PNNL

Abstract

Laboratory experiments were conducted to verify certain assumptions as to the swelling, chemical durability, and microcracking that might occur in a waste-form ceramic as 239Pu decays. To study to effects of 239Pu decay, 238Pu, a short-lived isotope, was incorporated into a pyrochlore-rich baseline titanate – one that is formulated for pyrochlore as the dominant phase. The self-irradiation with 238Pu provided information on damage to the crystal structures of the phases in the ceramic as well as changes in dimensions, densities, and chemical durability. Overall, the pyrochlore baseline material appears to be a viable material for the immobilization of weapons-ready Pu. The physical and chemical properties of this material are not adversely affected by the material becoming amorphous from radiation-induced damage.