THE URANIUM-THORIUM SYSTEM AND SOME ASPECTS OF URANIUM-THORIUM-ZIRCONIUM SYSTEM

The uranium-thorium system has been investigated over the whole composition range. A simple eutectic system is formed, with a region of liquid immiscibility extending from 6 to 49 at.% thorium. The solubility of thorium in uranium is 0.30 at.% at 900 C and <0.05 at.% at 700 C Solubility of uranium in thorium is also temperature-dependent, with limits of 0.15, 1.9, and 2.55 at.% at 800 , 1100 , and 1325 C, respectively. The effects of zirconium additions on the eutectic composition and temperature and on the occurrence of liquid immiscibility have also been studied.