Scaling Laws for Model Test Based BWR Steam Dryer Fluctuating Load Definitions

In recent years some Boiling Water Reactors have experienced significant steam dryer cracking. In some cases this cracking has necessitated unplanned outages to implement steam dryer repairs and has also resulted in de-rated operation of the affected units. In response to these recent steam dryer failures, GE has initiated a research program focused on identifying the nature of the fluctuating loads experienced by the steam dryer and developing predictive methods that can be used to develop load definitions for steam dryers. The physical mechanisms responsible for excitation of aero-acoustic resonances are not easily modeled using purely analytic methods; therefore, GE has decided to perform model tests to investigate the nature of the expected steam dryer loading. The objectives of the study documented in this paper are to: 1) Provide guidance regarding how to preserve, in the model, the significant fluid phenomena occurring in the plant, and 2) Derive scaling laws to convert model data to plant load predictions.