Investigation of polonium removal systems for lead-bismuth cooled fbrs

The alkaline extraction method is being investigated as a method to remove polonium (Po) from a lead-bismuth (Pb-Bi) cooled reactor. Tellurium (Te) was used as a surrogate for Po for these experiments to quantify the migration from Pb-Bi to molten alkaline (NaOH). Experiments provided direct evidence that molten NaOH can effectively remove Te from Pb-Bi. A reduction of three to four orders of magnitude in the Te concentration in the metals was measured in the experiments. The experimental results also showed a higher than expected concentration of NaOH in the Pb or Pb-Bi. A comparison between experiments operated at 427°C and 500°C indicates that the higher operating temperature produces a higher removal rate of Te. Experiments where hot NaOH was injected into the crucible at the same temperature as the lead-bismuth eutectic (LBE) resulted in the rapid removal rate of Te and remained constant until the experiment was completed.