New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

https://doi.org/10.1051/epjconf/201919800003

New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

https://doi.org/10.1007/s10751-016-1381-7

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

https://doi.org/10.1007/s10751-016-1331-4

Development of seismic assessment method toward the demonstration reactor of JSFR, 1; Project overview and element test

Kitamura, Seiji; Sawa, Naoki*; Iwasaki, Akihisa*; Monde, Masatsugu*; Matsubara, Shinichiro*; Okamura, Shigeki*

no journal, , 

no abstracts in English

Development of seismic assessment method toward the demonstration reactor of JSFR, 3; Vibration test of 1/1.5 scale test assembly in triangular arrangement

Iwasaki, Akihisa*; Sawa, Naoki*; Monde, Masatsugu*; Matsubara, Shinichiro*; Okamura, Shigeki*; Kitamura, Seiji

no journal, , 

no abstracts in English

Development of seismic assessment method toward the demonstration reactor of JSFR, 1; Vibration test of 1/2.5 scale test assembly in triangular arrangement

Iwasaki, Akihisa*; Monde, Masatsugu*; Sawa, Naoki*; Ikarimoto, Iwao*; Taniguchi, Yoshihiro*; Kitamura, Seiji

no journal, , 

The three-dimensional seismic analysis technology of a reactor core is developed. The vibration test of 1/2.5 scale test assembly in triangular arrangement was carried out, and the three-dimensional response behavior has been grasped.

Core seismic experiment of a full-scale single model for a fast reactor

Iwasaki, Akihisa*; Sawa, Naoki*; Matsubara, Shinichiro*; Kitamura, Seiji; Okamura, Shigeki*

no journal, , 

A fast reactor core consists of several hundred core elements, which are hexagonal flexible beams embedded at the lower support plate in a hexagonal arrangement, separated by small gaps, and immersed in a fluid. Core elements have no support for vertical fixing in order to avoid the influence of thermal expansion and swelling. These days, in Japan, larger earthquake vibrations are postulated in seismic evaluations. So, it is necessary to consider vertical displacements (rising) and horizontal displacements of the core elements simultaneously because vertical seismic vibrations are larger than the acceleration of gravity. The 3D vibration behavior is affected by the fluid force of the ambient coolant and contact with the surrounding core elements. In this study, single-model vibration tests using a full-scale test model were conducted, and the basic characteristics of 3D vibration behavior of the core element were examined. In addition, structures restricting vertical displacements (dashpot structure) were devised, and their effectiveness was verified. As a result of the tests, the effects of the ambient condition (in air, in static water, and in flowing water), gap between the pads, vibration directions, vibration waves, and dashpot structures on the vibration behavior of the core element were examined. As regards the ambient condition, the vertical displacements were larger in flowing water that simulates the coolant flow than in air and in static water, because of upward fluid force in flowing water. As regards the gap between the pads, the larger the gaps was, the stronger the interferences due to horizontal displacements, and the smaller the vertical displacements were. The dashpot structure was verified to be suitable for reducing vertical displacements.

Development of seismic assessment method for FR core, 3; Summary of development of FR core seismic analysis method

Yamamoto, Tomohiko; Matsubara, Shinichiro*; Iwasaki, Akihisa*; Kawamura, Kazuki*; Harada, Hidenori*

no journal, , 

A fast reactor core consists of hundreds of core elements, which lengthen due to thermal expansion and swelling. So, the core elements are self-standing on the core support structure and not restrained in the axial direction. The authors carried out vibration tests and verification of analysis code (REVIAN-3) to evaluate 3D core vibration behavior. This report describes the summary of some experimental results and analysis.

Study on the predictive evaluation method of nonlinear sloshing wave height and load of cylindrical tanks, 2; Shaking table test and analysis for nonlinear sloshing

Sago, Hiromi*; Yamamoto, Tomohiko; Miyazaki, Masashi; Tanaka, Masaaki; Yokoi, Shinobu*; Yamane, Yuma*; Nishiwaki, Yoshinori*; Morita, Hideyuki*; Iwasaki, Akihisa*; Ikesue, Shunichi*; et al.

no journal, , 

The design basis ground motions have been revised to improve the seismic resistance of nuclear power plants. The reduction of seismic forces not only horizontally but also vertically has required more critical than in the past to ensure the seismic resistance of components. Notably, the design of a Sodium-Cooled Fast Reactor will require reducing the seismic forces applied to the components because of the components with thin wall thickness. To overcome this problem, the authors plan to introduce a seismic isolation system. When the sloshing wave height is small, it can be approximated with a linear vibration model. However, when the sloshing wave height increases and the sloshing becomes nonlinear, it is necessary to evaluate the wave height using other methods such as numerical analysis. Although the evaluation of nonlinear sloshing wave height is important, there are few examples which quantitatively evaluate the wave height of nonlinear sloshing. This paper reports the results of the sloshing water test carried out to obtain test data for the construction of the evaluation method and the results of the reproduction analysis carried out using the VOF method.