In the MYRRHA GEN IV Accelerator Driven System (ADS) under development at SCK•CEN, liquid lead-bismuth (LBE) is foreseen as the reactor coolant and as spallation target for providing the required neutrons to the sub-critical reactor core. MYRRHA is a pool type reactor, with a large cover gas space and equipped with external LBE loops for chemistry control of the coolant.
Aerosols will be formed during operation of a heavy liquid metal cooled reactor such as MYRRHA. Although these aerosols can present an important hazard for safe operations, their formation and properties under MYRRHA operating conditions are not well understood. Due to the various formation mechanisms involved, aerosol particle sizes ranging from about 50 nm (freshly formed nuclei) to well over 100 µm (due to entrainment or coagulation) are expected. Their size, shape and composition will determine whether and where these aerosols are deposited.
In this PhD project we want to advance the knowledge regarding aerosols in heavy liquid metal cooled fast reactors. Specifically, we want to assess the impact of aerosols in MYRRHA by combining numerical tools and experiments for characterization of the aerosol formation mechanism, their particle size distribution and composition, the amount of aerosols formed and their deposition properties under normal and accident conditions in MYRRHA.
The results obtained will be used to determine the source term for radiological hazard calculations and for the design of a suitable filter setup aimed at minimizing the presence of aerosols in the cover gas over the entire envisaged particle size range.