b'Accomplishments:In the last year, GA-EMS has completed the conceptual design of the irradiation. A trade study was performed, in consultation with utilities and fuel vendors, to identify the optimal irradiation vehicle approach. The trade study identified modification of the guide tube thimble plug assemblies currently used in some commercial pressurized water reactors as the best solution. Housing the SiGA test articles within the thimble plug assembly, located at the top of the core, has been shown through neutronics calculations to have insignificant impact on reactor flux and power levels. Preliminary drawings have been completed for two separate capsule designs which will replace the guide tube thimble plug fingers. The capsules have minimal change to the form, fit, and function of the guide tube thimble plug assembly. The capsules will be inserted into the reactor for one cycle of irradiation. To simplify licensing (through a 10 CFR 50.59 process) and implementation, the SiGA test articles will not contain fuel. GA-EMS has designed the first capsule as a pressure vessel meeting American Society of Engineers Boiler and Pressure Vessel Code standards to insulate SiC test articles from the reactor coolant chemistryFigure 1. Conceptual layout of the irradiation vehicles with SiC test articles to test and pressure to investigate irradia- mechanical performance and corrosion of SiC after commercial PWR irradiation2023|AFC ACCOMPLISHMENTS 145'