Seismic response of the advanced gas cooled reactor core

Abstract

The seismic response of the Advanced Gas Cooled Reactor (AGR) core has been calculated using an idealisation having several hundred thousand degrees of freedom. The graphite bricks which make-up the core are idealised as rigid masses, whilst contact spring elements are used to represent the load transmissions or impacts that can take place between the bricks. The necessary input information for the contact spring elements (i.e. stiffness, damping and friction) has been obtained by test work. Whilst the dynamic analysis of the core itself is highly non-linear, the supporting steel structures are linearly elastic. Consequently, the dynamic characteristics of the supporting structures are evaluated with the non-linear core structure uncoupled and are then used with the non-linear core data in a step-by-step explicit time-history. This paper discusses the development of the analytical model, the theory and the computer codes used. Results from some of the parameter studies, sensitivity studies and predictions of core response to earthquakes are presented.