Beam-On Effects during Irradiation of Nuclear Materials

<i>In situ</i> characterization methods for nuclear materials performance hold enormous promise for faster discovery of nuclear materials science, radiation effects, and down-selection of optimal alloys for nuclear power applications. Advancements in combining traditional irradiations and post-irradiation examination with new, rapid analysis tools promises, and will be shown in this talk, to hasten data throughput by up to 1000x compared to purely traditional methods. Particular emphasis on building robust inference models, whereby properties of ultimate interest are tightly correlated to those which are more readily measured by <i>in situ </i>techniques, will be made via illustrative examples of nuclear materials discovery, down-selection, and optimization. We specifically focus on utilizing <i>in situ </i>ion irradiation transient grating spectroscopy (I3TGS) for prediction of high-temperature superconductor performance during irradiation, rapidly exploring new ternary alloy compositions for fusion structural and functional materials, and sorting materials by their resistance to major degradation modes such as void swelling. Finally, we will present a call to collaboration and requests for input from the community, on how to best build robust and easy-to-use TGS systems to help others establish similar <i>in situ </i>capabilities of their own.