Synthesis of nuclear waste monazites, ideal actinide hosts for geologic disposal
Monazite, an orthophosphate mineral of the lanthanides (Ln) and the actinides (An) U and Th, is a model for an ideal synthetic mineral waste form for geologic disposal of long-lived nuclear waste actinides. Natural monazites are known to have survived many of the conditions that might be inflicted on a nuclear waste repository by geological disruptions. High Th and U monazites with compositions typical of nuclear wastes have been synthesized with a routine calcination-pelletization-crystallization procedure. Charge balance for the Th/sup 4 +/ ..-->.. Ln/sup 3 +/ substitution can be provided by either an equimolar Ca/sup 2 +/ ..-->.. Ln/sup 3 +/ or Si/sup 4 +/ ..-->.. P/sup 5 +/ substitution. For U/sup 4 +/ ..-->.. Ln/sup 3 +/, only the Ca/sup 2 +/ ..-->.. Ln/sup 3 +/ substitution resulted in a phase-pure monazite. Unit cell parameter data were obtained for each nuclear waste monazite phase.
- Research Organization:
- The Pennsylvania State Univ., University Park
- OSTI ID:
- 6441395
- Journal Information:
- Mater. Res. Bull.; (United States), Journal Name: Mater. Res. Bull.; (United States) Vol. 13:11; ISSN MRBUA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACTINIDE COMPOUNDS
ACTINIDES
ELEMENTS
GEOLOGIC DEPOSITS
GEOLOGY
MANAGEMENT
METALS
MINERALS
MONAZITES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
RADIOACTIVE WASTE DISPOSAL
RARE EARTH COMPOUNDS
RARE EARTHS
STABILITY
SYNTHESIS
THORIUM COMPOUNDS
THORIUM MINERALS
THORIUM PHOSPHATES
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT