Laser cutting is expected to reduce the volume of radioactive substances based on their radioactive levels. The laser has the advantage of being able to access remotely (non-contact) substances in high-level radiation environments. The scattering of radioactive dust, such as fumes and spatter, generated throughout the laser cutting process, is a major issue faced when cutting highly radioactive substances. One driving force of the spatter could be collapse of the cavitation bubble which is caused by rapid thermal loading due to laser irradiation. To elucidate the spattering mechanism, a spark discharge in water was used to generate cavitation bubble. The growth and collapse behaviors influenced by the interaction between a free surface and bubble resulting in the spattering phenomena are observed by using an ultra-high-speed video camera. Numerical simulations also were performed. The spatter height increased as the distance between the bubble and the free surface decreased and the qualitative trend observed was described numerically using simulations.