Fluid-structure interaction experiments of PEC core mock-ups and numerical analysis performed by ENEA

The first part of the studies in progress in the framework of the Research Co-ordination Meeting (RCM) of IAEA CRP on ''Intercomparison of Liquid Metal Fast Breeder Reactor (LMFBR) Seismic Analysis Codes'' has been based on the results of dynamic experiments which were performed on various element groups of the PEC fast reactor core. In these tests, individual simplified elements and bundles of seven and nineteen simplified elements reproducing the actual fuel, reflecting and neutron shield elements in full scale were analyzed on shaking tables, in both air and water (simulating liquid sodium). Tests concerned both groups of equal elements and mixed configurations which corresponded to actual core parts. The effects of PEC core-restraint ring were also studied. Seismic excitations to 2.5 g were applied to core diagrid. The results were analyzed by ENEA using both the one-dimensional program CORALIE and the two-dimensional program CLASH. The study allowed the fluid effects in the PEC core to be evaluated; it also contributed to the validation of the above mentioned programs for their general use for fast reactor core analysis. This report describes the experimental and numerical studies and presents comparisons between ENEA calculations and measurements, stressing the most important test features and items which need for particular care in the numerical analyses of experimental data. (author). 24 refs, 19 figs, 10 tabs