NUMERICAL AND EXPERIMENTAL SIMULATION OF PIPING SYSTEMS WITH REGARD TO SYSTEM AND SUPPORT CONTROL AS WELL AS TO DEGRADED PIPE SECTIONS

摘要

Advances in science and technology have increased the standards for the construction and the operation of nuclear power plants especially as concerns the safety against catastrophic failure of pressurized components and systems. Analyses of the operational behaviour of high-quality components as well as flaw and damage analyses have shown that the knowledge of the boundary conditions especially the actual system and support control are of great importance. The behaviour of supports is studied by means of experimental vibration analysis and finite element calculations. Natural frequencies and related mode shapes are natural characteristics of mechanical systems. They reflect the actual load bearing performance of a mechanical system, A system control by vibration analysis with an experimental method to detect natural frequencies and related mode shapes is presented requiring no artifical excitation of the investigated structure. System parameters are asssessed quantitatively by fitting computations on experimental results. Ongoing work on structural and system analyses even for complete piping systems taking into account the actual support behaviour as well as degraded (cracked) pipe cross sections within the piping system is expected to fill the remaining gap between practical experience and the outcome of prediction methods. Predictions are possible as for the load bearing and deformation behaviour as well as validation of the flexibility of the complete piping system (system behaviour).