The dominant paradigm during this period favored ceramic immobilization of high-level radioactive waste using SYNROC-based mineral matrices, signaling a move away from glass-centric approaches. Research emphasized embedding waste into titanate- and zirconolite-rich phases to maximize chemical durability and long-term leach resistance in geologic disposal contexts. Methodological emphasis integrated solid-state chemistry, mineral engineering, and geochemical repository compatibility to unify waste form performance expectations.