In the "hot" portion of the thermal loop in a nuclear plant, the design must provide for a fail safe dam in case the heat exchanger must be dry repaired. The quick-bolt concept allows the dam to be installed with bolts that fully engage in a quarter turn.
To dam the nozzle from the core, personnel must crawl into the pipe with the dam and attachment hardware. To reduce the burden, the dam must be as light as possible. We performed shape optimization on a proposed design to minimize the weight while still fulfilling ASME code requirements.
The motor base for large motors must be carefully designed to avoid vibration. This particular motor base exhibited torsional vibration of the base that resulted in significant vibrational displacements.
Torsional vibration in shafting is difficult to detect in-service but the consequences of excessive torsional vibration invariably result in broken shafts. The analysis must consider all the possible exciting frequencies: vane passing, line and multiples, and the torque fluctuations from speed controllers.