Reactions between reactive metals and iodine in aqueous solutions

Volatile I2 is likely to be released from the core and primary system to the reactor containment in the event of a severe nuclear reactor accident. Within the containment, I2 will be distributed between the aqueous and gas phases which makes it very important to study how I2 will interact with containment surfaces in order to determine which processes might reduce the concentration of volatile I2. This study focused on the reactions of I2 with some reactive metals available in the aqueous phase of the containment. The experiments were done under conditions similar to those in the containment of a boiling water reactor in a severe accident situation. Copper, zinc and aluminium are all capable of reducing the concentration of I2 in the aqueous phase either by adsorption or by conversion of I2 to I−. Copper binds I2 on the surface as CuI, while zinc and aluminium converts I2 to I−. Rate constants were determined for the adsorption of I2 on Cu in the temperature range of 25–85 °C and for the conversion of I2 to I− on Zn and Al in the temperature range of 25–140 °C. The rates of adsorption and conversion increased with temperature.