Evaluation of condensation behavior for vaporized FP species

Takai, Toshihide  ; Sato, Isamu*; Yamashita, Shinichiro   ; Furukawa, Tomohiro  

Aerosols are produced when the vapor species released from overheated fuels are transported to reactor cooling system under severe accident. The chemical forms of the aerosol may be determined a region between the vapors release and the aerosols formation. No information is available about the chemical forms in the region. The using of hypothesis chemical forms in source term evaluation becomes one of the causes of uncertainty. For the improving evaluation accuracy, it is necessary to obtain the chemical forms data in the region. Applicability of a cascade impactor was investigated to determine the material properties of right after the aerosol formation, because it had possibility to collect aerosols in the classified stage in each particle size and determine the material properties for each stage.