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Calcium Phosphate: A Potential Host for Halide Contaminated Plutonium Wastes

  • Brian L. Metcalfe (a1), Ian W. Donald (a2), Shirley K. Fong (a3), Lee A. Gerrard (a4), Denis M. Strachan (a5) and Randall D Scheele (a6)...

Abstract

The presence of significant quantities of fluoride and chloride in four types of legacy wastes from plutonium pyrochemical reprocessing required the development of a new wasteform which could adequately immobilize the halides in addition to the Pu and Am. Using a simulant chloride-based waste (Type I waste) and Sm as the surrogate for the Pu3+ and Am3+ present in the waste, AWE developed a process which utilised Ca3(PO4)2 as the host material. The waste was successfully incorporated into two crystalline phases, chlorapatite, [Ca5(PO4)3Cl], and spodiosite, [Ca2(PO4)Cl]. Radioactive studies performed at PNNL with 239Pu and 241Am confirmed the process. A slightly modified version of the process in which CaHPO4 was used as the host was successful in immobilizing a more complex multi-cation oxide–based waste (Type II) which contained significant concentrations of Cl and F in addition to 239Pu and 241Am. This waste resulted in the formation of cation-doped whitlockite, Ca3-xMgx(PO4)2, β-calcium phosphate, β-Ca2P2O7 and chlor-fluorapatite rather than the chlorapatite and spodiosite formed with Type I waste.

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1. Kanazawa, T., editor, Inorganic Phosphate Materials, Materials Science Monograph 52, Kodancha (Tokyo), and Elsevier (Amsterdam), 1989, pp. 5577.
2. Narasaraju, T. S. B., Rai, U. S. and Rao, K. K., Indian Journal of Chemistry, 16A, 952, (1978).
3. Metcalfe, B. L., Donald, I. W., Scheele, R. D. and Strachan, D. M. in Scientific Basis For Nuclear Waste Management XXVI, edited by. Finch, R. J. and Bullen, D. B.. (Mat. Res. Soc. Symp. Proc., 757, Warrendale PA 2003) pp. 265271.
4. Deschanels, X., Lopez, C., Denauwer, C. and Bart, J. M., in Plutonium Futures- The Science, edited by Jorvinen, G. D., Amer. Inst. Physics, 59, (2003).
5. Shannon, R. D., Acta Crystallographica Section A 32:751, (1976).
6. Metcalfe, B. L., Fong, S. K. and Donald, I. W., in Scientific Basis For Nuclear Waste Management XXIX, edited by Van Iseghem, P., (Mat. Res. Soc. Symp. Proc. 932, Warrendale PA, 2006) pp. 727734.
7. Larson, A.C. and Von Dreele, R.B., Los Alamos National Laboratory Report LAUR, 2000, 86748.
8. Toby, B.H., J. Appl. Cryst., 34, 210, 2001.

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