Visualization of Bubbles Behavior in Lead-Bismuth Eutectic by Gamma-Ray Available to Purchase

As a fundamental study for a direct contact type of lead-bismuth-cooled fast reactor (PBWFR), the method of gamma-ray radiography was applied to the visualization of the nitrogen bubbles in lead-bismuth eutectic (LBE) in a vertical square duct with inner size of 10×10×73.3 mm³. Nitrogen gas was injected from a bottom nozzle with inner diameter of 3mm at the flow rate from 0.13 to 0.40NL/min. As γ–ray source, ⁶⁰Co with 11TBq was used, and a multi-crystal Gd₂O₂S (Tb) scintillator was employed for detection of γ–ray. The bubble behavior was visualized successfully by means of this method. Void fraction distributions were obtained by processing the visualized images, and the bubble length and bubbles rising velocity were determined from the result. There were some unstable bubble behavior depending on gas injection flow rate.