Brian Wirth
Nuclear Engineering Department
University of California, Berkeley
"Multiscale Investigation of Irradiation Effects and
the Promise of Irradiation Resistant Materials"
Radiation damage, and its consequence to a wide range of material properties, is a central issue in many advanced technologies, from light water reactor lifetime extension to the future development of advanced fusion power plants. Irradiation effects are initiated by the violent displacement of atoms from their lattice sites, and ultimately determined by the subsequent diffusional transport and evolution of the point defects and their clusters, along with the transport of solutes and impurities. Fortunately, nature has provided hints that it may be possible to scientifically tailor materials to be extremely resistant to irradiation effects by promoting the efficient recombination, or "self-healing", of the vacancy and self-interstitial point defects that are the principal radiation damage products. This presentation will first introduce the inherently multiscale nature of irradiation effects in materials and the extreme challenges facing materials for fusion power plants, followed by a description of a multiscale research paradigm involving a close integration of computational modeling and advanced experimental techniques to better understand irradiation effects. Select results will be presented from this hierarchical modeling approach that highlight improvements in understanding materials degradation in nuclear environments. In particular, results will presented that provide a basis for understanding dislocation loop evolution and the observations of Cr enrichment and depletion at grain boundaries observed in various irradiation experiments performed on binary Fe-Cr and ferritic-martensitic alloys, and the dislocation - obstacle interactions in irradiated fcc metals, which control observed mechanical property changes of irradiated materials. Finally, the scientific questions that determine the potential development of irradiation resistant materials for fusion applications will be discussed.
Brief Bio:
Brian Wirth received a BS in nuclear engineering from the Georgia Institute of Technology in 1992 and a PhD in mechanical engineering from the University of California, Santa Barbara in 1998, where he was a Department of Energy Nuclear Engineering Graduate Fellow. In 2002 he joined the faculty at the University of California, Berkeley as an Assistant Professor of Nuclear Engineering, following several years in the High Performance Computational Materials Science Group at Lawrence Livermore National Laboratory, and was promoted to Associate Professor in 2006. His research interests involve using multiscale modeling and advanced microstructural characterization techniques to develop improved understanding and models of microstructure - property relationships and microstructural evolution during processing and service in hostile environments, with an emphasis on irradiation effects. He has received a number of awards, including the 2003 Presidential Early Career Award for Scientists and Engineers (PECASE), an NSF CAREER award, the 2007 Fusion Power Associates Excellence in Fusion Engineering Award, a Graduate Student Gold Medal award from the Materials Research Society, and the Outstanding Scholastic Achievement Award as the top graduate of the Nuclear Engineering and Health Physics Program in 1992 at the Georgia Institute of Technology.
http://iron.nuc.berkeley.edu/~bdwirth/Public/WRG/wrg.html
Hosted by Prof. Thomas Pedersen
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