Investigations of mineral insulated cables exposed to high temperature and intense gamma radiation

The behaviour of Al2O3 and MgO insulated cables with four different cable diameters from 1 mm to 3 mm was investigated in the temperature range from 20°C to 800°C and under gamma dose rate exposures between 0 R/h up to 1×106R/h. Differences in the insulation resistance were found below 400°C due to the dominant gamma induced photocurrent. Between 400°C and 800°C both cable types show a very similar resistance behaviour which is influenced only by temperature.