Induced voltages and currents in copper and stainless steel core mineral insulated cables due to radiation and thermal gradients

Ludo Vermeeren, Marcel Wéber, Jean Dekeyser

    Research outputpeer-review


    To reconstruct the shape and position of the plasma boundary of ITER, in-vessel magnetic coils will be employed, which will be exposed to radiation and temperature gradients. A study was undertaken to assess their impact on magnetic coil measurements and on other tokamak diagnostics employing mineral-insulated (MI) cables. Thermally induced electromotive force voltages in MI cables with Cu and stainless steel (SS) cores were measured using a scanning oven, establishing a well-defined temperature profile. Next, the MI cables were irradiated in the BR2 reactor, with the cables guided through a double-wall tube to create significant temperature gradients during the irradiation. The core-to-sheath currents were measured and interpreted. No correlation was observed between the core-to-core-voltages and the core-to-sheath current asymmetry. Significant core-to-core voltages were observed, which could be interpreted as due to the Seebeck effect with increasing Seebeck coefficients during the irradiation. The coefficient of the Cu core cable increased proportionally to the neutron fluence, which could be attributed to transmutation of Cu to Ni. For the SS core cable the coefficient was found to saturate at a local fluence of about 10E19 n/cm² and depended on the local temperature during irradiation.
    Original languageEnglish
    Pages (from-to)1185-1191
    Journalfusion engineering and design
    Issue number5-14
    StatePublished - Oct 2007
    Event2006 - SOFT: 4th symposium on fusion technology - Warsaw University of Technology, Warsaw
    Duration: 11 Sep 200615 Sep 2006

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