Spatial variability in the coefficient of thermal expansion induces pre-service stresses in computer models of virgin Gilsocarbon bricks

Jose Arregui Mena, Lee Margetts, D V Griffiths, Louise Lever, Graham Hall, Paul Mummery

    Research output: Contribution to journalArticlepeer-review

    Abstract

    In this paper, the authors test the hypothesis that tiny spatial variations in material properties may lead to significant pre-service stresses in virgin graphite bricks. To do this, they have customized ParaFEM, an open source parallel finite element package, adding support for stochastic thermo-mechanical analysis using the Monte Carlo Simulation method. For an Advanced Gas-cooled Reactor brick, three heating cases have been examined: a uniform temperature change; a uniform temperature gradient applied through the thickness of the brick and a simulated temperature profile from an operating reactor. Results are compared for mean and stochastic properties. These show that, for the proof-of-concept analyses carried out, the pre-service von Mises stress is around twenty times higher when spatial variability of material properties is introduced. The paper demonstrates that thermal gradients coupled with material incompatibilities may be important in the generation of stress in nuclear graphite reactor bricks. Tiny spatial variations in coefficient of thermal expansion (CTE) and Young’s modulus can lead to the presence of thermal stresses in bricks that are free to expand
    Original languageEnglish
    Pages (from-to)793-804
    Number of pages12
    JournalJournal of Nuclear Materials
    Volume465
    DOIs
    Publication statusPublished - 19 Jun 2015

    Keywords

    • Gilsocarbon
    • Thermo-mechanical
    • Monte Carlo Simulation
    • Graphite
    • Nuclear
    • Reactor

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    • STFC Hartree Centre

      Lee Margetts (Visiting researcher)

      27 Jun 20161 Jul 2016

      Activity: External visiting positions or secondmentsVisiting an external academic institutionResearch

    • 2nd PACMAN Workshop

      Lee Margetts (Invited speaker)

      13 Jun 201615 Jun 2016

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