Numerical analysis and experimental validation of planar electrorefiner for spent nuclear fuel treatment using a tertiary model

Figures & data

Figure 1. (a) Schematic of rod-type ER geometry; (b) flat-plate-type ER geometry for numerical analysis; and (c) electrorefiner for validation.

Table 1. Boundary condition and parameters.

Anodic transfer coefficient	0.5 [21]
Cathodic transfer coefficient	0.5 [21]
Diffusion coefficient, Do	U(III)1.03e–9 m^2 s^−1 at 500 °C [25]
Electrical mobility	4.64e−8 m^2 (Vs)^−1 [26]
Exchange current density	60 mA cm^−^2 [27,28]
Applied current density	10, 100, 150 mA cm^−^2
Uranium deposited density	2000 kg m^−^3

Figure 2. (a) Grid of rod cathode using tetrahedral mesh; (b) grid of flat-plate cathode using mapped mesh; (c) changes in current density depending on changes in maximum mesh size.

Figure 3. (a) Current density distribution on rod cathode and (b) flat-plate cathode. (c) Comparison of uniformity of current density distribution at locations on rod and flat-plate cathodes.

Figure 4. (a) Graph of anode dissolution on rod cathode and (b) flat-plate cathode. (c) Graph of cathode electrodeposition on rod cathode (d) flat-plate cathode.

Figure 5. (a) Potential–current curve for rod and flat-plate cathode at No. 1 and No. 3. (b) Overpotential for rod and flat-plate cathodes as time passes at No. 1 and No. 3. (c) Uranium ion concentration depending for time spent at each location on rod and flat-plate cathodes.

Figure 6. (a) Comparison of differences in overpotential with respect to rod cathode convection effect. (b) Comparison of differences of overpotential with respect to the flat-plate cathode convection effect.

Figure 7. (a) Current density distribution on multi-arrayed (1 × 2, 3 × 4, 5 × 4) rod cathode; and (b) multi-arrayed (1 × 2, 3 × 4, 5 × 4) flat-plate cathode.

Figure 8. (a) Comparison of the differences in current density distribution on multi-arrayed (1 × 2, 3 × 4, 5 × 4) rod cathode, and (b) on multi-arrayed (1 × 2, 3 × 4, 5 × 4) flat-plate cathode.

Figure 9. (a) Current density distribution, (b) overpotential curve according to surface area ratio, (c) calculated potential--current curve, and (d) experimental potential--current curve according to the surface area ratio of anode to cathode.

Table 2. Experimental current efficiency for U electrorefining with electrode surface area ratio.

			Amount of U deposit (g)		Salt
Surface area ratio (A/C)	Current density (mA cm^−^2)	Applied current (A∙h)	Before washing	After washing	concentration (%)	Theoretical amount of U, g	Current efficiency, %
1.06	120	3.34406	15.36	8.48	44.79	9.89824	85.67
1.67	120	2.22704	10.99	5.95	45.86	6.59192	90.26
3.14	120	1.11352	5.89	3.01	48.9	3.29596	91.32

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