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Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.
Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06
Times Cited Count:0 Percentile:24.42(Astronomy & Astrophysics)We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.
Tonoike, Kotaro; Yamamoto, Toshihiro; Miyoshi, Yoshinori; Uchiyama, Gunzo; Watanabe, Shoichi*
Journal of Nuclear Science and Technology, 46(4), p.354 - 365, 2009/04
Times Cited Count:1 Percentile:10.23(Nuclear Science & Technology)A series of critical experiments were performed using heterogeneous cores at the Static Experiment Critical Facility in Japan Atomic Energy Agency in order to obtain systematic benchmark data concerning dissolving process in a reprocessing plant. Focusing on the introduction of the burn-up credit, critical mass measurement was conducted for a combination of uranium dioxide fuel rods (5wt% U) and uranyl nitrate solution (6wt% U) poisoned with pseudo fission product (FP) elements - samarium, cesium, rhodium, and europium. Fuel rods were arrayed with an 1.5-cm lattice interval in the poisoned fuel solution in a 60-cm diameter cylindrical tank. The uranium concentrations of the solution was roughly kept at about 320gU/L, and the FP element concentrations were adjusted to be equivalent to a burn-up of about 30GWd/t. The result provides basic experimental data for validation of computational methods to evaluate a reactivity effect of each FP element, as well as benchmark criticality data for validation of neutron multiplication factor calculation of heterogeneous systems of spent fuel. In the report, detail of the experiments and its benchmark models will be presented as well as the procedure and the result of separate reactivity worth evaluation for each FP element. The experimental result and the computational evaluation will also be compared.
Tonoike, Kotaro; Miyoshi, Yoshinori; Uchiyama, Gunzo; Watanabe, Shoichi*; Yamamoto, Toshihiro*
Proceedings of 8th International Conference on Nuclear Criticality Safety (ICNC 2007), p.222 - 227, 2007/05
In order to obtain systematic benchmark criticality data concerning dissolving process in a reprocessing plant for LWR spent fuel, a series of critical experiments were performed using heterogeneous cores at the Static Experiment Critical Facility (STACY) in Japan Atomic Energy Agency (JAEA). Focusing on the introduction of the burn-up credit to the process, critical mass measurement was conducted for a combination of uranium fuel rods and uranium solution where pseudo fission product (FP) materials were doped. In this report, the "pseudo FP materials" means elements such as Sm, Cs, Rh and Eu whose isotopic composition is natural but which contains some FP nuclide(s). The result is going to provide basic experimental data for validation of computational methods to evaluate a reactivity effect of each FP material, as well as benchmark criticality data for validation of neutron multiplication factor calculation of heterogeneous systems of spent fuel. In the report, detail of the experiments including a differential reactivity worth curve over the solution level variation is going to be provided as well as the procedure and the result of separate reactivity worth evaluation of each pseudo FP material. Comparison of the experimental result and the computational evaluation will also be presented.
Okuno, Hiroshi; Suyama, Kenya; Takahashi, Satoshi*; Watanabe, Shoichi*; Tonoike, Kotaro; Miyoshi, Yoshinori
Transactions of the American Nuclear Society, 95(1), p.283 - 284, 2006/11
no abstracts in English
Hirata, Mafumi*; Miyake, Yasuhiro*; Chujo, T.*; Kohagura, Junko*; Numakura, Tomoharu*; Shimizu, Kiyoaki*; Ito, Marie*; Kiminami, Serina*; Morimoto, Naomichi*; Hirai, Katsuaki*; et al.
Review of Scientific Instruments, 77(10), p.10E719_1 - 10E719_3, 2006/10
Times Cited Count:0 Percentile:0.01(Instruments & Instrumentation)no abstracts in English
Sumiyoshi, Kosuke*; Yamada, Shoichi*; Suzuki, Hideyuki*; Chiba, Satoshi
Physical Review Letters, 97(9), p.091101_1 - 091101_4, 2006/09
Times Cited Count:101 Percentile:93.09(Physics, Multidisciplinary)no abstracts in English
Sumiyoshi, Kosuke*; Yamada, Shoichi*; Suzuki, Hideyuki*; Shen, H.*; Chiba, Satoshi; Toki, Hiroshi*
Astrophysical Journal, 629(2, Part1), p.922 - 932, 2005/08
Times Cited Count:226 Percentile:97.41(Astronomy & Astrophysics)no abstracts in English
Watanabe, Shoichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori
Transactions of the American Nuclear Society, 91, p.431 - 432, 2004/11
Temperature effect is a main factor which affects the transient characteristics at a criticality accident. A series of reactivity effects due to changes in fuel temperatures were measured for two kinds of STACY heterogeneous lattice configurations. The core was composed of LWR-type fuel rod array and low-enriched uranyl-nitrate-solution concerning the dissolver of the reprocessing facility for LWR spent fuel. The critical solution heights at various solution temperatures were measured. From the change of the critical water height with fuel temperature, the reactivity effect was evaluated by a critical-solution-level worth method. The temperature effect was also calculated by using SRAC and the transport calculation code TWODANT. The experimental value was estimated to be -2.0 cent/C for the case "2.1cm-pitch", and -2.5 cent/C for the case "1.5cm-pitch". The calculated results gave agreement with the experiments within 10%.
Tonoike, Kotaro; Yamamoto, Toshihiro; Watanabe, Shoichi; Miyoshi, Yoshinori
Journal of Nuclear Science and Technology, 41(2), p.177 - 182, 2004/02
Times Cited Count:14 Percentile:66.17(Nuclear Science & Technology)As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function of detector signals and a real time evaluation function of alpha value with the Feynman- method was established, with which the kinetic parameter (alpha value) was measured at the STACY heterogeneous core. The Hashimoto's difference filter was implemented in the system, which enables the measurement at a critical condition. The measurement result of the new system agreed with the pulsed neutron method.
Watanabe, Shoichi; Yamane, Yuichi; Miyoshi, Yoshinori
JAERI-Tech 2003-045, 73 Pages, 2003/03
Since exact information is not always acquired in the criticality accident of fuel-solution, parametric survey calculations are required for grasping behaviors of the thermal-hydraulics. On the other hand, the practical methods of the calculation which can reduce the computation time with allowable accuracy will be also required, since the conventional method takes a long calculation time. In order to fulfill the requirement, a three-dimensional nuclear-kinetics analysis code considering thermal-hydraulic based on the multi-region kinetic equations with one-group neutron energy was created by incorporating the thermal-hydraulics analysis code PHOENICS as a subroutine. The computation time of the code was shortened by separating time mesh intervals of the nuclear- and heat-calculations from that of the hydraulics calculation, and by regulating automatically the time mesh intervals in proportion to power change rate. A series of analysis were performed for the natural-cooling characteristic test using TRACY in which the power changed slowly for 5 hours after the transient power resulting from the reactivity insertion of a 0.5 dollar. It was found that the code system was able to calculate within the limit of practical time, and acquired the prospect of reproducing the experimental values considerably for the power and temperature change.
Yamane, Yuichi; Miyoshi, Yoshinori; Watanabe, Shoichi; Yamamoto, Toshihiro
Nuclear Technology, 141(3), p.221 - 232, 2003/03
Times Cited Count:4 Percentile:31.71(Nuclear Science & Technology)no abstracts in English
Yamamoto, Toshihiro; Miyoshi, Yoshinori; Kikuchi, Tsukasa*; Watanabe, Shoichi
Journal of Nuclear Science and Technology, 39(7), p.789 - 799, 2002/07
Times Cited Count:5 Percentile:34.65(Nuclear Science & Technology)no abstracts in English
Watanabe, Shoichi; Miyoshi, Yoshinori; Yamane, Yuichi
JAERI-Tech 2002-043, 93 Pages, 2002/03
no abstracts in English
Watanabe, Shoichi; Miyoshi, Yoshinori
JAERI-Data/Code 2001-008, 62 Pages, 2001/03
no abstracts in English
Nishina, Kojiro*; Yamane, Yoshihiro*; Kobayashi, Iwao; Tachimori, Shoichi; ; Miyoshi, Yoshinori; Okuno, Hiroshi; Nakajima, Ken; Mitake, Susumu*; *; et al.
Nihon Genshiryoku Gakkai-Shi, 34(4), p.311 - 319, 1992/04
Times Cited Count:0 Percentile:0.49(Nuclear Science & Technology)no abstracts in English
; Miyoshi, Yoshinori; Tachimori, Shoichi
JAERI-M 91-184, 31 Pages, 1991/11
no abstracts in English
Yanagisawa, Hiroshi; Takeshita, Isao; Miyoshi, Yoshinori; Sugikawa, Susumu; Suzaki, Takenori; Tachimori, Shoichi
Proc. of the 91 Int. Conf. on Nuclear Criticality Safety,Vol. 2, p.V-65 - V-72, 1991/00
no abstracts in English
Tachimori, Shoichi; Miyoshi, Yoshinori
KURRI-TR-294, p.62 - 68, 1987/00
no abstracts in English
Watanabe, Shoichi; Tonoike, Kotaro; Yoshiyama, Hiroshi; Yamamoto, Toshihiro; Izawa, Kazuhiko; Miyoshi, Yoshinori
no journal, ,
no abstracts in English