抄録
In a nuclear power plant, it is one of the important point to evaluate the safety of reactor core and its pipes. Many studies about a seismic safety have been conducted in terms of structural dynamics. As a result there are a lot of knowledge about earthquake-resisting designs and geological assessment. In addition when a large-scale earthquake happens, safety measures, for example, automatic stop are adopted. However the influence of an earthquake on boiling two-phase flow in the fuel assembly is not fully understood. The fluctuation of the behavior of two-phase flow, for example the void fraction and the pressure, is expected to affect the power of the plant. In this study visualization experiment is conducted in order to investigate how the two-phase flow, especially bubbles in water are influenced when the structural oscillation is added. From this experiment and measurement, the influence of structural oscillation on bubble behavior is evaluated. And the data obtained from this study will be used to conduct accurate evaluation of Two-Phase Flow Simulation Code with Interface Tracking (TPFIT) the two-phase flow analysis code which takes into account the acceleration of structure vibration. In the first step of this study, the experimental apparatus to conduct the structure visualization experiment and oscillation table is designed. In order to compare the bubble behavior with structure vibration, we conducted the experiment in the condition without oscillation as the primary experiment. In this experiment,it is supposed that the bubble behavior, especially bubble size, position is related to the liquid flow velocity.
