ZIRCON - A HOST-PHASE FOR THE DISPOSAL OF WEAPONS PLUTONIUM

Zircon, ZrSiO4, is a well-characterized, naturally occurring phase tha t is extremely durable. Zircon has been synthesized with Pu-concentrat ions up to 10 wt. % and radiation-damage effects studied to saturation doses of nearly 0.8 displacements per atom. We propose that zircon be used as a waste form for the disposal of the more than 100 metric ton s of plutonium that will result from the dismantling of nuclear weapon s. There are already several demonstrated processing technologies, of which hot pressing offers the most potential. This highly durable mate rial, even under hydrothermal conditions, with its high waste loading and smaller volume allows deep, permanent disposal of the weapons plut onium in geologic environments in which the borosilicate waste-form gl ass would not be stable.