Ceramic materials for the immobilisation of high level radioactive waste

Walsh Atkins, Philip H. (2016). Ceramic materials for the immobilisation of high level radioactive waste. University of Birmingham. M.Sc.

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Abstract

The aim of this project was to investigate, both experimentally and theoretically, the perovskite mineral calcium titanate CaTiO\(_3\) and to gain a greater insight into its properties. Primarily, the properties studied were the defect chemistry of the material and the effect of doping on the structure, with particular attention being given to strontium and yttrium incorporation. This focus was chosen due to the potential applications of calcium titanate in radioactive waste immobilisation, primarily as one of the constituent phases in SYNROC.\(^1\) Experimentally, the effect on the structure of significant levels of strontium impurity was studied, with attention being given to phase changes and possible implications for the maximum level of doping in the structure. To compliment this, a theoretical investigation was undertaken into how defects within the CaTiO\(_3\) structure manifest themselves, how charge imbalances may be accounted for and the implications this has for radioactive waste immobilisation. Initially, substitutional defects were examined, followed by defect clustering and how multiple defects may interact with each other in the system. Strontium doping is of major concern in the CaTiO\(_3\) structure due to the use of the mineral in radioactive waste immobilisation, and consequently the effect of yttrium and zirconium doping is also of relative importance due to their formation in the \(^9\)\(^0\)Sr decay chain.

\(^1\) A. Ringwood, S. Kesson, N. Ware, W. Hibberson and A. Major, Nature, 1979, 278, 219-223.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

Supervisor(s):