Seismic design of the HDR/VKL-piping system without snubbers and preliminary results of building shaker tests

The reactor building of the HDR has recently been subjected to intense dynamic loads in a series of tests which induced cyclic base excitation of existing mechanical components and piping systems. A large, eccentric mass, coast-down shaker was installed on the operating floor of the building. Horizontal floor accelerations were measured in the vicinity of the VKL-piping system to be considered here in the course of various tests with different initial shaker coast-down frequencies. The corresponding response spectra are shown. They can be compared with an enveloped safety-earthquake spectrum at a relevant location of the reactor building of a modern PWR-plant in the FRG. Measured vertical floor accelerations were an order of magnitude smaller. (orig./HP)