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Fluorapatite, fluorinated calcium phosphate, has been identified as a potential matrix for the entombment of the zirconium fluoride fission product waste stream from the proposed FLEX process. If the efficacy of fluorapatite-based waste-storage can be demonstrated, then new and potentially more-efficient options for handling and separating high-level wastes, based on fluoride-salt extraction, will become feasible. This proposal will develop a dual-path research project to develop a process to fabricate a synthetic fluorapatite waste form for the ZrF4, FP waste stream, characterize the waste form, examine its performance under environmental conditions, and correlate the behavior of the waste form with natural analogs. Characterization of the material will be accomplished through probing the molecular-scale electronic and geometric structure of the materials in order to relate them to macroscopic properties, with the goal of developing techniques to evaluate and predict the performance of different waste-form materials. Time and funding permitting, other waste forms for the zirconium fluoride, fission product salt waste stream will be examined and benchmarked against the fluorapatite matrix baseline.
Highlights of Accomplishments:
1) Obtained SEM/EDS, FTIR and XRD for Zn-containing samples prepared using 75, 50 and 25% Ca/Zn molar ratios and the sintered sample of Ca/Zn molar ratio 75%. Additionally, XPS data were obtained for these samples together with a fluorapatite and a 100% Zn sample.
2) Prepared 4 different amounts of Zr-containing apatites using precipitation method and sintered these 4 samples at 1200 degrees of centigrade for one hour. SEM, XRD, FTIR and high temperature TGA/DSC data were obtained for these samples. A detailed analysis is in progress.
3) Determined the dependability of the Ca/P and (Ca +Sr)/P ratios in FAP based on the amount of Sr surrogate used in synthesis.
4) Preparation of Cu and Ni containing fluorapatite samples and powder diffraction spectra were obtained for the Cu-FAP sample.
Calcium phosphate; Fluorides; Fluorination; Hydroxyapatite; Phosphate minerals; Radioactive wastes — Storage; Separation (Technology); Strontium; Zinc; Zirconium compounds
Radioactive wastes--Storage; Separation (Technology); Zirconium compounds
Analytical Chemistry | Chemistry | Oil, Gas, and Energy | Physical Chemistry
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Lindle, D. W.,
Evaluation of Fluorapatite as a Waste-Form Material: First Quarter Report, January 1 - March 31, 2005.
Available at: https://digitalscholarship.unlv.edu/hrc_trp_separations/57