Iodine behaviour in spent nuclear fuel dissolution

The chemistry of iodine in spent nuclear fuel (SNF) solutions is extremely complex and numerous species have been identified. These include iodine (I-2), iodide (I-), iodate (IO3-), triiodide (I-3(-)) and insoluble colloidal compounds with the fission products silver and palladium (AgI and PdI2). The experimental parameters that control the removal of iodine from SNF solutions are poorly understood. Experiments were performed at two temperatures representative of dissolver conditions. It was found that iodine, added as iodide, was rapidly removed from solution; within 30 s over 70% and 90% of the initially added amount was removed at 60 and 80 degrees C, respectively.