## 5 Conclusions  
In this study, shaking table tests are performed to validate the inelastic seismic analysis method applicable to the nuclear metal components. To do this, a test mockup, which can simulate the hot leg surge line nozzle, known as one of the nuclear seismic fragile components in NSSS, was designed and tested on the shaking table with seismic input motions corresponding to design-basis earthquake (PGA = 0.3 g) and beyond-design-basis earthquake (PGA = 0.6 g) levels. To validate the inelastic seismic analysis method, detailed comparisons of seismic responses between the tests and inelastic seismic analyses were carried out, especially for the seismic responses of the principal strains at the nozzle and the accelerations at the pipe. From this study, some meaningful conclusions have been derived, as follows:  
1. The seismic responses obtained from the inelastic seismic time history analyses with an accurate inelastic material model using [PERSON]'s kinematic hardening model and the Voce isotropic hardening model for Type 316 stainless steel are in good agreement with those of the seismic shaking table tests.
2. From the comparison of the seismic strain time history responses at the nozzle between the tests and inelastic analyses, the location of the maximum strain responses from the inelastic analyses was found to be almost the same as the locations in the test results.
3. The structure damping value for the piping systems, recommended in the US NRC RG 1.61 [24], is 4% for the SSE level. However, in this study, the piping system made of Type 316 stainless steel revealed a much lighter damping value of about 0.57%.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Directions** & **PGA** & **Tests** & **Inelastic Seismic** \\  & **(g)** & **(g)** & **Analysis (g)** \\ \hline EW & 0.3 & 5.55 & 6.17 \\  & 0.6 & 8.76 & 9.90 \\ \hline NS & 0.3 & 9.26 & 12.68 \\  & 0.6 & 12.70 & 16.80 \\ \hline V & 0.3 & 6.23 & 8.71 \\  & 0.6 & 9.88 & 12.60 \\ \hline \hline \end{tabular}
\end{table}
Table 11: Comparison results of ZPA responses at the pipe end (Accelerometer-3).  
Figure 23: Comparison results of the response spectrum at the pipe end (Accelerometer-3) for PGA = 0.3 g.  
4. For earthquakes large enough to result in inelastic behavior at the nuclear metal components, the inelastic seismic analysis is useful for reducing the seismic responses by energy dissipation due to hysteretic damping.
5. From the validation results obtained from the test mockup simulating the actual nuclear component in this study, it is assured that the inelastic seismic analysis method can be used for the seismic design of nuclear metal components in large earthquake scenarios such as the beyond-design-basis earthquake, which can cause significant plastic deformations.  
Conceptualization, G.-H.K., S.-W.A., [PERSON]-K.H. and [PERSON]-S.K.; methodology, G.-H.K., S.-W.A. and J.-S.K.; validation, G.-H.K.; formal analysis, G.-H.K.; investigation, S.-W.A. and [PERSON]-S.K.; data curation, S.-W.A.; writing--original draft preparation, G.-H.K.; writing--review and editing, [PERSON]-W.A., [PERSON]-K.H. and [PERSON]-S.K.; funding acquisition, G.-H.K., [PERSON]-K.H. and J.-S.K. 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 authors declare no conflict of interest.