Characterization of the as-fabricated fuel is being performed at Pacific Northwest National Laboratory (PNNL) in accordance with Characterization Plan for the Fabrication of U-10Mo for the MP-1 Experiment, hereinafter the MP-1 Characterization Plan. Similar characterization work is also being performed at two other organizations, INL and Los Alamos National Laboratory, to provide a detailed understanding of the as-fabricated fuel that would be irradiated in the MP-1 experiment. Under the MP 1 Characterization Plan, fuel foils with different fabrication parameters (such as rolling condition, rolling thickness reduction, co-rolling with Zr layers) are being studied. Similar samples from master foils were sent to each of the three organizations, so that testing and analysis can be performed independently using similar equipment and a standardized set of measurement and analysis procedures. A final consolidated report will be prepared based on this work and it will summarize all of the information obtained from different labs. The MP-1 experiment will provide an opportunity to understand the effects of processing conditions on the final fuel microstructure, to compare results obtained independently, and achieve a three-way validation.
Currently, PNNL characterized 28 U-10Mo samples, by sectioning six pieces/specimens from each sample/foil, in accordance with the MP-1 Characterization Plan. These 28 samples consist of six types of MP-1 characterization foils from BWXT: 0.047 in. thick hot-rolled samples with and without Zr layers; 0.02 in. thick cold-rolled and annealed samples with and without Zr layers, and 0.01 in. thick cold-rolled and annealed samples with and without Zr layers.
During the first year, PNNL completed sectioning of two subsamples per sample/foil and performed the necessary characterization on all 28 U-10Mo samples. This report covers the results of the first year’s analyses of PNNL’s MP-1 fuel characterization samples. Microstructure, chemical composition, carbide morphology, U-10Mo foil thickness, Zr thickness, mechanical properties (microhardness), and density were evaluated in both longitudinal and transverse directions for foils of the three different thicknesses.