Study on atomic level analyses and stability evaluation for inert gas precipitations formed irradiated materials

Inert gases such as Xe and He precipitate easily in nuclear materials under irradiation, because of their very low solubility. The precipitations generally cause failures of the materials under irradiation and their behavior is one of key factors to determine their life time. In this study, an apparatus named Subnanotron which is possible to carry out insitu observation and state analysis under ion-irradiation was used. Xe precipitates in nano- and subnano- size were observed in dark field images of TEM (transmission electron microscope). Solid and liquid states of He gas precipitates could be discriminated by the EELS (electron energy loss spectrum) analysis. Regularization of inert gas atoms was revealed at the interface of gas precipitation by atomic level analysis on the surface structure. (A. Hishinuma)