Details

Autor(en) / Beteiligte

• Souček, P.
• Malmbeck, R.
• Mendes, E.
• Nourry, C.
• Sedmidubský, D.
• Glatz, J.-P.

Titel

Study of thermodynamic properties of Np–Al alloys in molten LiCl–KCl eutectic

Ist Teil von

• Journal of nuclear materials, 2009-10, Vol.394 (1), p.26-33

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2009

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Pyrochemical methods are investigated worldwide within the framework of Partitioning and Transmutation concepts for spent nuclear fuel reprocessing. Electroseparation techniques in a molten LiCl–KCl are being developed in ITU to recover all actinides from a mixture with fission products. During the process, actinides are selectively electrochemically reduced on a solid aluminium cathode, forming solid actinide–aluminium alloys. This work is focused on the thermodynamic properties of Np–Al alloys in a temperature range of 400–550 °C and on the characterisation of the structure and chemical composition of deposits obtained by electrodeposition of Np on solid Al electrodes in a LiCl–KCl–NpCl 3 melt. Cyclic voltammetry and open circuit chronopotentiometry have been used to examine the electrochemical behaviour of Np on inert W and reactive Al electrodes. Gibbs energies, enthalpy and entropy of formation and standard electrode potentials of Np–Al alloys were evaluated and compared with ab initio calculations. Galvanostatic electrolyses at 450 °C were carried out to recover Np onto Al plates and the solid surface deposits were characterised by XRD and SEM-EDX analyses. Stable and dense deposits consisting of NpAl 3 and NpAl 4 alloys were identified. In addition, the conversion of NpO 2 to NpCl 3 is described, using chlorination of the oxide in a molten salt media by pure chlorine gas.