[en] The properties of ion exchange material (D-mix), claimed to be representative of EPICOR-II first-stage liner media, have been investigated as a function of radiation dose. Gas generation, agglomeration, pH and corrosion of mild and stainless steel in contract with this material have been examined for unirradiated D-mix, and D-mix irradiated to 10₈ and 10₉ rad. It was found that during irradiation, H², CO², and CH⁴ were generated with H² being the major radiolytic gas. Although physical damage to D-mix occurs as a result of irradiation, agglomeration tests show only slight decrease in sluicability with increasing dose. Upon irradiation of D-mix, a substantial drop in the pH of the medium occurs due to the formation of acidic radiolysis products. Finally, substantial radiation enhancement of the corrosion of mild steel in contact with D-mix was observed while the corrosion of stainless steel was negligible. The properties of D-mix/cement composites have also been investigated as a function of total dose. These properties include gas generation, leachability, mechanical integrity, and corrosion of mild steel in contact with D-mix/cement components. These properties were measured on unirradiated composites and composites irradiated to 10₈ and 10₉ rad. H² was essentially the sole radiolytic gas produced. The leachability of Cs from unirradiated D-mix/cement components was substantially lower than that typically observed from organic ion exchange resin/cement composites. A slight increase in both the Cs and Sr release was observed for D-mix/cement composites fabricated from irradiated D-mix. Composites irradiated after fabrication showed no deleterious effects on leachability due to irradiation. Finally no deleterious effects due to irradiation were found in either the area of mechanical integrity or corrosion