This paper presents findings from our initial work in developing a seismic isolation system for the STAR-LM reactor design. Research and development was carried out to determine the characteristics of the isolator device. The heavy weight and small footprint presented a challenge in bearing design and bearing placement. Results are also presented from a study on the use of three-dimensional seismic isolation devices to the full-scale reactor. Both two-dimensional (i.e., one device for horizontal isolation only) and integral (i.e., one device for horizontal and vertical) concepts were explored. The seismic analysis responses of the two-dimensional and the three-dimensional isolation systems for the STAR-LM are compared with that of the conventional fixed base system. Finally, results are presented from a study on the effects of the levels of vertical and horizontal damping on the seismic response of STAR-LM.