Structural characterization by X-ray analytical techniques of calcium aluminate cement modified with sodium polyphosphate containing cesium chloride

The long-time experimental activities on pyroprocessing have generated waste eutectic salts contaminated with nuclear materials. Composition and degree of contamination of waste eutectic salts depended on their history. After reprocessing tests, waste eutectic salts should be appropriately treated, with a focus on Cl disposal considering its corrosive nature. Because characteristic of waste eutectic salts is not homogeneous, it is important to construct Cl confinement for the waste eutectic salts. Chlorapatite (Ca10(PO4)6Cl2) has great potential for Cl confinement due to Ca and P. The chemical reactivity of Cl will be drastically reduced if chlorapatite can be synthesized in calcium aluminate cement modified with sodium polyphosphate (CAP) containing CsCl. This study confirms the chemical state of Cl and metal elements in the cement by X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption fine structure analyses in the CAP containing CsCl. The analyses results suggest the existence of the Ca–Cl–Cs and Al–Cl–Cs bonds in CAP containing CsCl. The formation of the chemical bonds of Cl with metal elements might be one of important factors for the chlorapatite formation from the CAP containing CsCl.