Durability of Zirconium‐Containing Ceramic Waste Forms in Water

Abstract

The durability of three ceramic waste forms containing Zr as a constituent is examined at 90° and 150°C in HCl or deionized water. The three ceramic waste forms examined are: (A) 10‐mol%‐Y 2 O 3 ‐stabilized ZrO 2 , (B) La 2 Zr 2 O 7 with a pyrochlore structure, and (C) CaZrO 3 with a perovskite structure. Each form contains an appropriate amount of Ce, Nd, and Sr to simulate the leaching behavior of actinides, lanthanides, and alkaline‐earth fission products from highlevel nuclear waste. Two forms, (A) 10‐mol%‐Y 2 O 3 ‐stabilized ZrO 2 and (B) La 2 Zr 2 O 7 with a pyrochlore structure, show excellent durability in HCl and deionized water. For example, leach rates of all constituents in the La 2 Zr 2 O 7 waste form are less than about 10 −4 g·m −2 ·d −1 at 150°C for a leach time of 32 d in deionized water.