Influence of environment and temperature on oxidation behavior of fuel cladding

Nemoto, Yoshiyuki  ; Kaji, Yoshiyuki  ; Ogawa, Chihiro*; Nakashima, Kazuo*; Tojo, Masayuki*

To cope with the hypothetical loss-of-cooling or lost-of-coolant severe accident in spent fuel pools (SFPs), it is important to understand the high temperature oxidation behavior of the Zirconium claddings exposed in the air or in the atmosphere of air/steam mixture which are presumed for the environment in spent fuel rack internal in the SFP accident. The authors have investigated the detail of high temperature oxidation behavior of the Japanese fuel cladding materials in dry air with flow rate in the hypothetical SFP accident condition, and proposed oxidation models as well. Since there is not enough knowledge about influence of air / steam mixing ratio in atmosphere on cladding oxidation in SFP accident condition, the authors conducted high temperature oxidation tests of claddings in atmosphere of air / steam mixture with flow rate of hypothetical SFP accident condition, and investigated the influence of air / steam mixing ratio on cladding oxidation behavior.