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Hamdani, A.; Soma, Shu; Abe, Satoshi; Shibamoto, Yasuteru
Progress in Nuclear Energy, 185, p.105771_1 - 105771_13, 2025/07
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Nuclear Science Research Institute
JAEA-Review 2024-058, 179 Pages, 2025/03
JAEA-Review-2024-058.pdf:7.42MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2023 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
Nuclear Science Research Institute
JAEA-Review 2024-057, 178 Pages, 2025/03
JAEA-Review-2024-057.pdf:8.51MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2022 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
Kaburagi, Masaaki; Miyamoto, Yuta; Mori, Norimasa; Iwai, Hiroki; Tezuka, Masashi; Kurosawa, Shunsuke*; Tagawa, Akihiro; Takasaki, Koji
Journal of Nuclear Science and Technology, 62(3), p.308 - 316, 2025/03
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Brumm, S.*; Gabrielli, F.*; Sanchez Espinoza, V.*; Stakhanova, A.*; Groudev, P.*; Petrova, P.*; Vryashkova, P.*; Ou, P.*; Zhang, W.*; Malkhasyan, A.*; et al.
Annals of Nuclear Energy, 211, p.110962_1 - 110962_16, 2025/02
Times Cited Count：6 Percentile：94.85(Nuclear Science & Technology)Nagaya, Yasunobu
EPJ Nuclear Sciences & Technologies (Internet), 11, p.1_1 - 1_7, 2025/01
Japan Atomic Energy Agency (JAEA) has been developing a general-purpose continuous-energy Monte Carlo code MVP for nuclear reactor core analysis. Recently improvements to MVP have been focused on the development of an advanced neutronics/thermal-hydraulics coupling code. JAEA has also developed a new Monte Carlo solver Solomon for criticality safety analysis. Solomon aims to calculate the criticality of a damaged reactor core including fuel debris. This paper provides an overview of the capabilities and reviews recent applications of MVP and Solomon.
Calabrese, R.*; Hirooka, Shun
Progress in Nuclear Energy, 178, p.105516_1 - 105516_11, 2025/01
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Thermal creep is one of the key properties of mixed oxide (MOX) fuel for innovative fast reactors. Thermal creep of fuel affects markedly the interaction between the fuel and the cladding. A review of correlations available in the literature is presented. The effect of porosity, plutonium concentration, and stoichiometry are discussed also in the light of recent numerical results. Our analysis pointed out some inconsistencies concerning the modelling of the effect of porosity on diffusional creep and a re-evaluation of the effect of plutonium concentration. The discussion suggested that Evans's findings on the effect of stoichiometry should be better assessed as well as the level of increase in creep moving towards stoichiometry. Typical operating conditions of fast breeder reactors confirmed the need for an extension of porosity and temperature correlations' domains. Besides this, a new correlation based on a separate-effect approach has been proposed for fuel performance codes.
Yokoyama, Kenji; Hazama, Taira; Taninaka, Hiroshi; Oki, Shigeo
JAEA-Data/Code 2024-007, 41 Pages, 2024/10
JAEA-Data-Code-2024-007.pdf:1.1MB
The third version of the versatile reactor analysis code system, MARBLE3, has been developed. In the development of the former version of MARBLE, object-oriented scripting language Python (Python2) had been used and then the latest version of Python (Python3) was released. However, due to its backward incompatibility, MARBLE no longer worked with Python3. For this reason, MARBLE3 has been fully modified and maintained to work with Python3. In MARBLE3, newly developed analysis codes and newly proposed calculation methods were incorporated, and the user interface was extended and solvers were reimplemented for maintainability, extensibility, and flexibility. In MARBLE3, the three-dimensional hexagonal/triangular transport code MINISTRI Ver.7 (MINISTRI7) and the three-dimensional hexagonal/triangular diffusion code D-MINISTRI are available as the new analysis codes. These codes can be used in the neutronics analysis system SCHEME and the fast reactor burnup analysis system OPRHEUS, which are the subsystems of MARBLE. In addition, the user interface of CBG, a core analysis system embedded in MARBLE, was extended so that the diffusion and transport calculation solvers for the 2-dimensional RZ system of CBG can be used on SCHEME. On the other hand, MARBLE3 has extended the functionality of the burnup calculation solver so that it can use the numerical methods proposed in the papers on the improvement of the Chebyshev rational function approximation method and the minimax polynomial approximation method. From the viewpoint of maintainability, the point reactor kinetics solver POINTKINETICS, which was introduced in MARBLE2, has been newly reworked as the KINETICS solver in MARBLE3.
Pu
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powder using master sintering curve theoryNakamichi, Shinya; Sunaoshi, Takeo*; Hirooka, Shun; Vauchy, R.; Murakami, Tatsutoshi
Journal of Nuclear Materials, 595, p.155072_1 - 155072_11, 2024/07
Times Cited Count：1 Percentile：51.66(Materials Science, Multidisciplinary)Shimomura, Kenta; Yamashita, Takuya; Nagae, Yuji
Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 12 Pages, 2024/05
Fukuda, Kodai; Yamane, Yuichi
Journal of Nuclear Science and Technology, 60(12), p.1514 - 1525, 2023/12
Times Cited Count：1 Percentile：23.64(Nuclear Science & Technology)This study aims to clarify the effect of fuel particle radius on the criticality transient behavior and the total number of fissions in water-moderated solid fuel dispersion systems. Neutronics/thermal hydraulics-coupled kinetics analysis was performed in a hypothetical fuel debris system, where small fuel particles aggregate in water and become supercritical. Results showed that the number of fissions is 10 times larger when the fuel particle radius is reduced by one order of magnitude under conditions where heat transfer, i.e. from fuel to water, is emphasized. Moreover, there is a possibility that lower reactivity could give a larger number of fissions when the fuel particle size is very small. In addition, the number of fissions may be overestimated or underestimated to an unexpected extent unless appropriate fuel particle size is set on the analysis.
Katsumura, Kosuke*; Takagi, Junichi*; Hosomi, Kenji*; Miyahara, Naoya*; Koma, Yoshikazu; Imoto, Jumpei; Karasawa, Hidetoshi; Miwa, Shuhei; Shiotsu, Hiroyuki; Hidaka, Akihide*; et al.
Nihon Genshiryoku Gakkai-Shi ATOMO
, 65(11), p.674 - 679, 2023/11
no abstracts in English
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2023-009, 165 Pages, 2023/06
JAEA-Review-2023-009.pdf:5.76MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2020 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
Takino, Kazuo; Oki, Shigeo
JAEA-Data/Code 2023-003, 26 Pages, 2023/05
JAEA-Data-Code-2023-003.pdf:1.66MB
Since next-generation fast reactors aim to achieve a higher core discharge burn-up than conventional reactors do, core neutronics design methods must be refined. Therefore, a suitable analysis condition is required for the analysis of burn-up nuclear characteristics to accomplish sufficient estimation accuracy while maintaining a low computational cost. We investigated the effect of the analysis conditions on the accuracy of estimation of the burn-up nuclear characteristics of next-generation fast reactors in terms of neutron energy groups, neutron transport theory, and spatial mesh. This study treated the following burn-up nuclear characteristics: criticality, burn-up reactivity, control rod worth, breeding ratio, assembly-wise power distribution, maximum linear heat rate, sodium void reactivity, and Doppler coefficient for the equilibrium operation cycle. As a result, it was found that the following conditions were the most suitable: 18-energy-group structure, 6 spatial meshes per assembly with diffusion approximation. Additionally, these conditions should apply to correction factors for energy group structure, spatial mesh and transport effects.
Yamane, Yuichi
Journal of Nuclear Science and Technology, 59(11), p.1331 - 1344, 2022/11
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The reactivity was estimated from a time profile of neutron count rate or a simulated data in a quasi-steady state after sudden change of reactivity or external neutron source strength. The estimation was based on the equation of power in subcritical quasi-steady state. The purpose of the study is to develop the method of timely reactivity estimation from complicated time profile of neutron count rate. The developed method was applied to the data simulating neutron count rate created by using one-point kinetics code, AGNES, and Poisson-distributed random noise and to the transient subcritical experiment data measured by using TRACY. The result shows that the difference of the estimated and reference value was within about 5% or less for (
-1) for simulated data and within about 7% or less for 
-1.4 and -3.1 for the experimental data. It was also shown that the possibility of the reactivity estimation several ten seconds after the status change.
Nakamura, Hideo; Bentaib, A.*; Herranz, L. E.*; Ruyer, P.*; Mascari, F.*; Jacquemain, D.*; Adorni, M.*
Proceedings of International Conference on Topical Issues in Nuclear Installation Safety; Strengthening Safety of Evolutionary and Innovative Reactor Designs (TIC 2022) (Internet), 10 Pages, 2022/10
Task Force on Maintenance Optimization of Nuclear Facilities
JAEA-Technology 2022-006, 80 Pages, 2022/06
JAEA-Technology-2022-006.pdf:4.24MB
The Task force on maintenance optimization of nuclear facilities was organized in the Nuclear Science Research Institute (NSRI) of Japan Atomic Energy Agency (JAEA) since November 2020, in order to adequately respond to "the New nuclear regulatory inspection system since FY 2020" and to continuously improve the facility maintenance activities. In 2021, the task force has studied (1) optimization of the importance classification on maintenance and inspection of nuclear facilities, and (2) improvement in setting and evaluation of the performance indicators on safety, maintenance and quality management activities, considering "the Graded approach" that is one of the basic methodologies in the new nuclear regulatory inspection system. Each nuclear facility (research reactors, nuclear fuel material usage facilities, others) in the NSRI will steadily improve their respective safety, maintenance and quality management activities, referring the review results suggested by the task force.
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2021-067, 135 Pages, 2022/03
JAEA-Review-2021-067.pdf:7.31MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Coordination Office and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Fukushima Technology Development and Department of Decommissioning and Waste Management, and each departments manage facilities and develop related technologies to achieve the "Middle-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2017 as well as the activity on research and development carried out by the Nuclear Safety Research Center, Advanced Science Research Center, Nuclear Science and Engineering Center, Materials Sciences Research Center, and development activities of Nuclear Human Resources Development Center, using facilities of NSRI.
Engineering Services Department, Nuclear Science Research Institute
JAEA-Review 2021-054, 85 Pages, 2022/01
JAEA-Review-2021-054.pdf:95.12MB
The Engineering Services Department is in charge of operation and maintenance of utility facilities (water distribution systems, electricity supply systems, steam generation systems and drain water systems etc.) in whole of the institute. And also is in charge of operation and maintenance of specific systems (power receiving and transforming facilities, an emergency electric power supply system, an air/liquid waste treatment system, a compressed air supply system) in nuclear reactor facilities, nuclear fuel treatment facilities and usual facilities or buildings. In addition, the department is in charge of maintenance of buildings, design and repair of electrical/mechanical equipments. This annual report describes summary of activities, operation and maintenance data and technical developments of the department carried out in JFY 2020. We hope that this report may help to future work.
Nuclear Science Research Institute
JAEA-Review 2021-006, 248 Pages, 2021/12
JAEA-Review-2021-006.pdf:7.17MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Coordination Office and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Fukushima Technology Development and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Middle and long-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2015 and 2016 as well as the activity on research and development carried out by Nuclear Safety Research Center, Advanced Science Research Center, Nuclear Science and Engineering Center, Material Science Research Center, and development activities of Nuclear Human Resources Development Center, using facilities of NSRI.
