About this role
Reactive metal wastes produced across various nuclear fuel cycle operations, such as fuel cladding, coolants, structural components, and incineration residues, present severe conditioning challenges for long-term disposal. Encapsulating these reactive metals in conventional Portland cements triggers rapid metallic corrosion due to the highly alkaline pore environment ( ). This corrosion drives hydrogen gas evolution and expansive mineral formation, compromising the structural integrity of the waste form and risking repository safety. Magnesium potassium phosphate cements (MKPCs) offer a viable alternative due to their near-neutral pore solution ( ), rapid strength development, low water demand, and inherent chemical passivation capabilities through insoluble phosphate formation. This research investigates the immobilization and interfacial stability of simulated reactive metal wastes ( or ) within an optimized MKPC binder. The study focuses on formulating high-loading waste forms that comply with nuclear waste acceptance criteria regarding fresh-state workability, setting kinetics, and early/late-age mechanical strengths. Metal-matrix compatibility will be systematically evaluated by monitoring volumetric expansion and gas evolution, alongside high-resolution microstructural and phase analysis (SEM-EDS, XRD) to understand the reaction mechanisms at the metal-binder interfacial transition zone.