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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.
Cs solid-state NMR and density functional theory calculationsOkubo, Takahiro*; Okamoto, Takuya*; Kawamura, Katsuyuki*; Gu
gan, R.*; Deguchi, Kenzo*; Oki, Shinobu*; Shimizu, Tadashi*; Tachi, Yukio; Iwadate, Yasuhiko*
Journal of Physical Chemistry A, 122(48), p.9326 - 9337, 2018/12
Times Cited Count：13 Percentile：60.51(Chemistry, Physical)The structures of Cs adsorption on montmorillonite were investigated by the nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra of Cs adsorbed on montmorillonite samples were measured under different Cs contents and relative humidity levels. NMR parameters were evaluated by the first principle calculations in order to identify the relationship between adsorbed Cs structures and NMR parameters. The comparisons between experimental and theoretical NMR spectra revealed that Cs is preferentially adsorbed at sites near Al for low Cs substituted montmorillonites, and that non-hydrated Cs present in partially Cs substituted samples, even after being hydrated under high relative humidity.
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
Times Cited Count：7 Percentile：90.97(Physics, Atomic, Molecular & Chemical)Hirose, Takanori; Ando, Masami; Tanigawa, Hiroyasu; Okubo, Nariaki; McDuffee, J. L.*; Heatherly, D. W.*; Sitterson, R. G.*; Stoller, R. E.*; Yamamoto, Takuya*
Fusion Materials Semiannual Progress Report (DOE/ER-0313/46) (Internet), p.72 - 78, 2009/06
This work is being carried out under Annex I of the collaboration on Fusion Materials between the U.S. DOE and the Japan Atomic Energy Agency. The MFE-RB-15J capsule is a part of the Phase-V experiments with the goal of elucidating the effects of helium in fusion structural candidate engineering alloys, and verifying the irradiation response of alloy F82H and its joint for ITER-TBM (Test Blanket Module) application. The target dose of this capsule is 6 dpa at the peak and it will introduce 300 appm of transmutation helium in F82H with additional boron-10. Assembly of the MFE-RB-15J capsule was completed on April, 2008. Irradiation began for MFE-RB-15J with cycle 415, starting June 3, 2008. The MFE-RB-15J experiment was installed in location RB-1A with europium thermal neutron shield. A detailed specimen loading list for the capsule is provided in this report.
Fukui, Katsunori*; Okubo, Seisuke*; Inagaki, Daisuke; Hatsuyama, Yoshihiro*; Yamamoto, Takuya*
no journal, ,
no abstracts in English
Cs solid state NMR, 2; Cs MAS and 3Q MAS NMROkamoto, Takuya*; Okubo, Takahiro*; Iwadate, Yasuhiko*; Deguchi, Kenzo*; Shimizu, Tadashi*; Oki, Shinobu*; Tachi, Yukio
no journal, ,
The structures of Cs adsorption on montmorillonite were investigated by the nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra of Cs adsorbed montmorillonite samples with different Cs contents were collected by Cs Magic Angle Spinning (MAS) NMR and Cs Triple Quantum (3Q) MAS NMR. The adsorbed Cs structures were evaluated based on the correlations between the structural characteristics and the values of the NMR parameters predicted by the first principal calculations.
Okamoto, Takuya*; Okubo, Takahiro*; Iwadate, Yasuhiko*; Deguchi, Kenzo*; Shimizu, Tadashi*; Oki, Shinobu*; Tachi, Yukio
no journal, ,
The structures of Cs adsorbed on montmorillonite were investigated by Cs Magic Angle Spinning (MAS) NMR spectroscopy. The NMR spectra of Cs adsorbed on montmorillonite samples were measured under different relative humidity levels and were analyzed to evaluate the change in the structure of hydrated Cs sorbed on montmorillonite.
Ishii, Junichi; Izawa, Kazuhiko; Okubo, Takuya; Ogawa, Kazuhiko
no journal, ,
For compliance with the new regulatory requirements in Japan, the Static Critical Experiment Facility (STACY) has been remodeling the existing fuel storages. In the remodeling, the existing fuel storage spaces, to which shape and dimension management are applied, are designed to add a neutron absorber for the critical control, taking into account the case of shape and dimension collapse. In order to confirm the validity of the criticality safety design, subcritical calculations were performed. In the calculations, the Japanese Evaluated Nuclear Data Library, JENDL-3.2, was used to cross reference the data. The neutron multiplication factor was calculated using a continuous-energy Monte Carlo code, MVP, and PIJ code in the SRAC code system. It has been confirmed from the results that all fuel storages comply with the safety criteria required to ensure subcriticality.
Okubo, Takuya
no journal, ,
no abstracts in English
