シビアアクシデント時のセシウム放出・移行に与えるホウ素の化学的影響評価,1; ホウ素存在下における燃料放出直後のセシウム化学形の予測

Chemical impacts of boron on the cesium release and transport behavior under severe accident conditions, 1; Prediction of chemical forms of cesium just after release from fuel in the presence of boron

三輪 周平  ; 山下 真一郎   ; 逢坂 正彦  

Miwa, Shuhei; Yamashita, Shinichiro; Osaka, Masahiko

セシウム(Cs), ヨウ素(I), ホウ素(B)等のシビアアクシデント進展に応じた放出速度の温度変化・雰囲気依存性を考慮し、燃料放出直後のCs化学形の温度・雰囲気依存性を化学平衡計算により予測した。雰囲気・温度によりCs蒸気種が変化し、B存在下では雰囲気・温度に関わらずCsBO蒸気種が支配的となることがわかった。

The effects of temperature and atmosphere on cesium (Cs) chemical form just after release from fuel were estimated using chemical equilibrium calculation with consideration of the release kinetics of Cs, iodine (I), boron (B) and so on depending on temperature and atmosphere under a severe accident. The calculation results show that Cs vapor species changed according to temperature and atmosphere, and CsBO vapor species was dominant with the existence of B regardless of temperature and atmosphere.