Electrophysical processes in MI-cables during pulsed irradiation at BARS-6 fission reactor

The magnetic sensors (coils and loops), made of mineral insulated (MI) cables, are intended for ITER. In MI-cables the radiation initiates electric charge separation, emergence of the radiation induced electromotive force (RIEMF) and leakage current between cable strand and sheath. This effect may impact the magnetic measurements and other tokamak diagnostics using MI-cables. In this study a set of MI-cables (with different sizes and strand materials) were irradiated on the pulse reactor BARS-6 with dose rates from 10(3) Gy/s up to 10(5) Gy/s in pulse maximum. The analysis of the obtained data and the transient electric processes under pulse action permits us to propose a model of radiation-induced separation of electric charge in MI-cables between the insulated central cable strand and the grounded metal sheath.