Pyrochemical reprocessing of molten salt fast reactor fuel: focus on the reductive extraction step

Open access


The nuclear fuel reprocessing is a prerequisite for nuclear energy to be a clean and sustainable energy. In the case of the molten salt reactor containing a liquid fuel, pyrometallurgical way is an obvious way. The method for treatment of the liquid fuel is divided into two parts. In-situ injection of helium gas into the fuel leads to extract the gaseous fission products and a part of the noble metals. The second part of the reprocessing is performed by ‘batch’. It aims to recover the fissile material and to separate the minor actinides from fission products. The reprocessing involves several chemical steps based on redox and acido-basic properties of the various elements contained in the fuel salt. One challenge is to perform a selective extraction of actinides and lanthanides in spent liquid fuel. Extraction of actinides and lanthanides are successively performed by a reductive extraction in liquid bismuth pool containing metallic lithium as a reductive reagent. The objective of this paper is to give a description of the several steps of the reprocessing retained for the molten salt fast reactor (MSFR) concept and to present the initial results obtained for the reductive extraction experiments realized in static conditions by contacting LiF-ThF4-UF4-NdF3 with a lab-made Bi-Li pool and for which extraction efficiencies of 0.7% for neodymium and 14.0% for uranium were measured. It was concluded that in static conditions, the extraction is governed by a kinetic limitation and not by the thermodynamic equilibrium.

1. OECD. (2004). Pyrochemical separations in nuclear applications. Status report of OECD.

2. Long, J. T. (1978). Engineering for nuclear fuel reprocessing. 2nd ed. (pp. 242-272). American Nuclear Society.

3. Laidler, J. J., Battles, J. E., Miller, W. E., Ackerman, J. P., & Carls, E. L. (1997). Development of pyroprocessing technology. Prog. Nucl. Energy, 31(1/2), 131.

4. Bettis, E. S., & Robertson, R. C. (1970). The design and performance features of a single-fl uid molten salt breeder reactor. Nucl. Appl. Technol., 8, 190-207.

5. Whatley, M. E., McNeese, L. E., Carter, W. L., Ferris, L. M., & Nicholson, E. L. (1970). Engineering development of the MSBR fuel recycle. Nucl. Appl. Tech., 8, 170-178.

6. Delpech, S., Merle-Lucotte, E., Heuer, D., Allibert, M., Ghetta, V., Le-Brun, C., Doligez, X., & Picard, G. S. (2009). Reactor physic and reprocessing scheme for innovative molten salt reactor system. J. Fluor. Chem., 130(1), 11-17.

7. Delpech, S. (2013). Molten salts for nuclear applications. In F. Lantelme, & H. Groult (Eds.), Molten salt chemistry: from lab to applications (pp. 497-520). USA: Elsevier.

8. Briggs, R. B. (1966). Molten salt reactor program semiannual progress report for period ending February 28, 1966. USA: Oak Ridge National Laboratory (Report no. 3936).

9. Delpech, S. (2013). Possible routes for pyrochemical separations: focus on the reductive extraction in fl uoride media. Pure Appl. Chem., 85, 71-87.

10. Ferris, L. M., Mailen, J. C., Lawrance, J. J., Smith, F. J., & Nogueira, E. D. (1970). Equilibrium distribution of actinide and lanthanide elements between molten fluoride salts and liquid bismuth solutions. J. Inorg. Nucl. Chem., 32, 2019-2035.

11. Ferris, L. M., Smith, F. J., Mailen, J. C., & Bell, M. J. (1972). Distribution of lanthanide and actinide elements between molten lithium halide salts and liquid bismuth solutions. J. Inorg. Nucl. Chem., 34, 2921-2933.

12. Moriyama, H., Yajima, K., Nunogane, N., Ohmura, T., Moritani, K., & Oishi, J. (1984). Reductive extraction of lanthanide and actinide elements from molten LiF- -BeF2 salt into liquid bismuth. J. Nucl. Sci. Technol., 21(12), 949-958.

13. Moriyama, H., Yajima, K., Tominaga, Y., Moritani, K., & Oishi, J. (1983). Mechanism of distribution of actinide elements between molten fl uoride salts and liquid bismuth solutions. In Proceedings of the 1st International Symposium on Molten Salt Chemistry and Technolology, 20-22 April 1983 (pp. 419-422). Kyoto, Japan.

14. Moriyama, H., Seshimo, T., Moritani, K., Ito, Y., & Mitsugashira, T. (1994). Reductive extraction behavior of actinide and lanthanide elements in molten salt and liquid metal binary phase systems. J. Alloys Compd., 213/214, 354-359.

15. Lebedev, V. A. (1993). Selectivity of liquid metal electrodes in molten halides. Cheyabinsk: Metallurgiya.

16. Smith, F. J. (1972). The solubilities of thorium and neodymium in liquid lithium-bismuth solutions. J. Less-Com. Met., 27, 195-200.

17. Laplace, A., Vigier, J. F., Plet, T., Renard, C., Abraham, F., Slim, C., Delpech, S., & Picard, G. (2011). Elaboration de solutions solides d’oxydes d’actinides et de lanthanides en milieu sels fondus: application à un nouveau procédé de refabrication du combustible par voie pyrochimique. Patent no. FR 11/58572.

18. Delpech, S., Cabet, C., Slim, C., & Picard, G. S. (2010). Molten fl uorides for nuclear applications. Mat. Today, 13(12), 34-41.

19. Rouquette-Sanchez, S., & Picard, G. S. (2004). Chalcogenide chemistry in molten salts. I. Selenium(IV) acido-basic and redox properties in the LiCl-KCl eutectic melt at 450, 500, 550 and 600°C. J. Electroanal. Chem., 572, 173-183.

20. Jaskierowicz, S. (2012). Extraction des actinides et des lanthanides du combustible du réacteur rapide à sels fondus. Thesis of Univ. Paris Sud.

21. Gibilaro, M., Bolmont, S., Massot, L., Latapie, L., & Chamelot, P. (2014). On the use of liquid metals as cathode in molten fl uorides. J. Electroanal. Chem., 726, 84-90.

22. Moriyama, H., Miyazaki, M., Asaoka, Y., Moritani, K., & Oishi, J. (1991). Kinetics of reductive extraction of actinide and lanthanide elements from molten fl uoride into liquid bismuth. J. Nucl. Mater., 182, 113-117.

23. Lemort, F., Boen, R., Allibert, M., Perrier, D., Fautrelle, Y., & Etay, J. (2005). Kinetics of the actinides-lanthanides separation: mass transfer between molten fluorides and liquid metal at high temperatures. J. Nucl. Mater., 336, 163-172.


The Journal of Instytut Chemii i Techniki Jadrowej

Journal Information

IMPACT FACTOR 2017: 0.720
5-year IMPACT FACTOR: 0.610

CiteScore 2016: 0.55

SCImago Journal Rank (SJR) 2015: 0.205
Source Normalized Impact per Paper (SNIP) 2015: 0.461


All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 58 58 13
PDF Downloads 12 12 3