Self-castellation of tungsten monoblock under high heat flux loading and impact of material properties

Stephanie Panayotis, Takeshi Hirai, Valdimir Barabash, Alain Durocher, F. Escourbiac, Jochen Linke, Thorsten Loewenhoff, Mario Merola, Gerald Pintsuk, Inge Uytdenhouwen, Marius Wirtz

    Research outputpeer-review


    In the full-tungsten divertor qualification program at ITER Organization, macro-cracks, so called self-castellation were found in a fraction of tungsten monoblocks during cyclic high heat flux loading at 20MW/m2. The number of monoblocks with macro-cracks varied with the tungsten products used as armour material. In order to understand correlation between the macro-crack appearance and W properties, an activity to characterize W monoblock materials was launched at the IO. The outcome highlighted that the higher the recrystallization resistance, the lower the number of cracks detected during high heat flux tests. Thermo-mechanical finite element modelling demonstrated that the maximum surface temperature ranges from 1800 °C to 2200 °C and in this range recrystallization of tungsten occurred. Furthermore, it indicated that loss of strength due to recrystallization is responsible for the development of macro-cracks in the tungsten monoblock.
    Original languageEnglish
    Pages (from-to)1-5
    JournalNuclear Materials and Energy
    StatePublished - 27 Dec 2016

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