Nuclear nanocapsules and curved carbon structures Original Research Article

Recently we developed a reactor chamber for the secure handling of radioactive materials. Using the arc discharge method for fullerene synthesis we could test the carbon encapsulation capability of uranium. The samples obtained, characterized by bulk and direct observation methods, show that uranium encapsulates as a dicarbide with two types of carbon covers: graphene sheets parallel to the external surface and randomly oriented carbon crystallites. X-ray powder diffraction and high resolution transmission electron microscopy indicate that covers with parallel sheets of graphite are present with two different interlayer spacings. One corresponds to polyhedral particles with an interior gap between kernel and capsule. The other consists of rounded-vertex particles with no gap and with interlayer spacing between that of graphite and that corresponding to polyhedral nanocapsules. Extensive studies are described for the resolution of carbon structures and a transformation mechanism is proposed for the interpretation of rounded-vertex onion-like structures. Closed carbon covers chemically protect the actinide kernel and can provide safer handling and processing of toxic materials for medical and nuclear purposes.