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Journal Articles

Structural phase transition in cobalt oxyfluoride Co$$_{3}$$Sb$$_{4}$$O$$_{6}$$F$$_{6}$$ observed by high-resolution synchrotron and neutron diffraction

Shimono, Seiya*; Ishibashi, Hiroki*; Nagayoshi, Yusuke*; Ikeno, Hidekazu*; Kawaguchi, Shogo*; Hagihara, Masato; Torii, Shuki*; Kamiyama, Takashi*; Ichihashi, Katsuya*; Nishihara, Sadafumi*; et al.

Journal of Physics and Chemistry of Solids, 163, p.110568_1 - 110568_7, 2022/04

 Times Cited Count:0 Percentile:0.01(Chemistry, Multidisciplinary)

Journal Articles

Evaluation and countermeasures for impedance of fast extraction septa and fast extraction kickers at the J-PARC main ring

Kobayashi, Aine*; Toyama, Takeshi*; Nakamura, Takeshi*; Shobuda, Yoshihiro; Ishii, Koji*

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.287 - 291, 2021/10

no abstracts in English

Journal Articles

Promising neutron irradiation applications at the high temperature engineering test reactor

Ho, H. Q.; Honda, Yuki*; Hamamoto, Shimpei; Ishii, Toshiaki; Takada, Shoji; Fujimoto, Nozomu*; Ishitsuka, Etsuo

Journal of Nuclear Engineering and Radiation Science, 6(2), p.021902_1 - 021902_6, 2020/04

Journal Articles

Study on optimizing microwave heating denitration method and powder characteristics of uranium trioxide

Segawa, Tomomi; Kawaguchi, Koichi; Kato, Yoshiyuki; Ishii, Katsunori; Suzuki, Masahiro; Fujita, Shunya*; Kobayashi, Shohei*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05

A solution of plutonium nitrate and uranyl nitrate is converted into a mixed oxide by microwave heating denitration method. In the present study, for improving the efficiency of microwave heating and achieving high-temperature uniformity to produce homogeneous UO$$_{3}$$ powder, the microwave heating test of potassium chloride and uranyl nitrate solution, and numerical simulation analysis were conducted. The potassium chloride agar was adjusted to the dielectric loss, which is close to that of the uranyl nitrate solution and the optimum support table height was estimated to be 50 mm for denitration of the uranyl nitrate solution by microwave heating. The adiabator improved the efficiency of microwave heating denitration. Moreover, the powder yield was improved by using the adiabator owing to ease of scraping of the denitration product from the bottom of the denitration vessel.

Journal Articles

Electrochemical adsorption on Pt nanoparticles in alkaline solution observed using in situ high energy resolution X-ray absorption spectroscopy

Kusano, Shogo*; Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*

Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04

 Times Cited Count:3 Percentile:24.88(Chemistry, Multidisciplinary)

Journal Articles

Nowcast and forecast of galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes in magnetosphere and ionosphere; Extension of WASAVIES to earth orbit

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*; Ueno, Haruka*; Nagamatsu, Aiko*

Journal of Space Weather and Space Climate (Internet), 9, p.A9_1 - A9_11, 2019/03

 Times Cited Count:5 Percentile:42.72(Astronomy & Astrophysics)

Real-time estimation of astronaut doses during solar particle events (SPE) is one of the most challenging tasks in cosmic-ray dosimetry. We therefore develop a new computational method that can nowcast the solar energetic particle (SEP) as well as galactic cosmic-ray (GCR) fluxes on any Earth orbit during a large SPE associating with ground level enhancement. It is an extended version of WArning System for AVIation Exposure to Solar Energetic Particle, WASAVIES. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element data. Moreover, organ dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites.

Journal Articles

Feasibility study of new applications at the high-temperature gas-cooled reactor

Ho, H. Q.; Honda, Yuki*; Hamamoto, Shimpei; Ishii, Toshiaki; Takada, Shoji; Fujimoto, Nozomu*; Ishitsuka, Etsuo

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 6 Pages, 2018/10

Journal Articles

Numerical evaluation on fluctuation absorption characteristics based on nuclear heat supply fluctuation test using HTTR

Takada, Shoji; Honda, Yuki*; Inaba, Yoshitomo; Sekita, Kenji; Nemoto, Takahiro; Tochio, Daisuke; Ishii, Toshiaki; Sato, Hiroyuki; Nakagawa, Shigeaki; Sawa, Kazuhiro*

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10

Nuclear heat utilization systems connected to HTGRs will be designed on the basis of non-nuclear grade standards for easy entry of chemical plant companies, requiring reactor operations to continue even if abnormal events occur in the systems. The inventory control is considered as one of candidate methods to control reactor power for load following operation for siting close to demand area, in which the primary gas pressure is varied while keeping the reactor inlet and outlet coolant temperatures constant. Numerical investigation was carried out based on the results of nuclear heat supply fluctuation tests using HTTR by non-nuclear heating operation to focus on the temperature transient of the reactor core bottom structure by imposing stepwise fluctuation on the reactor inlet temperature under different primary gas pressures below 120C. As a result, it was emerged that the fluctuation absorption characteristics are not deteriorated by lowering pressure. It was also emerged that the reactor outlet temperature did not reach the scram level by increasing the reactor inlet temperature 10 C stepwise at 80% of the rated power as same with the full power case.

Journal Articles

Real time and automatic analysis program for WASAVIES; Warning system for aviation exposure to solar energetic particles

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

Space Weather, 16(7), p.924 - 936, 2018/07

 Times Cited Count:14 Percentile:68.41(Astronomy & Astrophysics)

A physics-based warning system of aviation exposure to solar energetic particles, WASAVIES, is improved to be capable of real-time and automatic analysis. In the improved system, the count rates of several neutron monitors (NM) at the ground level, as well as the proton fluxes measured by the GOES satellite are continuously downloaded at intervals of 5 min and used for determining the model parameters. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.

Journal Articles

Solvent extraction of uranium with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Sagawa, Hiroshi; Ishii, Sho; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 35(6), p.439 - 449, 2017/08

 Times Cited Count:4 Percentile:20.32(Chemistry, Multidisciplinary)

Solvent extraction of uranium from a nitric acid medium was performed with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide (DEHOA) by a single-stage batch method, and the distribution ratio equation of U(VI) was derived as $${it D}_{rm U}$$ = 1.1$$[rm NO^{-}_{3}]^{1.6}_{rm aq}[{rm DEHOA}]^{2}_{rm org}$$. Furthermore, the nitric acid distribution was also evaluated, and the distribution ratio equation $${it D}_{rm H}$$ = 0.12$$[rm H^{+}]^{0.76}_{rm aq}[{rm DEHOA_{rm Free}}]_{rm H}$$ was obtained. Batch experiments to evaluate the time dependence of U(VI) extraction and the U(VI) loading capacity of DEHOA were also performed. It was revealed that U(VI) extraction by DEHOA reached an equilibrium state within a few minutes, and the loading capacity was 0.71 mol/dm$$^{3}$$ (M) when the concentrations of DEHOA and nitric acid were 1.5 and 3.0 M, respectively.

JAEA Reports

Case studies of radiation dose assessment in emergency situation of nuclear facilities

Kawasaki, Masatsugu; Nakajima, Junya; Yoshida, Keisuke; Kato, Saori; Nishino, Sho; Nozaki, Teo; Nakagawa, Masahiro; Tsunoda, Junichi; Sugaya, Yuki; Hasegawa, Rie; et al.

JAEA-Data/Code 2017-004, 57 Pages, 2017/03

JAEA-Data-Code-2017-004.pdf:2.34MB

In emergency situation of nuclear facilities, we need to estimate the radiation dose due to radiation and radioactivity to grasp the influence range of the accident in the early stage. Therefore, we prepare the case studies of dose assessment for public exposure dose and personal exposure dose and contribute them to emergency procedures. This document covers about accidents of nuclear facilities in Nuclear Science Research Institute and past accident of nuclear power plant, and it can be used for inheritance of techniques of emergency dose assessment.

Journal Articles

A Kinetic analysis of cadmium accumulation in a Cd hyper-accumulator fern, ${it Athyrium yokoscense}$ and tobacco plants

Yoshihara, Toshihiro*; Suzui, Nobuo; Ishii, Satomi; Kitazaki, Mayu*; Yamazaki, Haruaki*; Kitazaki, Kazuyoshi*; Kawachi, Naoki; Yin, Y.-G.; Tanabata, Sayuri*; Hashida, Shinnosuke*; et al.

Plant, Cell & Environment, 37(5), p.1086 - 1096, 2014/05

 Times Cited Count:20 Percentile:65.6(Plant Sciences)

Journal Articles

Power coupler development for ERL main linac in Japan

Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2953 - 2955, 2010/05

We started to develop an input power coupler for a 1.3 GHz ERL superconducting cavity for main linac. We fabricated power coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a CW 30 kW IOT power source. During this test, the ceramic window was broken by the sudden heat load. We found that this heat load occurred by the unexpected dipole mode. We renewed the ceramic window and successfully carried out the high power test up to CW 27 kW input power.

Journal Articles

Lifetime measurements for the first 2$$^{+}$$ states in $$^{162,164}$$Gd populated by the $$beta$$ decay of $$^{162,164}$$Eu

Nagae, Daisuke*; Ishii, Tetsuro; Takahashi, Ryuta*; Asai, Masato; Makii, Hiroyuki; Osa, Akihiko; Sato, Tetsuya; Ichikawa, Shinichi; Shimizu, Yoshifumi*; Shoji, Takuya*

AIP Conference Proceedings 1224, p.156 - 160, 2010/04

 Times Cited Count:2 Percentile:65.47

JAEA Reports

Basic study on decontamination of TRU wastes with cerium mediated electrolytic oxidation method

Ishii, Junichi; Kobayashi, Fuyumi; Uchida, Shoji; Sumiya, Masato; Kida, Takashi; Shirahashi, Koichi; Umeda, Miki; Sakuraba, Koichi

JAEA-Technology 2009-068, 20 Pages, 2010/03

JAEA-Technology-2009-068.pdf:2.49MB

At Nuclear Fuel Cycle Safety Engineering Research Facility, the cerium mediated electrolytic oxidation method which is a decontamination technique to decrease the radioactivity of TRU wastes to the clearance-level has been developed for the effective reduction of TRU wastes generated from the decommissioning of a nuclear fuel reprocessing facility and so on. This method corrodes the oxide layer and the surface of metallic TRU metal wastes by the strong oxidation power of Ce$$^{4+}$$ in nitric acid. In this study, parameter tests were conducted to optimize the solution condition of Ce$$^{3+}$$ initial concentrations and nitric acid concentrations. The target corrosion rate of metallic TRU wastes set to be 2$$sim$$4$$ mu$$m/h for the practical use of this method. Under the optimized solution condition, a dissolution test of stainless steel simulating wastes was carried out. From the result of the dissolution test, the average corrosion rate was 3.3 $$mu$$m/h during the test time of 90 hours. Based on the supposition that the corrosion depth of metallic TRU wastes was 20 $$mu$$m enough to achieve the clearance-level, the treatment time for the decontamination was about 6 hours. It was confirmed from the result that the decontamination could be performed within one day and the decontamination solution could repeatedly reuse 15 times.

Journal Articles

Development of 20 kW input power coupler for 1.3 GHz ERL main linac; Component test at 30 kW IOT test stand

Sakai, Hiroshi*; Umemori, Kensei*; Sakanaka, Shogo*; Takahashi, Takeshi*; Furuya, Takaaki*; Shinoe, Kenji*; Ishii, Atsushi*; Nakamura, Norio*; Sawamura, Masaru

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.866 - 868, 2010/03

We started to develop an input coupler for a 1.3 GHz ERL superconducting cavity. Required input power is about 20 kW for the cavity acceleration field of 20 MV/m and the beam current of 100 mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied to the design for the CW 20 kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30 kW IOT power source and a test stand constructed for the high-power test. In this report, we mainly describe the results of the high-power test of ceramic window and bellows.

Journal Articles

Development of input power coupler for ERL main linac in Japan

Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru

Proceedings of 14th International Conference on RF Superconductivity (SRF 2009) (Internet), p.684 - 688, 2009/09

We started to develop an input coupler for a 1.3GHz ERL superconducting cavity for ERL main linac. Required input power is about 20kW for the cavity acceleration field of 20MV/m and the beam current of 100mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied for the CW 20kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30kW IOT power source and a test stand constructed.

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Journal Articles

Imaging of translocation and spatial distribution of the assimilated carbon and nitrogen in the host-root parasite system by PETIS

Sekimoto, Hitoshi*; Kawachi, Naoki; Honda, Shuzo*; Yamaguchi, Yoshie*; Kato, Shota*; Yoneyama, Kaori*; Fujimaki, Shu; Suzui, Nobuo; Ishii, Satomi; Watanabe, Satoshi; et al.

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 124, 2008/03

no abstracts in English

Journal Articles

Development of input power coupler for ERL main linac

Sakai, Hiroshi*; Shinoe, Kenji*; Ishii, Atsushi*; Umemori, Kensei*; Sakanaka, Shogo*; Takahashi, Takeshi*; Furuya, Takaaki*; Sawamura, Masaru

Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.592 - 594, 2008/00

We are developing a input coupler for the 1.3GHz 9-cell superconducting cavities to realize the ERL. Estimated input power is about 20kW for 20MV/m ERL operation. This coupler is based on the STF-BL input coupler, which adopts the TRISTAN type coaxial coupler, and some modifications are applied for the CW 20kW power operation. Now we are developing the high power coupler test stand to carry out the components test of the ceramic windows and bellows by using a 30kW IOT. In this paper, we report the design strategy of the input power coupler for ERL main linac and the recent status of the high power coupler test stand.

74 (Records 1-20 displayed on this page)