A review of brannerite structured materials for nuclear waste management

Brannerite structured materials (AB2O6) have attracted recent attention as nuclear materials particularly as candidate waste forms for the immobilization of uranium-rich radioactive wastes. As such, the fundamental aspects of brannerite such as synthesis, crystal chemistry, polymorphism, uranium valence states, vibrational modes, chemical durability, and radiation damage have been investigated. Besides full ceramics, brannerite based glass-ceramic composite materials have also been developed as advanced waste forms with unique advantages in terms of incorporating chemical impurities and ease of processing. This review will cover the latest advances of brannerite structured materials focusing on synthesis, structures and spectroscopies, waste form design strategies for both full ceramics and glass-ceramics, and briefly on processing techniques and waste form performance studies. In addition, technical challenges and perspectives are given to determine the knowledge gaps for future research.