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Journal Articles

Research and development of three-dimensional isolation system for sodium cooled fast reactor, 7; Development summary of three-dimensional isolation system

Watakabe, Tomoyoshi; Yamamoto, Tomohiko; Okamura, Shigeki; Miyazaki, Masashi; Miyagawa, Takayuki; Uchita, Masato*; Hirayama, Tomoyuki*; Somaki, Takahiro*; Yukawa, Masaki*; Fukasawa, Tsuyoshi*; et al.

Proceedings of ASME 2024 Pressure Vessels & Piping Conference (PVP 2024) (Internet), 10 Pages, 2024/07

To secure the seismic safety of the thin-walled mechanical components and piping under a severe design earthquake level, employing a three-dimensional (3D) seismic isolation system has been planned in a sodium-cooled fast reactor. The development results of the 3D isolation system have been reported in previous papers so far. Its update is reported in Part 7 to Part 9. Part 7 describes the overview of the development, the test plan of the isolation system in the assembled state of each element, and the performance of individual isolation elements. In part 8, the performance of the isolation device that each element was assembled into was investigated through loading tests. Part 9 reports analytical studies by an analysis model validated based on the insight of the test results.

Journal Articles

High sensitivity of a future search for effects of $$P$$-odd/$$T$$-odd interactions on the 0.75 eV $$p$$-wave resonance in $$overrightarrow{n}$$+$$^{139}overrightarrow{textrm{La}}$$ forward transmission determined using a pulsed neutron beam

Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Hirota, Katsuya*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.

Physical Review C, 109(4), p.L041602_1 - L041602_4, 2024/04

 Times Cited Count:1 Percentile:18.90(Physics, Nuclear)

Journal Articles

Spin dependence in the $$p$$-wave resonance of $$^{139}$$$overrightarrow{textrm{La}}$+$overrightarrow{n}$

Okudaira, Takuya*; Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.

Physical Review C, 109(4), p.044606_1 - 044606_9, 2024/04

 Times Cited Count:2 Percentile:74.11(Physics, Nuclear)

Journal Articles

Seismic design and applications using 3-dimensional seismic isolation system

Yamamoto, Tomohiko; Okamura, Shigeki; Hirayama, Tomoyuki*; Somaki, Takahiro*

Haikan Gijutsu, 65(13), p.1 - 4, 2023/11

The authors are conducting research and development on three-dimensional seismic isolation devices to improve the earthquake resistance of future sodium-cooled fast reactors. This paper introduces an overview of the device and how to use it.

Journal Articles

Research and development of three-dimensional isolation system for SFR (Experimental study on static characteristics using half scale size model)

Fukasawa, Tsuyoshi*; Hirayama, Tomoyuki*; Yokoi, Shinobu*; Hirota, Akihiko*; Somaki, Takahiro*; Yukawa, Masaki*; Miyagawa, Takayuki; Uchita, Masato*; Yamamoto, Tomohiko; Miyazaki, Masashi; et al.

Nihon Kikai Gakkai Rombunshu (Internet), 89(924), p.23-00023_1 - 23-00023_17, 2023/08

no abstracts in English

Journal Articles

Vibration test and fatigue test for failure probability evaluation method with integrated energy

Kinoshita, Takahiro*; Okamura, Shigeki*; Nishino, Hiroyuki; Yamano, Hidemasa; Kurisaka, Kenichi; Futagami, Satoshi; Fukasawa, Tsuyoshi*

Transactions of the 26th International Conference on Structural Mechanics in Reactor Technology (SMiRT-26) (Internet), 7 Pages, 2022/07

The seismic evaluation of key components such as reactor vessel is important for the Seismic Probabilistic Risk Assessment (S-PRA) in a Sodium-Cooled Fast Reactor (SFR). Many components were damaged by cumulative damage like fatigue damage during seismic ground motion. However, general evaluation method for key components under seismic ground motion has been based on static loads and elastic region of materials. More accurate evaluation method for S-PRA, which can evaluate the failure of key components such as reactor vessels, has been actually required. In this study, failure probability evaluation method with integrated energy was developed by comparing the energy with vibration tests and fatigue tests. Vibration tests were performed to evaluate integrated vibration energy at failure by energy balance equation and fatigue tests were performed to evaluate integrated vibration energy at failure based on experimental results of fatigue tests.

Journal Articles

Study on vertical restoring force device using disc springs; Examination of optimum combination of disc spring units and identification method of hysteresis loop

Fukasawa, Tsuyoshi*; Somaki, Takahiro*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Ishizuka, Futoshi*; Suzuno, Tetsuji*; Okamura, Shigeki*; Fujita, Satoshi*

Kozo Kogaku Rombunshu, B, 68B, p.462 - 475, 2022/04

Journal Articles

$$omega N$$ scattering length from $$omega$$ photoproduction on the proton near the reaction threshold

Ishikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.

Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05

 Times Cited Count:4 Percentile:36.67(Physics, Nuclear)

Journal Articles

Research and development of thick rubber bearing for SFR; Aging properties tests of semi full-scale thick rubber bearing

Watakabe, Tomoyoshi; Yamamoto, Tomohiko; Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Somaki, Takahiro*; Morobishi, Ryota*; Sakurai, Yu*; Kato, Koji*

Nihon Kikai Gakkai Rombunshu (Internet), 83(850), p.16-00444_1 - 16-00444_14, 2017/06

A seismic isolation system composed of a thick rubber bearing and an oil damper has been developed for Sodium-Cooled Fast Reactor. This paper focused on the aging properties of thick rubber bearings, such as basic mechanical properties and ultimate strength. Aging of the rubber bearings was reproduced using thermal degradation based on Arrhenius law.

Journal Articles

Development on rubber bearings for sodium-cooled fast reactor, 4; Aging properties of a half scale thick rubber bearings based on breaking test

Watakabe, Tomoyoshi; Yamamoto, Tomohiko; Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Somaki, Takahiro*; Morobishi, Ryota*; Sakurai, Yu*; Kato, Koji*

Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 8 Pages, 2016/07

A seismic isolation system composed of a thick rubber bearing and an oil damper has been developed for Sodium cooled Fast Reactor. One of the advantages of the isolation system is employing the thick rubber bearing in order to realize the longer vertical natural period of a plant, and it leads to mitigation of seismic loads to mechanical components. Rubber bearing technology has progressed based on many past studies, but test data regarding an aging effect is not enough. Also, there is no data of linear strain limit and breaking behavior for the thick rubber bearing after aging. This paper focuses on aging properties of the thick rubber bearing, such as basic mechanical properties and ultimate strength. An aging promote test of the thick rubber bearing was performed by using 1/2 scale and 1/8 scale rubber bearings. Aging of the rubber bearing was reproduced by thermal degradation, where the target aging period was 30 years and 60 years. The load deflection curves of the thick rubber bearing after aging were obtained through the horizontal and vertical static loading tests, and the aging effect was evaluated by comparing with the initial mechanical properties.

Journal Articles

Development on rubber bearings for sodium-cooled fast reactor, 2; Fundamental characteristics of half-scale rubber bearings based on static test

Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Yamamoto, Tomohiko; Kawasaki, Nobuchika; Somaki, Takahiro*; Sakurai, Yu*; Masaki, Nobuo*

Proceedings of 2015 ASME Pressure Vessels and Piping Conference (PVP 2015) (Internet), 10 Pages, 2015/07

This paper described the results of static loading tests using a half-scale rubber bearing model to investigate the fundamental characteristics such as restoring force of a rubber bearing applied to a Sodium-Cooled-Fast-Reactor (SFR). Since the SFR has thin-walled structures, a seismic isolation system is employed to mitigate the seismic force. The static loading tests were performed using the half-scale rubber bearing with a diameter of 800 mm in the range which exceeds a linear limit of horizontal direction and a yield stress of vertical direction to investigate the horizontal and vertical of each stiffness and damping ratio. The fundamental characteristic of rubber bearing employed to the SFR and the validity of a design formula became clear through the static tests.

Journal Articles

Development on rubber bearings for sodium-cooled fast reactor, 1; Examination plan

Yamamoto, Tomohiko; Kawasaki, Nobuchika; Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Somaki, Takahiro*; Samejima, Yusuke*; Masaki, Nobuo*

Proceedings of 2015 ASME Pressure Vessels and Piping Conference (PVP 2015) (Internet), 7 Pages, 2015/07

Since a SFR (Sodium-cooled Fast Reactor) has thin-walled component structures, a seismic isolation system is employed to mitigate the seismic force. Seismic isolation system for applying the SFR consists of the laminated rubber bearing considering characteristics of SFR structures. This paper describes a basic mechanical characteristic examination with a 1/8 scale model and a characterization examination plan of half-scale laminated rubber.

Journal Articles

The Effects of essence of chicken on the trace metal distribution in stressful mice brain slices by in-air micro-PIXE

Sakurai, Eiko*; Yanai, Kazuhiko*; Ishii, Keizo*; Fujiki, Kota*; Hiraishi, Shingo*; Yamazaki, Hiromichi*; Matsuyama, Shigeo*; Okamura, Nobuyuki*; Yokoyama, Akihito; Kada, Wataru; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 84, 2012/01

Journal Articles

Operation test result of a radio-proof cryogenic valve under cobalt 60 irradiation

Makida, Yasuhiro*; Ohata, Hirokatsu*; Okamura, Takahiro*; Ogitsu, Toru*; Nakamoto, Tatsushi*; Kimura, Nobuhiro*; Idesaki, Akira; Gokan, Mayo*; Morishita, Norio

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 34, 2007/02

A string of superconducting magnets is to be set at an arc section of the J-PARC neutrino beam line. To keep the magnets at superconducting condition, a helium cryogenic facility is to be constructed. Parts of cryogenic devices are located beside the magnets, so thier resistance to radiation with predicted dose of 1 MGy in maximum must be assured. A cryogenic control valve is one of the active devices used in the radio-active area, and its radio-proof characteristics is improved by (1) exchaging intolerant materials by proof ones, (2) moving the feed back control circuit unit including electronics from the valve body to a low radio-active area. Two prototype valves, a tuning valve and a Gauzky relief valve, have been prepared and have been tested by using the Cobalt 60 irradiation facility in JAEA. Actual operations of the both prototypes have been checked at the irradiation test bench, and they were successfully operated after irradiation of 1 MGy.

Journal Articles

Development of vertical component isolation system with coned disk springs for FBR plant

Kitamura, Seiji; Okamura, Shigeki; Takahashi, Kenji; Kamishima, Yoshio*; Somaki, Takahiro*; Morishita, Masaki

Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.209 - 216, 2005/00

A structural concept of a vertical component isolation system for fast reactors, assuming a building adopting a horizontal base isolation system, has been studied. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by vertical isolation devices consisting of large coned disk springs. We designed the isolation device, which could be achieved vertical isolation frequency of 1 Hz and damping ratio of 20 %. Full scale coned disk spring and damper performance tests were carried out to verify the validity of design equations. And a series of shaking table test using a 1/8 scale model was performed. The test results fit well the simulation analysis results, so the validity of the design methods was able to be verified. The prospect that the vertical component isolation system applied to the FBR plant could technically realize was obtained.

Oral presentation

Research and development of oil damper with high allowable velocity for seismic isolation, 5; Evaluation of damping force variation based on excitation tests

Fukasawa, Tsuyoshi*; Somaki, Takahiro*; Uchita, Masato*; Hirayama, Tomoyuki*; Yamamoto, Tomohiko; Watakabe, Tomoyoshi; Endo, Naoki*; Okamura, Shigeki; Fujita, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Fundamental study on failure evaluation method of integrated vibration energy for component (Integrated energy of simple examination specimen at random wave test)

Okamura, Shigeki*; Kinoshita, Takahiro*; Yamano, Hidemasa; Kurisaka, Kenichi; Futagami, Satoshi; Fukasawa, Tsuyoshi*

no journal, , 

The seismic evaluation of key components such as the reactor vessel is important for the seismic probabilistic risk assessment in sodium-cooled fast reactors. In the past, the correlation of the fatigue failure and the integrated vibration energy to the component was applied to the failure evaluation in the seismic assessment. The objective of this study is to develop a failure probability evaluation method, which evaluates integrated vibration energy to the component during an earthquake. The fatigue failure evaluation method is investigated with simple vibration examination to failure. The vibration examination with the simple examination specimens, of which main vibration mode is the bending vibration, has been carried out by the random wave. This paper describes the estimation of the integrated vibration energy with the random waves. The integrated vibration energy of the random wave was compared with the integrated vibration energy of the sine wave by the integrated energy per unit time. The integrated vibration energy of the random wave is in the range of the approximate line, which is estimated with the integrated vibration energy of the sine wave. The evaluation method investigated in this study is expected to estimate the integrated energy with the random wave by the integrated energy with the sine wave.

Oral presentation

Research and development of three-dimensional isolation system for SFR (Concept of isolation system and development plan)

Okamura, Shigeki*; Hirayama, Tomoyuki*; Yokoi, Shinobu*; Somaki, Takahiro*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Miyazaki, Masashi; Fukasawa, Tsuyoshi*; Fujita, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Development of failure probability evaluation method with integrated energy for seismic PRA in fast reactor, 2; Estimation of integrated energy based on fatigue test of material

Kinoshita, Takahiro*; Okamura, Shigeki*; Nishino, Hiroyuki; Yamano, Hidemasa; Kurisaka, Kenichi; Futagami, Satoshi; Fukasawa, Tsuyoshi*

no journal, , 

no abstracts in English

Oral presentation

Superconducting magnet system for the J-PARC neutrino experiment, 12; Development of a radio-proof control valve and a relief valve

Makida, Yasuhiro*; Iida, Masahisa*; Ohata, Hirokatsu*; Okamura, Takahiro*; Ogitsu, Toru*; Kimura, Nobuhiro*; Tanaka, Kenichi*; Nakamoto, Tatsushi*; Yamamoto, Akira*; Idesaki, Akira; et al.

no journal, , 

A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. Since the magnet system will be exposed to high radiation field, the radiation resistance of a cryostat is very important. We have developed radio-proof control valve and relief valve by selection of some parts and separation of the positioner. In this work, the developed valves were worked under the $$gamma$$ ray irradiation, and it was found that the valves show the radiation resistance above 1MGy.

41 (Records 1-20 displayed on this page)