Fusion-born Alpha Particle Ripple Loss Studies in ITER
Authors: G.J. Kramer, R.B. White, R. Nazikian, H.L. Berk
Abstract:
The impact of locally enhanced toroidal magnetic field ripple due to three test blanket modules
(TBMs) on fusion-born alpha particles is studied for two standard ITER scenarios. Only the (peaked) alpha particle birth profiles were taken into account without redistribution due to MHD activity. It was found that the inclusion of TBMs enhance the losses by up to 35% compared to the losses found for a toroidal field ripple of 0.2% optimized with ferritic inserts. Without TBMs the losses are spread uniformly over the first wall giving alpha particle heat loads of 10 kW/m2. When the TBMs are included localized losses occur in front of the TBMs with heat loads of up to 60 kW/m2 which is well below the 500 kW/m2 design value for the ITER first wall. We therefore conclude that ripple fields induced by the TBMs do not have a significant negative impact on the fusion-born alpha particle confinement or on the heat loads of the first wall. The alpha particle fluency at the hot spots might restrict the life time of the wall because of blister formation.
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Submitted to: Nuclear Fusion ((January 2009)
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