JOPSS - Search Results

Journal Articles

Development of the buckling evaluation method for thick cylindrical vessels with a conical section in fast reactors made of austenitic stainless steel

Okafuji, Takashi*; Miura, Kazuhiro*; Sago, Hiromi*; Murakami, Hisatomo*; Watakabe, Tomoyoshi; Ando, Masanori; Miyazaki, Masashi

Proceedings of the ASME 2025 Pressure Vessels & Piping Conference (PVP2025) (Internet), 8 Pages, 2025/07

https://doi.org/10.1115/PVP2025-154772

Journal Articles

Measurements of neutronic characteristics of rectangular and cylindrical coupled hydrogen moderators

Kai, Tetsuya; Kamiyama, Takashi*; Hiraga, Fujio*; Oi, Motoki; Hirota, Katsuya*; Kiyanagi, Yoshiaki*

Journal of Nuclear Science and Technology, 55(3), p.283 - 289, 2018/03

https://doi.org/10.1080/00223131.2017.1394235

Times Cited Count：1 Percentile：9.04(Nuclear Science & Technology)

Journal Articles

Neutronic performance of rectangular and cylindrical coupled hydrogen moderators in wide-angle beam extraction of low-energy neutrons

Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Kiyanagi, Yoshiaki*; Ikeda, Yujiro

Nuclear Instruments and Methods in Physics Research A, 550(1-2), p.329 - 342, 2005/09

https://doi.org/10.1016/j.nima.2005.04.082

Times Cited Count：20 Percentile：75.93(Instruments & Instrumentation)

Neutronic study was performed on coupled hydrogen moderators to maximize time-integrated and pulse-peak intensities of slow neutrons when a large number of beams was required. The total increased with the number of beams, although the average decreased due to a reflector-missing by the beam extraction holes in the reflector. At a large beam extraction angle (25 degree), the spatial distribution of the vector-flux of neutrons was undesirable for a rectangular shape moderator. As an alternative we proposed a cylindrical shape one, resulting in a much improved spatial distribution. In addition, neutronic performance was calculated as a function of the diameter, indicating the optimal diameter was about 140 mm. The cylindrical one gave higher pulse-peak intensities with narrower pulse widths without penalty in time-integrated intensities and pulse decay characteristics, providing a more uniform angle-dependence. Some explanations are given for the difference in the pulse characteristics between the two. We decided to adopt the cylindrical one for the Japanese spallation neutron source.

Journal Articles

Thermal-hydraulic design of J-PARC cold moderators

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

Journal Articles

Neutronic study on coupled hydrogen moderator for J-PARC spallation neutron source

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 $_{2}$ 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 $_{2}$ 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 $_{2}$ 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 $^{rm o}$ . Then, we propose a cylindrical shape coupled moderator which brings about a slight intensity decrease for 0 $^{rm o}$ but a increase in the averaged intensity over the angles of interest.