Iodine Partitioning in Pressurized Water Reactor Steam Generator Accidents

Measurements of iodine speciation in aqueous solution at 285° C and 1000 psig show a higher percentage as I₂ in solutions at trace concentrations than at higher concentrations. A 1 × 10⁻⁹ M I⁻ solution resulted in 2% I₂, whereas a 1 × 10⁻⁴ M I⁻ solution had only 0.1% I₂. These tests indicate that iodine at tracer concentrations can have a species distribution in solution that is not expected or observed at higher concentrations.