Formation behavior of gaseous iodine from sodium iodide under SFR severe accidental condition

Kikuchi, Shin  ; Kondo, Toshiki   ; Doi, Daisuke  ; Seino, Hiroshi ; Ogawa, Kengo*; Nakagawa, Takeshi*

In this study, thermal behavior of NaI in different atmospheric conditions was investigated using thermal analysis technique to understand the formation behavior of gaseous iodine. Based on the results, it was revealed that the thermal behavior of NaI in inert atmosphere is phase change and approximately 10 mass% of I2 could be formed from NaI in 20 vol% oxygen atmosphere. The chemical equilibrium simulation was also performed to understand the mechanism of I2 formation. The estimated value of I2 formation in 20 vol% oxygen atmosphere was comparable to the result of thermal analysis.