Hydrogen evolution in the radiolysis of boiling water and non-homogenous distribution

Katsumura, Yosuke*; Matsuura, Chihiro*; Yamashita, Shinichi; Hirade, Tetsuya  ; Iwamatsu, Kazuhiro; Taguchi, Mitsumasa

Relevant to the nuclear accident at Fukushima Dai-ichi Nuclear Power Station, a radiolysis study of boiling water irradiated with Co-60 rays has been conducted. The evolution of hydrogen gas was clearly detected under boiling condition, while an extremely small amount of gas formation was found under the stable condition without boiling even at 97C. The G(H) of 0.37 was obtained under boiling condition. It was found that solution of 3.5% NaCl, similar to seawater, enhances the evolution, and the value of 0.7 was obtained. On the contrary, the O gas formation was much lower than that of H, suggesting the formed HO is not decomposed and remained in liquid. In addition, it was found that the evolved hydrogen is distributed selectively at the inner surface of the container under boiling condition. Gas injection experiments were also done without irradiation to clarify the behavior of hydrogen in the container.