The Influence of Nuclear Radiation on Pool-Boiling Heat Transfer to Liquid Helium

Pool-boiling experiments were performed in helium from high purity copper which had been exposed to various amounts of fast neutron radiation. The residual effects of the radiation influenced the pool boiling in two ways: First by decreasing the thermal conductivity of the copper substrate; and second by inducing residual radioactivity in the copper. The changes in the conductivity influenced the unsteady heat conduction process associated with nucleate boiling. The residual radiation from the copper augmented the bubble nucleation in the superheated helium in a manner similar to a bubble chamber. The relative magnitudes of the two effects were influenced by surface smoothness.