Absorption of iodine from aqueous solutions on nuclear reactors alloys

Abstract

Iodide ions I-, molecular iodine I2 and iodate ions IO3 - absorption has been studied on the three alloys which are present, in majority, in french nuclear reactors: Inconel 600, Zircaloy and 304L stainless steel. Iodide and iodate anions are not absorbed on the three considered alloys and contribute only for a negligible quantity to iodine retention on the nuclear reactors materials. Molecular iodine is absorbed according to: 304 stainless steel < Zircaloy < Inconel 600. Influence of pH has been studied: absorption increases in acidic medium and decreases in basic medium. Molecular iodine absorption increases with temperature.Phenomenons which occur with iodine during the cold shutdown of a nuclear reactor and during its restart are discussed from the point of vue of iodine volatilization risk.