Abstract: A fuel element for a high temperature gas cooled nuclear reactor which aims at reducing the temperature difference between the fuel center and the coolant has a reduced thickness of heat transfer path and means for eliminating discontinuities therein. The fuel element has flat plates each having a inner fuel bearing sheet of coated nuclear fuel particles dispersed in a carbonaceous matrix material clad by preformed relatively thin artefacts of unfuelled carbonaceous material which have been platen pressed on to the external surfaces of the fuel sheet while both the fuel sheet and the artefacts are in the green state.