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Journal Articles

Analytical method for the determination of $$^{211}$$At using an $$alpha$$-scintillation-camera system and thin-layer chromatography

Segawa, Mariko; Nishinaka, Ichiro*; Toh, Yosuke; Maeda, Makoto

Journal of Radioanalytical and Nuclear Chemistry, 326(1), p.773 - 778, 2020/10

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Journal Articles

A Knowledge-sharing activity on the environmental radiation monitoring results affected by the Fukushima-Daiichi Nuclear Power Plant Accident at Tokai-Oarai area in Ibaraki Prefecture

Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.

Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06

After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, $$^{134}$$Cs/$$^{137}$$Cs activity ratio, and so on. In this report, the results of the dose rate and $$^{137}$$Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.

Journal Articles

Neutron capture cross-section measurement and resolved resonance analysis of $$^{237}$$Np

Rovira, G.*; Katabuchi, Tatsuya*; Tosaka, Kenichi*; Matsuura, Shota*; Terada, Kazushi*; Iwamoto, Osamu; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki; Segawa, Mariko; et al.

Journal of Nuclear Science and Technology, 57(1), p.24 - 39, 2020/01

Journal Articles

Performance evaluation of differential die-away system in an integrated active neutron NDA system for nuclear non-proliferation and nuclear security

Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke

Proceedings of 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (IEEE NSS/MIC 2018) (Internet), 4 Pages, 2019/10

Journal Articles

Charmed dibaryon resonances in the potential quark model

Oka, Makoto; Maeda, Saori*; Liu, Y.-R.*

International Journal of Modern Physics; Conference Series (Internet), 49, p.1960004_1 - 1960004_8, 2019/07

The charmed dibaryon resonances are given by a model Hamiltonian with the quark-model based short-range interaction and the long-range meson-exchange interactions. Sharp resonances states below the $$Sigma_{c}$$-$$N$$ and $$Sigma_{c}^{*}$$-$$N$$ thresholds are predicted.

Journal Articles

Simulation study on the design of nondestructive measurement system using fast neutron direct interrogation method to nuclear materials in fuel debris

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:1 Percentile:56.06(Nuclear Science & Technology)

Journal Articles

Development of active neutron NDA system for radioactive nuclear materials

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

JAEA Reports

Activity median aerodynamic diameter relating to contamination at Plutonium Fuel Research Facility in Oarai Research and Development Center; Particle size analysis for plutonium particles using imaging plate

Takasaki, Koji; Yasumune, Takashi; Hashimoto, Makoto; Maeda, Koji; Kato, Masato; Yoshizawa, Michio; Momose, Takumaro

JAEA-Review 2019-003, 48 Pages, 2019/03

JAEA-Review-2019-003.pdf:3.81MB

June 6, 2017, at Plutonium Fuel Research Facility in Oarai Research and Development Center of JAEA, when five workers were inspecting storage containers containing plutonium and uranium, resin bags in a storage container ruptured, and radioactive dust spread. Though they were wearing a half face mask respirator, they inhaled radioactive materials. In the evaluation of the internal exposure dose, the aerodynamic radioactive median diameter (AMAD) is an important parameter. We measured 14 smear samples and a dust filter paper with imaging plates, and estimated the AMAD by image analysis. As a result of estimating the AMAD, from the 14 smear samples, the AMADs are 4.3 to 11 $$mu$$m or more in the case of nitrate plutonium, and the AMADs are 5.6 to 14 $$mu$$m or more in the case of the oxidized plutonium. Also, from the dust filter paper, the AMAD is 3.0 $$mu$$m or more in the case of nitrate plutonium, and the AMAD is 3.9 $$mu$$m or more in the case of the oxidized plutonium.

Journal Articles

Development of differential die-away technique in an integrated active neutron NDA system for nuclear non-proliferation and nuclear security

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

Journal Articles

Resonance states in the $$Y_cN$$ potential model

Maeda, Saori*; Oka, Makoto; Liu, Y.-R.*

Physical Review C, 98(3), p.035203_1 - 035203_9, 2018/09

 Times Cited Count:7 Percentile:19.67(Physics, Nuclear)

We calculate two-body $$J^{pi}=0^{+}, 1^{+}$$, and $$J^{pi}=2^{+}$$ resonance states of $$Y_{c}$$ ($$= Lambda_{c}$$, $$Sigma_{c}$$, or $$Sigma_{c}^{*}$$) and $$N$$ using the complex scaling method. We employ the $$Y_{c}N$$-CTNN potentials, which were proposed in our previous study, and obtain four resonances near $$Sigma_{c}N$$ and $$Sigma_{c}^{*}N$$ thresholds. From the analysis by the binding energies of partial channel systems, we conclude that these resonance states are Feshbach resonances. We compare the results with the $$Y_{c}N$$ resonance states in the heavy quark limit, where the $$Sigma_{c}N$$ and $$Sigma_{c}^{*}N$$ thresholds are degenerate, and find that they form two pairs of the heavy-quark doublets in agreement with the heavy quark spin symmetry.

Journal Articles

Corrigendum; Study of the neutron multiplication effect in an active neutron method [J Nucl Sci Technol. 2017;54(11):1233-1239]

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:100(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.

Journal Articles

Development of active neutron NDA system for nuclear materials

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

Journal Articles

Development of active neutron NDA techniques for nuclear non-proliferation and nuclear security, 1; Performance evaluation of Next-Generation DDA technique

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

Journal Articles

Development of neutron resonance transmission analysis as a non-destructive assay technique for nuclear nonproliferation

Tsuchiya, Harufumi; Kitatani, Fumito; Maeda, Makoto; Toh, Yosuke; Kureta, Masatoshi

Plasma and Fusion Research (Internet), 13(Sp.1), p.2406004_1 - 2406004_4, 2018/02

Recently, it has become important in the field of nuclear nonproliferation and nuclear security to quantify nuclear materials (NMs) of uranium and plutonium in nuclear fuel using a non-destructive assay (NDA) technique. Currently, there is no reliable NDA system to apply to nuclear fuels such as spent fuel, fuel debris and next generation fuel for nuclear transmutation. Accordingly, development of NDA techniques for quantification of NMs in those fuels is an urgent issue. Neutron resonance transmission analysis (NRTA) is one candidate that is applicable to the quantification of NMs. Utilizing pulsed neutron beams, NRTA analyzes the content of a sample by measuring neutron beams that are transmitted from the sample. It is one of the reliable NDA methods that are based on a neutron time-of-flight technique for accurately evaluating nuclear data such as total cross sections and resonance parameters. A present NRTA system generally requires a large electron linear accelerator to produce intense neutron beams. Therefore this is not so easy to apply to various facilities that are used to measure NMs. Given this situation, a compact NRTA system would be required for practical applications of a method to quantify NMs in various samples. In order to realize a compact NRTA system, we consider two types of system: one uses a D-T neutron generator with pulse width of 10 $$mu$$sec and the other a small electron linac with pulse width of 1 $$mu$$sec Assuming each system is applied to measurements of NMs in spent fuel, numerical calculations were carried out and the results showed that the pulse widths of neutron beam largely affect the NRTA measurements. In this presentation, we will talk about the NRTA technique and give a schematic design of a compact NRTA system. Then, comparing calculation results for a D-T tube with those for a small electron linac, we especially discuss how the pulse widths of neutron beams to be used for NRTA affect the measurement of NMs in nuclear fuel.

Journal Articles

Characterization study of four candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station

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:1 Percentile:25.31

Journal Articles

Study of the neutron multiplication effect in an active neutron method

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:3 Percentile:49.25(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.

Journal Articles

Characterization study of four candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station, 4; Numerical simulations for active neutron technique

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 1$$times$$10$$^{6}$$ 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.

Journal Articles

R&D of active neutron NDA techniques for nuclear nonproliferation and nuclear security, 3; Validation of neutron transport code for design of NDA system

Maeda, Makoto; Komeda, Masao; Tobita, Hiroshi; Ozu, Akira; Kureta, Masatoshi; Bogucarska, T.*; Crochemore, J. M.*; Varasano, G.*; Pedersen, B.*

Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu (CD-ROM), 7 Pages, 2017/02

JAEA and EC/JRC are carrying out collaborative research to develop NDA techniques that can be utilized for quantification of high radioactive special nuclear materials such as spent fuel and next generation minor actinide fuels. In the research, reliability of neutron transport codes is important because it is utilized for design and development of a demonstration system of next-generation Differential Die-away (DDA) technique in JAEA. In order to evaluate the reliability, actual neutron flux distribution in a sample cavity was examined in PUNITA device using JRC type DDA technique and JAWAS-T device using JAEA type DDA technique, and then the measurement results were compared with the simulation results obtained by the neutron transport codes. The neutron flux distribution in the target matrix was also examined in the PUNITA and compared with the simulation results. We report on the measurement and simulation results of the neutron flux distribution and evaluation results of the reliability of the neutron transport codes.

Journal Articles

R&D of active neutron NDA techniques for nuclear nonproliferation and nuclear security, 2; Development of Next-Generation DDA technique

Ozu, Akira; Maeda, Makoto; Komeda, Masao; Tobita, Hiroshi; Kureta, Masatoshi

Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02

no abstracts in English

Journal Articles

Comparison between simulation and experimental results for neutron flux in DDA systems

Maeda, Makoto; Komeda, Masao; Ozu, Akira; Kureta, Masatoshi; Toh, Yosuke; Bogucarska, T.*; Crochemore, J. M.*; Varasano, G.*; Pedersen, B.*

EUR-28795-EN (Internet), p.694 - 701, 2017/00

96 (Records 1-20 displayed on this page)