After the emergency shutdown of the lead-bismuth fast reactor,the thermal stratification in the upper plenum has an important impact on the integrity of the reactor structure and the residual heat removal capacity of the natural circulation,which requires special attent...MORE After the emergency shutdown of the lead-bismuth fast reactor,the thermal stratification in the upper plenum has an important impact on the integrity of the reactor structure and the residual heat removal capacity of the natural circulation,which requires special attention.In order to overcome the defects of traditional ...