Special Materials Science & Engineering Seminar
Maulik K. Patel
University of Tennessee, Knoxville
"Radiation (Ion beams) induced modifications in nuclear materials"
Materials used in the nuclear reactors (fuels and structural materials including cladding) and in nuclear waste forms for disposal/transmutation of nuclear waste constantly experience the most complex extreme environment, one that includes radiation. Radiation causes microstructural modifications, which are initiated primarily by formation of point defects and at high temperatures lead to the nucleation of dislocations and voids. These defects then bring about deleterious changes in the thermo-physical, chemical and mechanical properties of materials used in nuclear fission reactor applications. Thus it is a big challenge to understand the complex phenomena of radiation damage, characterize the damage itself and finally correlate the material properties that can be modified to make more radiation tolerant materials. Some of the problems associated with studying radiation damage of materials irradiated in reactors or nuclear waste are, slow defect accumulation over long irradiation time scales. Secondly, the materials become radioactive themselves making it difficult to characterize damage by conventional techniques. Finally, simultaneous irradiation by several different radiation species makes it difficult to understand separate effects. Thus, in order to evaluate the performance of existing and futuristic materials used in nuclear environments, accelerated ion beams are used to experimentally simulate radiation damage and perform controlled separate effects studies in the lab. Thus in this presentation I will, (1) introduce the general topic of radiation damage, (2) outline various sources of radiation existing in a nuclear environment and the mode by which they cause damage, (3) how accelerated ion beams can be used to simulate radiation damage and its drawbacks and (4) various characterization techniques used to understand and correlate damage to material property. The contents of the talk will be kept at a level plausible to students from under grad. to graduate level.
Host: Prof. I.C. Noyan