Volatility of radioactive iodine under gamma irradiation. Effects of H₂O₂ and NaOH on the decomposition rate of volatile molecular iodine dissolved in aqueous solutions

The decomposition of molecular iodine by hydrogen peroxide and sodium hydroxide was kinetically studied in aqueous solutions at ambient temperature. To obtain an effective decomposition rate constant under experimental conditions, the concentration of triiodide ions was measured over time instead of that of molecular iodine. Overall, sodium hydroxide was regarded as a more effective decomposer than hydrogen peroxide. As demonstrated in the present study, existing methodologies can be simplified by grouping relevant reaction steps in order to estimate iodine volatility under a severe accident condition for a nuclear power plant. (author)