A Density-Functional Theory Structural Database for Discovery of Novel Actinide Waste Forms

While high-level nuclear waste is effectively incorporated into borosilicate glasses for disposal, issues remain for handling transuranic (TRU) elements. Computational methods can be used to increase the efficiency for novel waste form discovery that can sequester specific species within different waste streams. Density-functional theory databases, such as the Materials Project and the Open Quantum Materials Database, have aided in the discovery of new materials with targeted properties. This paper discusses a structural database to aid in the discovery of hierarchal waste form materials. Formation enthalpies for over 500 oxide-framework crystal structures containing TRU elements were calculated and ranked. The results suggest that phosphate frameworks are highly promising for forming stable TRU-containing waste forms. This information led to the synthesis of a novel uranium phosphate crystal that had a crystal structure similar to that proposed by the database, encouraging its use for other TRU materials.