Chemical interaction of CsOH vapor with UO and Fe-Zr melt

UOおよびFe-Zr融体とCsOH蒸気との化学的相互作用

中島 邦久  ; 高野 公秀 

Nakajima, Kunihisa; Takano, Masahide

1Fでは、シビアアクシデント解析コードを用いた解析や汚染水からの逆解析により相当量のCsが炉内にまだ残っていると推定されている。そのため、炉心領域で想定されるCs蒸気とUOあるいはFe-Zr融体との化学的な相互作用の有無を調べた。その結果、CsUOやCsZrOの生成が確認され、燃料から放出されたCsがUO燃料やFe-Zr融体と化学的な相互作用により付着する可能性があることが分かった。

At TEPCO's Fukushima Daiichi Nuclear Power Station, it is estimated that considerable amounts of cesium still remain in the reactors from the analysis results using the severe accident analysis codes and the reverse analysis from contaminated water. Since cesium is known to form stable compounds with uranium and zirconium, chemisorption experiments with uranium dioxide pellets and iron-zirconium melts for cesium hydroxide vapor were carried out. As the results, formations of cesium uranate, CsUO, and cesium zirconate, CsZrO, were confirmed, indicating that cesium was chemisorbed on both of the uranium dioxide pellets and the iron-zirconium melts in an Ar-H-HO flow and an Ar-H flow, respectively. Therefore, it was considered that cesium released from fuel might be trapped by chemisorption with fuels and/or iron-zirconium melts during light water reactor severe accidents.