Microbubble Spectra and Superheat in Water and Sodium, Including Effect of Fast Neutron Irradiation

Abstract

The microbubble spectrum in a sample of tap water was measured by the Coulter counter technique under various conditions, and at the same time the tensile strength (i.e., “superheat” capacity) of the tap water was measured by the ultrasonic cavitation technique. It was observed in this experiment that the microbubble population and size increased and the superheat decreased for increasing temperature and under fast neutron irradiation. Finally the generalized Noltingk-Neppiras equation was solved numerically for selected initial microbubble radii, and the suppression pressure (or superheat) determined by this numerical solution was compared with the experimental result. Apparent inconsistencies in experimental results may be primarily due to the neglect of the rectified diffusion effect in the present analysis.