Effect of Stainless Steel Can/Glass-Ceramic Interaction Layer on Aqueous Durability

Calcined high-level radioactive waste (HLW) stored at the Idaho National Laboratory (INL) will eventually be immobilised in a suitable wasteform before disposal. A tailored glass-ceramic wasteform, produced by hot isostatic pressing (HIPing) in stainless steel (SS) cans, has been developed at the Australian Nuclear Science and Technology Organisation (ANSTO) as a cost-saving alternative to glass which would improve waste loading and density, and reduce waste volume. We have studied the SS/wasteform interactions under HIPing conditions to understand whether such interactions would have any detrimental effect on long-term wasteform stability. This has been demonstrated by carrying out aqueous durability tests, under near-neutral and alkaline conditions, on the wasteform at the interaction layer, and on the wasteform distal to this reaction edge. Reaction during HIPing resulted in verifiable Cr diffusion from the can wall into the wasteform, yet without any detectable detrimental impact on the HIP can or the aqueous durability of the wasteform. (authors)