hide
Free keywords:
-
Abstract:
The high chemical durability of iodine-bearing apatite phases makes them
potentially attractive for immobilizing radioactive iodine. Reactive
spark plasma sintering provides a dense ceramic as a wasteform. A
design-of-experiments (DOE) approach was adopted to identify the main
process/material parameters and their first order interactions in order
to specify experimental conditions guaranteeing complete reaction,
relative density of the wasteform exceeding 92% and the largest possible
grain size. For a disposal of the wasteform in a deep geological
repository, these characteristics allow minimization of the iodine
release by contact with groundwater. It was found that sintering at a
temperature of 450 degrees C with an initial specific surface area of
3.3 m(2) g(-1) for the powder reactants is sufficient in itself to
achieve the targeted characteristics of the wasteform. However, this
relies on a liquid sintering regime the efficiency of which can be
limited by the lead iodide initial content in the mix as well as by its
particle size. (C) 2014 Elsevier B. V. All rights reserved.
