TY - JOUR

T1 - Anodic Processes of Uranium Alloys Containing Palladium and Neodymium in 3LiCl–2KCl–UCl3 Melts

AU - Nikitin, D. I.

AU - Polovov, I. B.

AU - Rebrin, O. I.

AU - Shchetinskii, A. V.

AU - Dedyukhin, A. S.

N1 - This work was supported by JSC Proryv.

PY - 2023/8/1

Y1 - 2023/8/1

N2 - A combined technological scheme for the reprocessing of a mixed nitride uranium–plutonium spent fuel, which consists of pyrochemical operations and hydrometallurgical refining of uranium, plutonium, and neptunium, is currently being developed at the reprocessing unit of the pilot demonstration power complex of the Siberian Chemical Plant. According to this scheme, the target pyrochemical reprocessing products (the actinide content not lower than 99.9%) purified from the main mass of fission products are directed to hydrometallurgical reprocessing. Pyrochemical reprocessing requires a technology of electrorefining of the metallized spent nuclear fuel. To carry out electrorefining, it is necessary to determine processes and conditions of anodic dissolution of the alloys simulating the product of primary “metallization” operation. The results of studying the anodic dissolution of model U–Pd and U–Pd–Nd alloys with different concentrations of palladium and neodymium in the melts based on 3LiCl–2KCl–UCl3 (10.1 wt % UCl3) at 550°C using different methods are presented. The uranium alloys containing palladium and neodymium are prepared by direct melting of metallic uranium, PdAP-1 metallic palladium powder, and metallic neodymium (99.99%) in a high-purity argon medium (99.998%). Electrochemical measurements are carried out on an Autolab 302N potentiostat/galvanostat equipped with a Booster 20A high-current device. The anodic polarization curves consist of only one oxidation wave attributed to the dissolution of uranium metal. An increasing in the palladium content in the alloy from 1.5 to 10.0 wt % does not affect the shape of the polarization curves. An increase in the neodymium content in the alloy from 1.0 to 10.0 wt % does not either influence on the shape of the polarization curves. The parameters of electrorefining of uranium alloys containing palladium and neodymium are determined. The limiting current density of uranium dissolution from the uranium alloys containing palladium and neodymium in the 3LiCl–2KCl–UCl3 (10.1 wt % UCl3) electrolyte at 550°C is 0.4 A/cm2. Palladium does not transfer into the melt due to anodic dissolution, and neodymium is accumulated in the electrolyte only for refining the alloy with 10.0 wt % neodymium, which is much higher than the possible real concentrations of components of the electrorefined uranium alloy in the technological flowsheet of processing the spent nuclear fuel.

AB - A combined technological scheme for the reprocessing of a mixed nitride uranium–plutonium spent fuel, which consists of pyrochemical operations and hydrometallurgical refining of uranium, plutonium, and neptunium, is currently being developed at the reprocessing unit of the pilot demonstration power complex of the Siberian Chemical Plant. According to this scheme, the target pyrochemical reprocessing products (the actinide content not lower than 99.9%) purified from the main mass of fission products are directed to hydrometallurgical reprocessing. Pyrochemical reprocessing requires a technology of electrorefining of the metallized spent nuclear fuel. To carry out electrorefining, it is necessary to determine processes and conditions of anodic dissolution of the alloys simulating the product of primary “metallization” operation. The results of studying the anodic dissolution of model U–Pd and U–Pd–Nd alloys with different concentrations of palladium and neodymium in the melts based on 3LiCl–2KCl–UCl3 (10.1 wt % UCl3) at 550°C using different methods are presented. The uranium alloys containing palladium and neodymium are prepared by direct melting of metallic uranium, PdAP-1 metallic palladium powder, and metallic neodymium (99.99%) in a high-purity argon medium (99.998%). Electrochemical measurements are carried out on an Autolab 302N potentiostat/galvanostat equipped with a Booster 20A high-current device. The anodic polarization curves consist of only one oxidation wave attributed to the dissolution of uranium metal. An increasing in the palladium content in the alloy from 1.5 to 10.0 wt % does not affect the shape of the polarization curves. An increase in the neodymium content in the alloy from 1.0 to 10.0 wt % does not either influence on the shape of the polarization curves. The parameters of electrorefining of uranium alloys containing palladium and neodymium are determined. The limiting current density of uranium dissolution from the uranium alloys containing palladium and neodymium in the 3LiCl–2KCl–UCl3 (10.1 wt % UCl3) electrolyte at 550°C is 0.4 A/cm2. Palladium does not transfer into the melt due to anodic dissolution, and neodymium is accumulated in the electrolyte only for refining the alloy with 10.0 wt % neodymium, which is much higher than the possible real concentrations of components of the electrorefined uranium alloy in the technological flowsheet of processing the spent nuclear fuel.

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UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=001156779200003

U2 - 10.1134/S0036029523080165

DO - 10.1134/S0036029523080165

M3 - Article

VL - 2023

SP - 970

EP - 976

JO - Russian Metallurgy (Metally)

JF - Russian Metallurgy (Metally)

SN - 0036-0295

IS - 8

ER -