HIGH-TEMPERATURE X-RAY DIFFRACTION STUDIES OF AMERICIUM OXIDE SURROGATES

摘要

European Space Agency radioisotope power systems (RPSs) will use ~(241)Am (in oxide form) as the heat source. The chemical form of the americium oxide fuel has yet to be decided. Consequently, the oxygen-to-americium ratio is a variable for investigation. Understanding the effect of different high temperature environments e.g. oxidising and reducing, on the americium oxide crystal structures is highly relevant and important for the development of the RPS fuel forms, as well as for understanding the potential behaviour of the fuel forms under different circumstances e.g. during operation, sintering, or potential extreme temperature environments. High temperature X-ray diffraction experiments are therefore highly relevant. As a step towards such investigations with active fuel, this paper presents a high temperature powder X-ray diffraction study with cerium neodymium oxide solid solutions, namely, Ce_(1-x)Nd_xO_(2-(x/2)). with different x values. A previous investigation has proposed that Ce_(1-x)Nd_xO_(2-(x/2)) with certain x values could be used as surrogates for certain AmO_(2-(x/2)) phases.