[en] The safety case relating to protection against the effects of earthquakes is discussed for the proposed Sizewell B nuclear power station. Conclusions on sensitivity studies of events beyond the safe shutdown earthquake (SSE) level, on the level of permissible stresses arising from SSE loads, on the pre-qualification approach to operating basis earthquake or operational shutdown earthquake loads, and on the absence of offshore tectonic features that might influence the seismicity of the Sizewell site are described. Additional work is required on load combinations and the provision of an external hazards trip. (UK)