Computer modeling of electrochemical processing of waste nuclear fuel

Abstract

Summary The purpose of the work is to study the influence of the electrodes geometry and the mutual arrangement of functional elements in the working space of a metallization electrolyzer on the distribution of the oxygen flux density in the electrolyte, as well as on the distribution of electric and temperature fields. In a computer model, the stationary operation mode of the electrolyzer for processing spent nuclear fuel immersed into the LiCl molten salt with the addition of Li2O was studied. The calculations were performed using the ANSYS software package. We studied eight designs of the electrolyzer, which differ in the immersion depth of the anodes into the melt as well in the types anode protective covers and the cathode baskets. Verification based on the comparison of the computer modeling with experimental data indicates the adequacy of the models used. The electrolyte velocity field and the temperature field are calculated, as well as the steady‐state picture of the distribution of electric current density over the working space of the electrolyzer. The efficiency of the electrochemical cell is determined.

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

“…The theoretical understanding of this process and its modeling are provided in the works 5‐8 . In fact, the final product obtained as a result of electrolytic reduction, in addition to U, can contain Pu and minor actinides (MA), noble metals, and decay products.…”

Electrode reaction of Pr on Sn electrode and its electrochemical recovery fromLiCl‐KClmolten salt

“…5 Thus, there is an urgent need for spent fuel reprocessing. 6 The recovery of actinide elements by partitioning and transmutation, considered as one of the promising options for spent fuel management, can make full use of nuclear fuel and minimize nuclear wastes, 7 which is conducive to increase the utilization rate of nuclear energy. [8][9][10][11][12][13] Since molten salt has some excellent characteristics, 14,15 for instance, radiation resistance, short cooling time, and antiproliferative properties, pyrometallurgical technology, employing molten salt as medium, is considered as a promising method in the field of separation and extraction of actinides, 16,17 which mainly includes reduction extraction in molten saltliquid metal system, 18,19 electrorefining, 20,21 and electrochemical extraction using reactive cathodes.…”

“…Whereas, how to supervise spent fuel safely and economically has become one of serious issues that we must have encountered 5 . Thus, there is an urgent need for spent fuel reprocessing 6 . The recovery of actinide elements by partitioning and transmutation, considered as one of the promising options for spent fuel management, can make full use of nuclear fuel and minimize nuclear wastes, 7 which is conducive to increase the utilization rate of nuclear energy 8‐13 .…”

Recoveryof actinidesand fission products from spent nuclear fuel via electrolytic reduction: Thematic overview

“…Initially, the oxide fuel is loaded into a permeable cathode basket, which is immersed into a bath filled with the molten LiCl‐(1 wt%)Li 2 O salt at the temperature of 650°C. By passing a controlled electric current, oxygen ions leave the cathode basket, they dissolve in the molten salt and oxidize at the anode, and then they are evolved in the gas form from the pyroelectrochemical cell 4,5 …”

“…Initially, the oxide fuel is loaded into a permeable cathode basket, which is immersed into a bath filled with the molten LiCl-(1 wt%)Li 2 O salt at the temperature of 650 C. By passing a controlled electric current, oxygen ions leave the cathode basket, they dissolve in the molten salt and oxidize at the anode, and then they are evolved in the gas form from the pyroelectrochemical cell. 4,5 LiCl or CaCl 2 electrolytes are the usually used for UO 2 and UO 2 -PuO 2 recovery. When electrolysis is carried out in the CaCl 2 bath at 850 C, a dense layer of reduced metallic uranium particles is formed at the cathode in the near-surface region of SNF.…”