[en] In order to perform the dynamic analysis of various structural components of the HFBR reactor building at Brookhaven National Laboratory (BNL) subjected to seismic disturbances, it is necessary to obtain the floor response spectra of the primary structure. The mathematical model includes the four floor levels of the internal structure, the dome, and soil spring effects. The standard time history analysis is adopted to obtain the response spectrum for each floor of the internal structure. This report summarizes the results both in tabular and graphical form for various damping values