Piping system response during high-level simulated seismic tests at the Heissdampfreaktor Facility: (SHAM Test Facility)

The SHAM seismic research program studied the effects of increasing levels of seismic excitation on a full-scale, in situ nuclear piping system containing a naturally aged United States (US) 8-in. motor-operated gate valve. The program was conducted by Kernforschungszentrum Karlsruhe at the Heissdampfreaktor near Frankfurt, Germany. Participants included the United States, Germany, and England. Fifty-one experiments were conducted, with the piping supported by six different piping support systems, including a typical stiff US piping support system of snubbers and rigid struts. This report specifically addresses the tests conducted with the US system. The piping system withstood large displacements caused by overload snubber failures and local piping strains. Although some limit switch chatter was observed, the motor operator and valve functioned smoothly throughout the tests. The results indicate that sufficient safety margins exist when commonly accepted design methods are applied and that piping systems will likely maintain their pressure boundary in the presence of severe loading and the loss of multiple supports