Reflooding Experiments on a Vertical Surface with Radiation-Induced Surface Activation

In this study, reflooding experiments were performed on a vertical rod surface before and after γ-ray irradiation to see the effect of Radiation-Induced Surface Activation (RISA) on the quenching speed. The test section was an annular channel with a concentric inner rod made of stainless steel SUS304 and an outer tube made of quartz glass. The inner rod was irradiated by 60Co γ-rays with predetermined radiation intensity and period to improve the surface wettability based on the radiation-induced surface activation phenomenon. Prior to the reflooding experiments, the contact angle of a droplet on the inner rod surface was measured using a CCD camera. It was indicated that the irradiated surface wettability was clearly improved and the quenching speed was enhanced after γ-ray irradiation.