Separation and Recovery of Uranium Metal from Spent Light Water Reactor Fuel Via Electrolytic Reduction and Electrorefining

Herrmann, Stephen D.; Li, Shelly

doi:10.13182/nt171-247

Cited by 113 publications

(62 citation statements)

References 8 publications

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“…After the salt drain, the cathode basket was removed from the OR apparatus and cooled at ambient temperature in the Ar glove box. The extent of reduction of the reduced simfuel was chemically determined by separating the metal and oxide phases in the reduced fuel sample, as described in the literature [19]. The salt samples obtained were subjected to elemental analysis using inductively coupled plasma-atomic emission spectroscopy (ICP-AES, JP Ultima-2C, Jovin Yvon).…”

Section: Methodsmentioning

confidence: 99%

“…Simultaneously, the oxygen ions (O 2− ) are oxidized to yield oxygen (O 2 ) gas on the platinum (Pt) anode (2O 2− → O 2 + 4e − ). The overall reaction involves the decomposition of MO 2 to M and O 2 (MO 2 = M + O 2 (g)) [9][10][11][12][13][14][15][16][17][18][19]. Next, during the ER process, the actinides in the reduction product obtained after OR are anodically dissolved into molten LiCl-KCl salt at 500 ∘ C (M → M 3+ + 3e − ).…”

Section: Introductionmentioning

confidence: 99%

“…Typically, a stainless steel (STS) wire mesh is used as the permeable basket containing the fuel in both OR and ER processes. The reduction product obtained after the OR process is then used as an anode in the ER process by loading it in a new STS wire mesh basket [19,25]. Thus, the separation of the reduction product from the OR cathode basket is required.…”

Section: Introductionmentioning

confidence: 99%

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Separation of Electrolytic Reduction Product from Stainless Steel Wire Mesh Cathode Basket via Salt Draining and Reuse of the Cathode Basket

Choi

Lee

Heo

et al. 2017

Science and Technology of Nuclear Installations

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We demonstrated that the metallic product obtained after electrolytic reduction (also called oxide reduction (OR)) can be simply separated from a stainless steel wire mesh cathode basket only by using a salt drain. First, the OR run of a simulated oxide fuel (0.6 kg/batch) was conducted in a molten Li 2 O-LiCl salt electrolyte at 650 ∘ C. The simulated oxide fuel of the porous cylindrical pellets was used as a cathode by loading a stainless steel wire mesh cathode basket. Platinum was employed as an anode. After the electrolysis, the residual salt of the cathode basket containing the reduction product was drained by placing it at gas phase above the molten salt using a holder. Then, at a room temperature, the complete separation of the reduction product from the cathode basket was achieved by inverting it without damaging or deforming the basket. Finally, the emptied cathode basket obtained after the separation was reused for the second OR run by loading a fresh simulated oxide fuel. We also succeeded in the separation of the metallic product from the reused cathode basket for the second OR run.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Separation of Electrolytic Reduction Product from Stainless Steel Wire Mesh Cathode Basket via Salt Draining and Reuse of the Cathode Basket

Choi

Lee

Heo

et al. 2017

Science and Technology of Nuclear Installations

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“…47,69 The reported rates of Li 2 O consumption during the reduction process vary widely between references; an inconsistency that is attributed to the previously mentioned difficulties in quantifying the concentration of Li and Li 2 O in the salt, the quantity of Li that is lost to side reactions, and the quantity of Li and Li 2 O that remain in the cathode basket. 6,42,72,84,127 The final aspect of the role of lithium in the electrolytic reduction of actinide oxides to be discussed is the underpotential deposition (UPD) of Li + . UPD is the formation of single monolayers of atoms on a foreign substrate at a potential more noble than is required to reduce successive bulk metal onto the initial monolayer.…”

Section: Before Reductionmentioning

confidence: 99%

Review—Metallic Lithium and the Reduction of Actinide Oxides

Merwin

Williamson

Willit

et al. 2017

J. Electrochem. Soc.

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Extensive research and process development has been conducted on the electrolytic reduction of actinide oxides in molten LiCl-Li 2 O. It is now accepted that the reduction of these metal oxides occurs via two separate reduction mechanisms: direct electro-chemical reduction and mediated chemical reduction by metallic lithium. The deposition of metallic lithium at the cathode (mediated chemical reduction mechanism) during the process is known to be essential in order to achieve high process throughputs and reduction yields, and yet a knowledge gap exists regarding the nature of metallic lithium in this system. This review summarizes the formation of lithium during the process and its dispersion into the molten salt electrolyte. Previously reported aspects of the physical chemistry of the LiCl-Li 2 O-Li system are presented with a specific focus on the dispersion of Li in the solution. Finally, issues regarding the effect of the presence of lithium on the electrolytic reduction process are discussed. Evidence shows that electrochemically generated metallic lithium is likely a significant source of experimental uncertainty, low current efficiency and Li 2 O consumption in the oxide reduction process. The reduction of uranium, plutonium and minor actinide oxides to a metallic form is an important nuclear fuel cycle process.2-9 The ability of metallic lithium to reduce various uranium oxides, importantly UO 2 and U 3 O 8 , has been known for many years.10 A molten salt metalothermic reduction process employing metallic lithium (Li) as a reductant dissolved in molten LiCl was first developed by Argonne National Laboratory (ANL) to consolidate a variety of forms of actinide oxides for integration into a single electrometallurgical reprocessing system. 11-13 An electrolytic process, often referred to as electro-deoxidation or simply oxide reduction, was subsequently developed as a more controllable method of reducing metal oxides. A feasibility study conducted by Poa et al. demonstrated that oxides of uranium and plutonium could be reduced electrochemically in molten salts as long as the reduction potential of the metal oxide in question was more noble than the cation of the electrolyte.14,15 This approach was further developed by Gourishankar et al. to better understand processes chemistry and develop the electrolytic cell technology. 13,[16][17][18][19][20] Independent research conducted by Fray, Farthing, and Chen (FFC) applied the principles of electrochemical reduction in molten salt electrolytes to a variety of metal oxide reduction processes. 21,22 The FFC process has been the subject of several literature reviews.23-25 While these review articles address the processes associated with the reduction of nuclear fuel in LiCl, they focus on the electro-deoxidation phenomena and the CaCl 2 -CaO system. Additionally, the process engineering of the electrolytic reduction of nuclear fuel, and experience in incorporating oxide fuel into pyroprocessing, has been the focus of a recent review article. 26 The current review wi...

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“…Ti 2+ + 2e -= Ti [9] Some refining also takes place as some of the elements will remain in the anode when the titanium ions dissolve in the salt and others will either accumulate in the salt or evaporate, thereby producing a purer titanium than the TiOC anode. Results for these reduction/refining experiments for titanium dioxide, shown in Table 1, indicate that significant refining has taken place (40).…”

Section: Combined Reduction and Electrorefiningmentioning

confidence: 99%

(Max Bredig Award in Molten Salt and Ionic Liquid Chemistry) Exploring Novel Uses of Molten Salts

Fray

2013

ECS Trans.

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Molten salts have been used successfully in processes for the extraction of metals, high temperature batteries and fuel cells for decades which give confidence to the fact that other processes can be explored which can be sufficiently exciting to be of practical importance. In this paper, the following relatively new processes will be discussed: electrodeoxidation where metal oxides are electrochemically reduced to metals, alloys, intermetallic compounds, combined reduction and electrorefining which can be applied to the reduction and purification of oxycarbides of many metals, cathodic protection of Group IV elements in order to prevent oxygen pickup during high temperature processing, the use of lithium intercalation into graphite to create carbon nanoparticles and nanotubes which can be used in lithium ion batteries, and, finally, ion exchange reactions.

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Separation and Recovery of Uranium Metal from Spent Light Water Reactor Fuel Via Electrolytic Reduction and Electrorefining

Cited by 113 publications

References 8 publications

Separation of Electrolytic Reduction Product from Stainless Steel Wire Mesh Cathode Basket via Salt Draining and Reuse of the Cathode Basket

Separation of Electrolytic Reduction Product from Stainless Steel Wire Mesh Cathode Basket via Salt Draining and Reuse of the Cathode Basket

Review—Metallic Lithium and the Reduction of Actinide Oxides

(Max Bredig Award in Molten Salt and Ionic Liquid Chemistry) Exploring Novel Uses of Molten Salts

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