Abstract: A simplified methodology for assessing the shock and vibration effects of the aircraft impact on nuclear power plant (NPP) is discussed in this paper. Both the force time-history method (FTHM) and the missile-target interaction method (MTIM) are used to assess NPP shock response and its propagation. Then, the effects of both the material nonlinearity and the soil-structure interaction (SSI) on NPP in-structure shock response spectra are presented. Finally, an example of assessing the shock effects on the safety-related system, equipment, and component is provided based on NPP seismic margin assessment. The results show that the maximum displacement and the displacement time history of the NPP impact location obtained from both the FTHM and MTIM are almost the same, but the response spectrum obtained from the MTIM show more high frequency energy than those from FTHM. The shock response will obviously decrease as the shock propagation distance increases, and the difference between the in-structure response spectra obtained from these two methods will also decrease. Both the material nonlinearity and SSI will significantly reduce the NPP shock response, and the response spectrum of the seismic margin assessment can be used as the acceptance criteria for the shock assessment.