Acoustic emission monitoring of water boiling on fuel cladding surface at 1Â bar and 130Â bar

This paper aimed to observe the acoustic emission (AE) signals of water boiling occurring on fuel cladding surfaces under flow conditions at 325 °C and 130 bar. Visualization test was first performed to identify a correlation between the water boiling phenomenon and AE signals in a transparent glass cell at 1 bar. Based on the correlations obtained at 1 bar, the boiling AE signals were obtained at 325 °C and 130 bar and successfully analyzed through various AE parameters, such as frequency, energy and hit number. Relatively small bubbles were formed at 130 bar, and the bubble density increased with the increase of the internal heater temperature.