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Okuda, Yukihiko; Nishida, Akemi; Sakai, Michiya*; Shiogama, Yuzo*; Li, Y.
Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 6 Pages, 2021/08
To develop a more realistic seismic evaluation method of nuclear power plants, it is necessary to evaluate the seismic behavior considering the joints of each component that are treated as independent models during design evaluation, such as buildings, equipment, and piping systems. Particularly, the piping support structure, which is the joint between the building and piping, is important in the seismic evaluation of the piping system. While the current seismic evaluation of piping support structures is performed within the elastic range, it is important to consider the realistic elastic-plastic response of piping support structures for fragility assessment in seismic probabilistic risk assessment. However, the seismic evaluation method that considers the elastic-plastic response of piping support structures has not yet been established, and there is a need to improve seismic evaluation methods. In this study, a hybrid dynamic response test for simulating the seismic behavior of the piping support structure, including the elastic-plastic response, has been conducted. Specifically, static cyclic loading tests and hybrid dynamic response tests were conducted using four types of piping support structures to understand the basic mechanical behavior. This report presents the details of the tests and test results.
Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki; Kondo, Makoto; Sakai, Michiya*; Shiogama, Yuzo*
Progress in Nuclear Science and Technology (Internet), 2, p.576 - 581, 2011/10
Design evaluation of nuclear facilities would be facilitated by a numerical evaluation system that can evaluate both global and local behaviors under severe seismic loading. A critical part of such a system is the numerical model describing the dynamic physical interactions among component connections, called the elastic-plastic connection model. Here we propose such a model and use it to simulate dynamic interactions using real earthquake and plant data from the High Temperature Engineering Test Reactor (HTTR) of the JAEA. We focus on joints connecting the component supports and the building walls, which generally involve fixed/pinned boundary conditions. The results confirmed a reduction in the vibration response and a change in the natural frequencies of individual components under large virtual earthquake loading, which are considered to have resulted from dynamic interactions between the joints connecting the component supports and the building walls.
Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki; Kondo, Makoto; Sakai, Michiya*; Shiogama, Yuzo*
Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 6 Pages, 2010/10
The objective of this research is to contribute to the seismic design evaluation of nuclear facilities through the construction of a numerical evaluation system which is able to evaluate both global and local behaviors of facilities under severe seismic events. As one of the technology components to realize this objective, we are developing a physical model describing the dynamic interaction characteristics of component connections, called as the elastic-plastic connection model. We focused on the joints of the support structures of the component and the building in nuclear plants which generally designed as fixed/pinned boundaries, and tried to consider their dynamic interaction effects. In this paper, we show the proposal of the elastic-plastic connection model and the application of the model to a numerical simulation using a real plant data. The precision of the model was optimized by adjusting its parameters using the data obtained in the experiment.
Sakai, Michiya*; Shiogama, Yuzo*; Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki
no journal, ,
For the purpose of an advancement of the evaluation technology for earthquake resistance of the nuclear plants, we paid attention to the support structures of component system of the nuclear plants generally designed as fixed/pinned boundaries. The specimens were prepared and static cyclic load experiments and hybrid earthquake response experiments were carried out for them. From the experimental results, we got some knowledge about the basic load resistant characteristics and the damage modes of those support structures.
Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki; Kondo, Makoto; Sakai, Michiya*; Shiogama, Yuzo*
no journal, ,
In this study, we propose a physical model that can describe dynamic characteristics of the joints between different components in a nuclear plant, with a view to understanding the entire and local behaviors of the nuclear plant simultaneously. The physical model, called as the elastic-plastic connection model, is presented in this paper, which considers the dynamic interaction between the joints of the support structures of the component and the building itself. By using this model, it becomes possible to introduce a partial elastic-plastic (non-linear) model into a large-scale three-dimensional elastic (linear) model. The precision of the elastic-plastic connection model was optimized by adjusting its parameters using the data obtained in the experiment. In addition, we showed that the elastic-plastic connection model can be used for numerical simulation with three-dimensional real plant data.
Sakai, Michiya*; Shiogama, Yuzo*; Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki; Kondo, Makoto
no journal, ,
We focused on the joints of support structures in nuclear plants which generally designed as fixed/pinned boundaries and evaluated their earthquake-resistant properties through finite element analyses. A piping support structure and a component support structure were modeled and elastic-plastic analyses were performed on them. The analytical results were compared with the experimental results, and it was confirmed that the load-displacement relations, the concentration of the local deformations or strains, and the strain accumulation behavior obtained by analytical results had proper precision.
