Evaporation of polonium from lead-bismuth eutectic nuclear coolant

The neccessity of finding a suitable solution for the disposal of radioactive waste has led to a growing interest in the last few decades in the development of accelerator-driven systems (ADS) which could efficiently perform the transmutation of this waste transforming it to shorter-lived, less hazardous radioactive species. One of the most prominent ADS projects worldwide is MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications). MYRRHA is currently under development at the Belgian Nuclear Research Centre (SCK CEN). MYRRHA consists of a subcritical core coupled to a proton accelerator and cooled by lead-bismuth eutectic (LBE). The use of LBE in ADS such as MYRRHA is supported by advantageousnbsp;properties. However it also presents certain challenges. One important concern with the use ofnbsp;as coolant is the formation of large quantities of 210Po due to neutron capture reaction with bismuth (Bi). Polonium (Po) is critical to safety of ADS due to its elevatednbsp;and propensity to evaporate. A qualitative and quantitative understanding of Po evaporation from LBE is thus required for safety assessments, design and licensing ofnbsp;nuclear systems. In this work the evaporation of Po from LBE was investigated with the so-called transpiration method under different conditions relevant to MYRRHA.