On Modeling Piping Supports in Dynamic Analysis of Nuclear-Power Piping Systems

Piping analysis and its corresponding design evaluation according to ASME are complicated and tedious. One typical reason is the modeling of supports and their design evaluation. It is not exaggerated if one claims that this part of the work can consume about 1/3 of the total budgeted costs that are needed for a piping system analysis. The engineering practices of how a support should be modelled in a piping analysis differ between different regions in the world. The difference arises mainly from in what way the following two parts are weighted in a piping analysis: (1) the dynamic interaction effect between supports and piping, and (2) the big safety margin or, in other words, the conservatism, for a piping system which fulfills ASME’s requirements. In this paper a review of these practices will be first given and, thereafter, an analysis of piping-support interaction will be carried out, and finally our suggestions will be given. Some practical examples from recent projects in Nordic countries will be discussed.