Development and application of an efficient method for performing modal analysis of steam generator tubes in nuclear power plants

摘要: Abstract A typical pressurized water reactor (PWR) steam generator has approximately 10,000 tubes. These tubes have different geometries, supporting conditions, and material properties due to the non-uniform temperature distribution throughout generator. Even though some may same geometry boundary of coolant densities adjacent causes them added mass effects dynamic characteristics. Therefore, for a reliable design generator, separate modal analysis each tube is necessary perform FIV (flow-induced vibration) analysis. However, including finite element modeling cumbersome takes lots time. And when commercial code used, interfacing result, such as natural frequencies mode shapes, with procedure requires an additional significant amount time can possibly incur inadvertent error complexity data processing. It therefore impossible complete ten thousands designing or maintaining although it necessary. Rather, verify safe against FIV, only couple are chosen based on engineering judgment past experience. In this paper, computer program, PIAT-MODE, was developed which able all PWR in very efficient way. The geometries conditions every were incorporated into PIAT-MODE using appropriate mathematical formulae. Material property effect also included program. Once specific selected, program automatically constructs model generates quickly. be performed single straight When coupled gives amazing benefit, makes possible within limited during maintenance period. Using stability ratio regarding fluid-elastic instability amplitude vibration resulting from turbulence flow excitation calculated according standard ASME Code, therefore, much more related failures achieved. For operating plant, there requirement that must quantitatively checked whether wear would than 40% thickness next operation If yes, plugged prevent severe failure wall penetration. order decide plugging, leads plant performance degradation, prediction required. needs by ultrasonic testing will power tool enabling period supplying