Estimation of the lifetime of resin insulators against baking temperature for JT-60SA in-vessel coils

In the present study, the thermal endurance of epoxy-based, bismaleimides, and cyanate ester resins for the current design of the in-vessel coils was measured by performing acceleration tests to assess their insulation properties using the thermal endurance defined by the International Electrotechnical Commission (IEC-60216 Partl -Part 6) for a minimum of 5,000h in the 180-240 degrees C temperature range. It was found that none of the resin insulators could tolerate the baking conditions of 40,000 h at 200 degrees C in the JT-60SA vacuum vessel. Therefore, the design of the in-vessel coils, including the error field correction coils (EFCC), was changed from the type without water cooling to with water cooling on JT-60SA. (C) 2015 Elsevier B.V. All rights reserved.