HTGR Knowledge Base

Conference Article: Effect of foundation embedment on the seismic response of a high-temperature gas-cooled reactor plant

Lee, T.H.; Thompson, R.W.; Charman, C.M. (General Atomic Co., San Diego, CA)

Abstract

The effects of soil-structure interaction during seismic events upon the dynamic response of a High Temperature Gas-Cooled Reactor plant (HTGR) have been investigated for both surface-founded and embedded basemats. The influence from foundation embedment has been quantitatively assessed through a series of theoretical studies on plants of various sizes. The surface-founded analyses were performed using frequency-independent soil impedance parameters, while the embedded plant analyses utilized finite element models simulated on the FLUSH computer program. The seismic response of the surface-founded plants has been used to establish the standard-site design in-structure response spectra. These analyses were performed by using the linear modal formulation based on conventional soil stiffness and damping values. They serve as reference solutions to which the response data of the corresponding embedded plants are compared. In these comparison studies the responses of embedded plants were generally found to be lower than those of the corresponding surface-founded plants. Additional studies on the surface-founded plants have recently been performed by considering inelastic soil behavior. These inelastic solutions, which treat the soil as an elasto-plastic medium exhibiting hysteretic unloading-reloading characteristics in time, have reduced the response of surface-founded plants. Numerical results are presented in terms of in-structure response spectra along with other pertinent seismic load data at key levels of the plant. Analysis techniques for future studies using viscoelastic halfspace representation and inelastic finite element modeling for soil are also discussed.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
IAEA IWGGCR specialists' meeting on gas-cooled reactor seismic design problems and solutions. San Diego, CA (USA). 30 Aug - 1 Sep 1982
International Atomic Energy Agency, Vienna (Austria).
IWGGCR--6, pp:207-236