  December 1991 legislation in France has spurred research on enhanced
separation and conditioning or transmutation of long-lived radionuclides from
high level radioactive wastes (HLW). In this field, we have studied
zirconolite-based glass-ceramics in which the crystalline phase (zirconolite:
CaZrTi2O7) aimed to preferentially incorporate minor actinides is embedded in a
glassy calcium aluminosilicate matrix. At the laboratory scale, the
crystallization of the parent glass is carried out thanks to a two-step thermal
treatment: a nucleation stage followed by a growth stage. This paper presents
the evolution of the crystallization, followed by scanning electron microscopy
(SEM) and X-ray diffraction (XRD), with the temperature of the crystal growth
thermal treatment, in the range 950 degrees - 1350 degrees C.
