Increased Molybdenum Loading for Vitrified High Level Waste

Abstract

The solubility of molybdenum in borosilicate glasses is low. The UK National Nuclear Laboratory has developed a new glass formulation containing calcium and zinc for the vitrification of high molybdenum containing waste arising from the Post Operational Clean Out of the Highly Active Storage Tanks at Sellafield that will decrease the number of product containers required, reducing both production and disposal costs. The new formulation increases the quantity of molybdenum that can be vitrified through the formation of a durable CaMoO 4 phase once the solubility limit of molybdenum in the glass has been exceeded. Extensive laboratory trials confirmed the potential to increase the Mo loading significantly. Recently full scale testing has been performed on the Vitrification Test Rig using highly active liquor simulants to determine the maximum MoO 3 loading that can be achieved. This paper explores the full scale testing and product quality of the glass manufactured during this study.