Study on the pH Control Influence in PCV on the Emission of Gaseous Inorganic/Organic Iodine

Abstract

When a severe accident occurs in nuclear power plant, irradiated iodine would be formed. The irradiated iodine is basically trapped into the cooling water by existing in the ionized condition. However, it is assumed that the gaseous iodine might be re-volatilized from the cooling water in the suppression pool chamber by the irradiation effect. The iodine volatilize behavior is said to be affected by pH control of the pool water. In this study, volatilize behavior of inorganic/organic iodine with pH control under gamma-ray irradiation is evaluated, based on simulated actual plant environments. The pH control to alkaline environment is effective to the inhibition of re-volatilization of iodine. The emission behavior of organic iodine gas is mainly due to the reaction between the epoxy paint of gaseous phase in PCV inner wall and volatilized inorganic iodine gas.