Electrochemical reduction behavior of a highly porous SIMFUEL particle in a LiCl molten salt

Choi, Eun-Young; Lee, Jae Won; Park, Jang Jin; Hur, Jin‐Mok; Kim, Jong-Kook; Jung, Kyeong Youl; Jeong, Sang Mun

doi:10.1016/j.cej.2012.06.161

Cited by 54 publications

(31 citation statements)

References 28 publications

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“…24,25 The results obtained in this study with CaCl 2 -48 mol% NaCl melt showed that the surface metal layer could remain porous at the cell temperature of 973 K. Similar results have been reported on electro-reduction of UO 2 in LiCl-(0-3 wt%) Li 2 O melt by different groups. [21][22][23][24]28,29,33 However, as reported in our earlier publication, 36 we have noticed cracks developed perpendicular to the thickness of the UO 2 pellets electrolysed in CaCl 2 -48 mol% NaCl melt, which in turn could have helped the reduction process by providing a better access of the electrolyte melt to the interior parts of the pellets. The reason for this physical phenomenon is not clear.…”

Section: Effect Of Porosity Of Uo 2 Pellets-mentioning

confidence: 78%

Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt

Vishnu

Sanil

Panneerselvam

et al. 2013

J. Electrochem. Soc.

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The electrochemical conversion of solid oxide preforms to metal by molten salt electrolysis is influenced by many parameters like duration of electrolysis, temperature, applied voltage, open porosity of the preform and mode of electrolysis. The effect of these parameters on the electro-reduction of UO 2 pellets in CaCl 2 -48 mol% NaCl melt was studied in the temperature range 923-1173 K with graphite rod as the counter electrode. U metal formation started at the surface of the dense UO 2 pellets (95% TD) and it extended towards the bulk with time. Enhanced electrochemical activity was observed during the initial phase of electrolysis with porous UO 2 pellets (52% TD). The rate of deoxidation increased with increase in the electrolysis temperature from 923 K to 1023 K, but decreased on further increase to 1173 K, due to sintering of U particles on the surface of the pellet. The thickness of U metal layer increased with increase in the applied voltage from 3.1 to 3.3 V whereas no reduction of the oxide occurred at 2.8 V. The behavior of the graphite anode, in relation to the electro-reduction of the UO 2 pellets under different experimental conditions, was studied by determining the mass loss of the electrode and discussed.Direct electrochemical reduction of solid metal oxides to metals is a novel method of metal production, named as FFC (Fray-FarthingChen) Cambridge process, reported recently by Chen et al and this created a flurry of research and developmental studies in the field of electro-pyrometallurgy. 1-3 Presently the Direct Oxide Electrochemical Reduction (DOER) method is being studied with different oxides right from TiO 2 available on earth 1 to that of the monolith samples from lunar surface. 4 Many groups all over the world have reduced different individual metal oxides as well as their mixtures. 1,[5][6][7][8][9][10][11][12][13][14][15] The electro-deoxidation process is known to be influenced by various experimental parameters such as the duration of electrolysis, temperature, applied voltage, open porosity of the solid preforms, mode of electrolysis etc. and the oxides with different chemical and electrical properties were found to follow different electro-reduction mechanisms. 2,6,16,17 Yan and Fray discussed the effect of some of the parameters such as the particle size of the precursor, porosity of the pellets etc. on the electrochemical reduction of Nb 2 O 5 in molten CaCl 2 -NaCl eutectic. 18 Mohandas and Fray discussed the various issues influencing the electro-reduction of ZrO 2 and TiO 2 in molten CaCl 2 . 9 Peng et al. 19 reported the electrolytic synthesis of consolidated Zr and Zr-2.5 Nb tubes, wherein it was claimed that the reduction improved with increase in the magnitude of cell voltage, temperature and duration of electrolysis. However, this lowered the current efficiency and increased the energy consumption of the reduction process. Bixia et al 20 observed that the TiO 2 pellets sintered in the temperature range of 1273-1373 K for a duration of 4 h were found to undergo better redu...

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Section: Effect Of Porosity Of Uo 2 Pellets-mentioning

confidence: 78%

Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt

Vishnu

Sanil

Panneerselvam

et al. 2013

J. Electrochem. Soc.

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“…Furthermore, the alteration to the Li|Li + open circuit potential that occurs with varying concentrations of Li in the melt is not Nernstian; it behaves as if the activity of the reduced form, Li is not unity and changes based on concentration 13 . These facts suggest that molten solutions of LiCl and Li contain additional Li complexes other than LiCl and Li; a hypothesis that has been debated without confirmation for decades 15 20 21 46 48 50 51 52 . It was noted that Li clusters possess significantly different ionization potentials than metallic Li 36 37 ; therefore they are expected to exhibit thermodynamic activity that is different from the metallic phase.…”

Section: Discussionmentioning

confidence: 99%

Presence of Li Clusters in Molten LiCl-Li

Merwin

Phillips

Williamson

et al. 2016

Sci Rep

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Molten mixtures of lithium chloride and metallic lithium are of significant interest in various metal oxide reduction processes. These solutions have been reported to exhibit seemingly anomalous physical characteristics that lack a comprehensive explanation. In the current work, the physical chemistry of molten solutions of lithium chloride and metallic lithium, with and without lithium oxide, was investigated using in situ Raman spectroscopy. The Raman spectra obtained from these solutions were in agreement with the previously reported spectrum of the lithium cluster, Li8. This observation is indicative of a nanofluid type colloidal suspension of Li8 in a molten salt matrix. It is suggested that the formation and suspension of lithium clusters in lithium chloride is the cause of various phenomena exhibited by these solutions that were previously unexplainable.

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“…The use of the STS wire mesh allows the molten salts to pass through with ease in addition to helping in decreasing the amount of residual salt in the fuel, a consequence of having sufficient number of openings in the mesh (Choi et al, 2012a(Choi et al, , 2013(Choi et al, , 2014Herrmann et al, 2006;Herrmann and Li, 2010). In previous works involving the study of the pyroprocessing series, the metallic product produced during the electrolytic reduction process was unloaded from the STS wire mesh basket cathode and subsequently reloaded into a new basket, which was used as the anode during an electrorefining process (Herrmann and Li, 2010;Sakamura and Omori, 2010;Sakamura and Akagi, 2012).…”

Section: Introductionmentioning

confidence: 99%

Use of a single fuel containment material during pyroprocessing tests

Choi

Won

Lee

et al. 2015

Annals of Nuclear Energy

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Electrochemical reduction behavior of a highly porous SIMFUEL particle in a LiCl molten salt

Cited by 54 publications

References 28 publications

Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt

Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt

Presence of Li Clusters in Molten LiCl-Li

Use of a single fuel containment material during pyroprocessing tests

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Electrochemical reduction behavior of a highly porous SIMFUEL particle in a LiCl molten salt

Cited by 54 publications

References 28 publications

Factors Influencing the Direct Electrochemical Reduction of UO2Pellets to Uranium Metal in CaCl2-48 mol% NaCl Melt

Factors Influencing the Direct Electrochemical Reduction of UO2Pellets to Uranium Metal in CaCl2-48 mol% NaCl Melt

Presence of Li Clusters in Molten LiCl-Li

Use of a single fuel containment material during pyroprocessing tests

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Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt

Factors Influencing the Direct Electrochemical Reduction of UO₂Pellets to Uranium Metal in CaCl₂-48 mol% NaCl Melt