Nemoto, Takahiro; Arakawa, Ryoki; Kawakami, Satoru; Nagasumi, Satoru; Yokoyama, Keisuke; Watanabe, Masashi; Onishi, Takashi; Kawamoto, Taiki; Furusawa, Takayuki; Inoi, Hiroyuki; et al.
JAEA-Technology 2023-005, 33 Pages, 2023/05
During shut down of the HTTR (High Temperature engineering Test Reactor) RS-14 cycle, an increasing trend of filter differential pressure for the helium gas circulator was observed. In order to investigate this phenomenon, the blower of the primary helium purification system was disassembled and inspected. As a result, it is clear that the silicon oil mist entered into the primary coolant due to the deterioration of the charcoal filter performance. The replacement and further investigation of the filter are planning to prevent the reoccurrence of the same phenomenon in the future.
Watanabe, Masao; Kihara, Takumi*; Nojiri, Hiroyuki*
Quantum Beam Science (Internet), 7(1), p.1_1 - 1_10, 2023/03
A pulsed magnet system has been developed as a new user-friendly sample environment equipment at the Materials and Life Science Experimental Facility in Japan Proton Accelerator Research Complex. It comprises a vacuum chamber, a 4 K closed-cycle refrigerator for samples, and a nitrogen bath made of a stainless-steel tube with a miniature solenoidal coil. The coil is cooled by liquid nitrogen supplied by an automatic liquid nitrogen supply system, and the sample is cooled by a refrigerator. This combination facilitates the automatic high magnetic field diffraction measurement for the user's operation. A relatively large scattering angle is up to 42 degrees, which is significantly wider than the previous setup. Neutron diffraction experiments were performed on a multiferroic TbMnO and the field dependence of the diffraction peaks was clearly observed. The new pulsed magnet system was established for a practical high magnetic field diffraction for the user program.
Hamamoto, Shimpei; Shimizu, Atsushi; Inoi, Hiroyuki; Tochio, Daisuke; Homma, Fumitaka; Sawahata, Hiroaki; Sekita, Kenji; Watanabe, Shuji; Furusawa, Takayuki; Iigaki, Kazuhiko; et al.
Nuclear Engineering and Design, 388, p.111642_1 - 111642_11, 2022/03
Following the Fukushima Daiichi Nuclear Power Plant accident in 2011, the Japan Atomic Energy Agency adapted High-Temperature engineering Test Reactor (HTTR) to meet the new regulatory requirements that began in December 2013. The safety and seismic classifications of the existing structures, systems, and components were discussed to reflect insights regarding High Temperature Gas-cooled Reactors (HTGRs) that were acquired through various HTTR safety tests. Structures, systems, and components that are subject to protection have been defined, and countermeasures to manage internal and external hazards that affect safety functions have been strengthened. Additionally, measures are in place to control accidents that may cause large amounts of radioactive material to be released, as a beyond design based accident. The Nuclear Regulatory Commission rigorously and appropriately reviewed this approach for compliance with the new regulatory requirements. After nine amendments, the application to modify the HTTR's installation license that was submitted in November 2014 was approved in June 2020. This response shows that facilities can reasonably be designed to meet the enhanced regulatory requirements, if they reflect the characteristics of HTGRs. We believe that we have established a reference for future development of HTGR.
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Nawa, Kazuhiro*; Hirai, Daigoro*; Kofu, Maiko; Nakajima, Kenji; Murasaki, Ryo*; Kogane, Satoshi*; Kimata, Motoi*; Nojiri, Hiroyuki*; Hiroi, Zenji*; Sato, Taku*
Physical Review Research (Internet), 2(4), p.043121_1 - 043121_11, 2020/12
The spin excitations of the = anisotropic triangular antiferromagnet CaReOCl were investigated by inelastic neutron-scattering experiments. The spin excitation spectrum exhibits sharp dispersive modes in addition to a spinonlike continuum. The consistency with the simulated spectrum based on the random-phase approximation is better for CaReOCl than for CsCuCl, indicating that the spin system in the former remains closer to a Tomonaga-Luttinger liquidlike disordered state.
Fogh, E.*; Kihara, Takumi*; Toft-Petersen, R.*; Bartkowiak, M.*; Narumi, Yasuo*; Prokhnenko, O.*; Miyake, Atsushi*; Tokunaga, Masashi*; Oikawa, Kenichi; Srensen, M. K.*; et al.
Physical Review B, 101(2), p.024403_1 - 024403_12, 2020/01
Watanabe, Masao; Nojiri, Hiroyuki*
Journal of Neutron Research, 21(1-2), p.39 - 45, 2019/05
Magnetic field acts directly on the spin and the orbital motion of electron in the material and interesting quantum phenomena and phase transition are found in high magnetic field. Recently, experimental equipments using neutron beams in high magnetic field have been rapidly developed. For example, superconducting DC magnet up to 17 T has developed for neutron scattering experiments. Although the sample environment team in the MLF have several DC superconducting magnets up to 7 T as a sample environment apparatus, some users have requested the preparation of higher field magnets. However, another magnet technology is needed to generate higher than 20 T. However, it is difficult to construct such a large system in the MLF from the point of view of construction space. It is practical to employ a pulsed magnetic field as it enables operation of smaller energy as well as downsizing of the instruments. Therefore, we have been developed a compact and movable pulsed magnet system up to 30 T.
Watanabe, Masao; Nojiri, Hiroyuki*; Ito, Shinichi*; Kawamura, Seiko; Kihara, Takumi*; Masuda, Takatsugu*; Sahara, Takuro*; Soda, Minoru*; Takahashi, Ryuta
JPS Conference Proceedings (Internet), 25, p.011024_1 - 011024_5, 2019/03
Recently, neutron scattering experiments have been rapidly progressed under high magnetic field. In the J-PARC, proto-type compact pulse magnet system with the power supply, the coil and the sample stick has been developed. Basic specifications of the power supply are as follows; maximum charged voltage with capacitor is 2 kV, maximum current is 8 kA, repetition rate is a pulse per several minutes and pulse duration is several msec. Maximum magnetic field in the coil is more than 30 Tesla. The sample stick is designed for Orange-Cryostat. In this presentation, We report the details of the pulsed magnet system and the performance of it on neutron scattering experiments at MLF beam line (HRC).
Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.
JAEA-Technology 2011-031, 123 Pages, 2012/01
The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.
Shinohara, Masanori; Yanagi, Shunki; Tochio, Daisuke; Shimazaki, Yosuke; Nojiri, Naoki; Owada, Hiroyuki; Sato, Nao; Sagawa, Hiroshi; Umeda, Masayuki
JAEA-Technology 2011-029, 39 Pages, 2011/12
JAEA plans and performs the safety demonstration test using the HTTR to develop High Temperature Gas Reactor technologies. Cold test of the loss of forced cooling was conducted prior to the safety demonstration test, to check test procedure and plant behavior. Cold test consists of two phases, Phase1, 1 or 2 Vessel Cooling System (VCS) terminates, in the Phase2, all 3 Gas circulators and 1 VCS terminates. Cold test could confirm test process, and obtain data necessary to analysis and 2-dimensional horizontal sectional model analysis was verified to simulate actual measurement value.
Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of Physics; Conference Series, 211, p.012010_1 - 012010_6, 2010/02
Matsuda, Masaaki; Oyama, Kenji*; Yoshii, Shunsuke*; Nojiri, Hiroyuki*; Frings, P.*; Duc, F.*; Vignolle, B.*; Rikken, G. L. J. A.*; Regnault, L.-P.*; Lee, S.-H.*; et al.
Physical Review Letters, 104(4), p.047201_1 - 047201_4, 2010/01
Masuda, Takatsugu*; Kitaoka, Shuji*; Takamizawa, Satoshi*; Metoki, Naoto; Kaneko, Koji; Rule, K. C.*; Kiefer, K.*; Manaka, Hiroshi*; Nojiri, Hiroyuki*
Physical Review B, 81(10), p.100402_1 - 100402_4, 2010/00
Spin dynamics of the square lattice Heisenberg antiferromagnet, BaMnGeO, is studied by a combination of bulk measurements, neutron diffraction, and inelastic neutron-scattering techniques. Easy plane type antiferromagnetic order is identified at T4.0 K. The exchange interactions are estimated as = 27.8(3) eV and = 1.0(1) eV, and the saturation field is 9.75 T. Magnetic excitation measurements with high experimental resolution setup by triple axis neutron spectrometer reveals the instability of one magnon excitation in the field range of 0.7 0.85.
Matsuda, Yasuhiro*; Her, J. L.*; Inami, Toshiya; Owada, Kenji; Ouyang, Z. W.*; Okada, Kyoko*; Nojiri, Hiroyuki*; Mitsuda, Akihiro*; Wada, Hirofumi*; Yoshimura, Kazuyoshi*; et al.
Journal of Physics; Conference Series, 190, p.012019_1 - 012019_6, 2009/11
Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Inami, Toshiya; Owada, Kenji; Suzuki, Motohiro*; Kawamura, Naomi*; Mitsuda, Akihiro*; Wada, Hirofumi*
Physical Review Letters, 103(4), p.046402_1 - 046402_4, 2009/07
X-ray magnetic circular dichroism (XMCD) at the Eu L edge in two compounds exhibiting valence fluctuation, namely EuNi(SiGe) and EuNiP, has been investigated at high magnetic fields of up to 40T. A distinct XMCD peak corresponding to the trivalent state (Eu), whose ground state is nonmagnetic (J = 0), was observed in addition to the main XMCD peak corresponding to the magnetic (J = 7/2) divalent state (Eu). This result indicates that the 5 electrons belonging to both valence states are magnetically polarized. It was also found that the ratio (3+)/(2+) between the polarization of 5 electrons() in the Eu state and that of Eu depends on the material. The possible origin of the XMCD and an explanation of the material dependence of (3+)/(2+) are discussed in terms of hybridization between the conduction electrons and the f electrons.
Tomimoto, Hiroshi; Kato, Yasushi; Owada, Hiroyuki; Sato, Nao; Shimazaki, Yosuke; Kozawa, Takayuki; Shinohara, Masanori; Hamamoto, Shimpei; Tochio, Daisuke; Nojiri, Naoki; et al.
JAEA-Technology 2009-025, 29 Pages, 2009/06
The first driver fuel of the HTTR (High Temperature Engineering test Reactor) was loaded in 1998 and the HTTR reached first criticality state in the same year. The HTTR has been operated using the first driver fuel for a decade. In Fuel elements assembling, 4770 of fuel rods which consist of 12 kinds of enrichment uranium are loaded into 150 fuel graphite blocks for HTTR second driver fuel elements. Measures of prevention of fuel rod miss loading, are employed in fuel design. Additionally, precaution of fuel handling on assembling are considered. Reception of fuel rods, assembling of fuel elements and storage of second driver fuels in the fresh fuel storage rack in the HTTR were started since June, 2008. Assembling, storage and pre-service inspection were divided into three parts. The second driver fuel assembling was completed in September, 2008. This report describes concerns of fuel handling on assembling and storage work for the HTTR fuel elements.
Tochio, Daisuke; Nojiri, Naoki; Hamamoto, Shimpei; Inoi, Hiroyuki; Sekita, Kenji; Kondo, Masaaki; Saikusa, Akio; Kameyama, Yasuhiko; Saito, Kenji; Fujimoto, Nozomu
JAEA-Technology 2009-005, 47 Pages, 2009/05
HTTR is now conducted in-service operation through the rise-to power operation with rated operation or high-temperature test operation from achievement of first criticality at 1998. In order to demonstrate to supply stable heat to heat utilization system for long-term, HTTR was conducted rated/parallel-loaded 30-days operation. This paper reports the characteristics of long-term operation for HTTR.
Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of the Physical Society of Japan, 78(3), p.033707_1 - 033707_4, 2009/03
Fujii, Yasuhiko; Arai, Masatoshi; Kadono, Ryosuke*; Kanaya, Toshiji*; Kamiyama, Takashi*; Niimura, Nobuo*; Nojiri, Hiroyuki*; Noda, Yukio*; Yagi, Takehiko*; Yamada, Kazuyoshi*
Kotai Butsuri, 43(7), p.441 - 450, 2008/07
no abstracts in English
Nojiri, Naoki; Owada, Hiroyuki; Kato, Yasushi
JAEA-Technology 2008-045, 38 Pages, 2008/06
This paper describes the inspection method, the measured area, etc. of the ultrasonic test of the in-service inspection (ISI) for welding lines of the reactor pressure vessel of the HTTR and the inspection results of the longitudinal welding line of the bottom dome. The pre-service inspection (PSI) results for estimation of occurrence and progression of defects to compare the ISI results is described also.