Finite Element Study of Pressure Wave Attenuation by Reactor Fuel Subassemblies

Abstract

The attenuation of pressure waves by the subassembly walls in a reactor core was studied by a two dimensional, finite element program. For these purposes, a hydro-dynamic finite element was incorporated in an existing dynamic structural program. The resulting program has the advantage that complex boundary conditions and the interaction of structural and fluid elements are handled in a straightforward manner. The program was used to model a section of the hexcan and the surrounding fluid; the hexcan was modelled by beam elements. It is shown that the hexcan walls attenuate pressure peaks by about 33 percent in the adjacent subassembly. Thus the subassembly walls may play an important role in confining the effects of local accidents.