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Ito, Shinji*; Shimizu, Hiroyuki*; Ono, Shintaro*; Takayama, Yusuke
Doboku Gakkai Rombunshu (Internet), 80(8), p.24-00030_1 - 24-00030_18, 2024/08
In the design consideration of a geological disposal facility for radioactive waste, it is essential to perform a mechanical evaluation that takes into account phenomena that may occur from construction and operation to post-closure. With this background, we have developed the long-term mechanical analysis system MACBECE. In this research, we have built an analysis system that can consistently evaluate the mechanical behavior considering the thermal and hydraulic evolution after the closure of the repository by incorporating the constitutive model for unsaturated soils and coupling with the thermal-hydraulic analysis. As a validation, a mechanical analysis was conducted for the in-situ experiment for full-scale engineered barrier system performance experiment at Horonobe URL. Despite some discrepancies due to constraints in two-dimensional analysis, the extended functionality of the analysis code was confirmed to effectively repro-duce the measured data.
Saito, Yuki*; Ishiwata, Tobimaru*; Horiuchi, Misato*; Nishiki, Yuto*; Kikuchi, Ryosuke*; Otake, Tsubasa*; Kawakita, Ryohei; Takayama, Yusuke; Mitsui, Seiichiro; Sato, Tsutomu*
Shigen, Sozai Koenshu (Internet), 11(1), 7 Pages, 2024/03
no abstracts in English
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:7 Percentile:72.25(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.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru
2020 9th International Congress on Advanced Applied Informatics (IIAI-AAI 2020), p.797 - 801, 2021/07
Kimoto, Kazushi*; Okano, Aoi*; Saito, Takayasu*; Sato, Tadanobu*; Matsui, Hiroya
Doboku Gakkai Rombunshu, A2 (Oyo Rikigaku) (Internet), 76(2), p.I_97 - I_108, 2020/00
This study investigates the propagation characteristics of surface wave traveling in a random heterogeneous medium. For this purpose, ultrasonic measurements are performed on a granite block as a typical randomly heterogeneous medium. In this measurement, a line-focus transducer is used to excite ultrasonic waves, whereas a laser Doppler vibrometer is used to pickup the ultrasonic motion on the surface of the granite block. The measured waveforms are analysed in the frequency domain to evaluate the travel-time for each measurement point based on the Fermat's principle. From the ensemble of travel-times, the probability distribution is established as a function of travel-distance. The uncertainty of the travel-time and its spatial evolution are then investigated using the standard deviation of the travel-time as a measure of the uncertainty. As a result, it was found that the uncertainty is approximately proportional to the mean travel-time divided by the square root travel-distance.
Kamide, Hideki; Ito, Takaya*; Kotake, Shoji*
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(9), p.562 - 566, 2018/09
Sodium-cooled Fast Reactors (SFRs) have significant characteristics on sustainability as follows, highly effective utilization of Uranium resource, burning of TRU long-life nuclide, e.g., Plutonium, reduction of volume and toxicity of high level radioactive waste of spent fuels. SFRs are one of promising concepts at a step of demonstration phase of development. BN-800 in Russia has already started commercial operation. This is a great step toward the commercialization of SFRs. Russia stated that SFR entered the step of commercial use and next step was demonstration of safety and economy of SFRS by means of operation of BN-1200. Construction of a demo reactor of 600 MWe started in China. In India, operation of PFBR is planned near future and also constructions of 6 units of commercial reactors are also planned. In this report such SFR development plans of oversea countries are summarized including development status and future direction in Japan,
Kotake, Shoji*; Chikazawa, Yoshitaka; Takaya, Shigeru; Otaka, Masahiko; Kubo, Shigenobu; Arai, Masanobu; Kunogi, Kosuke; Ito, Takaya*; Yamaguchi, Akira*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
A maintenance management required to prototype nuclear power reactors is proposed. Monitoring and control of sodium impurity and thermal transient are extremely important for sodium boundary maintenance for sodium-cooled fast reactors. At the fast stage of the prototype reactor Monju operation, degradation mechanism on the piping should be demonstrated based on operation experiences. Therefore inspection on a representative position for crack indication and pipe thickness is proposed. Due to less experience of SFR plants, early detection of boundary failure is considered. For a matured operation stage, when degradation mechanism is well demonstrated based on inspection data, inspection cycle could be extended. And for commercial reactors, maintenance without inspection will be established based on accumulated operation experiences including those of the prototype reactor Monju.
Arai, Masanobu; Kunogi, Kosuke; Aizawa, Kosuke; Chikazawa, Yoshitaka; Takaya, Shigeru; Kubo, Shigenobu; Kotake, Shoji*; Ito, Takaya*; Yamaguchi, Akira*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
Applications for maintenance program on piping support of prototype fast breeder reactor Monju are studied. Based on degradation mechanism, snubbers in Monju primary cooling system showed lifetime more than the plant lifetime of 30 years by experiments conservatively. For the first step during construction, visual inspection on accessible all supports could be available. In that visual inspection, mounting conditions and damages of all accessible supports could be monitored. One of major features of the Monju primary piping system is large thermal expansion due to large temperature difference between maintenance and operation conditions. Thanks to that large thermal expansion, integrity of the piping support could be monitored by measuring piping displacement. When technologies of piping displacement monitoring are matured in Monju, visual inspection on piping support could be shifted to piping displacement monitoring. At that stage, the visual inspection could be limited only on representative supports.
Masuda, Ryo*; Kobayashi, Yasuhiro*; Kitao, Shinji*; Kurokuzu, Masayuki*; Saito, Makina*; Yoda, Yoshitaka*; Mitsui, Takaya; Hosoi, Kohei*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; et al.
Scientific Reports (Internet), 6, p.20861_1 - 20861_8, 2016/02
Times Cited Count:10 Percentile:42.27(Multidisciplinary Sciences)Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki; Tobita, Norimitsu; Hayashi, Naoki; Kinsho, Michikazu; Irie, Yoshiro*; Okabe, Kota; Tani, Norio; Naito, Shingo*; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1169 - 1174, 2015/09
The new injection bump power supply for the shift bump magnet of the beam injection sub-systems at the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid Cycling Synchrotron) has been developed and manufactured. The power capacity of the new power supply was more than doubled with the injection beam energy upgrading of the LINAC (Linear Accelerator) from 181 MeV to 400 MeV. Furthermore, the low ripple noise on the output current was required to prevent the resonance of the RF shield loop at the ceramic duct with the excitation magnetic field. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform). This paper reports characteristic about the new power supply.
Kishimoto, Shunji*; Mitsui, Takaya; Haruki, Rie*; Yoda, Yoshitaka*; Taniguchi, Takashi*; Shimazaki, Shoichi*; Ikeno, Masahiro*; Saito, Masatoshi*; Tanaka, Manobu*
Journal of Instrumentation (Internet), 10(5), p.C05030_1 - C05030_6, 2015/05
Times Cited Count:6 Percentile:27.01(Instruments & Instrumentation)Kamide, Hideki; Ando, Masato*; Ito, Takaya*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
JAEA, JAPC and MFBR have been conducted design study for the Japan Sodium-cooled Fast Reactor (JSFR), which is a design concept aiming at future commercial use as sustainable electric power source. Since 2011, in order to contribute to the development of safety design criteria (SDC) and safety design guideline (SDG), which include the lesson learned from the TEPCO's Fukushima Dai-ichi Nuclear Power Plants accident, in the frame work of generation IV international forum (GIF), the design study is focusing on the design measures against sever external events such as earthquake and tsunami. At the same time, the design study is going into detail and paying much attention to the maintenance and repair to make surer its feasibility. This paper summarizes the design concept of the demonstration version of JSFR in which progress of design work was incorporated.
Kishimoto, Shunji*; Mitsui, Takaya; Haruki, Rie*; Yoda, Yoshitaka*; Taniguchi, Takashi*; Shimazaki, Shoichi*; Ikeno, Masahiro*; Saito, Masatoshi*; Tanaka, Manobu*
Review of Scientific Instruments, 85(11), p.113102_1 - 113102_5, 2014/11
Times Cited Count:9 Percentile:38.80(Instruments & Instrumentation)Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Kurokuzu, Masayuki*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Saito, Makina*; Masuda, Ryo*; Mitsui, Takaya; Yoda, Yoshitaka*; Seto, Makoto*
Hyperfine Interactions, 226(1), p.687 - 691, 2014/04
Times Cited Count:3 Percentile:68.90(Physics, Atomic, Molecular & Chemical)Kurokuzu, Masayuki*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Saito, Makina*; Masuda, Ryo*; Mitsui, Takaya; Yoda, Yoshitaka*; Seto, Makoto*
Journal of the Physical Society of Japan, 83(4), p.044708_1 - 044708_4, 2014/04
Times Cited Count:4 Percentile:33.86(Physics, Multidisciplinary)Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; et al.
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 179, 2014/03
Three electrostatic accelerators at TIARA were operated on schedule in fiscal year 2012 except changing its schedule by cancellations of users. The yearly operation time of the 3 MV tandem accelerator, the 400 kV ion implanter and the 3MV single-ended accelerator were in the same levels as the ordinary one, whose operation time totaled to 2,073, 1,847 and 2,389 hours, respectively. The tandem accelerator had no trouble, whereas the ion implanter and the single-ended accelerator stopped by any troubles for one day and four days, respectively. The molecular ion beam of helium hydride was generated by the ion implanter, because the users required irradiation of several cluster ions in order to study the effect of irradiation. As a result, its intensity of beam was 50 nA at 200 kV. The ion beam of tungsten (W) at 15 MeV was accelerated by the tandem accelerator, whose intensity was 20 nA at charge state of 4+, because of the request from a researcher in the field of nuclear fusion.
Masuda, Ryo*; Kobayashi, Yasuhiro*; Kitao, Shinji*; Kurokuzu, Masayuki*; Saito, Makina*; Yoda, Yoshitaka*; Mitsui, Takaya; Iga, Fumitoshi*; Seto, Makoto
Applied Physics Letters, 104(8), p.082411_1 - 082411_5, 2014/02
Times Cited Count:21 Percentile:63.92(Physics, Applied)A detection system for synchrotron-radiation (SR)-based Mssbauer spectroscopy was developed to enhance the nuclear resonant scattering counting rate and thus increase the available nuclides. In the system, a windowless avalanche photodiode (APD) detector was combined with a vacuum cryostat to detect the internal conversion (IC) electrons and fluorescent X-rays accompanied by nuclear de-excitation. As a feasibility study, the SR-based Mssbauer spectrum using the 76.5 keV level of Yb was observed without Yb enrichment of the samples. The counting rate was five times higher than that of our previous system, and the spectrum was obtained within 10 h. This result shows that nuclear resonance events can be more efficiently detected by counting IC electrons for nuclides with high IC coefficients. Furthermore, the windowless detection system enables us to place the sample closer to the APD elements and is advantageous for nuclear resonant inelastic scattering measurements. Therefore, this detection system can not only increase the number of nuclides accessible in SR-based Mssbauer spectroscopy but also allows the nuclear resonant inelastic scattering measurements of small single crystals or enzymes with dilute probe nuclides that are difficult to measure with the previous detection system.
Aoto, Kazumi; Chikazawa, Yoshitaka; Okubo, Tsutomu; Okada, Keizo*; Ito, Takaya*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable Scenarios (FR-13) (USB Flash Drive), 10 Pages, 2013/03
Overview of Japan Sodium-cooled Fast Reactor (JSFR) development status and reflection of lessons learned from the TEPCO's Fukushima Dai-ichi Nuclear Power Plant (1F) accident have been summarized. JSFR was recognized as a promising next generation nuclear reactor. Even though the JSFR safety design already took into account measures against severe accident situations and passive safety features such as passive shutdown system and natural convection decay heat removal systems in the 2010 design version, it is become aware of importance of design measures against severe accidents and extreme external events by the 1F accident. As recent activities, external hazard evaluations and design improvements reflecting lessons learned from 1F accident have been conducted. This paper also discusses importance of development of global safety design criteria and international Research and Development cooperation on safety design measures.