Neutronic design of basic cores of the new STACY

Izawa, Kazuhiko; Ishii, Junichi; Okubo, Takuya; Ogawa, Kazuhiko; Tonoike, Kotaro

Proceedings of 11th International Conference on Nuclear Criticality Safety (ICNC 2019) (Internet), 9 Pages, 2019/09

Japan Atomic Energy Agency, JAEA, is conducting the renewal program of the heterogeneous water moderated critical assembly STACY (Static Experiment Critical Facility) in order to verify the criticality calculation considering fuel debris which have been produced in the accident of Fukushima Daiichi Nuclear Power Station. The first criticality of the new STACY is scheduled at the beginning of 2021. After the first criticality, it is necessary to perform a series of critical experiments with a series of basic experimental core in order to gain a proficiency of operators and grasp the uncertainty that accompanies the result of critical experiments in STACY. Prior to the construction of the new STACY, a series of neutronic calculation was carried out for licensing and planning first series of critical experiment. In this paper, possible core configuration of the basic experimental core and their limitations are discussed and presented.

Observation of momentum-dependent charge excitations in hole-doped cuprates using resonant inelastic X-ray scattering at the oxygen edge

Ishii, Kenji*; Toyama, Takami*; Asano, Shun*; Sato, Kentaro*; Fujita, Masaki*; Wakimoto, Shuichi; Tsutsui, Kenji*; Sota, Shigetoshi*; Miyawaki, Jun*; Niwa, Hideharu*; et al.

Physical Review B, 96(11), p.115148_1 - 115148_8, 2017/09

AA2017-0402.pdf:0.81MB

https://doi.org/10.1103/PhysRevB.96.115148

Observation of momentum-resolved charge fluctuations proximate to the charge-order phase using resonant inelastic X-ray scattering

Yoshida, Masahiro*; Ishii, Kenji; Naka, Makoto*; Ishihara, Sumio*; Jarrige, I.*; Ikeuchi, Kazuhiko*; Murakami, Yoichi*; Kudo, Kazutaka*; Koike, Yoji*; Nagata, Tomoko*; et al.

Scientific Reports (Internet), 6, p.23611_1 - 23611_8, 2016/03

https://doi.org/10.1038/srep23611

Effect of stability of passive film on resistance of rust staining of stainless steels

Fuji, Hiroyuki*; Aoki, So; Ishii, Tomohiro*; Sakai, Junichi*

Zairyo To Kankyo, 64(5), p.178 - 182, 2015/05

https://doi.org/10.3323/jcorr.64.178

This study focused on a breakdown of passive film which is followed by rust staining, and the objective of this study was to clarify the effect of stability of passive film on the resistance of rust staining of stainless steels. Atomospheric exposure test was carried out for 12 months. In order to compare the stability of passive film, measurements of potential-decay curves, and potentiostatic polarization tests were performed in acidic aqueous chloride solution. As a result, rust area of austenitic stainless steel was higher than that of ferritic stainless steel. This order didn't follow the orders of pitting potentials and densities of inclusions on surface between specimens. On the contrary, the order of the resistance of rust staining of stainless steels followed the order of the stability of passive film. One of the reasons why the resistance of rust staining of austenitic stainless steel was worse than that of ferritic stainless steel was seemed that chloride more easily broke passive film on the surface of austenitic stainless and formed micro pits which become initiations of rust staining and increase density of stains.

Development of mineralization techniques for organic solvents by the silver mediated electrochemical oxidation process with the ultrasound agitation

Kobayashi, Fuyumi; Ishii, Junichi; Shirahashi, Koichi; Umeda, Miki; Sakuraba, Koichi

Kakuhan, Kongo Gijutsu To Toraburu Taisaku, p.341 - 344, 2014/10

The silver mediated electrochemical oxidation (Ag/MEO) process with the ultrasound agitation has been developed for the purpose of the mineralization of organic wastes containing transuranium nuclides at the nuclear fuel reprocessing process. In the Ag/MEO process, organic solvents are decomposed by divalent silver cations under the relatively low temperature and the ambient pressure condition. The ultrasound agitation is effective in mixing the electrolytic solutions and the organic solvents, and is expected to promote the oxidation of the organic solvents. Therefore, the Ag/MEO process with the ultrasound agitation could be a candidate for the treatment of organic solvents. Destruction tests of TBP and dodecane by the Ag/MEO process were conducted to optimize some treatment conditions. Under optimized conditions, the destruction tests of kerosene and TODGA were carried out. It was confirmed that the Ag/MEO process is effective for the mineralization of these organic solvents.

Superconductivity in noncentrosymmetric iridium silicide LiIrSi

Pyon, S.*; Kudo, Kazutaka*; Matsumura, Junichi*; Ishii, Hiroyuki*; Matsuo, Genta*; Nohara, Minoru*; Hojo, Hajime*; Oka, Kengo*; Azuma, Masaki*; Garlea, V. O.*; et al.

Journal of the Physical Society of Japan, 83(9), p.093706_1 - 093706_5, 2014/09

https://doi.org/10.7566/JPSJ.83.093706

Bipartite magnetic parent phases in the iron oxypnictide superconductor

Hiraishi, Masatoshi*; Iimura, Soshi*; Kojima, Kenji*; Yamaura, Junichi*; Hiraka, Haruhiro*; Ikeda, Kazutaka*; Miao, P.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Miyazaki, Masanori*; et al.

Nature Physics, 10(4), p.300 - 303, 2014/04

https://doi.org/10.1038/nphys2906

Instrumental upgrades of the RIXS spectrometer at BL11XU at SPring-8

Ishii, Kenji; Jarrige, I.*; Yoshida, Masahiro*; Ikeuchi, Kazuhiko*; Inami, Toshiya; Murakami, Yoichi*; Mizuki, Junichiro

Journal of Electron Spectroscopy and Related Phenomena, 188, p.127 - 132, 2013/06

https://doi.org/10.1016/j.elspec.2012.12.003

Operation databook of the fuel treatment system of the Static Experiment Critical Facility (STACY) and the Transient Experiment Critical Facility (TRACY); JFY 2004 to JFY 2008

Kokusen, Junya; Sumiya, Masato; Seki, Masakazu; Kobayashi, Fuyumi; Ishii, Junichi; Umeda, Miki

JAEA-Technology 2012-041, 32 Pages, 2013/02

JAEA-Technology-2012-041.pdf:1.6MB

Uranyl nitrate solution fuel used in the STACY and the TRACY is adjusted in the Fuel Treatment System, in which such parameters are varied as concentration of uranium, free nitric acid, soluble neutron poison, and so on. Operations for concentration and denitration of the solution fuel were carried out with an evaporator from JFY 2004 to JFY 2008 in order to adjust the fuel to the experimental condition of the STACY and the TRACY. In parallel, the solution fuel in which some kinds of soluble neutron poison were doped was also adjusted in JFY 2005 and JFY 2006 for the purpose of the STACY experiments to determine neutron absorption effects brought by fission products, etc. After these experiments in the STACY, a part of the solution fuel including the soluble neutron poison was purified by the solvent extraction method with mixer-settlers in JFY 2006 and JFY 2007. This report summarizes operation data of the Fuel Treatment System from JFY 2004 to JFY 2008.

Electroplating of Ni microstructures on the cross section of Cu wire using PMMA mother fabricated by proton beam writing

Tanabe, Yusuke*; Iwamoto, Takashi*; Takahashi, Junichi*; Nishikawa, Hiroyuki*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 129, 2013/01

https://doi.org/10.11484/jaea-review-2012-046