Application of Fast Fourier Transformation Methods in the Frame of Uncertainty and Sensitivity Studies for Reflood Experiments

摘要

In the present paper, an uncertainty studied related to reflood experiments is performed with TRACE (thermo-hydraulic evaluation), FFTBM (parameter range evaluation of the uncertain parameters) and SUSA (uncertainty and sensitivity evaluation). Experimental data of the FEBA (Flooding Experiments with Blocked Arrays) program are selected and modeled with the thermal-hydraulic system code TRACE to investigate the influence of the variation of selected parameters like the interfacial friction/heat transfer, the wall-to-fluid friction/heat transfer, etc. One of the main concerns of this investigation is the definition of the range of the variation of these parameters since no experimental (measured) data are available. Therefore, by means of fast Fourier transformation, the ranges will be calculated with the FFTBM software. The obtained uncertainty ranges will be used afterwards in an uncertainty and sensitivity study carried out with the SUSA software package. The obtained results for the cladding temperatures and the quench front propagation are compared to the experimental results showing a good agreement to the experimental trends and that these trends are, in most of the cases, are enveloped by the calculated uncertainty range. Furthermore, it will be shown that the uncertainty ranges will increase with elevation and also with transient progression.