Research on the stability of fuel debris consisting of oxides and alloys, 12; Chemical state analysis and stability evaluation for oxidative degradation of the simulated debris

Watanabe, Masayuki   ; Kumagai, Yuta   ; Kusaka, Ryoji  ; Nakada, Masami  ; Akiyama, Daisuke*; Kirishima, Akira*; Sato, Nobuaki*; Sasaki, Takayuki*

Metal-alloyed debris would be formed by the reaction of nuclear fuels with the zircaloy cladding, control rods, and other reactor structural materials such as stainless steel (SUS) at high temperature at the Fukushima Daiichi Nuclear Power Plant in Japan. The chemical reaction and the dissolution behavior from the surface on the debris are required for the evaluation of the chemical stability on the debris under the reactor environment. In this study, immersion tests of some simulated debris synthesized by UO, SUS and zirconium into water or hydrogen peroxide and quantitative analysis of solution were performed. Laser spectroscopy and Mssbauer spectroscopy were also employed for the evaluation of chemical evolution of the simulated debris resulting of immersion tests.