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Nakamura, Izumi*; Takito, Kiyotaka; Shimazu, Ryuya*; Okuda, Yukihiko; Sakai, Michiya*; Otani, Akihito*; Watakabe, Tomoyoshi; Okuda, Takahiro; Shibutani, Tadahiro*; Shiratori, Masaki*
Proceedings of the ASME 2024 Pressure Vessels & Piping Conference (PVP 2024) (Internet), 9 Pages, 2024/07
Nakamura, Izumi*; Otani, Akihito*; Okuda, Yukihiko; Watakabe, Tomoyoshi; Takito, Kiyotaka; Okuda, Takahiro; Shimazu, Ryuya*; Sakai, Michiya*; Shibutani, Tadahiro*; Shiratori, Masaki*
Dai-10-Kai Kozobutsu No Anzensei, Shinraisei Ni Kansuru Kokunai Shimpojiumu (JCOSSAR2023) Koen Rombunshu (Internet), p.143 - 149, 2023/10
In 2019, the JSME Code Case for seismic design of nuclear power plant piping systems was published. The Code Case provides the strain-based fatigue criteria and detailed inelastic response analysis procedure as an alternative design rule to the current seismic design, which is based on the stress evaluation by elastic response analysis. In 2022, it was approved to revise the Code Case with improving the cycle counting method for fatigue evaluation to the Rain flow method. In addition, the discussion to incorporate the elastic-plastic behavior of support structures is now in progress for the next revision of the Code Case. This paper discusses the contents and background of the 2022 revision, the progress of the next revision, and future tasks.
Morishita, Masaki; Otani, Akihito*; Nakamura, Izumi*; Watakabe, Tomoyoshi; Shibutani, Tadahiro*; Shiratori, Masaki*
Journal of Pressure Vessel Technology, 142(2), p.021203_1 - 021203_14, 2020/04
Times Cited Count：17 Percentile：61.35(Engineering, Mechanical)A Code Case in the framework of the Nuclear Codes and Standards of Japan Society of Mechanical Engineers (JSME) has been published to incorporate seismic design evaluation methodologies for piping systems by detailed inelastic response analysis and strain-based fatigue criteria as an alternative design rule to the current rule, in order to provide a more rational seismic design evaluation by taking directly the response reduction due to plasticity energy absorption into account. The Code Case provides two strain-based criteria; one is a limit to maximum amplitude of equivalent strain amplitude derived from detailed analysis and the other is a limit to the fatigue usage factor also based on the equivalent strain amplitude. The Code Case also provides a guideline for recommended standard analysis method. Discussions are provided on the safety margin and reliability of fatigue evaluation by the detailed inelastic response analysis provided in the Code Case.
Watakabe, Tomoyoshi; Nakamura, Izumi*; Otani, Akihito*; Morishita, Masaki; Shibutani, Tadahiro*; Shiratori, Masaki*
Proceedings of the ASME 2017 Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 10 Pages, 2017/07
To provide a more rational seismic design, a new Code Case for seismic design of piping is now under development in the framework of JSME Nuclear Codes and Standards. The Code Case incorporates a dynamic elastic-plastic analysis procedure by employing finite element analysis as an alternative to the current design analysis method of elastic assumption. To confirm the applicability of inelastic response analysis, benchmark analyses have been conducted.
Morishita, Masaki; Otani, Akihito*; Watakabe, Tomoyoshi; Nakamura, Izumi*; Shibutani, Tadahiro*; Shiratori, Masaki*
Proceedings of the ASME 2017 Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 7 Pages, 2017/07
Nakamura, Izumi*; Otani, Akihito*; Morishita, Masaki; Shiratori, Masaki*; Watakabe, Tomoyoshi; Shibutani, Tadahiro*
Proceedings of the ASME 2017 Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 10 Pages, 2017/07
Nakamura, Izumi*; Takito, Kiyotaka; Shimazu, Ryuya*; Okuda, Yukihiko; Sakai, Michiya*; Watakabe, Tomoyoshi; Okuda, Takahiro; Otani, Akihito*; Shiratori, Masaki*; Shibutani, Tadahiro*
no journal, ,
no abstracts in English
Nakamura, Izumi*; Otani, Akihito*; Morishita, Masaki; Okuda, Yukihiko; Watakabe, Tomoyoshi; Shibutani, Tadahiro*; Takito, Kiyotaka; Okuda, Takahiro; Shiratori, Masaki*
no journal, ,
no abstracts in English
Takito, Kiyotaka; Nakamura, Izumi*; Okuda, Yukihiko; Sakai, Michiya*; Shimazu, Ryuya*; Otani, Akihito*; Watakabe, Tomoyoshi; Okuda, Takahiro; Shibutani, Tadahiro*; Shiratori, Masaki*
no journal, ,
The Piping systems in the nuclear power plants are known to exhibit significant elastic plastic behavior before failure caused by the response displacement under serve seismic load. Current Code Case considers the elastic-plastic behavior of piping system itself, but assumes the elastic behavior for the support structure. Thus, it is desirable to incorporate the inelastic behavior of piping support structure as the future upgrading of the Code Case. In order to develop an evaluation method for inelastic behavior of support structures, the authors as the JSME task group carried out benchmark analyses of piping support structures. Then, the purpose of the benchmark analysis is in order to evaluate the influence of the analysis parameters in the elastic plastic analysis of piping support structures and to obtain knowledge on the variability of the analysis results. This paper reports on the outline and progress of the benchmark analyses.
