A Versatile two-step process for immobilizing excess plutonium.

As a consequence of weapon stockpile reduction and the associated shutdown of weapons production facilities, approximately 50 metric tons of plutonium (both weapons-grade and non-weapons-grade) has been declared excess by the US. Recent experiments demonstrated the feasibility of using high-level waste stored at the Idaho Chemical Processing Plant to immobilize plutonium. The most effective plutonium host phase identified in these experiments was a plutonium zirconate solid solution. Results of recent experiments are reported that show the feasibility of using the highly durable plutonium zirconate host phase as a feed material for high and low temperature encapsulation processes, thereby increasing the potential applications of this material for plutonium dispositioning.