Possibility of processing tungsten dust waste from the nuclear fusion process by a combination of several technologies

Abstract

The processing of tungsten dust waste from the nuclear fusion process is being considered for the EU DEMO within the Workpackage Safety and Environment in the EUROfusion programme.A multi-step procedure with a combination of several independent technologies is proposed. Specific technologies are gradually being proposed, however their combination has not been tested yet. Removal of tritium from tungsten dust by a Molten Salt Oxidation technology (MSO) is investigated while, simultaneously, tungsten is retained in the molten salt and tritium is trapped in the form of condensed tritium water. Tungsten salts are concentrated in several stages by a combination of chemical methods, settling, and centrifugation. The dissolution and concentration procedures alternate in a defined manner. The concentrate is gradually enriched with tungsten and tungsten salts. The molar volume of tungsten progressively increases in the concentrated salt suspension.Further removal of certain impurities, decomposition of salts, and the increase of the tungsten concentration in the product can be achieved by means of Induction Melting or Induction Heating in a Cold Crucible (IMCC or IHCC) in a suitable atmosphere. The final stage is the reprocessing of the concentrated tungsten product from the dust form into a compact piece of material. Induction Heating technology will enable its sintering, compaction, and reduction of porosity.