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2014 ANNUAL REPORT 11 After five years as an early career researcher at the South Africa Nuclear Energy Corporation Dr. Isabella van Rooyen went to work on her countrys pebble bed modular reactor program.When the govern- ment withdrew funding from that program in 2011 she decided the U.S. offered the best opportunities for her to pursue her passion for studying nuclear materials particularly tristructural isotropic TRISO-coated fuel particles. Partly because of its involvement with the Next Generation Nuclear Plant NGNP program and partly because of her broad respected background in the nuclear field INL welcomed her with open arms. I had also gained a lot of experience working in the industrial sector van Rooyen says. That turned out to be a big advantage because now I not only think about what Im working on at that moment I think about what the application of that product will be for the end user. When she first came to INL she split her time between studying the viability ofTRISO-coated particles and working on the light water reactor LWR sustainability program. Her success withTRISO fuels soon won out and this year she and her colleagues Dr.Thomas Lillo and Dr.Yaqiao Wu received an INL Outstanding Paper award for Identification of Silver and Palladium in IrradiatedTRISO-Coated Particles which was published in the Journal of Nuclear Materials in 2014. I had started trying to solve the silver transport mechanism problem in South Africa says van Rooyen and I learned a lot there but I could never go to the next stage because we couldnt study irradiated particles. That hurdle was overcome at INL and resulted in a breakthrough discovery. We always knew from gamma spectrometry that under irradiation silver is released outside these tiny silicon-carbide-coated particles van Rooyen explains but we never knew where and how. Now that we know the path it follows we can work toward a solution to prevent that release from happening. While they have not yet tracked the full mechanism they feel very close to gaining a new set of knowledge. Using transmission electron microcopy we are currently looking systematically at the orientation and grain boundary characteristics of each grain that is adjacent to the silver we have found says van Rooyen. Once we find the grain characteristics we can manipulate the release process in such a way that does not favor the driving transport mechanisms. Isabella van Rooyen