The IPPE experience in investigation of problem of high hazardous alpha-radioactive polonium generated in lead-bismuth eutectic (LBE) of naval liquid metal reactors has been considerably improved and applied to the safety research and development of generation IV small power LBE reactors and liquid metal targets for accelerator driven systems (ADS). It was shown that polonium hazard appears in cases of primary circuit depressurization and heat exchanger failure, as well as while repair and maintenance works, fuel reloading and accidents with radioactive LBE spill. The rules of polonium release from LBE into high temperature environment have revealed that it is precipitated in the form of intermetallic compounds of lead and bismuth polonides and is accompanied by unstable gaseous compounds of polonium hydride. As far as generation IV small power LBE reactors concerned the main contributor of polonium hazard is Po-210 isotope, while that concerned LBE targets for the ASD it is isotopes of Po-210, Po-209, and Po-208. Taking into account high radiation hazard of polonium along with potential danger of other volatile and gaseous nuclides accumulated in radioactive LBE one can conclude that a corresponding technology culture of polonium treatment and special means of radiation safety ensuring are required. In this connection the analysis of LBE purification from Po-210 isotope using alkali melts in air and inert gas atmosphere was presented.
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