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Thermal Treatment of Fuel Residues and Problematic Nuclear Wastes

Barlow, Sean (2019) Thermal Treatment of Fuel Residues and Problematic Nuclear Wastes. PhD thesis, University of Sheffield.

[img] Text (Sean Barlow PhD Thesis)
STB Thesis V3.4.pdf
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Problematic nuclear wastes and fuel residues plague the nuclear industry worldwide. In this Thesis thermal treatment is demonstrated through the development of various simulated nuclear wasteforms and surrogate materials from a variety of nuclear waste topics. Development of vitreous wasteforms for the treatment of intermediate level Magnox sludge from the Storage Ponds at Sellafield is discussed in this Thesis with both low activity uranium and surrogate materials. Magnesium borosilicate glasses were found to have comparable durability with current UK high level waste (HLW) glass whilst incorporating the whole spectrum of waste anticipated into a single composition. Highly metallic feeds could be incorporated into the wasteform with no adverse effects on the dissolution of such samples. If implemented, this composition could result in a 25% volume reduction in waste to be disposed saving approximately £82 million compared to the current baseline plan. Ascertaining the long-term integrity and safety of fuel residues arising from nuclear meltdowns, such as the Chernobyl and Fukushima accidents, through thermal synthesis of low activity simulants is explored in this Thesis. Two simulant Chernobyl ‘lava-like’ fuel containing materials (LFCM) were developed recreating the typical morphology and microstructure found in real samples, including a World first to successfully document formation of Chernobylite from a glass melt whilst aqueous durability was analogous to that of UK borosilicate HLW glass. Investigating how thermal treatment of americium waste built-up in stockpiles of civil plutonium is outlined in this Thesis. A novel cerium niobite, a simulant for americium, was synthesised with the crystal structure and suitability as a wasteform assessed. One potential use for an americium ceramic could be as a power source in a radioisotope thermoelectric generator (RTG); however it was determined an Am structured niobite for this application would be unsuitable, due to the phase transformation this material exhibited at elevated temperatures. This work opens avenues for further research on other potential materials.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Materials Science and Engineering (Sheffield)
Depositing User: Dr Sean Barlow
Date Deposited: 13 Jul 2020 07:54
Last Modified: 13 Jul 2020 07:54
URI: http://etheses.whiterose.ac.uk/id/eprint/26998

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