Erosion of installations in ports of a fusion reactor by hot fuel atoms

Abstract

Charge-exchange interactions between plasma ions and neutrals, recycling from the first wall of a fusion reactor, generate c-x atoms of high energy. These may get into openings of diagnostic ports in the wall, leading to enhanced erosion of installations there, e.g., first mirrors. The energetic spectra of c-x atoms are modeled with the plasma density, electron and ion temperatures varying across the flux surfaces and by taking into account the inhomogeneity of the neutral density along the surfaces due to the absence of recycling at the opening position. The rate of erosion caused by physical sputtering with hot atoms on installations inside the port is computed for the plasma conditions expected in the DEMO fusion reactor, for several fusion relevant materials (beryllium, iron, molybdenum and tungsten), versus the port opening radius and clearance to the installation surface. Keywords: Plasma, Impurity, Numerical methods