This paper describes the seismic analysis of reactor building of a Nuclear Power Plant including the soil structure interaction analysis for uniform soil. The soil stiffness of the soil below foundation has been computed from two standards ASCE 4-98 and RCC-G and comparison is made. Simplified lumped mass stick model for time history analysis of reactor containment building along with internal structures is made in SAP2000 advanced V 11.0.2. The time history of Kashmir Earthquake on October 8, 2005 is used as input motion. In SSI analysis, the elastic half space theory is used for calculating translational and rotational springs from both RCC-G and ASCE 4-98 Standards. Floor response spectra are generated at various floors of the reactor building using stiffness values computed from both standards and comparison is made. This analysis gives a better understanding of the differences between RCC-G and ASCE 4-98 in terms of SSI which found to be significant. It is found that the RCC-G standard gave more conservative responses so it should be given preference where the soil is sandy and uniform.
