Seismic margins tests of a piping system at the HDR facility

In the actual state of SHAM test analysis the key results can be summarized as follows: - the design of all configurations proved to be conservative, since all stesses were limited to the allowable values. Forces in supports were partly under- and partly overestimated. - The piping system could be exposed to at least 300% of the design loads in 5 different support configurations. The HDR-configuration which was not designed for seismic loads withstood a 200% SSE load without any damage or global residual deformation. - The Energy Absorbers behaved in all aspects as expected. The replacement of 6 snubbers by only 3 Energy Absorbers was sufficient to keep pipe stresses within the limits. - The replacement of all snubbers by Seismic Stops kept the pipe stresses within the allowable limits. - The stiff NRC-configuration was tested up to 8 times the design loads. In the 600% SSE test 3 snubbers failed. They were not replaced for the 800% SSE tests, during which another snubber failed from o verloading. Nevertheless, the pipe was not damaged and showed no global plastic deformation. - The flexible support configuration designed by Siemens/KWU could be exposed to 8 times the design loads without any problems. - In the highest stressed points of the pipe strain ranges of 1.5% were measured and residual strains accumulated to 1.2%. - Seismic margins of rigid struts are clearly greater than the expected factor of 3 to 4. None of the struts failed in any of the tests although overloadings of up to a factor of 9 were realized.