Dust Particles in Controlled Fusion Devices: Generation Mechanism and Analysis

• Generation and in-vessel accumulation of carbon and metal dust are perceived to be serious safety andeconomy issues for a steady-state operation of a fusion reactor, e.g. ITER. This contribution provides acomprehensive account on: (a) properties of carbon and metal dust formed in the TEXTOR tokamak; (b) dustgeneration associated with removal of fuel and co-deposit from carbon PFC from TEXTOR and Tore Supra; (c)surface morphology of wall components after different cleaning treatments. The amount of loose dust found on thefloor of the TEXTOR liner does not exceed 2 grams with particle size range 0.1 m – 1 mm. The presence of fine(up to 1 m) crystalline graphite in the collected matter suggests that brittle destruction of carbon PFC could takeplace during off-normal events. Carbon is the main component, but there are also magnetic and non-magnetic metalagglomerates. The fuel content in dust and co-deposits varies from 10% on the main limiters to 0.03% on theneutralizer plates. Fuel removal by oxidative methods or by annealing in vacuum disintegrates co-deposits and, in thecase of thick layers, makes them brittle thus reducing the adherence to the target. Also photonic cleaning by laserpulses produces debris, especially under ablation conditions. The results obtained strongly indicate that in a carbonwall machine the disintegration of flaking co-deposits on PFC is the main source of dust.

Ämnesord

NATURVETENSKAP  -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)

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ref (ämneskategori)

kon (ämneskategori)