[Comparison of Characterization Methods for Anisotropy and Microstructure of TRISO Particle Layer]. INERI-2006-003-F FY07 Annual Report

This INERI was created to support a comparative study between the newly developed two modulator generalized ellipsometry microscope (2-MGEM) at the Oak Ridge National Laboratoryand the more traditional optical polarimeter (RAPAX) at the Commissariat l nergie Atomique (CEA). These two systems are used to measure the anisotropy of the pyrocarbon layers in tri-isotropic (TRISO) coated particle fuel, which is an important parameter related to fuel performance. Although this project was only just started in June 2007, good progress has already been made. A kickoff meeting was held at ORNL on July 30-31, 2007 to present early progress and discuss details of the proposed work plan. This meeting was of great benefit to the participants, offering an opportunity to overcome the language barrier and more thoroughly communicate project relevant information. Each technical lead gave a presentation explaining the analysis techniques used in his task and presented data on early measurements of the German reference fuels. Plans were finalized regarding what work needed to be done and how to proceed with the comparative study. Possibilities for the inclusion of other coated particle samples, in addition to the two German reference fuels originally proposed, were also discussed. A list of these additional sample has now been generated and approved. Coating fragments from this series of different TRISO particle fuels have been sent from ORNL to the CEA and TEM analysis is in progress. Comparisons have already been made between the microstructure of the two German reference fuels which are the primary samples for this project. Specimens have also been prepared from the German reference fuels for comparative analysis between the 2-MGEM and RAPAX devices and initial measurements performed. Plans are to exchange specimens of the various fuel types in early FY08 for comparative analysis.