Material migration and fuel retention studies during the JET carbon divertor campaigns

Paul Coad (Corresponding Author), Marek Rubel, Jari Likonen, Nicolas Bekris, Sebastijan Brezinsek, Guy Matthews, Matej Mayer, Anna Widdowson, JET Contributors

    Research output: Contribution to journalArticleScientificpeer-review

    25 Citations (Scopus)


    The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994–5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favouring the inner divertor region result from drift in the scrape-off layer. A new monolithic divertor structure was installed in 1996 which produced heavy deposition at shadowed areas in the inner divertor corner, which is where the majority of the tritium was trapped by co-deposition during the deuterium-tritium experiment in 1997. Different divertor geometries have been tested since such as the Gas-Box and High-Delta divertors; a principle objective has been to predict plasma behaviour, transport and tritium retention in ITER. Transport modelling experiments were carried out at the end of four campaigns by puffing 13C-labelled methane, and a range of diagnostics such as quartz-microbalance and rotating collectors have been installed to add time resolution to the post-mortem analyses. The study of material migration after D-D and D-T campaigns clearly revealed important consequences of fuel retention in the presence of carbon walls. They gave a strong impulse to make a fundamental change of wall materials. In 2010 the carbon divertor and wall tiles were removed and replaced with tiles with Be or W surfaces for the ITER-Like Wall Project.

    Original languageEnglish
    Pages (from-to)78-108
    JournalFusion Engineering and Design
    Publication statusPublished - 1 Jan 2019
    MoE publication typeNot Eligible


    • fusion
    • JET
    • divertor
    • carbon
    • plasma-facing components
    • Divertor
    • Plasma-facing components
    • Carbon
    • Fusion


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