Analysis of Silver Release from Furnace-Tested TRISO Particles

High temperature testing of intact TRISO particles previously irradiated in AGR-1 experiments was performed. Higher levels of Ag release were found at 1300 C compared to both lower and higher temperatures. Additionally, some of the particles released a majority of their inventory while others did not appear to release radioactivity under similar irradiation and testing conditions. An analysis of the Ag release data from furnace for irradiated TRISO testing was performed. A few possibilities for the Ag diffusion behavior are presented in this work including impurities in the SiC, and the Si to C atom ratio near grain boundaries. The diffusion of Eu from TRISO particles was also considered. The hypothesis for this behavior is variability in the formation of Eu oxides and carbides depending on kernel chemistry.