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Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)Okamura, Tomohiro*; Katano, Ryota; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Asano, Hidekazu*; Takeshita, Kenji*
Journal of Nuclear Science and Technology, 60(6), p.632 - 641, 2023/06
Times Cited Count：2 Percentile：53.91(Nuclear Science & Technology)The Okamura explicit method (OEM) for depletion calculation was developed by modifying the matrix exponential method for dynamic nuclear fuel cycle simulation. The OEM suppressed the divergence of the calculation for short half-life nuclides, even for long time steps. The computational cost of the OEM was small, equivalent to the Euler method, and it maintained sufficient accuracy for the fuel cycle simulation.
Okamura, Tomohiro*; Nishihara, Kenji; Katano, Ryota; Oizumi, Akito; Nakase, Masahiko*; Asano, Hidekazu*; Takeshita, Kenji*
JAEA-Data/Code 2021-016, 43 Pages, 2022/03
JAEA-Data-Code-2021-016.pdf:3.06MB
The quantitative prediction and analysis of the future nuclear energy utilization scenarios are required in order to establish the advanced nuclear fuel cycle. However, the nuclear fuel cycle consists of various processes from front- to back-end, and it is difficult to analyze the scenarios due to the complexity of modeling and the variety of scenarios. Japan Atomic Energy Agency and Tokyo Institute of Technology have jointly developed the NMB code as a tool for integrated analysis of mass balance from natural uranium needs to radionuclide migration of geological disposal. This user manual describes how to create a database and scenario input for the NMB version 4.0.
Okamura, Tomohiro*; Katano, Ryota; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Asano, Hidekazu*; Takeshita, Kenji*
Bulletin of the Laboratory for Advanced Nuclear Energy, 6, p.29 - 30, 2022/02
Takeshita Laboratory, Tokyo Institute of Technology, has been developing Nuclear Material Balance code version 4.0 (NMB4.0) in collaboration with Japan Atomic Energy Agency (JAEA). This report summarized the outline and functions of NMB4.0.
Okamura, Tomohiro*; Katano, Ryota; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Asano, Hidekazu*; Takeshita, Kenji*
EPJ Nuclear Sciences & Technologies (Internet), 7, p.19_1 - 19_13, 2021/11
Nuclear Material Balance code version 4.0 (NMB4.0) has been developed through collaborative R&D between Tokyo Institute of Technology and JAEA. Conventional nuclear fuel cycle simulation codes mainly analyze actinides and are specialized for front-end mass balance analysis. However, quantitative back-end simulation has recently become necessary for considering R&D strategies and sustainable nuclear energy utilization. Therefore, NMB4.0 was developed to realize the integrated nuclear fuel cycle simulation from front- to back-end. There are three technical features in NMB4.0: 179 nuclides are tracked, more than any other code, throughout the nuclear fuel cycle; the Okamura explicit method is implemented, which contributes to reducing the numerical cost while maintaining the accuracy of depletion calculations on nuclides with a shorter half-life; and flexibility of back-end simulation is achieved. The main objective of this paper is to show the newly developed functions, made for integrated back-end simulation, and verify NMB4.0 through a benchmark study to show the computational performance.
Okamura, Tomohiro*; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Takeshita, Kenji*
JAEA-Data/Code 2020-023, 32 Pages, 2021/03
JAEA-Data-Code-2020-023.pdf:1.67MB
Nuclear Material Balance code (NMB code) have been developed in Japan Atomic Energy Agency. The NMB code will be updated with the function of mass balance analysis at the backend process such as reprocessing, vitrification and geological disposal. In order to perform its analysis with high accuracy, it is necessary to expand the number of FP nuclides calculated in the NMB code. In this study, depletion calculation by ORIGEN code was performed under 3 different burn-up conditions such as spent uranium fuel from light water reactor, and nuclides were selected from 5 evaluation indexes such as mass and heat generation. In addition, the FP nuclides required to configure a simple burnup chain with the same calculation accuracy as ORIGEN in the NMB code was selected. As the result, two lists with different number of nuclides, such as "Detailed list" and a "Simplified list", were created.
Okamura, Tomohiro*; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Takeshita, Kenji*
Bulletin of the Laboratory for Advanced Nuclear Energy, 5, P. 31, 2021/02
The Takeshita Laboratory at Tokyo Institute of Technology has started to develop a Nuclear Material Balance code (NMB code) in collaboration with Japan Atomic Energy Agency. This report summarized the results of the joint research conducted in 2019.
Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
no journal, ,
Okamura, Tomohiro*; Oizumi, Akito; Minari, Eriko*; Nakase, Masahiko*; Asano, Hidekazu*; Nishihara, Kenji; Takeshita, Kenji*
no journal, ,
Takeshita Laboratory, Tokyo Institute of Technology, has been improving the Nuclear Material Balance code (NMB code) developed by Japan Atomic Energy Agency based on the knowledge of the nuclear fuel cycle simulation conducted so far. The previous NMB code was specialized in the evaluation of mass balance of actinide and lacked the function of back-end scenario analysis. In this improvement, 3 main points were researched and developed that (1) selection of FP nuclides to be introduced into the NMB code, (2) development of a nuclear data library preparation tool for the NMB code, and (3) burnup calculation and its error evaluation. In this presentation, we reported the results of the studies in (1) to (3).
Okamura, Tomohiro*; Nishihara, Kenji; Oizumi, Akito; Nakase, Masahiko*; Takeshita, Kenji*
no journal, ,
Tokyo Institute of Technology and Japan Atomic Energy Agency are jointly developing a nuclear material balance code (NMB code), which is a mass balance analysis code for nuclear fuel cycle. The burnup calculation of this code is performed for each reactor or fuel batch using the matrix exponential method. Since the number of burnup calculations is very large depending on the analysis conditions, reducing the calculation cost has been an issue. In particular, to solve the short half-life nuclides by the matrix exponential method, the time step must be sufficiently shorter than the half-life and the calculation must be performed to a high order, which requires computational cost. Therefore, the accelerated exponential method was devised as a method to calculate the short half-life nuclides with enough accuracy for nuclear fuel cycle simulation without incurring computational cost.
Okamura, Tomohiro*; Katano, Ryota; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Asano, Hidekazu*; Takeshita, Kenji*
no journal, ,
In order to study the future nuclear energy utilization scenarios, it is necessary to analyze the front-end, reactor operation, and back-end of the nuclear fuel cycle in an integrated manner. On the other hand, the nuclear fuel cycle simulation codes that have been developed in various institutes are specialized in front-end scenario analysis, and it is not to provide user flexible analysis of the back-end simulation. Therefore, Tokyo Institute of Technology and Japan Atomic Energy Agency have jointly developed NMB4.0, a computational platform for integrated and flexible analysis of front-end to back-end scenarios of nuclear fuel cycle. In this presentation, the general functions and computational performance of NMB4.0 were reported.
Nishihara, Kenji; Oizumi, Akito; Okamura, Tomohiro*; Nakase, Masahiko*; Takeshita, Kenji*
no journal, ,
This study analyzes the nuclear fuel cycle when the partitioning and transmutation technology is introduced in the reprocessing of LWR spent fuel in the latter half of this century. In Japan, LWRs will continue to be used for power generation for the time being, and the treatment and disposal of uranium and plutonium spent fuel will be an issue. Assuming that the partitioning and transmutation of minor actinides becomes feasible in the reprocessing of these spent fuels in the middle of this century, it is shown that the burden of high-level waste disposal after that can be greatly reduced.
Minari, Eriko*; Mihara, Morihiro; Makino, Hitoshi; Okamura, Tomohiro*; Oizumi, Akito; Nishihara, Kenji; Nakase, Masahiko*; Takeshita, Kenji*
no journal, ,
no abstracts in English
Okamura, Tomohiro*; Nishihara, Kenji; Katano, Ryota; Oizumi, Akito; Nakase, Masahiko*; Takeshita, Kenji*
no journal, ,
The integrated nuclear fuel cycle simulation from front- to back-end processes is required for the establishment of the advanced nuclear energy system. However, the existing nuclear fuel cycle simulators, which have been developed by various research institutes, specialized in front-end scenario analysis, and the scope of back-end simulation is limited. In addition, most of the simulators are not open to he public and have not been established as an basic system that can be used by various stakeholders. Tokyo Institute of Technology and JAEA have jointly developed a nuclear material balance analysis code version 4.0 (NMB4.0), which models the entire nuclear fuel cycle from natural uranium mining to nuclide migration for geological disposal. In order to establish the code as a domestically produced nuclear fuel cycle simulator, it has been released free of charge. In this presentation, the general functions and calculation performance of NMB4.0 will be introduced.
Takeshita, Kenji*; Okamura, Tomohiro*; Nakase, Masahiko*; Nishihara, Kenji; Abe, Takumi
no journal, ,
Database of nuclear power plant and dry reprocessing required for the metal fuel fast reactor cycle was maintained in the nuclear fuel cycle simulator NMB4.0. In addition, the introduction scenario of metal-fueled fast reactors was verified using sample scenarios.
Okamura, Tomohiro*; Nishihara, Takahiro*; Nakase, Masahiko*; Nishihara, Kenji; Abe, Takumi
no journal, ,
NEUChain (New Chain), a research and development project aiming at the digitization of the nuclear fuel cycle, is being implemented. The basic concept of NEUChain, its application, and the use of distributed ledger technology in the nuclear field will be discussed.
