[en] The author of this thesis investigated the diffusional behaviour of cesium in silicon carbide layers to get information on their ability of trapping this important fission product. In order to simulate the conditions prevailing in a reactor the cesium 133 has been implanted in different types of plane silicon carbide layers in a concentration of 10¹⁸ to 10¹⁹ atoms per cm³ -which is characteristic for the fuel burnup. Diffusion coefficients were derived from the alteration of the cesium concentration profile transverse to the coated surface when treating the samples at temperatures of 1400⁰C and 1700⁰C respectively. The concentration profiles were determined by mass spectroscopy of secondary ions. (C.R.)