Development of a non-destructive post-irradiation examination technique using high-energy X-ray computer tomography

Katsuyama, Kozo ; Nagamine, Tsuyoshi; Nakamura, Yasuo

High-energy X-ray computer tomography (X-ray CT) is one of the most powerful non-destructive test tools for checking the inner condition of structure materials. This technique has been applied to the inspection of structure materials such as the booster rocket and the engine of automobile. However, the application of X-ray CT technique to the post irradiation examination (PIE) of nuclear reactor fuel was impossible due to the effects of ray emissions from an irradiated fuel assembly. In order to minimize the effects of the ray emissions from the irradiated fuel assembly, the 12 MeV X-ray pulse was used in synchronization with the switch-in of the detector, and then clear cross section CT image could be successfully obtained. This technique makes it possible to observe the inner condition of irradiated fuel assembly (maximum radioactivity:210Bq) by non-destructive method for the first time in the world.