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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：47.15(Nuclear Science & Technology)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.

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 sec and the other a small electron linac with pulse width of 1 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.

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：22.74Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi

Nippon Genshiryoku Gakkai-Shi, 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：3 Percentile：46.57(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.

Koizumi, Mitsuo; Rossi, F.; Rodriguez, D.; Takamine, Jun; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.

EPJ Web of Conferences (Internet), 146, p.09018_1 - 09018_4, 2017/09

Times Cited Count：1 Percentile：22.74Komeda, 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.

Seya, Michio; Hajima, Ryoichi*; Kureta, Masatoshi

Proceedings of INMM 58th Annual Meeting (Internet), 10 Pages, 2017/07

Large size freight cargo containers are the most vulnerable items from nuclear security points of view because of their large volume and weight of cargo inside for hiding heavily shielded objects. For strengthening nuclear security, secure detection of NMs in heavily shielded objects, and safe handling (dismantlement) of detected (suspicious) objects, are essential. These require secure detection of NMs, inspection of detailed interior structures of detected objects, rough characterization of NMs (for nuclear bomb or RDD etc.) and confirmation of existence of explosives etc. By using information obtained by these inspections, safe dismantlement of objects is possible. In this paper, we propose a combination of X-ray scanning system with NRF-based NDD system using monochromatic -ray beam for a secure detection and interior inspections. We also we propose active neutron NDA system using a DT source for interior inspection of NM part.

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.

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

Seya, Michio; Hajima, Ryoichi*; Kureta, Masatoshi

Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu (CD-ROM), 10 Pages, 2017/02

Large size freight cargo containers are the most volunurable items from nuclear security points of view because of their large volume and weight of cargo inside for hiding heavily shielded objects. For strengthning nuclear security, secure detection of NMs in heavily shielded objects, and safe handling (dismatlement) of detected / suspicious objects for taking out of NMs, are essential. These require the following things, (1) Introduction of secure detection system of NMs, (2) Inspection of deteiled and interior structures of detected objects, (3) Rough chracterization of NMs (for nuclear bomb or RDD etc.) / Confirmation of existence of explosives etc.. By using information obtained by interior inspections, safe dismantlement of objects and taking NMs out are possible. In this papaer, we propose a combined system of X-ray scanning system with NRF-based NDD system using monochromatic -ray beam not only as a secure detection system of NMs but also interior inspection system (covering (1) and (2)). Also we propose active neutron NDA system using a D-T source for interior inspection of NM part (covering (3)).

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

Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Kureta, Masatoshi; Koizumi, Mitsuo; Seya, Michio; et al.

EUR-28795-EN (Internet), p.684 - 693, 2017/00

Koizumi, Mitsuo; Sakasai, Kaoru; Kureta, Masatoshi; Nakamura, Hironobu

Nippon Genshiryoku Gakkai-Shi, 58(11), p.642 - 646, 2016/11

no abstracts in English

Kureta, Masatoshi

Kagaku Kogaku, 80(8), p.464 - 467, 2016/08

A neutron radiography is technology which carries out visualization and measurement of the inside of a substance using neutrons. This technology has the complementary feature comparing with X-ray radiography (Roentgen technique). In this review paper, the measurement principle, some application examples such as visualization of oil in the working car engine, and about the leading-edge technology using high-intensity proton beam accelerator facility J-PARC (common neutron imaging facility), etc. It was introduced in the form where the whole neutron radiography technology for every dimension of measurement were covered.

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

Proceedings of INMM 57th Annual Meeting (Internet), 6 Pages, 2016/07

From a viewpoint of nuclear safeguards and nuclear security, it has recently become important to develop a non-destructive assay (NDA) system that accurately determines the amount of special nuclear materials (SNMs) in various samples such as spent fuels, next generation MA-Pu fuels and fuel debris. One candidate of those NDA techniques is neutron resonance transmission analysis (NRTA). It relies on a neutron time-of-flight measurement and is a well-established method to apply for the accurate evaluations of nuclear data, including total cross sections and resonance parameters. The potential of NRTA to quantify SNM in complex materials has been already demonstrated by performing NRTA measurement at IRMM/GELINA under collaboration of JAEA and JRC. However, a present NRTA system usually has a large electron accelerator facility to generate intense neutrons, whereas this is very difficult to apply to various facilities that need to measure SNM. Therefore a compact NRTA system would be required for practical applications of quantifying SNM in a variety of samples. In order to realize a compact NRTA system, we are developing a prototype with a D-T neutron generator that has a pulse width of 10 s and an average maximum neutron yield ranging from n/s to n/s. Numerical calculations were used to optimize the system performance to quantify SNM and MA in spent and MA-Pu fuels. In this presentation, those numerical calculation results, together with a brief description of the prototype, are presented. In addition, we discuss a future prospect of a compact NRTA system equipped with a neutron source with a shorter pulse width (ex. 100 ns) and a more intense neutron yield.

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

Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07

The JAEA and EC/JRC have started collaborative research to develop a technique that can be utilized for quantification of high radioactive special nuclear materials such as next generation minor actinide fuels. In the study of a Differential Die-Away (DDA) technique, which is one of the techniques to be improved in the collaborative research, JRC type and JAEA type DDA techniques are compared. In the JRC type DDA technique, large amount of thermal neutron is generated using D-T neutron generator and graphite moderator to accomplish high detection sensitivity for small amount of fissile material. On the other hand, in JAEA type, relatively hard neutron spectrum and moderation of neutron in the target matrix are utilized to minimize position dependence of detection efficiency. Estimation of the neutron field is important to evaluate the performance of the system in DDA technique. The purpose of this study is to validate simulation results by experimental results and evaluate neutron flux distribution in the system by the simulation and the experiment. In this paper, we present the evaluation results of the neutron flux distributions in PUNITA which utilizes JRC type DDA technique and JAWAS-T which utilizes JAEA type DDA technique obtained by Monte Carlo simulation and activation method.

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

Proceedings of INMM 57th Annual Meeting (Internet), 8 Pages, 2016/07

Under the collaboration program with EC Joint Research Center, we have carried out the R&D program "Development of active neutron NDA techniques for nuclear nonproliferation and nuclear security" with DDA (Differential Die-away Analysis), NRTA, PGA / NRCA and DGS. In this paper, we presents the outline of the current activity and study on next generation DDA. The goal of this study is to establish the DDA technique for high radiation nuclear materials with small measurement uncertainty. Lastly simulation study on newly developed prototype system "Active-N" which will be constructed at JAEA/NUCEF/BECKY facility in 2017 is presented.

Komeda, Masao; Maeda, Makoto; Furutaka, Kazuyoshi; Tobita, Hiroshi; Hattori, Kentaro; Shimofusa, Taichi; Ozu, Akira; Kureta, Masatoshi

Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07

We are working on the development of a non-destructive assay (NDA) measurement system using the Fast Neutron Direct Interrogation (FNDI) method. The FNDI method is a kind of active neutron technique and can measure the total amounts of fissile materials (U-235, Pu-239, Pu-241). We have already carried out design analyses of an NDA measurement system for measuring the debris assuming use of the Three Mile Island (TMI) canister model. The result was presented at the Institute of Nuclear Materials Management (INMM) 56th Annual Meeting. Since then, we have modified the design of the NDA measurement system for the fuel debris and canister models at 1F. In this paper, we provide the calculation and evaluation results using the modified NDA measurement system. Moreover, we provide analytical investigations of the influence of fuel debris including high fissile material content on measurements.