SOME PHYSICAL PROPERTIES OF PLUTONIUM

Abstract

Plutonium, the 94th element in the Periodic Table, is the only one of the “man-made” elements that has been produced in large quantities. This interest in plutonium has arisen because it is fissile, i.e. can be used as a source of nuclear energy, and for this reason a considerable amount of work has been done on the properties of the metal and its alloys. But it has been clear since about 1960 that plutonium in a metallic form is not suitable for use as a fuel material in power-producing reactors, and attention has now turned to oxides, carbides, and nitrides, and to plutonium-bearing cermets. Plutonium itself is, however, a most unusual and interesting metal, and has many remarkable features which present to the theoretical and experimental metallurgist alike a challenge and an opportunity to enhance our understanding of the metallic state. With eight electrons of high quantum number outside the inert gas core, many of the peculiarities of plutonium must arise because of the exaggeration of mechanisms which may well occur in metals of lower atomic number but do so less obtrusively. It follows, therefore, that there is much to be gained from a study of plutonium and by comparing and contrasting its behaviour with that of the transition metals or the rare earths. This review surveys the main physical properties of the metal, and outlines some of the theoretical problems set by its behaviour.