2018 | ANNUAL REPORT 29 technique to provide 3D distribu- tion of microstructures in materials at nano-length scale, along with near exact chemistry mapping of the elements.The APT work done in the past to analyze irradiated metallic and oxide fuels for correlating microstruc- ture with the performance of fuel has been limited. However, Bachhav and his colleagues described in the paper how they carried out systematic APT study on Uranium-Molybdenum (U-Mo) alloy fuel particles coated with a diffusion barrier layer of zirconium nitride (ZrN) and dispersed in an aluminum matrix.APT analysis on irradiated U-Mo fuel revealed a uniform distri- bution of spherical-shaped clusters enriched with fission products such as ruthenium, palladium and cadmium. Quantification of the fission products relied on the operating conditions of the APT instrument (base temperature, pulse rate, detection rate, laser and mode of operation).They found that low-base temperature and voltage mode during APT analysis offered better spatial resolution and quantifi- cation of the fission products formed in irradiated U-Mo fuel.Transmission Electron Microscopy (TEM) analysis offered high-resolution images of bubbles, along with the distribution of uranium and molybdenum, though it has some limitation when it comes to quantification of fission products. Although APT offers high chemical and spatial resolution that no other technique can match, the team said there are still challenges involved with multicomponent materials and interfaces, such as what is called the local magnification effect, arising from differences in evaporation fields of adjacent phases. “These differences can lead to ion trajectory overlaps near the interface and loss of spatial resolu- tion,” the researchers wrote. Bachhav has been awarded with several DOE-NE NSUF proposals, which are in close collaboration with universities such as University of Wisconsin, University of Florida, United States Naval Academy and Massachusetts Institute ofTechnology. While he is a recognized reviewer for several publications, including Journal of Applied Physics Letters, Journal of Nuclear Materials, and Materials Science & Engineering B, Bachhav is also a member of the International Youth Nuclear Congress. IYNC’s goal is to provide a global network for young professionals in the nuclear field, especially when it comes to the transfer of knowledge from the current generation of leading scientists and engineers to a new generation.