Observations on some current issues pertaining to nuclear power plant seismic design

In this paper the author addresses some of those areas in which it is believed major research and development should be undertaken in the years immediately ahead if significant advances in earthquake engineering especially applicable to nuclear power plant design are to be achieved. From the standpoint of excitation (loading) the paper dwells extensively on concepts of so-called effective acceleration, with some comments also given on response spectra and modifications thereto. In the areas of resistance of structures attention is devoted to the topics of damping, ductility (energy absorption), and associated margins of strength to resist overloading. The need for developing comprehensive field measurement programs of ground and structural response throughout the world is cited. Future progress in earthquake engineering hinges in large part on developing a confirmatory basis for the technology, partly through continuing developments of analysis techniques and corresponding laboratory testing, but most importantly field observations in actual earthquakes which can be interpreted rationally to lend verification and support to the theoretical and design bases. Finally, the important topic of equipment seismic resistance is singled out for attention. (orig.)