Investigation of annealed and metamict pyrochlore minerals by x-ray absorption spectroscopy. [Synthetic pyrochlores with general formula (RE)/sub 2/Ti/sub 2/O/sub 7/, RE = Er, Y/sub 2/, Gd/sub 2/, Dy, La]

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5651628

Greegor, R B; Lytle, F W; Ewing, R C; Chakoumakos, B C; Lumpkin, G R

Materials of the pyrochlore structure type exhibit a variety of interesting properties including phases capable of acting as hosts for actinides in radioactive wastes. Studies of curium doped gadolinium titanate phases (Gd/sub 2/Ti/sub 2/O/sub 7/) have been made which showed that the radiation damage ingrowth followed an exponential relationship. For the study reported here a series of synthetic pyrochlores were produced having the titanate phase with the general formula (RE)/sub 2/Ti/sub 2/O/sub 7/, RE = Er, Y/sub 2/, Gd/sub 2/, Dy, La. Additionally a set of metamict (radiation damaged) pyrochlores was examined in both a natural and post temperature annealed state. Experiments were conducted on these samples using the Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES) techniques. In summary, these studies show that in pyrochlore structure types the Ti-O cage undergoes changes due to radiation damage. The individual Ti-O bonds become more disordered which leads to a loss of short and long range order and, ultimately, to expansion of the bulk material. 2 refs., 2 figs.

• Research Organization: Boeing Co., Seattle, WA (USA); New Mexico Univ., Albuquerque (USA)
• DOE Contract Number: FG06-84ER45121
• OSTI ID: 5651628
• Report Number(s): CONF-841157-94; ON: DE85014040
• Country of Publication: United States
• Language: English

Related Subjects

052001 -- Nuclear Fuels-- Waste Processing
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
360605* -- Materials-- Radiation Effects
ABSORPTION SPECTROSCOPY
ACTINIDES
CHEMICAL PREPARATION
CRYSTAL DOPING
CURIUM
ELEMENTS
FOURIER TRANSFORMATION
INTEGRAL TRANSFORMATIONS
METALS
MINERALS
PHYSICAL RADIATION EFFECTS
PYROCHLORE
RADIATION EFFECTS
SPECTROSCOPY
SYNTHESIS
TRANSFORMATIONS
TRANSPLUTONIUM ELEMENTS
TRANSURANIUM ELEMENTS