Experiment of floating seismic isolation system

Mori, Takashi*; Shimada, Takahiro*; Kai, Satoru*; Otani, Akihito*; Yamamoto, Tomohiko; Yan, X.

Proceedings of ASME 2023 Pressure Vessels and Piping Conference (PVP 2023) (Internet), 8 Pages, 2023/07

https://doi.org/10.1115/PVP2023-102224

XAFS measurement of simulated waste glass samples (Joint research)

Nagai, Takayuki; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamagishi, Hirona*; Ota, Toshiaki*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*; Takahashi, Tomoe*; et al.

JAEA-Research 2019-003, 94 Pages, 2019/09

JAEA-Research-2019-003.pdf:7.92MB

The local structures of glass-forming elements and waste elements would change by the chemical composition of waste glass including those elements. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus (P) or vanadium (V), and we investigated local structures of boron, sodium, and waste elements in these P glass and V glass samples by using synchrotron XAFS measurements in soft and hard X ray region.

Application of JSME Seismic Code Case by elastic-plastic response analysis to practical piping system

Otani, Akihito*; Kai, Satoru*; Kaneko, Naoaki*; Watakabe, Tomoyoshi; Ando, Masanori; Tsukimori, Kazuyuki*

Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 10 Pages, 2018/07

This paper demonstrates an application result of the JSME Seismic Code Case to an actual complex piping system. The secondary coolant piping system of Japanese Fast Breeder Reactor, Monju, was selected as a representative of the complex piping systems. The elastic-plastic time history analysis for the piping system was performed and the piping system has been evaluated according to the JSME Seismic Code Case. The evaluation by the Code Case provides a reasonable result in terms of the piping fatigue evaluation that governs seismic integrity of piping systems.

Shielding performance of newly developed boron-loaded concrete for DT neutrons

Sato, Satoshi*; Konno, Chikara; Nakashima, Hiroshi; Shionaga, Ryosuke*; Nose, Hiroyuki*; Ito, Yuji*; Hashimoto, Hirohide*

Journal of Nuclear Science and Technology, 55(4), p.410 - 417, 2018/04

https://doi.org/10.1080/00223131.2017.1403380

In order to enhance the neutron shielding performance, we developed concrete with boron of more than 10 wt%. We performed a neutron shielding experiment using the mockup of the newly developed boron-loaded concrete and DT neutrons at FNS in JAEA, and measured the reaction rates of the Nb(n,2n)Nb and Au(n,)Au reactions in the mockup. The calculations were conducted by using MCNP-5.14 and FENDL-2.1. The calculation results agreed well with the measured ones, and we confirmed that the accuracy was very good on the atomic composition data of the boron-loaded concrete and their nuclear data. In addition, we calculated effective dose rates and reaction rates of the Co(n,)Co and Eu(n,)Eu reactions in the boron-loaded concrete and other concretes. It is concluded that the boron-loaded concrete has much better shielding performance for DT neutrons than other concretes.

Activities of Working Group on Verification of PASCAL; Fiscal year 2015

Li, Y.; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Kanto, Yasuhiro*; Suzuki, Masahide*; Masaki, Koichi*

JAEA-Review 2017-005, 80 Pages, 2017/03

JAEA-Review-2017-005.pdf:16.85MB

For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in JAEA based on latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressurized thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to verify the probabilistic variables, functions and models incorporated in the PASCAL and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL3 which is a PFM analysis module of PASCAL, and the source program of PASCAL3 was released to the members of working group. Through one year activities, the applicability of PASCAL in structural integrity assessments of domestic RPVs was confirmed with great confidence. This report summarizes the activities of the working group on the verification of PASCAL in FY2015.

Investigation on ultimate strength of thin wall tee pipe for sodium cooled fast reactor under seismic loading

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Otani, Akihito*; Moriizumi, Makoto; Kaneko, Naoaki*

Mechanical Engineering Journal (Internet), 3(3), p.16-00054_1 - 16-00054_11, 2016/06

http://doi.org/10.1299/mej.16-00054

It is important to investigate the failure mode and ultimate strength of piping components in order to evaluate the seismic integrity of piping. Many failure tests of thick wall and high pressure piping for Light Water Reactors (LWRs) have been conducted, and the results suggest that the failure mode that should be considered in the design of a thick wall piping for LWRs under seismic loading is low cycle fatigue. On the other hand, Sodium cooled Fast Reactors (SFRs) is thin wall when compared to LWRs piping. Failure tests of a thin wall piping are necessary because past failure tests for LWRs piping are not enough to discuss failure behavior of a thin wall piping. Therefore, this present work investigated the failure mode and the ultimate strength of thin wall tees.

Study on strength of thin-walled tee pipe for fast breeder reactors under seismic loading

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Otani, Akihito*; Moriizumi, Makoto; Kaneko, Naoaki*

Proceedings of 2014 ASME Pressure Vessels and Piping Conference (PVP 2014) (DVD-ROM), 8 Pages, 2014/07

In recent years, earthquakes over design condition were observed in Japan. Confirming the ultimate strength and design safety margin of mechanical components is important for the seismic integrity. This study focused on piping components, and it was one of the most important mechanical components for protecting boundary of coolant. Failure tests of thick-walled piping components for Light Water Reactors (LWRs) described previously in the literature. According to these tests, the failure mode of thick-walled piping components under seismic cyclic loading was low cycle fatigue. However, failure tests have scarcely been performed on thin-walled piping components pressurized at low levels for Fast Breeder Reactors (FBRs). This paper presents dynamic failure tests of thin-walled piping components in FBRs. Based on the test results, the failure mode, the ultimate strength, and the elastic-plastic behavior are discussed.

Study on piping response under multiple excitation; Validation for multiple excitation analysis of piping

Kai, Satoru*; Watakabe, Tomoyoshi; Kaneko, Naoaki*; Tochiki, Kunihiro*; Moriizumi, Makoto; Tsukimori, Kazuyuki

Dynamics and Design Conference 2013 (D&D 2013) Koen Rombunshu (USB Flash Drive), 10 Pages, 2013/08

The piping in a nuclear power plant is laid across multiple floors of a single building or multiple buildings which support the piping at many points. As the piping is excited by multiple-inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, only a few experiments involving such multiple excitations have been performed to verify the validity of multiple excitation analysis. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and to verify the validity of the analytical method by multiple excitation tests. This paper reports the validation results of the multiple excitation analysis of piping compared with the results of the multiple excitations shaking test using triple uni-axial shaking table and a 3-dimensional piping model.

Study on piping response under multiple excitation, 2; Validation for multiple analysis of piping

Kai, Satoru*; Watakabe, Tomoyoshi; Kaneko, Naoaki*; Tochiki, Kunihiro*; Moriizumi, Makoto; Tsukimori, Kazuyuki

Proceedings of 2013 ASME Pressure Vessels and Piping Conference (PVP 2013) (DVD-ROM), 9 Pages, 2013/07

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many points. As the piping is excited by multiple inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few experiments involving such multiple excitations have been performed to verify the validity of multiple excitation analysis. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and verify the validity of the analysis method by multiple excitation test. This paper reports the validation result of the multiple excitation analysis of piping compared with the results of the multiple excitations shaking test by using triple uni-axial shaking table and a 3-dimensional piping model (89.1 mm diameter and 5.5 mm thickness).

Performance test of a centrifugal supercritical hydrogen pump

Tatsumoto, Hideki; Aso, Tomokazu; Otsu, Kiichi; Uehara, Toshiaki; Sakurayama, Hisashi; Kawakami, Yoshihiko; Kato, Takashi; Futakawa, Masatoshi; Yoshinaga, Seiichiro*

Proceedings of International Cryogenic Engineering Conference 23 (ICEC-23) and International Cryogenic Materials Conference 2010 (ICMC 2010), p.377 - 382, 2010/07

A dynamic gas bearing centrifugal pump that circulated supercritical hydrogen with a large flow rate of more than 0.16 kg/s was developed to minimize the hydrogen density change at the moderator. The two pumps were simultaneously operated in parallel for redundancy. The performance test results indicated that the dimensionless characteristics for the single and the parallel operations existed on an identical curve. An outstanding peak adiabatic efficiency exited at the flow coefficient of 0.046, independently of the revolution. It was verified that the developed hydrogen pump satisfied the design requirement.