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Tokunaga, Sho; Horiguchi, Hironori; Nakamura, Takemi
JAEA-Technology 2023-001, 37 Pages, 2023/05
JAEA-Technology-2023-001.pdf:1.39MB
The cold neutron source (CNS) of the research reactor JRR-3 converts thermal neutrons generated in the reactor into low-energy cold neutrons by moderating them with liquid hydrogen stored in the moderator cell. Cold neutrons generated by the CNS are transported to experimental instruments using neutron conduits, and are used for many studies of physical properties, mainly in life science, polymer science, environmental science, etc. Improvement of cold neutron intensity is essential to maintain competitiveness with the world's research reactors in neutron science, and we are developing a new CNS that incorporates new knowledge. The current moderator cell for the CNS of JRR-3 is a stainless-steel container which is a canteen bottle type, and the cold neutron intensity can be improved by changing the material and shape. Therefore, the basic specifications of the new moderator cell were changed to aluminum alloy which has a smaller neutron absorption cross section, and the shape was optimized using a Monte Carlo code MCNP. Since these changes in specifications will result in changes in heat generation and heat transfer conditions, the CNS of JRR-3 was re-evaluated in terms of self-regulating characteristic, heat transport limits, heat resistance and pressure resistance, etc., to confirm its feasibility in thermal-hydraulic design. This report summarizes the results of the thermal-hydraulic design evaluation of the new moderator cell.
Teshigawara, Makoto; Ikeda, Yujiro*; Yan, M.*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*
Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01
Times Cited Count：2 Percentile：54.89(Chemistry, Multidisciplinary)To enhance neutron intensity below cold neutrons, it is proposed that nanosized graphene aggregation could facilitate neutron coherent scattering under particle size conditions similar to nanodiamond. It might also be possible to use it in high neutron radiation conditions due to graphene's strong sp2 bonds. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section, and small-angle neutron scattering on nanosized graphene aggregation. The measured data revealed, for the first time, that nanosized graphene aggregation increased the total cross-sections and small-angle scattering in the cold neutron energy region, most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamond.
Nishida, Satoru*; Nishino, Soichiro*; Sekine, Masahiko*; Oka, Yuki*; Harjo, S.; Kawasaki, Takuro; Suzuki, Hiroshi; Morii, Yukio*; Ishii, Yoshinobu*
Materials Transactions, 62(5), p.667 - 674, 2021/05
Times Cited Count：5 Percentile：41.35(Materials Science, Multidisciplinary)Ma, B.*; Teshigawara, Makoto; Wakabayashi, Yasuo*; Yan, M.*; Hashiguchi, Takao*; Yamagata, Yutaka*; Wang, S.*; Ikeda, Yujiro*; Otake, Yoshie*
Nuclear Instruments and Methods in Physics Research A, 995, p.165079_1 - 165079_7, 2021/04
Times Cited Count：2 Percentile：34.88(Instruments & Instrumentation)We have optimized a cold neutron moderator to be operated at the RIKEN accelerator-driven compact neutron source. We selected a safe and easy to manage material, mesitylene, as the RANS cold moderator. An efficient moderator system was designed by studying and optimizing a coupled cold neutron moderator of mesitylene at 20 K with a polyethylene (PE) pre-moderator at room temperature in the slab geometry with Particle and Heavy Ion Transport code System (PHITS) simulations. The parameters of mesitylene and PE thickness, the reflector, and the shielding configuration were studied to increase cold neutron intensities. Consequently, an integrated cold neutron intensity of 1.15
10
n/cm
/
A at 2 m from the neutron-producing target was finally achieved, which was 12 times higher than that of the current PE moderator. The results showed attractive application prospect of mesitylene as cold neutron moderator material.
Teshigawara, Makoto; Tsuchikawa, Yusuke*; Ichikawa, Go*; Takata, Shinichi; Mishima, Kenji*; Harada, Masahide; Oi, Motoki; Kawamura, Yukihiko*; Kai, Tetsuya; Kawamura, Seiko; et al.
Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06
Times Cited Count：16 Percentile：86.05(Instruments & Instrumentation)A nano-diamond is an attractive neutron reflection material below cold neutron energy. The total neutron cross section of a nano-diamond was derived from a neutron transmission measurement over the neutron energy range of 0.2 meV to 100 meV because total neutron cross section data were not available. The total cross section of a nano-diamond with particle size of approximately 5 nm increased with a decrease in neutron energy to 0.2 meV. It was approximately two orders of magnitude larger than that of graphite at 0.2 meV. The contribution of inelastic scattering to the total cross section was to be shown negligible small at neutron energies of 1.2, 1.5, 1.9, 2.6, and 5.9 meV in the inelastic neutron scattering measurement. Moreover, small-angle neutron scattering measurements of the nano-diamond showed a large scattering cross section in the forward direction for low neutron energies.
Tamura, Itaru
Hamon, 28(4), p.204 - 207, 2018/11
A Neutron guide is one of the devices to transport neutron beam for long distance without sacrificing much neutrons; therefore, it can supply neutrons to many experimental instruments distributed in a large experimental hall. Also, by using a curved guide, only the neutrons in a required energy range can be transported, and 
rays and fast neutrons can be effectively eliminated, therefore the signal to background ratio is improved. In addition, a neutron beam can be branched by applying curved guides. Neutron guides are also used to control the divergence angle and intensity of the neutron beam supplied to the neutron instrument.
Arai, Masaji; Tamura, Itaru; Hazawa, Tomoya
JAEA-Technology 2015-010, 52 Pages, 2015/05
JAEA-Technology-2015-010.pdf:7.11MB
In the Department of Research Reactor and Tandem Accelerator, developments of high-performance CNS moderator vessel that can produce cold neutron intensity about two times higher compared to the existing vessel have been performed in the second medium term plans. We compiled this report about the technological development to solve several problems with the design and manufacture of new vessel. In the present study, design strength evaluation, mockup test, simulation for thermo-fluid dynamics of the liquid hydrogen and strength evaluation of the different-material-bonding were studied. By these evaluation results, we verified that the developed new vessel can be applied to CNS moderator vessel of JRR-3.
Oyama, Yukio; Ikeda, Yujiro
Hoshasen To Sangyo, (107), p.45 - 51, 2005/09
JAERI and KEK are jointly conducting high intensity proton accelerator project (J-PARC). The outline of the J-PARC project and a design concept of the neutron source facility at J-PARC are described in detail.
Matsubayashi, Masahito; Soyama, Kazuhiko
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.384 - 388, 2004/08
Times Cited Count：8 Percentile：48.81(Instruments & Instrumentation)no abstracts in English
Aso, Tomokazu; Sato, Hiroshi; Kaminaga, Masanori; Hino, Ryutaro; Monde, Masanori*
Proceedings of ICANS-XVI, Volume 2, p.935 - 944, 2003/07
no abstracts in English
Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 3, p.657 - 666, 2003/07
Neutronic design studies were carried out on the J-PARC coupled H
moderator. The highest time- and energy- integrated intensity below 15 meV, pulse peak intensity at 2 meV and 10 meV, were given by 100% para-H moderators, but the optimal moderator thickness was different for each: more than 220 mm, about 120 mm and 80 mm, respectively. Finally, we concluded 140 mm was the optimal thickness for the 100% para-H coupled moderator. Cold neutron distributions on the moderator viewed surface were found to exhibit an intensity-enhanced region at a picture frame part near premoderator. This rather peculiar distribution suggested that the moderator and the viewed surface must be designed so as to take the brighter region near premoderator in use. The intensity decreases along with beam-extraction angle to the normal direction down to about 70% at 25.4
. Then, we propose a cylindrical shape coupled moderator which brings about a slight intensity decrease for 0 but a increase in the averaged intensity over the angles of interest.
range for International Fusion Materials Irradiation Facility (IFMIF)Nakamura, Hiroo; Ida, Mizuho*; Nakamura, Hideo; Takeuchi, Hiroshi; IFMIF International Team
Fusion Engineering and Design, 65(3), p.467 - 474, 2003/04
Times Cited Count：4 Percentile：31.64(Nuclear Science & Technology)IFMIF is an accelerator-based neutron source for development of fusion materials. The Li target system consists of a target assembly, a Li purification system and various diagnostics. An intense deuterium beam power up to 10 MW in a footprint of 205 cm corresponds to ultra high heat flux up to 1 GW/m. To handle such an ultra high heat flux, the high-speed liquid Li flow with a velocity of 20 m/s and a concave flow configuration are necessary. According to thermal-hydraulic analysis, an induced centrifugal force (160 G) under the concave back wall of a radius of 25 cm is sufficient for IFMIF operation. To confirm the hydraulic characteristics of Li flow, water jet experiment has been done. Moreover, validation experiment in Li loop is planned. In addition, to control tritium and impurities such as C, N, O below permissible levels, a cold trap and two hot traps are used. These technologies have similarities in plasma facing components in fusion reactor. In presentation, the IFMIF Li target technology and its application of to the plasma facing component will be discussed.
Aso, Tomokazu; Kaminaga, Masanori; Hino, Ryutaro; Monde, Masanori*
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 8 Pages, 2003/04
no abstracts in English
Sakurai, Fumio; Horiguchi, Yoji; Kobayashi, Shinsho; Takayanagi, Masaji
Physica B; Condensed Matter, 311(1-2), p.7 - 13, 2002/01
Times Cited Count：9 Percentile：45.24(Physics, Condensed Matter)no abstracts in English
Kawabata, Yuji*; Ebisawa, Toru*; Tasaki, Seiji*; Suzuki, Masatoshi; Soyama, Kazuhiko
JAERI-Research 2000-019, p.20 - 0, 2000/03
JAERI-Research-2000-019.pdf:0.83MB
no abstracts in English
; ; ; Kaieda, Keisuke
KAERI/GP-128/98, p.205 - 221, 1998/00
no abstracts in English
Watanabe, Noboru*; Teshigawara, Makoto*; Takada, Hiroshi; Nakashima, Hiroshi; Oyama, Yukio; *; Kai, Tetsuya; Ikeda, Yujiro; Kosako, Kazuaki*
Proc. of 14th Meeting of the Int. Collaboration on Advanced Neutron Sources (ICANS-14), 2, p.728 - 742, 1998/00
no abstracts in English
Matsubayashi, Masahito; *
Dai-2-Kai Hoshasen Shimpojiumu Koen Rombunshu, p.130 - 135, 1997/10
no abstracts in English
Soyama, Kazuhiko; ; Ichikawa, Hiroki; *
Genshiryoku Kogyo, 43(10), p.36 - 41, 1997/10
no abstracts in English
Yonezawa, Chushiro; ; ; Hoshi, Michio; Sawahata, Hiroyuki*; Ito, Yasuo*
Proc. of 9th Int. Symp. on Capture Gamma-ray Spectroscopy and Related Topics, 0, p.705 - 712, 1997/00
no abstracts in English
