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Tsuchiya, Harufumi; Toh, Yosuke; Ozu, Akira; Furutaka, Kazuyoshi; Kitatani, Fumito; Maeda, Makoto; Komeda, Masao
Journal of Nuclear Science and Technology, 12 Pages, 2023/00
Times Cited Count:0Komeda, Masao; Toh, Yosuke
Applied Radiation and Isotopes, 188, p.110391_1 - 110391_6, 2022/10
Times Cited Count:0 Percentile:0.01(Chemistry, Inorganic & Nuclear)Komeda, Masao; Toh, Yosuke; Tanabe, Kosuke*; Kitamura, Yasunori*; Misawa, Tsuyoshi*
Annals of Nuclear Energy, 159, p.108300_1 - 108300_8, 2021/09
Times Cited Count:2 Percentile:48.75(Nuclear Science & Technology)Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo
Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 8 Pages, 2021/08
Harada, Hideo; Takayama, Naoki; Komeda, Masao
Journal of Physics Communications (Internet), 4(8), p.085004_1 - 085004_17, 2020/08
A new convention of epithermal neutron spectrum is formulated for improving accuracy of resonance integrals. The new type function is proposed as an approximating function of epithermal neutron spectrum based on calculations by the state-of-art Monte Carlo code MVP-3. Bias effects on determination of resonance integrals due to utilizing approximating functions of the traditional types and the new type are compared. The other bias effect is also investigated, which is caused by neglecting position dependence of a neutron spectrum inside an irradiation capsule. For demonstrating the bias effects due to these assumptions on neutron spectrum quantitatively in a practical case, the thermal neutron-capture cross section and resonance integral of Cs measured at a research reactor JRR-3 are re-evaluated. A superior property of the proposed new convention is discussed. The experimental method is proposed to determine the new shape factor
introduced in the convention by a combinational use of triple flux monitors (
Au,
Co and
Zr), and its analytical methodology is formulated.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke
Proceedings of 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2019), Vol.1, p.101 - 104, 2020/08
Komeda, Masao; Toh, Yosuke
Annals of Nuclear Energy, 135, p.106993_1 - 106993_6, 2020/01
Times Cited Count:2 Percentile:32(Nuclear Science & Technology)This paper presents a conceptual study of a novel active method using a neutron source. The main feature of this new method is the fast rotation of a neutron source in order to derive the fission neutron counts and applying the counts to detect the nuclear material. Irradiating neutrons to a container that involves nuclear material, the measurement data include both neutrons from the neutron source and fission neutrons. However, if the neutron source is rotated quite fast, the components of the irradiation neutrons and fission neutrons are separated. Since this novel method does not require an expensive D-T tube, this new system is expected to be affordable and easy to assemble.
Komeda, Masao
Bunseki, 2019(10), p.459 - 461, 2019/10
no abstracts in English
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke
Proceedings of 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2018) (Internet), 4 Pages, 2019/10
Maeda, Makoto; Furutaka, Kazuyoshi; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Toh, Yosuke
Journal of Nuclear Science and Technology, 56(7), p.617 - 628, 2019/07
Times Cited Count:2 Percentile:26.23(Nuclear Science & Technology)Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo
Proceedings of INMM 60th Annual Meeting (Internet), 7 Pages, 2019/07
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke; Koizumi, Mitsuo; Seya, Michio
Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 4 Pages, 2018/11
Komeda, Masao; Ozu, Akira; Mori, Takamasa; Nakatsuka, Yoshiaki; Maeda, Makoto; Kureta, Masatoshi; Toh, Yosuke
Journal of Nuclear Science and Technology, 55(8), P. 962, 2018/08
Times Cited Count:0 Percentile:1.39(Nuclear Science & Technology)We correct the derivation of equations in the derivation of equations in the paper of "Study of the neutron multiplication effect in an active neutron methods [J Nucl Sci Technol. 2017;54(11):1233-1239]". Although the derivations are not correct, the obtained equations are correct. Therefore, the results and discussions of the paper remain the same.
Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo; Heyse, J.*; Paradela, C.*; et al.
Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07
Sakoda, Akihiro; Nakatsuka, Yoshiaki; Ishimori, Yuu; Nakashima, Shinichi; Komeda, Masao; Ozu, Akira; Toh, Yosuke
Journal of Nuclear Science and Technology, 55(6), p.605 - 613, 2018/06
Times Cited Count:1 Percentile:12.95(Nuclear Science & Technology)For better nuclear material accountancy, we had developed a non-destructive assay system dedicated to uranium waste drums (JAWAS-N: JAEA Waste Assay System at Ningyo-toge). The system is based on a fast neutron direct interrogation (FNDI) method. To clarify the characteristics of the FNDI method and the performance of JAWAS-N, experimental and computational mock-up tests were carried out using various dry materials that contained known amounts of natural uranium. As a result, linearity between the die-away time () and the counts of fast neutrons attributed to
U fission was confirmed experimentally and analytically. Moreover, the MCNP simulation was performed to discuss the radial and axial dependences of
U fission probability, neutron detection efficiency, and sensitivity on uranium distributions in the drum. The simulation results agreed with the empirical results reported in a previous paper, providing valuable information on the practice of FNDI-based uranium determination. Furthermore, the nominal detection limits of natural uranium in JAWAS-N were estimated to be 15, 4, and 2 g for
= 0.2, 0.3, and 0.4 msec, respectively. The findings obtained here will contribute to the implementation of the FNDI method to assess the quantities of
U in actual uranium waste drums.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Furutaka, Kazuyoshi; Toh, Yosuke
Nihon Kaku Busshitsu Kanri Gakkai Dai-38-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2018/04
no abstracts in English
Nagatani, Taketeru; Komeda, Masao; Shiba, Tomooki; Nauchi, Yasushi*; Maeda, Makoto; Sagara, Hiroshi*; Kosuge, Yoshihiro*; Kureta, Masatoshi; Tomikawa, Hirofumi; Okumura, Keisuke; et al.
Energy Procedia, 131, p.258 - 263, 2017/12
Times Cited Count:5 Percentile:94.83Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(12), p.700 - 704, 2017/12
no abstracts in English
Komeda, Masao; Ozu, Akira; Mori, Takamasa; Nakatsuka, Yoshiaki; Maeda, Makoto; Kureta, Masatoshi; Toh, Yosuke
Journal of Nuclear Science and Technology, 54(11), p.1233 - 1239, 2017/11
Times Cited Count:7 Percentile:61.02(Nuclear Science & Technology)The previous active neutron method cannot remove the influence of the multiplication effect of neutrons produced by second- and subsequent fission reactions, and it might overestimate the amount of nuclear material if an item contains large amounts. In this paper, we discussed the correction method for the neutron multiplication effect on the measured data in the fast neutron direct interrogation (FNDI) method, one of the active neutron methods, supposing that the neutron multiplication effect is caused mainly by third-generation neutrons from the second-fission reactions under the condition that the forth-generation neutrons are much fewer. This paper proposed a correction method for the neutron multiplication effect in the measured data. Moreover we have shown a possibility that this correction method gives rough estimates of the effective neutron multiplication factor and the subcriticality.
Komeda, Masao; Maeda, Makoto; Ozu, Akira; Kureta, Masatoshi; Toh, Yosuke
Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 3 Pages, 2017/09
We have developed a special Nuclear Material Accountancy (NMA) technique using the Fast Neutron Direct Interrogation (FNDI) method which is one of active neutron techniques. A measurement system, for fuel debris at Fukushima Daiichi Nuclear Power Station, implemented in the simulation was designed as follows. This system has a neutron generator, which can produce neutron yield of 110
per pulse in 1 kHz repetition rate. The length of the system is 140 cm, and the outer diameter is 80cm. Sixteen He-3 detectors, 100 cm in length and 2.5 cm in diameter, are installed. Simulations were carried out using the Monte Carlo code MVP developed at JAEA. This work provides simulation results and the applicable range of the FNDI method for fuel debris, using various debris model parameters for example, burn-up composition and heterogeneous materials.