20172020

Research output per year

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Personal profile

Research Statement

Understanding wastes arising from the nuclear fuel cycle is an essential prerequisite for the deployment of new nuclear generation around the world. Wastes, once disposed of, need to remain stable in their final package for thousands of years.The underlying chemical processes that occur in such wastes, however, are often poorly understood. Molecular modelling and modern electronic structure calculations present a set of tools that can investigate the chemistry in these problematic materials. Our research has focused on one waste stream found at the Sellafield site known as Magnox sludge. The First Generation Magnox Storage Pond (FGMSP) represents one of the highest priority targets for risk reduction at the Sellafield Site. A ‘legacy’ storage pond for spent Magnox fuel, it has accumulated a deep layer of sludge over many years, formed primarily from corroding Magnox alloy, but also from wind blown debris and decaying organic matter. The composition of this sludge is complex and uncertain. Additionally, it contains dissolved fission products where fuel cladding has failed and split, or even fragments of spent fuel where cladding has corroded entirely. A consequence of the sludge is the emission of methane and hydrogen gas, complicating its future handling and storage. One possible source of the gases in the sludge is radiolytic decomposition of the primary brucite mineral. While a project currently underway will transfer the sludge from the legacy ponds to an engineered storage facility, permanent disposal will require that potential gas production in situ is quantified. Molecular modelling employing quantum mechanical calculations offers a unique view of the fundamental chemistry at the heart of the matter. Our work uses electronic structure calculations to visualise the effect of excess electrons, and electron holes, arising in the waste material as a consequence of radiation. The ultimate goal is to understand the various possible mechanisms of hydrogen gas production through a radiolytic route, and to assess their feasibility and relevance within the legacy ponds context.

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Research Output

  • 4 Article
  • 1 Conference contribution

AiiDA 1.0, a scalable computational infrastructure for automated reproducible workflows and data provenance

Huber, S. P., Zoupanos, S., Uhrin, M., Talirz, L., Kahle, L., Häuselmann, R., Gresch, D., Müller, T., Yakutovich, A. V., Andersen, C. W., Ramirez, F. F., Adorf, C. S., Gargiulo, F., Kumbhar, S., Passaro, E., Johnston, C., Merkys, A., Cepellotti, A., Mounet, N., Marzari, N. & 2 others, Kozinsky, B. & Pizzi, G., 08 Sep 2020, In : Scientific Data.

Research output: Contribution to journalArticle

Open Access
File
  • 11 Downloads (Pure)

    Characterization and Performance of Cement-based Thermoelectric Materials

    Jani, R., Holmes, N., West, R. P., Gaughan, K., Liu, X., Orisakwe, E., Johnston, C., Qu, M., Kohanoff, J., Stella, L. & Yin, H., Aug 2020, Civil Engineering Research in Ireland (CERI) 2020.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Open Access
    File
  • Ab initio study of the structure, isotope effects, and vibrational properties in KDP crystals

    Menchón, R., Colizzi, G., Johnston, C., Torresi, F., Lasave, J., Koval, S., Kohanoff, J. & Migoni, R., 28 Sep 2018, In : Physical Review B. 98, 10, 17 p., 104108.

    Research output: Contribution to journalArticle

    Open Access
    File
  • 3 Citations (Scopus)
    263 Downloads (Pure)

    On the role of magnesium in a LiF:Mg,Ti thermoluminescent dosimeter

    Massillon-Jl, G., Johnston, C. S. N. & Kohanoff, J., 06 Dec 2018, In : Journal of Physics: Condensed Matter. 31, 2, p. 025502 11 p.

    Research output: Contribution to journalArticle

    Open Access
    File
  • 2 Citations (Scopus)
    70 Downloads (Pure)

    Production of H2 by water radiolysis in cement paste under electron irradiation: A joint experimental and theoretical study

    Le Caër, S., Dezerald, L., Boukari, K., Lainé, M., Taupin, S., Kavanagh, R. M., Johnston, C. S. N., Foy, E., Charpentier, T., Krakowiak, K. J., Pellenq, R. J. M., Ulm, F. J., Tribello, G. A., Kohanoff, J. & Saúl, A., Oct 2017, In : Cement and Concrete Research. 100, p. 110-118 9 p.

    Research output: Contribution to journalArticle

    Open Access
    File
  • 3 Citations (Scopus)
    293 Downloads (Pure)

    Thesis

    Exploration of Hydrogen Gas Evolution from Radioactive Sludges

    Author: Johnston, C., Jul 2019

    Supervisor: Tribello, G. (Supervisor) & Kohanoff, J. (Supervisor)

    Student thesis: Doctoral ThesisDoctor of Philosophy

    File