Nuclear Island Soil-Structure Interaction

AREVA developed an advanced nuclear power plant (NPP) design and was pursuing design certification with the US NRC for standard and site-specific applications.  The plant consists primarily of a nuclear island (NI) and several other significant structures outside of and in close proximity to the NI. The individual structures comprising the NI share a common foundation basemat embedded approximately 11.6 meters below the ground surface.

SC Solutions was retained to perform detailed seismic soil-structure interaction (SSI) analysis of the NI using the same refined and calibrated FE model as was used for stress analysis and design.  This allowed the SSI analysis to accurately address effects such as basemat and wall/diaphragm flexibilities, concrete cracking, spatial distribution of mass, and structure-soil-structure interaction with adjacent buildings.  Additionally, the use of a single unified model between SSI and stress analysis helped to streamline the exchange of complex information, and eliminate potential errors resulting from changes and/or updates when dealing with different models for various aspects of design.

Seismic SSI analysis was performed for a suite of generic and site-specific soil profiles, various standard and tailored ground motions, and with both cracked and uncracked concrete properties.  Results produced included transfer functions, in-structure response spectra, acceleration contours, and displacement profiles.

Analyses were performed in the frequency-domain using the SASSI software.  Due to the large model size and number of required analysis cases, SC Solutions developed a High Performance Computing (HPC) solver for SASSI.  These HPC capabilities re-invigorated SASSI to efficiently handle the next generation of nuclear SSI challenges.