Effects of temperature, concentration, and uranium chloride mixture on zirconium electrochemical studies in LiCl KCl eutectic salt

Abstract

Experimental studies were performed to provide measurement and analysis of zirconium (Zr) electrochemistry in LiCl-KCl eutectic salt at different temperatures and concentrations using cyclic voltammetry (CV). An additional experimental set with uranium chloride added into the system forming UCl 3-ZrCl 4-LiCl-KCl was performed to explore the general behavior of these two species together. Results of CV experiments with ZrCl 4 show complicated cathodic and anodic peaks, which were identified along with the Zr reactions. The CV results reveal that diffusion coefficients (D) of ZrCl 4 and ZrCl 2 as the function of temperature can be expressed as D Zr(IV) = 0.00046exp(-3716/T) and D Zr(II) = 0.027exp(-5619/T), respectively. The standard rate constants and apparent standard potentials of ZrCl 4 at different temperatures were calculated. Furthermore, the results from mixture of UCl 3 and ZrCl 4 indicate that high concentrations of UCl 3 hide the features of the smaller concentration of ZrCl 4 while Zr peaks become prominent as the concentration of ZrCl 4 increases.

Electrochemical Recovering Zr from Molten Salt Using an Fe Electrode

“…However, after long-term service of the cladding material, the fission product will penetrate into cladding materials, causing the Zr alloys to lose excellent properties . It is reported that the contaminated Zr alloys account for more than 40% of spent fuels assembly volume, and the content of Zr could reach 10.8 wt % in the irradiated driving fuel. , Thus, recovering Zr from contaminated Zr alloys and spent fuels not only reduce the volume of radioactive waste but also brings economic benefits to the nuclear power industry. In recent decades, this has always been a hot issue in the nuclear field.…”

Raman and Electrochemical Study of Zirconium in LiCl-KCl-LiF-ZrCl4

“…Factors such as temperature, concentration of zirconium, salt composition have been considered. In chloride-based salt mixtures such as LiCl-KCl-ZrCl 4 , 2,4,[7][8][9][10][11][12][13][14][15][16][17] NaCl-KCl-ZrCl 4 , 18 NaCl-ZrCl 4 , 8 it was believed that the reduction of Zr(IV) followed a multi-step mechanism, two soluble states of Zr(IV) and Zr(II) and two insoluble states of Zr(I) and Zr were confirmed. In fluoride-based salt mixtures, the reduction was thought to be less complicated, a single-step reduction of Zr(IV) to Zr(0) was approved in LiF-NaF-ZrF 4 , 19 LiF-CaF 2 -ZrF 4 , 20 and LiF-KF-ZrF 4 , 21 and a two-step reduction was endorsed in LiF-NaF-K 2 ZrF 6 , 22 LiF-KF-ZrF 4 .…”

Chemical Species Transformation during the Dissolution Process of U3O8 and UO3 in the LiCl–KCl–AlCl3 Molten Salt

“…To overcome the shortcoming of volatilization of AlCl 3 , it is worth considering in future work to control the amount of dissolved AlCl 3 in LiCl−KCl salts through appropriate preparation steps by adopting the method developed by Hoover et al The amount of dissolved U 3 O 8 and UO 3 can be more accurately monitored. 35 Although the measurement results deviate from the true value, the overall trend of the U dissolution process reflected by the results of ICP-OES should be acceptable. Moreover, it can also be seen that the molten salt becomes viscous in Figure 3b after the dissolution of U 3 O 8 for 5 h. Whereas, according to Figure 3c,d, the bright yellow of the molten salt was obviously observed, which reveals that the dissolved product of UO 3 in the molten salt may be different from U 3 O 8 .…”

“…In addition, the volatilization phenomenon of AlCl 3 in the molten salt is more obvious with the increase of its content during the dissolution of uranium oxides, which may be the main reason for the measurement errors of the U ion concentration. To overcome the shortcoming of volatilization of AlCl 3 , it is worth considering in future work to control the amount of dissolved AlCl 3 in LiCl–KCl salts through appropriate preparation steps by adopting the method developed by Hoover et al The amount of dissolved U 3 O 8 and UO 3 can be more accurately monitored . Although the measurement results deviate from the true value, the overall trend of the U dissolution process reflected by the results of ICP-OES should be acceptable.…”