Rabi-oscillation spectroscopy of the hyperfine structure of muonium atoms

Nishimura, Shoichiro*; Torii, Hiroyuki*; Fukao, Yoshinori*; Ito, Takashi; Iwasaki, Masahiko*; Kanda, Sotaro*; Kawagoe, Kiyotomo*; Kawall, D.*; Kawamura, Naritoshi*; Kurosawa, Noriyuki*; et al.

Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08

https://doi.org/10.1103/PhysRevA.104.L020801

Estimation of mitigation effects of sodium nanofluid for SGTR accidents in SFR

Ichikawa, Kenta*; Kanda, Hironori; Yoshioka, Naoki*; Ara, Kuniaki; Saito, Junichi; Nagai, Keiichi

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07

Studies on the suppression of the reactivity of sodium itself have been performed on the basis of the concept of suspended nanoparticles in liquid sodium (sodium nanofluid). According to the experimental and theoretical results of studies for sodium nanofluid, velocity and heat of sodium nanofluid-water reaction are lower than those of the pure sodium-water reaction. The analytical model for the peak temperature of a sodium nanofluid-water reaction jet has been developed in consideration of these suppression effects by the authors. In this paper, the prediction method for mitigation effects for a damage of adjacent tubes in a steam generator tube rupture (SGTR) accidents is arranged by applying this analytical model for the peak temperature of the reaction jet. On the assumption that the sodium nanofluid is used for the secondary coolant of sodium-cooled fast reactor (SFR), mitigation effects under the design-base accident (DBA) condition and the design-extension condition (DEC) of SGTR are estimated by using this method. As a result, there is a possibility to reduce the number of damaged tubes and to suppress the pressure generated by SGTR accidents by using sodium nanofluid in the secondary coolant.

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

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

Study on chemical reactivity control of liquid sodium; Development of nano-fluid and its property and applicability to FBR plant

Saito, Junichi; Ara, Kuniaki; Sugiyama, Kenichiro*; Kitagawa, Hiroshi*; Nakano, Haruyuki*; Ogata, Kan*; Yoshioka, Naoki*

Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 4 Pages, 2008/05

no abstracts in English

Metal sorption to ; Influence of pH, ionic strength and metal concentrations

Takenaka, Yoko*; Saito, Takumi*; Nagasaki, Shinya*; Tanaka, Satoru*; Kozai, Naofumi; Onuki, Toshihiko

Geomicrobiology Journal, 24(3-4), p.205 - 210, 2007/09

https://doi.org/10.1080/01490450701457337

no abstracts in English

Extended steady-state and high-beta regimes of net-current free heliotron plasmas in the large helical device

Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node31.htm#5947

The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high and long pulse.

High-melt-strength polypropylene with electron beam irradiation in the presence of polyfunctional monomers

Yoshii, Fumio; Makuuchi, Keizo; *; *; *; *

Journal of Applied Polymer Science, 60, p.617 - 623, 1996/00

https://doi.org/10.1002/(SICI)1097-4628(19960425)60:4<617::AID-APP16>3.0.CO;2-W

no abstracts in English

Conceptual design study of nuclear shielding for the steady state tokamak device JT-60SU

Miya, Naoyuki; ; *; Nakamura, Hiroo; Ushigusa, Kenkichi; Oikawa, Akira; Nishitani, Takeo; ; *; Nakagawa, S.*; et al.

Fusion Engineering and Design, 23, p.351 - 358, 1993/00

https://doi.org/10.1016/0920-3796(94)90019-1

no abstracts in English

Design of super-heat-resisting structural materials using a d-electron alloy theory (II)

*; Morinaga, Masahiko*; Saito, Junichi*; *; *

PNC TJ9623 92-001, 81 Pages, 1991/07

PNC-TJ9623-92-001.pdf:6.46MB

[PURPOSE] For structural materials serviced in the Li environments, both Nb-based and Mo-based alloys are selected as the candidate materials. In this study, a simple method was proposed for evaluating the high temperature strength of these alloys. Also, the corrosion resistance in liquid metals was investigated in order to get fundamental information for the design and development of high performance alloys. [EXPERIMENTAL AND CALCULATING METHODS] With a variety of ternary alloys high temperature micro-hardness was measured systematically. The results were analyzed by referring to the relationship between the hardness and the tensile strength reported in previous publications. Also, some alloys designed last year were exposed to the liquid Na at 650 C, and the attendant changes were examined with respect to the weight, microstructure and local composition of alloys. Some of the results were understood in terms of the free energy for the oxide formation of Na and other elements in alloys. Another effort to understand the corrosion properties was made by the molecular orbital calculation of the electronic states of various elements in liquid Li, K and Na. [RESULTS] The high temperature tensile strength of both the alloys was found to be predictable by using a linear relationship between the hardness and the tensile strength of room temperature to 1200 C. The corrosion resistance was much poorer in the Nb-based alloys than in the Mo-based alloys. This is partially due to the enhancement of corrosion by the preferred oxidation of Nb and Ta in the Nb-based alloys, whereas no such oxidation took place in the Mo-based alloys. In addition, it was found from the molecular orbital calculation that Li is the liquid metal of more strongly-bonded with every alloying element, compared to K and Na liquid metals. Futhermore, it was shown that the hardness of each alloy correlated well with the atomic-size difference and also the young's modulus difference ...