Development of Electrochemical Separation Methods in Molten LiF-NaF-KF for the Molten Salt Reactor Fuel Cycle

Abstract

Electrochemical methods for the separation of fission products from fission material in molten fluoride salt media have been studied in the context of their application within the framework of the developed Molten Salt Reactor fuel cycle. The separation possibilities of selected actinides (U, Th) and lanthanides (Nd, Eu, Gd) in molten eutectic LiF-NaF-KF at 530 C were evaluated by means of cyclic voltammetry. The applicability of different electrochemical techniques is discussed with reference to the new results from this study, and a basic flow sheet for the Molten Salt Reactor fuel cycle is outlined.

Electrochemical separation of uranium in the molten system LiF–NaF–KF–UF4

“…However, it does not mean that the mass transfer is controlled predominantly by diffusion. Shape of this voltammogram is in a reasonable agreement with the previous works [9,43,50]. In all cases, a two-step mechanism was published.…”

“…Utilization of liquid fuel mix in MSR concepts provides its continual (online) reprocessing. The electrochemical techniques [9] together with molten salt/liquid metal extraction and fluoride volatility method are regarded as usable methods for online processing in terms of the MSR fuel cycle.…”

“…Mamantov and Manning analysed uranium behaviour in the melts LiF-NaF-KF and LiFBeF 2 -ZrF 4 [42][43][44][45][46]. Recently, the electrochemistry of the system LiF-NaF-KF-UF 4 was studied [9]. Hamel et al [47] investigated electrochemical behaviour of uranium in the systems LiF-NaF and LiF-CaF 2 , Nourry et al [48] in the mixtures LiF-CaF 2 and LiFCaF 2 -NdF 3 and Afronichkin et al [49] in the molten mixture LiFThF 4 .…”

Electrochemical Behavior of UO2F2and Its Electrodeposition from UO2F2-FLiNaK Melt

“…26 These results of UF 4 -FLiNaK melt were consistent with the reported researches. 25,26,[28][29][30] For UO 2 F 2 -FLiNaK melt, the anodic peak H 2 ' at 3.48 V in the curve also belonged to the dissolution of Pt electrode and was more positive than that in the blank FLiNaK melt, which might be induced by the passivation of the Pt electrode surface due to the existence of oxidizing UO 2 2+ in the melt. It was found that when the work electrode was passivated, the oxidation potential of passivated electrode could shift positively and the sight anodic current was generated by dissolved passivated film before the oxidation of electrode, 31 which was also observed in UO 2 F 2 -FLiNaK melt as shown in the inset of Fig.…”

Potentialities of fluoride-based salts for specific nuclear reprocessing: Overview of the R&D program at CEA

“…A first rough assessment of such a technique necessarily goes through preliminary electrochemical studies in fluoride electrolytes of interest. These studies are very few on actinides [6][7][8][9][10]. Furthermore, to our knowledge, no electrochemical data in molten fluorides has ever been published on minor actinides.…”