Pyrochemical reprocessing

Recent process development efforts have been devoted to more expeditious and less costly pyrochemical reprocessing of residues created by the metal preparation and purification process. We intend to establish an internal recycle which yields either reusable or discardable residues and recovers all plutonium for feed to the electrorefining purification system. This internal recycle is to be performed in a more timely and less costly operation than in the present reprocessing mode. 

Brand, G. E. Murbach, E. W., "Experiments on Pyrochemical Reprocessing of Uranium Carbide Fuel" in "Symposium on Reprocessing of Nuclear Fuels, The Metallurgical Society of AIME, Ames, Iowa, August, 1969", Nucl. Metallurgy, Vol. 15, 1969. 

Miles, K. M., Argonne National Laboratory, "The Pyrocivex Processes are Proliferation Resistant Pyrochemical Reprocessing Methods such as the Zinc Distillation or Modified Salt Transport Process," Private Communication, 1979. 

To the melts containing a trivalent cation belong a great number of systems of alkali metal halide-rare earth metal halide systems. Lanthanide halides play an important role in the production of lanthanide metals by molten salt electrolysis and they are also used in a number of applications ranging from lighting to catalysis, through pyrochemical reprocessing of nuclear fuel. 

This study demonstrated that liquid-liquid oxidative back-extraction is a very simple and fast process, based on a thermodynamic equilibrium and perfectly adapted to the pyrochemical reprocessing developed by the CEA Marcoule. With this study, the core of the process is now well defined and its feasibility is successfully demonstrated. In the near future, the main tasks will consist in demonstrating the feasibility of important head-end steps, that is actinide conversion, salt distillation, thermal treatment, in order to validate the complete process. 

Grandjean, A. (2005) Feasibility of immobihzing fluorinated pyrochemical reprocessing salts in a glass-ceramic matrix. Mater. Res. Soc. Symp. Proc, 84818, Symposium FF, Paper FF9-32. 

Pulsed Neutron Diffraction Study of Molten CsCl-NaCl-YCl3 Approaches from Fundamentals to Pyrochemical Reprocessing... 

Iwadate, Y, Matsuura, H., Kajinami, A. et al. (2009) Local stmeture analyses of molten lanthanum trichloride-alkali chloride ternary systems approaches from fundamentals to pyrochemical reprocessing. Electrochemistry, 77(8), 736-740. 

Pyrochemical reprocessing using molten salts has the potential to recover actinides from spent nuclear fuels [1,2], Since some fission products of rare earth elements have large neutron capture cross-sections, separating them from actinides is desirable. In order to control the separation performance, monitoring the concentration of each element is important. Absorption spectrophotometric analysis is superior to determine the solute concentration and hence its application is examined. 

Volkovich, VA., Griffiths, T.R., and Thied, R.C. (2003) Treatment of molten salt wastes by phosphate precipitation removal of fission product elements after pyrochemical reprocessing of spent nuclear fuels in chloride melts. J. Nucl. Mater, 323(1), 49-56. 

Volkovich, V.A., Vasin, B.D., Griffiths, T.R. et al. (2007) Behaviour of rare earth elements in molten salts in relation to pyrochemical reprocessing of spent nuclear fuels. ECS Trans, 3(35), 493-502. 

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