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Nishida, Akemi; Igarashi, Sayaka*; Sakamoto, Shigehiro*; Uchiyama, Yasuo*; Yamamoto, Yu*; Muramatsu, Ken*; Takada, Tsuyoshi*
Transactions of the 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 10 Pages, 2013/08
Most probabilistic risk assessments (PRA) of structures involve the use of probabilistic schemes such as the scheme using probabilistic seismic hazard and fragility curves. Even when earthquake ground motions are required in Monte Carlo Simulations (MCS), they are generated to fit the specified response spectra, such as uniform hazard spectra at a specified exceedance probability. These ground motions, however, are not directly linked with corresponding seismic source characteristics. In this context, the authors propose a methodology based on MCS to reproduce a set of input ground motions to develop an advanced PRA scheme that can explain the exceedance probability and sequence of functional loss in a nuclear power plant. These generated motions are consistent with the seismic hazard for the target site and their seismic source characteristics can be recognized in detail.
Minagawa, Keisuke*; Fujita, Satoshi*; Yamaguchi, Akira*; Takata, Takashi*; Kurisaka, Kenichi
Transactions of the 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 9 Pages, 2013/08
Application of seismic isolation system using rubber bearings into nuclear power plants has been expected. Generally, rubber bearings have nonlinear characteristics in case of large deformation. In addition, the horizontal nonlinear characteristics depend on vertical load. Therefore it is important to consider these nonlinearity and coupling effect. Authors have already reported results of seismic response analysis of an isolated reactor building considering the nonlinearity of rubber bearings. In this paper, seismic response analysis considering the coupling effect of horizontal and vertical deformation of rubber bearings is investigated by numerical simulations. The summaries of the simulations are as follows. The vertical motion affected the start displacement of hardening, so that the coupling effect decreased isolation performance of horizontal direction. However the isolation system is still effective to reduce seismic force even if the nonlinearity and the coupling effect were considered.
Wakai, Takashi; Inoue, Osamu*; Ando, Masanori; Kobayashi, Sumio
Transactions of the 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 9 Pages, 2013/08
Watakabe, Tomoyoshi; Kitamura, Seiji; Tsukimori, Kazuyuki; Morishita, Masaki
Transactions of the 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 10 Pages, 2013/08
It is important to confirm failure modes and safety margin until ultimate strength of piping components from the point of view of seismic safety. Though, many dynamic failure tests of the thick-wall piping components for Light Water Reactors (LWRs) have been performed, there are little dynamic failure test data of the thin-wall pipe for Fast Breeder Reactors (FBRs). This paper presents a series of dynamic failure tests of thin-wall elbows with the diameter/thickness ratio close to that of the main piping of FBRs and discusses about vibration characteristics in elastic-plastic region, failure modes under dynamic load and the results of piping design evaluation for the test model. Moreover, the test results were compared to the Finite Element Analysis (FEA) results.
Nakajima, Norihiro; Nishida, Akemi; Matsubara, Hitoshi*; Hazama, Osamu*; Suzuki, Yoshio; Sawa, Kazuhiro; Iigaki, Kazuhiko
Transactions of the 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 10 Pages, 2013/08
It is not convenient to experimentally analyze its behavior under strong loads of earthquakes, since the facility is extremely huge and complex. The proposed system performs numerical simulations to evaluate the behaviors of an assembly like a nuclear facility. This system projects the components of an assembly onto both/either a distributed and/or a parallel computing environment in order to conduct a simulation of the behavior of an assembly such as a nuclear facility. In a result discussion, a numerical experiment was carried out with a cantilever model and its result was compared with theoretical data. A good corresponding among them was obtained as a structural analysis of an assembly by using a parallel computer. As a conclusion, a suggested methodology has shown to calculate a behavior of an assembly with High Temperature engineering Test Reactor.