Tomikawa, Hirofumi; Koizumi, Mitsuo; Tamai, Hiroshi
Genshiryoku Heiwa Riyo To Kakufukakusan, Kakusekyuriti; NSA/Commentaries, No.25, p.167 - 174, 2020/06
Japan's efforts for research and development on nuclear material detection and nuclear forensics and international cooperation are introduced focusing on the various aspects implemented in JAEA.
Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi*; Tsutagi, Koichi; Nishida, Naoki; Kitao, Takahiko; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A.*; Browne, M.*
JAEA-Technology 2019-023, 160 Pages, 2020/03
The International Atomic Energy Agency (IAEA) has proposed in its Research and Development plan (STR-385), the development of technology to enable real-time flow measurement of nuclear material as a part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, Japan Atomic Energy Agency (JAEA) has been tackling development of a new detector to enable monitoring of Pu in solutions with numerous FPs as a joint research program with U.S. DOE to cover whole reprocessing process. In this study, High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant was used as the test field. At first, the design information of HALW storage tank and radiation (type and intensity) were investigated to develop a Monte Carlo N-Particle Transport Code (MCNP) model. And then, dose rate distribution outside/ inside of the concrete cell where the HALW tank is located was measured to design new detectors and check MCNP model applicability. Using the newly designed detectors, gamma rays and neutron were continuously measured at the outside/ inside of the concrete cell to assess the radiation characteristics and to optimize detector position. Finally, the applicability for Pu monitoring technology was evaluated based on the simulation results and gamma-ray/neutron measurement results. We have found that there is possibility to monitor the change of Pu amount in solution by combination both of gamma-ray and neutron measurement. The results of this study suggested the applicability and capability of the Pu motoring to enhance safeguards for entire reprocessing facility which handles Pu with FP as a feasibility study. This is final report of this project.
Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi*; Tsutagi, Koichi; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A.*; Browne, M.*
Proceeding IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 8 Pages, 2018/11
The IAEA has proposed, in its Research and Development plan (STR-385), the development of technology to enable real-time flow measurement of nuclear material as part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, JAEA and JNFL had previously designed and developed a neutron coincidence based non-destructive assay system to monitor Pu in solution directly after a purification process. To enhance this technology for entire reprocessing facilities, as a feasibility study, JAEA has been tackling development of a new detector to enable monitoring of Pu in solutions with numerous fission products (FPs) as a joint research program with the U.S. DOE. In this study, the High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant (TRP) was used as the test bed. The design information of the HALW storage tank and radiation (type and intensity) were investigated, to develop a Monte Carlo N-Particle Transport Code (MCNP) model. Then, dose rate distribution inside the concrete cell where the HALW tank is located was measured, to enable design of new detectors and check the integrity of the MCNP model and its applicability. Using the newly-designed detectors, -rays and neutrons could be measured continuously at the outside/inside of the concrete cell, to optimize detector position and the radiation characteristics. The applicability as a Pu-monitoring technology was evaluated, based on the simulation results and -ray/neutron measurement results. We have found that there is a possibility to monitor the change of Pu amount in solution by combination of -ray and neutron measurements. The results of this study suggest a feasibility study into the applicability and capability of Pu monitoring to enhance the entire reprocessing facility handling Pu with FPs. In this paper, a summary of the project will be presented.
Shiba, Tomooki; Tomikawa, Hirofumi; Hori, Masato
Proceeding IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 6 Pages, 2018/11
Rodriguez, D.; Tanigawa, Masafumi; Nishimura, Kazuaki; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Takamine, Jun; Suzuki, Satoshi*; Sekine, Megumi; Rossi, F.; et al.
Journal of Nuclear Science and Technology, 55(7), p.792 - 804, 2018/07
Nuclear material in reprocessing facilities is safeguarded by random sample verification with additional continuous monitoring applied to solution masses and volume in important tanks to maintain continuity-of-knowledge of process operation. Measuring the unique rays of each solution as the material flows through pipes connecting all tanks and process apparatuses could potentially improve process monitoring by verifying the compositions in real time. We tested this ray pipe-monitoring method using plutonium-nitrate solution transferred between tanks at the PCDF-TRP. The rays were measured using a lanthanum-bromide detector with a list-mode data acquisition system to obtain both time and energy of -ray. The analysis and results of this measurement demonstrate an ability to determine isotopic composition, process timing, flow rate, and volume of solution flowing through pipes, introducing a viable capability for process monitoring safeguards verification.
Koizumi, Mitsuo; Seya, Michio; Tomikawa, Hirofumi; Hori, Masato; Naoi, Yosuke
Proceedings of INMM 59th Annual Meeting (Internet), 8 Pages, 2018/07
no abstracts in English
Sekine, Megumi; Matsuki, Takuya; Tokoro, Hayate; Tsutagi, Koichi; Kitao, Takahiko; Nakamura, Hironobu; Tomikawa, Hirofumi
Proceedings of INMM 59th Annual Meeting (Internet), 10 Pages, 2018/07
In a reprocessing facility, it is necessary to develop a detector which can measure plutonium (Pu) content in the Pu solutions containing fission products (FP) in order to expand the application of Pu monitoring. In order to establish this technology, JAEA has studied a system measure -rays was utilized since it applicable for Pu monitoring. Ce:GAGG (Ce:GdAlGaO) scintillator detector can measure a wide energy range in a high-dose environment and has reasonable resolution. -ray measurements were performed inside of the concrete cell containing the High Active Liquid Waste tank at the Tokai reprocessing plant. In the spectra, the two significant peaks were measured by the GAGG above 800 keV and were considered to be from Eu-154. There -ray measurements will be combined with previous neutron measurements and both will be compared to MCNP models for future Pu monitoring technology. This presentation will describe the detector selection, the design system, the results of -ray spectral measurements and the applicability for Pu monitoring. This project has been carried out under the support of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese government.
Sekine, Megumi; Matsuki, Takuya; Tokoro, Hayate; Tsutagi, Koichi; Tomikawa, Hirofumi; Nakamura, Hironobu
Nihon Kaku Busshitsu Kanri Gakkai Dai-38-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2018/04
In a reprocessing facility, it is necessary to develop a detector which is measurable plutonium (Pu) amount in the Pu solution containing the Fission Product (FP) in order to expand the application of Pu monitoring. To investigate rays which is applicable for Pu monitoring, Ce:GAGG (Ce: GdAlGaO) scintillator which can measure a wide range of energy at high dose and has high resolution (Target: High Active Liquid Waste (HALW)) was newly designed and developed in deal with aim for Pu quantitativeness. ray measurement was performed to the HALW in the concrete cell using the detector, and it was confirmed that high energy rays (9.5 MeV) could be measured and high energy rays spectra over 3 MeV without deriving from FP at the first time. In this presentation, detector design, results of ray spectra measurement, applicability evaluation to Pu monitoring and the future plan are presented. This project has been carried out under the support of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese government.
Sekine, Megumi; Tomikawa, Hirofumi
Energy Procedia, 131, p.274 - 278, 2017/12
The IAEA has proposed in its long-term R&D plan, development of real-time measurement technology for monitoring and verifying nuclear material movement continuously. At a PULEX reprocessing facility, HNO solution with dissolved spent fuel, such as FPs and nuclear materials, flows in pipes and stores in tanks. In order to detect and deter nuclear material being stolen from the process, measuring the 10.8 MeV rays emitted by N(n,)N reaction activated by spontaneous neutrons might be useful for continuous monitoring of liquid flow. In general, since high dose rays emitted from FPs are dominant below 3 MeV, it is expected that the 10.8 MeV peak would not be affected by the FP peaks. As the first step, some kinds of detectors and measurement configuration were analyzed through MCNP based on 10.8 MeV rays activated by neutrons from a Cf source.
Shiba, Tomooki; Maeda, Shigetaka; Sagara, Hiroshi*; Ishimi, Akihiro; Tomikawa, Hirofumi
Energy Procedia, 131, p.250 - 257, 2017/12
In the present paper, the ray source data was developed for the debris composition based on "best estimates", and the subsequent photon transportation calculation was performed to evaluate the leakage ray spectra according to the fuel debris. Since the creation of the line spectrum source requires a great deal, we have developed the relatively simple but accurate enough method to build up ray source, coupling of baseline spectra evaluated by ORIGEN2 code and several line spectra of interest. One of the advantages of the method is taking bremsstrahlung X rays into consideration by utilizing the bremsstrahlung libraries of ORIGEN2. The new ray source was used to calculate the detector response of HPGe detector and the results was compared as a benchmark with experimental measurement results of irradiated fuel pins. As the result, the simulated ray spectrum shape agreed well with the shape of ray spectrum obtained by the experiment.
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
Shiba, Tomooki; Sagara, Hiroshi*; Tomikawa, Hirofumi
Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 3 Pages, 2017/09
Since the removal of fuel debris from the Fukushima Daiichi Nuclear Power Plant is planned to commence in 2021, measurement technologies for quantification of the nuclear material in fuel debris will be required for appropriate nuclear material management. In this paper, an outline of a passive gamma technique as one of the measurement technologies is briefly described, and the results of phase 1 and 2 of the so-called common set of simulation models for fuel debris and canisters are reported. The newly developed coupling method is applied to produce a gamma ray source for simulation. As the result of phase 1, it is revealed that the variation in the composition of fuel debris does not affect the gamma ray leakage behavior from canisters. According to the result of phase 2, the primary peak of Eu-154 at 1.27 MeV is clearly observable, although the debris is centrally located in canister. In addition, rotational scanning is effective for correcting the deviation in detection efficiency due to debris located off-center in canisters.
Tamai, Hiroshi; Okubo, Ayako; Kimura, Yoshiki; Shinohara, Nobuo; Tazaki, Makiko; Shimizu, Ryo; Suda, Kazunori; Tomikawa, Hirofumi
Proceedings of INMM 58th Annual Meeting (Internet), 6 Pages, 2017/07
Nuclear forensics is a technical measure to analyse and collate samples of illegally used nuclear materials, etc., to clarify their origins, routes, etc. and contribute to criminal identifications. Close collaboration with police and judicial organizations is essential. The national response framework is being built up with international cooperation. Discussions on promoting technical capability and regional cooperation are presented.
Matsuki, Takuya; Yamanaka, Atsushi; Sekine, Megumi; Suzuki, Satoshi*; Yasuda, Takeshi; Tsutagi, Koichi; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A. M.*; Browne, M. C.*
Proceedings of INMM 58th Annual Meeting (Internet), 8 Pages, 2017/07
The Tokai Reprocessing Plant (TRP) has been developing a new detector from 2015 to 2017 for purpose to monitor Pu amount in High Active Liquid Waste (HALW) containing FP. It can make a contribution to an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities because it becomes available to monitor and verify nuclear material movement continuously by a new detector, which has proposed by IAEA. For the second step of this project, we conducted dose rate measurement on the guide rail installing in the cell storing the HALW tank and comparison between measured dose rate distribution and calculation result by MCNP simulation in order to investigate the dose rate distribution which is needed for shielding design of a new detector that is used for radiation (neutron/ spectrum) measurement in the cell and inquest on the monitoring position of the detector for Pu monitoring. In this paper, we report the result of the dose rate measurement in the cell, improvement of the simulation model which is cleared by comparison between measurement result and calculation result and our future plan.
Shiba, Tomooki; Tomikawa, Hirofumi; Sagara, Hiroshi*; Ishimi, Akihiro
57th Annual Meeting of the Institute of Nuclear Materials Management (INMM 2016), Vol.1, p.365 - 374, 2017/02
Fission products (FPs) such as Ce and Eu seem to be very low volatile even in high temperature environment in the severe accident of nuclear reactors. They are supposed to chemically coexist with nuclear fuel. In our passive gamma ray spectroscopy, gamma rays from such FPs are measured and their amount and burnup are estimated. Then we multiply the mass ratio of the FPs and nuclear materials, and we obtain the mass of nuclear material of interest. According to hypothetical fuel debris and canister models, we performed simulation of leakage gamma rays from canister of debris. gamma ray source spectra were derived from the composition of the hypothetical fuel debris and the photon transport calculation was carried out. In addition, we conducted experiments of gamma ray measurement from intact spent fuels irradiated in the Experimental Fast Reactor Joyo in order to validate the prediction performance of the simulation by the comparison of the experiments and simulation.
Tamai, Hiroshi; Okubo, Ayako; Kimura, Yoshiki; Kokaji, Lisa; Shinohara, Nobuo; Tomikawa, Hirofumi
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu (CD-ROM), 8 Pages, 2017/02
Nuclear Forensics capability has been developed under the international collaborations. For its effective function, technical development in analysis of seized nuclear materials as well as the institutional development in comprehensive response framework are required under individual national responsibility. In order to keep the "chain of custody" in the proper operation of sample collection at the event scene, radiological analysis at the laboratory, storage of the samples, and further inspection and trial, close cooperation and information sharing between relevant organisations are essential. IAEA issues the Implementing Guide to provide the model action plan and assists individual national development. International cooperation for the technical improvement and awareness cultivation is promoted. Examples in such national developments will be introduced and prospective technical/institutional prerequisite for nuclear forensics response framework will be studied.
Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi; Tanigawa, Masafumi; Yasuda, Takeshi; Yamanaka, Atsushi; Tsutagi, Koichi; Nakamura, Hironobu; Tomikawa, Hirofumi; LaFleur, A. M.*; et al.
EUR-28795-EN (Internet), p.788 - 796, 2017/00
The IAEA has proposed in its long-term R&D plan, the development of technology to enable real-time flow measurement of nuclear material as a part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, JAEA has designed and developed a neutron coincidence based nondestructive assay system to monitor Pu directly in solutions which is after purification process and contains very little fission products (FPs). A new detector to enable monitoring of Pu in solutions with numerous FPs is being developed as a joint research program with U.S. DOE at the High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant. As the first step, the design information of HALW tank was investigated and samples of HALW was taken and analyzed for Pu concentration and isotope composition, density, content of dominant nuclides emitting ray or neutron, etc. in order to develop a Monte Carlo N-Particle Transport Code (MCNP) of the HALW tank. In addition, ray source spectra simulated by Particle and Heavy Ion Transport code System (PHITS) was developed by extracting peaks from the analysis data with germanium detector. These outputs are used for the fundamental data in the MCNP model which is then used to evaluate the type of detector, shielding design and measurement positions. In order to evaluate available radiations to measure outside the cell wall, continuous ray and neutron measurement were carried out and the results were compared to the simulation results. The measurement results showed that there are no FP peaks above 3 MeV. This paper presents an overview of the research plan, characteristics of HALW, development of source term for MCNP, simulation of radiation dose from the HALW tank and radiation measurement results at outside of cell wall.
Kawakubo, Yoko; Sekine, Megumi; Tomikawa, Hirofumi
JAEA-Review 2016-017, 57 Pages, 2016/10
Nuclear transparency is recognized as essential to provide additional assurance and enhance confidence building in the Asia-Pacific as this region has a broad spectrum of nuclear development underway and planned in the future. It is expected that elevated nuclear transparency should also supplement and reinforce International Atomic Energy Agency (IAEA) safeguards. With this recognition, Japan Atomic Energy Agency (JAEA) has committed various studies and activities for enhancing regional transparency mainly with U.S. Department of Energy (DOE) and its national laboratories. The efforts include transparency concept study, development of the remote monitoring system at the Experimental Fast Reactor JOYO, cooperation to Council for Security and Cooperation in Asia Pacific (CSCAP) to develop internet-based transparency tools, establishment of Information Sharing Framework (ISF), and the hosting of a series of workshops. Based on all the achievements of the past efforts, JAEA is now moving from "study phase" toward the "implementation phase" of information sharing for enhancing its nuclear transparency. The ISF website was opened in 2015 as a part of Asia Pacific Safeguards Network (APSN) website for JAEA to provide relevant information to APSN members. This report summarizes the past studies and activities performed in JAEA for almost 20 years to enhance regional nuclear transparency and discusses the future prospect.
Naoi, Yosuke; Oda, Tetsuzo; Tomikawa, Hirofumi
Nippon Genshiryoku Gakkai-Shi, 58(9), p.536 - 541, 2016/09
Japan has been promoting nuclear energy research and development, and the use of nuclear energy for only peaceful purposes in accordance with Atomic Energy Basic Acts enacted in 1955. In order to ensure limited to their peaceful utilization, it has been performing a nuclear material accountancy and reporting it based on bilateral nuclear agreement (Japan and the United States, Japan and France, Japan and Canada and so on) before concluding the comprehensive safeguards agreement with the IAEA. After the conclusion of that in 1977, the Japanese national law had been revised. The nuclear material accountancy and its reports to the IAEA have been implemented based on the revised law. In 1999, Japan ratified the additional protocol. Then it has been responding a new obligation in the additional protocol. The correctness and completeness of the declaration of nuclear activities in Japan have been verified by the IAEA, and then the "broader conclusion" was given to Japan in 2004. There indicates no diversion or undeclared nuclear activities in Japan. Since then Japan has been obtaining the "broader conclusion" every year. In this report we will report the JAEA's contribution to the IAEA safeguards on technical research and development and human resource development.
Matsuki, Takuya; Masui, Kenji; Sekine, Megumi; Tanigawa, Masafumi; Yasuda, Takeshi; Tsutagi, Koichi; Ishiyama, Koichi; Nishida, Naoki; Horigome, Kazushi; Mukai, Yasunobu; et al.
Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07
The International Atomic Energy Agency (IAEA) has proposed in its long-term research and development (R&D) plan, development of a real-time measurement technology to monitor and verify nuclear material movement continuously as part of an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities. Since the Tokai Reprocessing Plant (TRP) has solutions containing both Pu and fission products (FP), a new detector development project to monitor Pu with FP is being carried out from 2015 to 2017. This project is mainly conducted in the High Active Liquid Waste Storage (HALWS) in the TRP. For the first step of this project, as the confirmation of composition of high active liquid waste (HALW) to evaluate neutron/-ray emitted from solution in the selected HALW tank which has the most amount of Pu in HALW tanks at the TRP, we took HALW sample and conducted -ray spectrum measurement for HALW. As a study of detector setting location, to survey the available neutron/-ray (i.e. intensity) at the outside surface of the cell where HALW tank is located, we implemented continuous measurement by neutron/-ray detector. In this paper, we report three -ray peaks related with Pu and Pu measured in the composition research of HALW, which is needed to identify Pu amount by the new detector that we are developing and the result of radiation measurement on the surface of the cell.