Hydrodynamic loading and response of reactor internals using 3D STEALTH/WHAMSE

A three-dimensional methodology was developed for realistically predicting fluid-structure interaction transient loads and the structural response of the rector vessel, core support barrel, and core during the subcooled portion of a hypothetical loss-of-coolant accident. As described in this paper, the methodology uses a hydrodynamic computer program. STEALTH 3D, coupled with a structural response program WHAMSE 3D, to calculate the hydrodynamic and structural behavior of two tests in the HDR blowdown program in Karlstein, Germany. The posttest calculation of one test and the pretest calculation of the other are compared with the experimental data from the two tests, and reasonably good agreement is observed. The methodology was then applied to the calculation of the structural response of simulated pressure vessel internals during a postulated LOCA of a PWR. The model was a modification of the model in one of the HDR calculations. The PWR/HDR model included a simplified core represented by an axially located center beam so that the configuration was more typical of a large PWR than was the HDR model. Results of the PWR/HDR calculation are compared with the HDR results. Transient response of the axially distributed beam core is also discussed. (orig.)