Development of seismic safety assessment technology for SSI systems of nuclear power plants

This paper presents the seismic safety assessment technology developed by the Korea Institute of Nuclear Safety (KINS) for soil-structure interaction (SSI) systems of nuclear power plants. In the study, SSI analysis methods were developed and complemented such as the substructure method utilizing a lumped-parameter model and the direct method based on the infinite element and the hyper element. Based on the methods, the computer codes, LUMSSI, KIESSI, HYPER3X were developed. The computer codes FREE and M-SHAKE were also developed for site response analysis. The M-SHAKE is a user-friendly, complemented version of the previously developed code SHAKE. To validate the analysis methodologies and the computer codes, KIESSI, LUMSSI, HYPER3X, and SASSI which had been already installed in the KINS, we are participating in the Hualien LSST project which is an international cooperative research project. For the Hualien LSST, blind prediction and post-correlation analyses for the forced vibration of the test model before and after backfill, and earthquake response analyses were carried out. Earthquake response analysis of the Lotung LSST model in Taiwan, and forced vibration analysis and earthquake response analysis of the test model by TEPSCO, Japan, were also performed by using thee LUMSSI and the KIESSI. The analyses gave satisfactory results. In addition, guidelines for seismic safety assessment of SSI systems were developed in the study through utilizing the SSI analysis results of the test models and performing additional parametric studies. (author). 11 refs., 11 figs