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Kubo, Shigenobu; Chikazawa, Yoshitaka; Ohshima, Hiroyuki; Kamide, Hideki
Handbook of Generation IV Nuclear Reactors, Second Edition, p.173 - 194, 2023/03
Handbook of Generation IV Nuclear Reactors, Second Edition is a fully revised and updated comprehensive resource on the latest research and advances in generation IV nuclear reactor concepts. Editor Igor Pioro and his team of expert contributors have updated every chapter to reflect advances in the field since the first edition published in 2016. JAEA contributes to Chapter 5; Sodium-cooled Fast Reactors (SFRs) and Chapter 12; Generation-IV Sodium-cooled Fast Reactor (SFR) concepts in Japan. Major characteristics and current technology developments including safety enhancement were described in Chapter 5. Chapter 12 shows design activities of SFR. Innovative technology developments, and update of the Japan sodium-cooled fast reactor design with lessons learned from the TEPCO Fukushima Daiichi NPP accident.
Hazama, Taira
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, p.87 - 161, 2022/07
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Hasegawa, Yuta; Imamura, Toshiyuki*; Ina, Takuya; Onodera, Naoyuki; Asahi, Yuichi; Idomura, Yasuhiro
Proceedings of 13th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Heterogeneous Systems (ScalAH22) (Internet), p.10 - 17, 2022/00
The ensemble data assimilation of computational fluid dynamics simulations based on the lattice Boltzmann method (LBM) and the local ensemble transform Kalman filter (LETKF) is implemented and optimized on a GPU supercomputer based on NVIDIA A100 GPUs. To connect the LBM and LETKF parts, data transpose communication is optimized by overlapping computation, file I/O, and communication based on data dependency in each LETKF kernel. In two dimensional forced isotropic turbulence simulations with the ensemble size of 
and the number of grid points of 
, the optimized implementation achieved 
speedup from the naive implementation, in which the LETKF part is not parallelized. The main computing kernel of the local problem is the eigenvalue decomposition (EVD) of 
real symmetric dense matrices, which is computed by a newly developed batched EVD in EigenG. The batched EVD in EigenG outperforms that in cuSolver, and 
speedup was achieved.
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950
C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Fukui, Yasuhito
Biographical Dictionary of Secretaries-General of International Organizations (Internet), 5 Pages, 2020/09
Mr. Yukiya Amano, former director general of IAEA died in July 2019. In order to register in the dictionary of the heads of the international organisations, the author wrote his biography starting from his childhood, university days, the days of the director general of IAEA.
Nakagawa, Hiroshi; Kataoka, Mikio*
Biochimica et Biophysica Acta; General Subjects, 1864(4), p.129536_1 - 129536_6, 2020/04
Times Cited Count：4 Percentile：18.03(Biochemistry & Molecular Biology)The rigidity and flexibility of a protein is reflected in its structural dynamics. Studies on protein dynamics often focus on flexibility and softness; this review focuses on protein structural rigidity. The extent of rigidity can be assessed experimentally with incoherent neutron scattering; a method that is complementary to molecular dynamics simulation. This experimental technique can provide information about protein dynamics in timescales of pico- to nanoseconds and at spatial scales of nanometers; these dynamics can help quantify the rigidity of a protein by indices such as force constant, Boson peak, dynamical transition, and dynamical heterogeneity. These indicators also reflect the rigidity of a protein's secondary and tertiary structures. In addition, the indices reveal how rigidity is influenced by different environmental parameters, such as hydration, temperature, pressure, and protein-protein interactions. Hydration affects both rigidity and softness more than other environmental factors. Interestingly, hydration affects harmonic and anharmonic motions in opposite ways. This difference is probably due to the protein's dynamic coupling with water molecules via hydrogen bonding.
Saito, Yoshimoto*; Hirano, Shinichi*; Nagaoka, Toru*; Amano, Yuki
Ecological Genetics and Genomics, 12, p.100042_1 - 100042_9, 2019/10
Culture-independent molecular techniques enable us to analyze microflora in various environments. Many uncultured prokaryotes have been detected by the molecular methods from extreme environments, including anaerobic, no light, high-pressure, and high temperature. Recently, microbial eukaryotes were also detected in deep-sea environments, suggesting that microbial eukaryotes can adapt to a wider range of environments than previously thought. Here, we performed a culture-independent analysis of eukaryotes from approximately -250 m depth in the Horonobe Underground Research Laboratory at Horonobe, Japan. Our results indicate that fungi are the dominant eukaryotic flora in deep sedimentary rocks of Horonobe. We detected a wide range of species, including Zygomycete, Basidiomycete, and Ascomycete fungi from the rocks. This study is the first report of eukaryotic diversity in deep subsurface sedimentary rocks.
Yamashita, Takuya; Sato, Ikken; Abe, Yuta; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji
Proceedings of 12th International Conference of the Croatian Nuclear Society; Nuclear Option for CO
Free Energy Generation (USB Flash Drive), p.109_1 - 109_15, 2018/06
no abstracts in English
Suzuki, Kiichi; Okita, Takatoshi; Aono, Shigenori
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 10 Pages, 2017/06
Japan Atomic Energy Agency has developed mixed plutonium-uranium oxide (MOX) fuel fabrication technologies in large-scale and fabricated MOX fuel assemblies for experimental fast reactor "JOYO" and prototype fast reactor "MONJU" at Plutonium Fuel Production Facility (PFPF) since 1988. Low density pellet is adopted as MONJU fuel. For the low density pellet fabrication in large-scale, various challenges were encountered. In order to resolve these challenges, countermeasures such as new pore former with high softening temperature and improved granulation method for MOX powder were considered. In this presentation, accumulated MOX fuel fabrication technologies as mentioned above and recent R&D activity such as new pelletizing method, or die wall lubrication pelletizing, for low-decontaminated TRU fuel fabrication will be discussed.
Yamada, Yoshikazu; Segawa, Tomoomi; Kato, Masato
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 8 Pages, 2017/06
Japan Atomic Energy Agency (JAEA) have proposed the transmutation of minor actinides by fast reactors as a way to contribute significantly to the reduction of the volume and the potential radiotoxicity of radioactive wastes. In order to achieve this goal, it is important to introduce a fully automated and remote operation fuel fabrication plant with shielded hot cells and manipulators. JAEA's facilities including Plutonium Fuel Production Facility (PFPF) have fabricated MOX fuel. On the basis of the operational and technical experience obtained in above facilities, the conceptual design of engineering-scale plant applied the simplified MA-bearing fuel fabrication process with shielded hot cells and manipulator was done. It will be able to fabricate high MA-bearing fuel and to perform the maintenance and repairing of each equipment with manipulators. This plant will be constructed based on this concept and development plan.
Hirooka, Shun; Kato, Masato
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 6 Pages, 2017/06
Young's modulus of MOX pellets was evaluated by measuring the sound velocities of longitudinal and transverse waves in the pellets as functions of porosity, oxygen-to-metal ratio (O/M) and plutonium content. The results showed that porosity was the most important factor that 20% of the porosity decreased Young's modulus by neatly 100 GPa while O/M and plutonium content could change the Young's modulus by ~20 GPa. From the measured sound velocities, temperature dependence on Young's modulus and specific heat capacity were calculated on the Debye model by leveraging the thermal expansion data. The temperature dependence that Young's modulus decreases with increasing temperature is in good agreement with literature data. The specific heat capacity also agrees with that of calculated value by Kopp's method, taken the Schottky term and the excited term into account.
Hayafune, Hiroki; Chikazawa, Yoshitaka; Kamide, Hideki; Iwasaki, Mikinori*; Shoji, Takashi*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 11 Pages, 2017/06
Design studies on a next generation sodium-cooled fast reactor (SFR) considering the safety design criteria (SDC) developed in the generation IV international forum (GIF) was summarized. To meet SDC including the lessons learned from the TEPCO's Fukushima Dai-ichi Nuclear Power Plants accident, the heat removal function was enhanced to avoid loss of the function even if any internal events exceeding design basis or severe external event happen. Several design options have been investigated and auxiliary core cooling system using air as ultimate heat sink has been selected as an additional cooling system regarding system reliability and diversification. Even though the next generation SFR already adopts seismic isolation system, main component designs have been improved considering revised earthquake conditions. For other external events, design measures for various external events are taken into account. Reactor building design has been improved and important safety components are diversified and located separately improving independency. Those design studies and evaluations on the next generation sodium-cooled reactor have contributed to the development of safety design guidelines (SDG) which is under discussion in the GIF framework.
Yamano, Hidemasa; Suzuki, Toru; Kamiyama, Kenji; Kudo, Isamu*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 11 Pages, 2017/06
This paper describes basic visualization experiments on eutectic reaction and relocation of boron carbide (B
C) and stainless steel (SS) under a high temperature condition exceeding 1500C as well as the importance of such behaviors in molten core during a core disruptive accident in a Generation-IV sodium-cooled fast reactor (750 MWe class) designed in Japan. At first, a reactivity history was calculated using an exact perturbation calculation tool taking into account expected behaviors. This calculation indicated the importance of a relocation behavior of the BC-SS eutectic because its behavior has a large uncertainty in the reactivity history. To clarify this behavior, basic experiments were carried out by visualizing the reaction of a BC pellet contacted with molten SS in a high temperature-heating furnace. The experiments have shown the eutectic reaction visualization as well as freezing and relocation of the BC-SS eutectic in upper part of the solidified test piece due to the density separation.
Hayafune, Hiroki; Glatz, J.-P.*; Yang, H.*; Ruggieri, J.-M.*; Kim, Y.-I.*; Ashurko, Y.*; Hill, R.*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 12 Pages, 2017/06
The SFR system arrangement Phase II became effective on 16 February 2016 by signatures of CEA, JAEA, KAERI, USDOE, and Rosatom, and was extended for additional 10 years. Collaboration of GIF SFR is growing adding new reactor concepts and related RDs. In 2015, a project arrangement on SFR System Integration and Assessment (SIA) has been signed by 7 members : China, EU, France, Japan, Korea, Russia and US. In the SIA project, RD needs from the SFR design will be shown to the RD project, and RD results from each RD project will be integrated into the designs.
Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Uemoto, Yohei*; Kurokawa, Masaaki*; Hiramatsu, Takashi*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 9 Pages, 2017/06
Inspection in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. To facilitate operations and maintenance activities, various under sodium viewers (USVs), including horizontal USVs for obstacle detection for a long distance and imaging USVs for a short and middle distance imaging, have been developed in several research institutes and countries. In this study, an imaging USV for a middle distance, approximately 1 m, has been developed. The USV in this study adopts an optical receiving system which measures the vibration displacement of diaphragm by using a laser as a receiving sensor. This study mainly focuses on the sensitivity improvement for a transmission sensor and the receiving sensor. In addition, an imaging experiment in the water was conducted using the new transmission sensor and receiving sensor. The experimental results showed that the newly developed USV sensors can make higher resolution images of a target than the previous sensors.
Sekio, Yoshihiro; Yamagata, Ichiro; Akasaka, Naoaki; Sakaguchi, Norihito*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 8 Pages, 2017/06
The widths of void denuded zones (VDZs) which were formed near random grain boundaries by neutron irradiation were analyzed in order to perform quantitative evaluations for the irradiation-induced point defect behavior in the modified 316 stainless steel (PNC316) having been developed by JAEA. Namely, the temperature dependence of VDZ width was investigated and vacancy migration energy of the PNC316 steel was estimated from the VDZ width analysis for the neutron-irradiated specimens. The obtained value of vacancy migration energy was estimated as 1.46 eV, which was consistent with that from the exiting method using electron in-situ examination. This indicates that VDZ analysis could be effective method to evaluate especially vacancy migration energy during irradiation, and this would be realized from not in-situ observation but post-irradiation examination in the case of neutron irradiation.
Nakai, Ryodai
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 10 Pages, 2017/06
The GIF Safety Design Criteria Task Force (SDC TF) has been developing a set of safety design guidelines (SDG) to support practical application of SDC since the completion of the "SDC Phase I Report" that clarifies safety design requirements for Gen-IV SFR systems. The main objective of the SDG development is to assist SFR developers and vendors to utilize the SDC in their design process for improving the safety in specific topical areas including the use of inherent/passive safety features and the design measures for prevention and mitigation of severe accidents. The first report on "Safety Approach SDGs" aims to provide guidance on safety approaches covering specific safety issues on fast reactor core reactivity and on loss of heat removal. The second report on "SDGs on key Structures, Systems and Components (SSCs)" focuses on the functional requirements for SSCs important to safety; reactor core system, reactor coolant system, and containment system.
Sofu, T.*; Okano, Yasushi
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 8 Pages, 2017/06
The Generation-IV International Forum (GIF) completed development of Safety Design Criteria (SDC) for the Generation-IV SFR systems in May, 2013. SDC reflects the high-level GIF safety and reliability goals and follows GIF basic safety approach. It aims to establish reference criteria for safety design of structures, systems and components and achieve harmonization of safety approaches among GIF member states. Following its public release, SDC report was distributed to international organizations and national regulatory bodies for review and feedback. Based on comments received during the following two-year period, SDC report underwent a revision reflecting feedback received from IAEA, NRC (USA), IRSN (France), and NNSA (China). This paper provides an overview of SDC development effort, and summarizes its revisions based the comments/suggestions received from the international review.
Aoyagi, Mitsuhiro; Uchibori, Akihiro; Kikuchi, Shin; Takata, Takashi; Ohno, Shuji; Ohshima, Hiroyuki
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 10 Pages, 2017/06
The present PIRT process is aimed to identify key phenomena involved in sodium fire accidents that involve complex phenomena in sodium-cooled fast reactor plants. In this PIRT process, the figures of merit (FOMs) are specified through factor analysis. Associated phenomena are identified through the element- and sequence-based phenomena analyses. Importance of each associated phenomenon is evaluated by considering the sequence-based analysis of associated phenomena correlated with the FOMs. Then, we complete the ranking table through the factor and phenomenon analyses. An assessment matrix of important phenomena and experiments is completed finally for model validation.
