THE HIGH-TEMPERATURE VAPORIZATION DECOMPOSITION OF ACTINIDE MATERIALS- FUNDAMENTAL AND TECHNOLOGICAL ASPECTS/

The unique and variable chemistry exhibited across the actinide series offers a scientifically challenging group of elements. Investigations of their high-temperature materials science and thermodynamics can pr ovide important insights into fundamental actinide science and generat e critical information for technological applications. The wide variat ions in the physicochemical properties and the availability of the var ious actinide elements necessitates special experimental techniques be employed, even when investigating a single property (e.g., the enthal py of vaporization). Experimental approaches range can from classical to novel methods to permit studies of the rarer and the more intensely radioactive members. We have developed special equipment and techniqu es to investigate the high-temperature, physicochemical properties of several actinides through Md, as well as the precursor elements, radiu m and actinium. These experimental approaches employed both alloys and solid solutions of compounds, in addition to the pure elements themse lves. The vaporization/decomposition of compounds and the sublimation of the elements, together with the associated thermodynamics, are the main issues. Results for several of the actinide elements, some of the techniques employed and systematic comparisons of the thermochemical aspects of bonding are discussed to give a fuller understanding of the series as a whole. (C) 1997 Elsevier Science B.V.