New Methodology of Modal Analysis for a Dual Cooled Fuel Rod with and without Water in a Flow Channel

To compare the effects of water inside on outside of a hollow cylinder of dual cooled fuel rod, a new methodology of modal analysis is suggested and verified by experiments. When mass of water inside and outside the rod is the same, the latter decreases natural frequencies further than the former does. In this paper, we describe the method in detail and explain the variation of the dynamic properties according to the ratio of the mass of water inside to outside of a dual cooled fuel rod.