## 5 Conclusions  
In this study, the shaking table tests of the lead inserted small-sized LRBs were performed with the dummy mass system and the applicability of the horizontal seismic isolation to the nuclear facility components was investigated in detail.  
Through all shaking table tests specified in the test matrix and the seismic verification analyses, some valuable conclusions are derived as follows;  
1. The tests of full-scaled LRBs can assure the reliability of the seismic isolation performance by removing the uncertainties potentially contained in the reduced-scale tests.
2. It was confirmed that the mechanical characteristics of LRB identified by the quasi-static tests were very similar to the results of the dynamic seismic shaking table tests.
3. The lead plug inserted in the center of the LRB reveals a good damping function by adequately restricting the shear displacement as targeted in the LRB design.
4. As intended in the test matrix starting tests sequentially from large to small level earthquakes, it was confirmed that LRB maintains seismic isolation performance against aftershocks even after experiencing the level of beyond design basis earthquakes.
5. The smaller the seismic input load level, the less the seismic isolation effect. This is because in the region where the shear displacement of LRB is small, the initial stiffness effect of the lead plug is large, and the frequency shift effect of the seismic isolation system is reduced.
6. As a result of performing the same repeated shaking table tests for each different LRB set of mockups, almost the same test results were obtained, and from this, the reliability of manufacturing the lead inserted small-sized LRB was confirmed.
7. It is confirmed that the developed LRB in this study has a seismic capacity accommodating PGA = 0.5 g (seismic fragility capacity, 0.625 g) at the 137 ft elevation of the nuclear power plant building structures.
8. It is recommended that the allowable seismic shear strain of LRB developed in this study is 400% for application to the nuclear facility components. When applied to  
Figure 22: LRB shear displacement responses: (**a**) Comparison of maximum values; (**b**) Hysteretic response with Bi-linear model.  
input seismic load exceeding this stain level, more additional shaking table tests are required to confirm higher shear strain limit.
* From the comparison results between the shaking table tests and the seismic analyses, it is found that the Bi-linear model or the equivalent stiffness-damping model of LRB can be used in the seismic analysis as a simple method when using well-identified stiffness and damping value of LRB.  
Conceptualization, G.-H.K., T.-M.S., and S.-J.M.; methodology, G.-H.K. and T.-M.S.; validation, G.-H.K.; formal analysis, G.-H.K.; investigation, T.-M.S. and S.-J.M.; writing--original draft preparation, G.-H.K.; writing--review and editing, T.-M.S. and S.-J.M.; funding acquisition, G.-H.K., T.-M.S. All authors have read and agreed to the published version of the manuscript.  
This study was funded by the Ministry of Trade, Industry, and Energy through KETEP (Korea Institute of Energy Technology Evaluation Planning) (No. 20181510102380).  
The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
Not Applicable.  
This study was supported by the Ministry of Trade, Industry, and Energy through KETEP (Korea Institute of Energy Technology Evaluation Planning) (No. 20181510102380).  
The authors declare no conflict of interest.