilizing Local Electrode Atom Probe (LEAP) as well as Transmission Electron Microscopy (TEM) on advanced nanostructured alloys are presented. Intermetallic precipitates (α’) were found on in the high Cr steels as after exposures to more than 100 displacements per atom (dpa) of neutron dose. While microstructural evolution information is important, the resulting mechanical property changes must also be understood and predicted. New micro-mechanical testing techniques, such as nanoindentation and micro-compression, are described. These techniques present challenges, but offer a number of advantages, such as making ion beam irradiation mechanical properties studies possible. The other key challenge is corrosion by coolants, like liquid metals (Lead-Bismuth Eutectic, LBE), that are primarily unique to nuclear applications. It is shown how TEM and scanning probe techniques can provide detailed insight in the corrosion process while micromechanical testing allows opens new doors to measurements, like characterizing the force it takes to spall off protective layers.
Bio: Peter Hosemann is an assistant professor in the Department for Nuclear Engineering at the University of California Berkeley. Professor Hosemann received his PhD in Material Science from the Montanuniversitaet Leoben, Austria in 2008. However, his research on LBE corrosion, ion irradiations and microscale testing was actually carried out at Los Alamos National Laboratory both as a student and post doc. Professor Hosemann joined the faculty at Berkeley in 2009. His work has been recognized by a number of awards and he has been extremely professionally active in organizing conferences and workshops.