Improving the Integral Fast Reactor's Proposed Salt Waste Management System

An often cited weakness of the Integral Fast Reactor (IFR) concept is that the chloride salt-based radioactive waste generated by its electrorefiner (ER) cannot be vitrified. Although that assertion is literally true, it is also misleading because it would be quite simple to recycle that waste's chloride and vitrify its cationic components (mostly alkali metals and fission products). Producing this alternative to Argonne National Laboratory's ceramic waste form would entail vitrification of a mixture of orthophosphoric acid, ferric oxide, and powdered ER salt with a melter able to efficiently disengage gas bubbles, e.g., a Stir Melter. The HCl evolved by this process would be absorbed by an aqueous lithium/potassium hydroxide scrub solution, which would then be dried and recycled as fresh ER electrolyte. Because radioiodide would otherwise accumulate in the ER salt, the caustic scrub solution would occasionally be contacted with cuprous or silver chloride before recycle. This scenario's primary advantages would be much lower cost and approximately fivefold greater effective waste loading. This paper describes the experimental work supporting these contentions.