Electrolytic reduction of a simulated oxide spent fuel and the fates of representative elements in a Li2O-LiCl molten salt

Park, Wooshin; Choi, Eun-Young; Kim, Sung-Wook; Jeon, Sang‐Chae; Cho, Young-Hwan; Hur, Jin‐Mok

doi:10.1016/j.jnucmat.2016.04.058

Cited by 25 publications

(11 citation statements)

References 21 publications

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“…Namely, the cathode potential sharply shifts to the positive region and becomes equal to the potential of the uranium electrode. 39,40 Thus, the consumption of the reduced lithium for the ZrO 2 reduction is typical only at the initial moments of electrolysis. During the long-term electrolysis, lithium accumulated as a separate phase and only a small amount of it consumed on the ZrO 2 reduction.…”

Section: Resultsmentioning

confidence: 99%

Reduction of ZrO₂ during SNF Pyrochemical Reprocessing

Nikolaev

Suzdaltsev

Pavlenko

et al. 2021

J. Electrochem. Soc.

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Reduction of ZrO 2 by lithium during electrolysis of LiCl-KCl-Li 2 O melt at 650°C was studied using a set of physicochemical methods of analysis. Influence of ZrO 2 in the space near a molybdenum cathode on the kinetics of the cathode process was established. Possible variations of the electrode reaction associated with the zirconium reduction were proposed. The appearance of ZrO 2 in the cathode space resulted in consumption of reduced lithium and in increase in the potential relaxation time of the molybdenum cathode after cathode polarization. Long-term galvanic impulse electrolysis of LiCl-KCl-Li 2 O melt at 650°C was carried out using the molybdenum cathode which was immersed into the ZrO 2 powder. According to the X-ray fluorescence analysis as well as the method of nuclear reactions the reduction product was presented by the ZrO 2 , Li 2 ZrO 3 , Zr 3 O phases. Additionally, by alloying the reduction product with tin, the ZrO 2 reduction degree to metallic zirconium was estimated, which was close to zero. It was assumed that the main pathway for the appearance of the metallic zirconium in the ZrO 2 reduction product during electrolysis of the LiCl-KCl-Li 2 O melt was direct electroreduction of dissolved zirconium in the melt.

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Section: Resultsmentioning

confidence: 99%

Reduction of ZrO₂ during SNF Pyrochemical Reprocessing

Nikolaev

Suzdaltsev

Pavlenko

et al. 2021

J. Electrochem. Soc.

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“…Only simple SrO and SrZrO 3 were considered in the calculation (Table 2); thus, the behavior of Sr may not have been accurately predicted. Similarly, the chemical behavior of Sr in the SNFs and SSFs remains unknown in the oxide reduction step of pyroprocessing, where LiCl molten salt is used as an electrolyte [23][24][25]. Sr was supposed to be dissolved into the LiCl salt during the oxide reduction reaction, but the experimental results revealed unexpectedly low Sr accumulation in the salt after the reaction [23,24].…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, the chemical behavior of Sr in the SNFs and SSFs remains unknown in the oxide reduction step of pyroprocessing, where LiCl molten salt is used as an electrolyte [23][24][25]. Sr was supposed to be dissolved into the LiCl salt during the oxide reduction reaction, but the experimental results revealed unexpectedly low Sr accumulation in the salt after the reaction [23,24]. e poor dissolution behavior of SrZrO 3 in the LiCl molten salt was identified in comparison to the highly dissolvable BaZrO 3 , emphasizing the importance of the chemical states of Sr in the molten salt system [25].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, no evidence of the dissolution of Eu or Rh was identified through the experiment. Eu in SNFs has been regarded as a LiCl-soluble nuclide during oxide reduction [23,24]. Similar to the Sr case, the dissolution behavior of Eu has not been clearly revealed [23,24], and it is thought that the chemical states of Eu in the SNFs might affect the unexpected behavior.…”

Section: Resultsmentioning

confidence: 99%

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Dissolution Behavior of Simulated Spent Nuclear Fuel in LiCl-KCl-UCl3 Molten Salt

Lee

Kim

Jang

et al. 2021

Science and Technology of Nuclear Installations

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Considering the necessity of the development of methods to reduce the burden of storage and disposal of high-level radioactive waste, in this study, we propose a nuclide separation technique using molten salt immersion. The dissolution behavior of simulated spent nuclear fuels (SSFs) immersed in a LiCl-KCl-UCl3 (LKU) molten salt at 500°C was investigated using a combination of thermodynamic and experimental studies. Surrogates of transuranic elements (TRUs), that is, rare earth elements (REs), in the SSFs were dissolved into the molten salt without any damage to the UO2 structure of the SSFs. The results suggest that the LKU salt technique can be used to separate REs and, potentially, TRUs from actual spent nuclear fuels (SNFs). It is thought that this technique is advantageous over the conventional TRU recovery techniques because the majority of the SNFs (i.e., UO2) remained stable, thus reducing the process burden. Several SNF treatment process options using this technique were suggested. This study will serve as a guide for future studies on the management of high-level waste discharged from nuclear reactors.

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“…The second reason is because of the low surface area of the used cylindrical porous pellets with the size of ⌀6.1 mm × 7.0 mmH (Figure 3(a)). In our previous study [30], we had conducted OR in a 1 kg/batch apparatus using a smaller crushed pellet (Figure 3(b)) which had the size of 1-4 mm and density of 10.67 g/cm 3 . We made an attempt to separate the reduction product from the cathode basket through the salt drain similar to the method used in the present study (the data on the residual salt were not reported in the previous study).…”

Section: Resultsmentioning

confidence: 99%

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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Electrolytic reduction of a simulated oxide spent fuel and the fates of representative elements in a Li2O-LiCl molten salt

Cited by 25 publications

References 21 publications

Reduction of ZrO₂ during SNF Pyrochemical Reprocessing

Reduction of ZrO₂ during SNF Pyrochemical Reprocessing

Dissolution Behavior of Simulated Spent Nuclear Fuel in LiCl-KCl-UCl3 Molten Salt

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

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Electrolytic reduction of a simulated oxide spent fuel and the fates of representative elements in a Li2O-LiCl molten salt

Cited by 25 publications

References 21 publications

Reduction of ZrO2 during SNF Pyrochemical Reprocessing

Reduction of ZrO2 during SNF Pyrochemical Reprocessing

Dissolution Behavior of Simulated Spent Nuclear Fuel in LiCl-KCl-UCl3 Molten Salt

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

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Reduction of ZrO₂ during SNF Pyrochemical Reprocessing

Reduction of ZrO₂ during SNF Pyrochemical Reprocessing