Analyses of Anodic Behavior of Metallic Fast Reactor Fuel Using a Multidiffusion Layer Model

Abstract

Anodic behavior of U-Zr or U-Pu-Zr alloys during electrorefining in molten chloride electrolyte was modeled on the basis of recent findings from the observation of anode residues after a number of electrorefining tests, such as the formation of an intermediate region that has a composition corresponding to the phase. Simulation of anodic dissolution of the U-Zr alloy during the engineering-scale electrorefining tests using the model showed that the calculated dissolution ratios of uranium and zirconium were in agreement with the experimental results when the alloy pin was chopped to as short as 5 mm. Three runs of laboratory-scale electrorefining tests with uncladded U-Pu-Zr ternary alloy were also simulated. The characteristic change of the anode potential during these tests was well reproduced in the calculation using the fitting parameters for uranium activity in the porous zirconium layer. The results of some predictive calculations showed that the required period to attain a certain uranium dissolution ratio is drastically increased with the increase in pin length, and that the zirconium dissolution ratio is largely increased when a higher anodic current density is applied to improve the electrorefining processing rate.

Anodic dissolution of irradiated metallic fuels in LiCl–KCl melt

“…It is thus obvious that during the electrorefining the amount of dissolved Zr should be minimized. However, not very much has been done until now on the electrorefining with reduced Zr co-dissolution [16][17][18]. Therefore, for designing and optimizing the process, it is necessary to collect more experimental data, especially using irradiated fuels, which have not been reported yet.…”

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

“…The modeling of electrochemical dissolution of spent fuel has been implemented using various methodologies 39‐48 . At first glance, it seems that the measurement of the amount of dissolved elements in the molten salt can be used to control the electrorefining process.…”

Pyrochemical fuel cycle technologies for processing of spent nuclear fuels

“…Therefore, the complex anodic dissolution of metallic fuel (U-Zr or U-Pu-Zr alloys) was modeled (Iizuka and Moriyama, 2010) on the basis of the findings from a number of past electrorefining tests. However, the TRAIL code cannot model the spent metallic fuel anode, which is essentially a composite of solid phases changing its structure, dimension, and composition of every moment.…”