Abstract
Japan Atomic Energy Research Institute (JAERI) proposed a passive safety reactor called the System-integrated Pressurized Water Reactor (SPWR). In the SPWR design, the Pressure Balanced Injection System (PBIS) was introduced. The characteristics of the PBIS were examined experimentally by using a water column oscillator. The water column oscillator is unique on some points that self-induced oscillation, low dimensional fluid system, a model of a practical system, a coolant system of nuclear reactors in future. Oscillation phenomena like the water column oscillator are very important in vibration and control engineering. However, sufficient knowledge about them have not been got yet. In this study, the behavior of the water column oscillator is examined experimentally and analytically. Experiment was proposed and made in order to elucidate the mechanism of the complex oscillation. The apparatus simulates the behavior of PBIS. A cover gas simulation vapor generation by residual heat of the core is constantly supplied. In this system, irregular or periodic oscillations occur depending on the conditions. An analytical model was built in order to represent the phenomena observed in the experiment of the PBIS simulation system and to present a theoretical consideration. The purpose of this research is to prove this phenomenon to be chaotic.
