Literature Review of Polonium Removal Techniques from LBE

The use of heavy liquid metals like Lead and LBE as coolants for fast reactors offers several advantages. However, several important technological issues still need be addressed. One of the most important issue is the radiological hazard associated with the activation of LBE coolant upon neutron bombardment. Polonium-210, a toxic alpha-emitter of 138.38 days half-life, is formed from Bismuth-209 by neutron capture. Most of the Polonium is retained in the LBE coolant during normal operating conditions and can cause problems during maintenance operations or if coolant leakage occurs. However, some polonium migrates to the cover gas in the reactor plenum and will diffuse outside the primary system when the reactor is opened for refueling or maintenance. The polonium hazard can be significantly reduced by continuous online, or batch extraction from the reactor coolant because the rate of polonium release under any circumstances is proportional to its concentration in the LBE melt. None of the extraction techniques experimented to date was tested beyond the laboratory scale. This is a state of the art of the existing knowledge by providing an exhaustive literature study op studied Polonium removal techniques and to provide recommendations for future R&D activities related to this topic.