Thermal analyses of the W7-X plasma vessel for operation phase 2

The W7-X plasma vessel (PV) is part of the cryostat wall and forms a vacuum thermal barrier between hot interior superconducting coils. thermally loaded from inside actively cooled by numerous cooling water pipes in order to control its temperature. However, due complex geometry large number different types ports, are distributed irregularly with varying distances them. So temperature distribution PV becomes quite inhomogeneous even homogeneous load density, impermissible spots >130 °C may arise. Particularly for upcoming long pulse operation phase 2 (OP2), it necessary know locally allowed loads on PV. Therefore, maps heat 1 kW/m2 12 were calculated determine corresponding spots. available CAD was not convenient this extensive analysis; therefore, simplified shell-beam model employed get an approximate distribution, correction formula derived calculate more accurate values at positions interest. In some areas pipes, additional copper stripes welded onto improve transfer. For these regions local models built distributions, and, course analysis, judge effect stripes. calculation results indicate be additionally protected will used safe limits.