Investigation on the Added Mass and Added Damping of a Circular Cylindrical Structure Enclosed in a Container with Narrow Passage (Study Using a Rigid Body Model)

A neutron reflector, a newly designed core internal structure, is supposed to be adopted to the advanced pressurized water reactor (=APWR). This neutron reflector is composed of multi-stage ring type structures and is installed in a core barrel with very narrow passages at the 4 corner portion. Thus, it is considered that the coupling effect with a core barrel through liquid will become very predominant due to very large added mass and added damping effects. The authors have evaluated the added mass and added damping using a simplified neutron reflector model which is a rigid, one-degree of freedom model, and systematically investigated the effects of various parameters such as frequency, liquid temperature, and so on. This report summarizes those results as a knowledge data base.