Currently, the development of evaluation technology for vibration and shock loads transmitted to spent nuclear fuel and structural integrity of spent nuclear fuel under normal conditions of transport is progressing in Korea by the present authors. Road transportation tests using surrogate spent nuclear fuel were performed in September, 2020 using a test model of KORAD-21 transportation cask and sea transportation tests were conducted from September 30 to October 4, 2021. Finally, the shake table tests and rolling test were conducted from October 31 to November 2, 2022. The shake table test was performed with the input load produced conservatively from the data obtained from the road and sea transportation tests. The test input was produced based on the power spectral densities and shock response spectrums from the transportation tests. In addition to the test inputs from the road and sea tests, sine sweep input and half sine input were used to verify the vibration characteristics of assemblies under boundary conditions during normal conditions of transport. Because the input load of the shake table test was produced conservatively, a slightly larger strain than the strain value measured in road and sea transportation tests was measured from the shake table tests. In the case of the sea test, it is considered that the process of enveloping the data in the 20 to 80 Hz range generated by the engine propeller system was performed excessively conservatively. As a result of analyzing the test results for the difference in boundary conditions, it was confirmed that the test conditions of loading the basket generated a relatively large strain compared to the conditions of loading the disk assembly for the same input load. Therefore, it is concluded that a transportation cask having a structure in which a basket and a disk are separated, such as KORAD-21, is more advantageous in terms of vibration shock load characteristics under normal conditions of transport than a transportation cask having an integral internal structure in which a basket and a disk are a single unit. However, this effect will be insignificant because the load itself transmitted to the disk assembly is very small.

In this study, we conducted a shake table test to verify the seismic performance of the paneling system with steel truss composed of bolt connections. The control group was set to the traditional paneling system with steel truss connected by spot welding method. Test results showed that the bolted connection type paneling system has excellent deformation capacity without cracking or brittle fracture of the steel truss connection parts compared to the welding type paneling system. Furthermore, in the bolted connection type, slight damage occurred at the time of occurrence of the same story drift angle as compared with the existing method, it is considered that it has excellent seismic performance. In compliance with the performance-based design recommended for the current code (ASCE 41-13) on non-structural components, it is judged that in the case of the bolted connection type paneling system, it can be applied to all risk category structures without restriction. However, in the case of traditional paneling system with spot welding method, it is considered that it can be applied limitedly.

In this study, dynamic characteristics and seismic capacity of the nuclear power plant piping system are evaluated by model test results using multi-platform shake table. The model is 21.2 m long and consists of straight pipes, elbows, and reducers. The stainless steel pipe diameters are 60.3 mm (2 in.) and 88.9 mm (3 in.) and the system was assembled in accordance with ASME code criteria. The dynamic characteristics such as natural frequency, damping and acceleration responses of the piping system were estimated using the measured acceleration, displacement and strain data. The natural frequencies of the specimen were not changed significantly before and after the testing and the failure and leakage of the piping system was not observed until the final excitation. The damping ratio was estimated in the range of 3.13 ~ 4.98 % and it is found that the allowable stress(345 MPa) according to ASME criteria is 2.5 times larger than the measured maximum stress(138 MPa) of the piping system even under the maximum excitation level of this test.

In this study, the shake table tests were performed for seismic performance evaluation of fire protection riser pipes. The specimen was subjected to a tri-axial time history shake table test with acceleration levels corresponding to the 0.5g and 0.7g ZPA design level.

In this study, the shake table test of the damaged reinforced concrete frame was carried out and the damage and dynamic response characteristics were evaluated. The static lateral-cyclic test for the specimen was followed by the dynamic test. As a result of the shake table test, damage was concentrated on existing cracks and the maximum inter-story drift ratio was calculated as 1.94% at the final excitation step.

이 연구에서는 유체저장탱크의 내진 설계 고도화에 활용하기 위하여 정사각형 수조의 슬러싱 진동대실험에 대한 상관해석을 수행 하였다. 이를 위하여 CFD 프로그램인 ANSYS CFX를 이용하였다. CFD 해석 프로그램 검증을 위해 슬러싱 공진이 발생하는 운동에 대한 해석 모델의 요소크기 및 난류모델에 대한 슬러싱응답의 민감도해석을 수행하였다. 그 결과, 수직방향 요소크기 뿐만 아니라 수평방향 요소크기에 따라 수위 예측에 민감한 영향을 미치는 것을 알 수 있었다. 또한, SST 난류모델을 사용한 CFD해석 결과가 실험 결과와 매우 잘 일치하는 것을 알 수 있었다. 이로부터 결정된 CFX 해석모델을 사용하여, 가진 주파수와 가진 진폭이 다른 3가지 실험 결과에 대하여 상관해석을 수행하였다. 그 결과, CFD해석모델을 사용하여 지진해석을 수행할 경우, 슬러싱응답이 실험 결과와 매우 잘 일치하는 것을 알 수 있었다.

Interest in seismic performance evaluation is increased due to various earthquake in the world. Many studies about fragility analysis of structure are performing which is based on probability analysis of failure for infrastructures maintenance. In this study, probability of failure for a numerical model of prototype square-shape reinforced concrete column was calculated in accordance with amplitude of seismic ground motion. The numerical model was updated based on results from shake table tests. The probability of failure will be used for comparing with that for scaled models. The difference of fragilities from prototype and scaled model can be confirmed by the comparing in a further study.