Following several reports in the past few years about compositional changes on palladium used as a cathode in heavy water electrolysis, the purpose of this research project was to reproduce this results. Two experiments were performed using two cells connected in series, an experimental cell and a control cell. Both experiments used platinum anodes, the experimental cell had a palladium cathode and the control cell had a platinum cathode. The electrolyte was D20 with H2S04. Radiation was monitored during both experiments. Also temperature and voltage were recorded for both experiments, to allow statements about excess heat of the experimental cell in comparison to the control cell. Both experiments had problems with unequal electrolyte loss, so that no statements about excess heat could be made. No significant radiation was detected in either experiment. Also no compositional changes on the palladium cathodes after electrolysis in both experiments could be detected. Impurities in grain-shaped defects on the palladium cathode before the experiment were found in either experiment. These impurities were Si, Ca, 0, and sometimes also Mg, Na and Fe. Localized findings of Au and Pt, in a distance of 1-2μm to each other, were made on the palladium cathode from the second experiment before electrolysis. Spot, grain-shaped and longitudinal defects were found on the original palladium foil used for the cathodes in either experiment No evidence for fusion, or any other nuclear reaction in the crystal lattice of palladium, used as cathode in heavy water electrolysis, was observed.