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Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

 Times Cited Count:3 Percentile:80.29(Nuclear Science & Technology)

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Measurements of the $$^{243}$$Am neutron capture and total cross sections with ANNRI at J-PARC

Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06

 Times Cited Count:11 Percentile:85.03(Nuclear Science & Technology)

Journal Articles

Levelized cost of electricity evaluation of SFR system considering safety measures

Mukaida, Kyoko; Kato, Atsushi; Kamiya, Masayoshi; Ishii, Katsunori

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 10 Pages, 2019/05

The levelized cost of electricity is one of key indicator to evaluate economic competitiveness of energy systems. This report estimated the levelized cost of SFR system considering additional safety measures identified after the 1F incident and social cost, using major calculation tools: G4-ECONS and the calculation tool developed by the Governmental WG in Japan (CEWG-tool). The calculation results of G4-ECONS showed that the additional safety measures raise 160% of levelized cost in the case of the safety enhanced SFR system with 1500 MWe of twin looped cooling system. As a result of calculation with 3% discount rate and social cost, the levelized cost of the safety enhanced SFR system with 1200 MWe of Single looped cooling system was estimated 84 mills/kWh by CEWG-tool. This result is almost equal to the estimated levelized cost of similar standard LWR system, and it was indicated the economic competitiveness of the future SFR system.

Journal Articles

Measurements of gamma-ray emission probabilities in the decay of americium-244g

Nakamura, Shoji; Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Takamiya, Koichi*; Fujii, Toshiyuki*

Journal of Nuclear Science and Technology, 56(1), p.123 - 129, 2019/01

 Times Cited Count:1 Percentile:11.41(Nuclear Science & Technology)

Accurate data of $$gamma$$-ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by $$gamma$$-ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces $$^{244}$$Am after neutron capture. The 744-keV $$gamma$$-ray decaying from the ground state of $$^{244}$$Am has a relatively large $$gamma$$-ray emission probability c.a. 66%, however, its uncertainty is as large as 29%. The uncertainty of the $$gamma$$-ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the $$gamma$$-ray emission probability was measured by using an activation method and an examined level structure of $$^{244}$$Cm. In this study, the emission probability of 744-keV $$gamma$$ ray was derived as 66.5$$pm$$1.1%, and its uncertainty was improved from 29% to 2%.

Journal Articles

The Prospect of economics of fast reactor cycle

Mukaida, Kyoko; Kato, Atsushi; Kamiya, Masayoshi; Ishii, Katsunori

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 61(1), p.40 - 47, 2019/01

Japan Atomic Energy Agency has proceeded on the research and development (R&D) of fast neutron rector fuel cycle with a system which has economic competitiveness in contrast with light water reactor systems as one of development objectives, from the start of its development. This report shows the evaluation results of generation cost of fast reactor fuel cycle in light of additional safety measure cost and social cost, based on the design of fast reactor and related fuel cycle facilities which considered in FaCT phase I.

Journal Articles

Measurements of neutron total and capture cross sections of $$^{241}$$Am with ANNRI at J-PARC

Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10

AA2017-0628.pdf:2.06MB

 Times Cited Count:16 Percentile:88.54(Nuclear Science & Technology)

Journal Articles

Upgrade of vacuum chamber at RCS beam injection area aimed at lower radiation and maintainability increase

Kamiya, Junichiro; Yamamoto, Kazami; Yanagibashi, Toru*; Sato, Atsushi*; Miki, Nobuharu*

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.645 - 648, 2018/08

Surround of the beam injection point in the J-PARC 3 GeV Rapid Cycling Synchrotron is the area where the residual radioactive dose is higher than other areas due to the beam scattering by the charge stripping foil. However, there is very little space to install radiation shields around the vacuum chamber in the beam injection point. Furthermore, the vacuum leak has often occurred due to the heat expansion of the chamber flange due to the induced current by the nearby pulse magnet. To solve such problems for minimizing the radiation exposure of maintenance workers, the vacuum chamber rin the beam injection point was newly designed. The space for the radiation shields was created by lengthening and the changing the cross-sectional shape. The titanium alloy with high mechanical strength was used for the flange material so that the flange was able to be fastened with higher tightening torque.

Journal Articles

Technical developments for accurate determination of amount of samples used for TOF measurements

Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu; Harada, Hideo; Takamiya, Koichi*; Hori, Junichi*

EPJ Web of Conferences, 146, p.03019_1 - 03019_4, 2017/09

 Times Cited Count:2 Percentile:86.61

The research project entitled "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started to improve the reliability of the neutron cross section date of MAs. In order to obtain accurate cross section data, it is indispensable to determine the amount of MA sample accurately and non-destructively. However, the uncertainty concerning the amount of sample is not assured in some cases. Therefore, as a part of the AIMAC project, this study is aimed to development the technique for accurate determination of the amount of samples by two different methods: $$gamma$$-ray spectroscopic method and calorimetric method. This contribution presents the developed techniques together with results obtained by two independent techniques.

Journal Articles

Research and development for accuracy improvement of neutron nuclear data on minor actinides

Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

EPJ Web of Conferences, 146, p.11001_1 - 11001_6, 2017/09

 Times Cited Count:2 Percentile:78.24

Journal Articles

Measurements of $$gamma$$-ray emission probabilities of $$^{241,243}$$Am and $$^{239}$$Np

Terada, Kazushi; Nakamura, Shoji; Nakao, Taro; Kimura, Atsushi; Iwamoto, Osamu; Harada, Hideo; Takamiya, Koichi*; Hori, Junichi*

Journal of Nuclear Science and Technology, 53(11), p.1881 - 1888, 2016/11

 Times Cited Count:3 Percentile:28.38(Nuclear Science & Technology)

$$gamma$$-ray emission probabilities of $$^{241,243}$$Am and $$^{239}$$Np have been precisely measured with $$gamma$$- and $$alpha$$-ray spectroscopic methods. The activities of $$^{243}$$Am samples were determined by measuring alpha particles using a Si semiconductor detector. $$gamma$$-rays emitted from the samples were measured with a planar type High-Purity Germanium (HPGe) detector. An efficiency curve of the Ge detector was derived with uncertainties of 0.7% from 50 to 1332 keV and 1.3% below 50 keV by combining measured efficiencies and Monte Carlo simulation. The $$gamma$$-ray emission probabilities for the major $$gamma$$-rays of these nuclides were determined with uncertainties less than 1.2%.

Journal Articles

A Non-destructive profile monitor using a gas sheet

Ogiwara, Norio; Hikichi, Yusuke; Namekawa, Yuya; Kamiya, Junichiro; Kinsho, Michikazu; Hatanaka, Kichiji*; Shima, Tatsushi*; Fukuda, Mitsuhiro*

Proceedings of 7th International Particle Accelerator Conference (IPAC '16) (Internet), p.2102 - 2104, 2016/06

Journal Articles

JT-60SA superconducting magnet system

Koide, Yoshihiko; Yoshida, Kiyoshi; Wanner, M.*; Barabaschi, P.*; Cucchiaro, A.*; Davis, S.*; Decool, P.*; Di Pietro, E.*; Disset, G.*; Genini, L.*; et al.

Nuclear Fusion, 55(8), p.086001_1 - 086001_7, 2015/08

 Times Cited Count:30 Percentile:83.62(Physics, Fluids & Plasmas)

The most distinctive feature of the superconducting magnet system for JT-60SA is the optimized coil structure in terms of the space utilization as well as the highly accurate coil manufacturing, thus meeting the requirements for the steady-state tokamak research: A conceptually new outer inter-coil structure separated from the casing is introduced to the toroidal field coils to realize their slender shape, allowing large-bore diagnostic ports for detailed plasma measurements. A method to minimize the manufacturing error of the equilibrium-field coils has been established, aiming at the precise plasma shape/position control. A compact butt-joint has been successfully developed for the Central Solenoid, which allows an optimized utilization of the limited space for the Central Solenoid to extend the duration of the plasma pulse.

Journal Articles

Accuracy improvement of neutron nuclear data on minor actinides

Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

EPJ Web of Conferences, 93, p.06001_1 - 06001_5, 2015/05

 Times Cited Count:4 Percentile:85.45

Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program" at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background, overall plan, and recent progress of the AIMAC project will be reviewed.

Journal Articles

Fabrication of microstructures embedded in SC-CVD diamond with a focused proton microbeam

Kada, Wataru*; Kambayashi, Yuya*; Miura, Kenta*; Saruya, Ryota*; Kubota, Atsushi*; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Hanaizumi, Osamu*

Key Engineering Materials, 643, p.15 - 19, 2015/05

Journal Articles

Development of embedded Mach-Zehnder optical waveguide structures in polydimethylsiloxane thin films by proton beam writing

Kada, Wataru*; Miura, Kenta*; Kato, Hijiri*; Saruya, Ryota*; Kubota, Atsushi*; Sato, Takahiro; Koka, Masashi; Ishii, Yasuyuki; Kamiya, Tomihiro; Nishikawa, Hiroyuki*; et al.

Nuclear Instruments and Methods in Physics Research B, 348, p.218 - 222, 2015/04

 Times Cited Count:6 Percentile:46.16(Instruments & Instrumentation)

Journal Articles

Cross section measurements of the radioactive $$^{107}$$Pd and stable $$^{105,108}$$Pd nuclei at J-PARC/MLF/ANNRI

Nakamura, Shoji; Kimura, Atsushi; Kitatani, Fumito; Ota, Masayuki; Furutaka, Kazuyoshi; Goko, Shinji*; Hara, Kaoru; Harada, Hideo; Hirose, Kentaro; Kin, Tadahiro*; et al.

Nuclear Data Sheets, 119, p.143 - 146, 2014/05

 Times Cited Count:10 Percentile:57.51(Physics, Nuclear)

We have started the measurements of the neutron-capture cross sections for stable $$^{105,108}$$Pd nuclei as well as the radioactive $$^{107}$$Pd. The neutron-capture cross-section measurements by the time-of flight method were performed using an apparatus called "Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI)" installed at the neutron Beam Line No.4 of the Materials and Life science experimental Facility (MLF) in the J-PARC. The neutron-capture cross sections of $$^{107}$$Pd and $$^{105,108}$$Pd have been measured in the neutron energy range from thermal to 300 eV. Some new information was obtained for resonances of these Pd nuclei.

Journal Articles

Capture cross-section measurement of $$^{241}$$Am(n,$$gamma$$) at J-PARC/MLF/ANNRI

Harada, Hideo; Ota, Masayuki; Kimura, Atsushi; Furutaka, Kazuyoshi; Hirose, Kentaro; Hara, Kaoru; Kin, Tadahiro*; Kitatani, Fumito; Koizumi, Mitsuo; Nakamura, Shoji; et al.

Nuclear Data Sheets, 119, p.61 - 64, 2014/05

 Times Cited Count:18 Percentile:76.16(Physics, Nuclear)

Journal Articles

Study on ferromagnetic ordering of FeRh thin films induced by energetic heavy ion irradiation by means of X-ray magnetic circular dichroism

Aiko, Kazuma*; Toki, Atsushi*; Okuda, Shuichi*; Saito, Yuichi; Kamiya, Tomihiro; Nakamura, Tetsuya*; Kinoshita, Toyohiko*; Iwase, Akihiro*; Matsui, Toshiyuki*

Nuclear Instruments and Methods in Physics Research B, 314, p.99 - 102, 2013/11

 Times Cited Count:4 Percentile:33.13(Instruments & Instrumentation)

Journal Articles

Feeder components and instrumentation for the JT-60SA magnet system

Yoshida, Kiyoshi; Kizu, Kaname; Murakami, Haruyuki; Kamiya, Koji; Honda, Atsushi; Onishi, Yoshihiro; Furukawa, Masato; Asakawa, Shuji; Kuramochi, Masaya; Kurihara, Kenichi

Fusion Engineering and Design, 88(9-10), p.1499 - 1504, 2013/10

 Times Cited Count:6 Percentile:44.21(Nuclear Science & Technology)

The modifying of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by both parties of Japanese government and European commission (EU) in the Broader Approach agreement. The magnet system for JT-60SA consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules, and 6 Equilibrium Field (EF) coils. The manufacturing of the JT-60SA magnet system is in progress in EU and Japan. The JT-60SA superconducting magnet system generates an average heat load of 3.2 kW at 4 K to the cryoplant, from nuclear and thermal radiation, conduction and electromagnetic heating, and requires current supplies 20 kA for 4 CS modules and 6 EF coils, 25.7 kA to 18 TF coils. The helium flow to remove this heat, consisting of supercritical helium at pressures up to 0.5 MPa and temperature between 4.4-4.8 K, is distributed to the coils and structures through the valve box (VB) from the cryoline connecting to the auxiliary cold box located outside the torus hall. The feeders also contain the electrical supplies from the current lead transitions to room temperature to the coil. The feeder components consist of the in-cryostat feeders with flexible parts to allow coil operational displacements from the connection pipes out of the cryostat, including S-bend conductor to allow differential thermal contraction and the coil terminal boxes (CTBs) with HIS current leads. A measurement and control system is required to monitor and control these coils and feeders for safety and optimal operational availability. For each coil, both current and supercritical helium are supplied from external systems and are controlled from a central system as part of the regular operation with plasma pulses. Quench detection instruments for superconducting coils, feeders and HTS current leads are provided as a separate, stand alone system.

Journal Articles

MFM observation of micrometer-sized magnetic patterns produced by heavy ion microbeam irradiation in FeRh films

Aiko, Kazuma*; Toki, Atsushi*; Matsui, Toshiyuki*; Iwase, Akihiro*; Sato, Takahiro; Takano, Katsuyoshi*; Koka, Masashi; Saito, Yuichi; Kamiya, Tomihiro

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 133, 2013/01

102 (Records 1-20 displayed on this page)