Development of Advanced Small Reactors

Aqueous Dissolution of Silver Iodide and Associated Iodine Release under Reducing Conditions with FeCl2 Solution

“…During reprocessing of the spent fuels in Japan, 129 I is collected as a chemical form of silver iodide (AgI) by using silver-loaded adsorbents that are considered as one of the major reprocessing wastes. 1,2) The form of AgI will be confined into more durable waste forms to be disposed of in geological formation, and several kinds of potential waste forms have been proposed, such as crystallized Al 2 O 3 , SiO 2 , cement and other materials, along with their fabrication techniques. 1,2) Since 129 I has an extremely long half-life (T 1=2 ¼ 1:57 Â 10 7 y) and weak adsorption on geological media, [2][3][4][5] the performance of the waste forms to immobilize 129 I for a long time is one of the key issues to be evaluated for the safety assessment of geological disposal.…”

“…1,2) The form of AgI will be confined into more durable waste forms to be disposed of in geological formation, and several kinds of potential waste forms have been proposed, such as crystallized Al 2 O 3 , SiO 2 , cement and other materials, along with their fabrication techniques. 1,2) Since 129 I has an extremely long half-life (T 1=2 ¼ 1:57 Â 10 7 y) and weak adsorption on geological media, [2][3][4][5] the performance of the waste forms to immobilize 129 I for a long time is one of the key issues to be evaluated for the safety assessment of geological disposal. Since the recent safety assessment requires that the waste forms should perform for more than a hundred thousand years, 1,2) the performance should be evaluated based on a sound understanding of the fundamental chemical and/or physical behavior including AgI dissolution itself under the disposal conditions.…”

“…1,2) Since 129 I has an extremely long half-life (T 1=2 ¼ 1:57 Â 10 7 y) and weak adsorption on geological media, [2][3][4][5] the performance of the waste forms to immobilize 129 I for a long time is one of the key issues to be evaluated for the safety assessment of geological disposal. Since the recent safety assessment requires that the waste forms should perform for more than a hundred thousand years, 1,2) the performance should be evaluated based on a sound understanding of the fundamental chemical and/or physical behavior including AgI dissolution itself under the disposal conditions. Although some studies have been carried out to evaluate the performance of the proposed waste forms, only a few studies have focused on the fundamental chemical and/or physical behavior of the AgI dissolution itself.…”