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Fukahori, Tokio
Kaku Deta Nyusu (Internet), (137), p.1 - 10, 2024/02
At the request of the EC/Joint Research Center, the author attended on an EU-sponsored side event "Providing the best nuclear data for tomorrow's nuclear solutions: challenges and opportunities" held simultaneously at the IAEA 67th General Conference as a panelist. Presented were the prospects for nuclear data activities in Japan and discussed the sustainability and revitalization of nuclear data activities. In addition, based on the roundtable discussion at this side event, the Nuclear Data Section held a meeting consisting mainly of panelists to consider future responses. In this article, I would like to report on the side event and subsequent follow-up meetings and discuss the background of these meetings.
Fukahori, Tokio; Nakayama, Shinsuke; Katabuchi, Tatsuya*; Shigyo, Nobuhiro*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 65(12), p.726 - 727, 2023/12
The Investigative Committee on Nuclear Data investigates and observes global trends in nuclear research and development and conducts comprehensive examinations of Japanese nuclear data activities from a broader perspective, as well as cooperation with domestic and foreign academic institutions in a wide range of fields other than the Atomic Energy Society. We aim to establish a system for communication, information exchange, and interdisciplinary cooperation. In this report, we will report on three of the main activities for the 2021-2022 term: a request list site for nuclear data, human resource development, and roadmap production.
Tada, Kenichi; Endo, Tomohiro*
Journal of Nuclear Science and Technology, 60(11), p.1397 - 1405, 2023/11
Times Cited Count：1 Percentile：72.91(Nuclear Science & Technology)The probability table method is a well-known method for addressing self-shielding effects in the unresolved resonance region. A long computational time is required to generate the probability table. The effective way to reduce the generation time of the probability table is the reduction of the number of ladders. The purpose of this study is the estimation of the optimal number of ladders using the statistical uncertainty in the probability table. To this end, the statistical uncertainty quantification method of the probability table was developed and the convergence behavior of the statistical uncertainty was investigated. The product of the probability table and the average cross section was considered the target of the statistical uncertainty. The convergence rate was affected by the average level spacing and reduced neutron width. The generation time of the probability table was less than half when the input parameter was changed from the number of ladders to the tolerance value.
Fukahori, Tokio
INDC(JPN)-210 (Internet), 5 Pages, 2023/10
The 
U(n,f) cross section values were not correctly compiled in the ENDF format, and wrong values are disseminated in the JENDL/HE-2007 file. The high energy part of the U(n,f) cross section for the JENDL/HE-2007 library was evaluated by using the results of the FISCAL code. The correct U(n,f) cross section values of the JENDL/HE-2007 library above 200 MeV is given in this report.
Maeda, Makoto; Segawa, Mariko; Toh, Yosuke; Endo, Shunsuke; Nakamura, Shoji; Kimura, Atsushi
Journal of Radioanalytical and Nuclear Chemistry, 332(8), p.2995 - 2999, 2023/08
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)Okita, Shoichiro; Fukaya, Yuji; Sakon, Atsushi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
Nuclear Science and Engineering, 197(8), p.2251 - 2257, 2023/08
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Suzuki, Seiya; Arai, Yoichi; Okamura, Nobuo; Watanabe, Masayuki
Journal of Nuclear Science and Technology, 60(7), p.839 - 848, 2023/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The fuel debris, consisting of nuclear fuel materials and reactor structural materials, generated in the accident of Fukushima Daiichi Nuclear Power Plant can become deteriorated like rocks under the changes of environmental temperature. Although the fuel debris have been cooled by water for 10 years, they are affected by seasonal and/or day-and-night temperature changes. Therefore, in evaluating the aging behavior of the fuel debris, it is essential to consider the changes in environmental temperature. Assuming that the fuel debris are deteriorated, radioactive substances that have recently undergone micronization could be eluted into the cooling water, and such condition may affect defueling methods. We focused on the effect of repeated changes in environmental temperature on the occurrence of cracks, and an accelerated test using simulated fuel debris was carried out. The length of the crack increases with increasing number of heat cycle; therefore, the fuel debris become brittle by stress caused by thermal expansion and contraction. In conclusion, it was confirmed that the mechanical deterioration of the fuel debris is similar to that of rocks or minerals, and it became possible to predict changes in the length of the crack in the simulated fuel debris and environmental model.
Fukahori, Tokio
Kaku Deta Nyusu (Internet), (135), p.19 - 25, 2023/06
Initially, the Sigma Committee consisted of two sides of the same coin: the Atomic Energy Society of Japan (AESJ) Sigma Special Committee and the Japan Atomic Energy Research Institute (JAERI) Sigma Research Committee. It is original the Sigma Committee conducts actual work such as research, evaluation and evaluation of nuclear data (including measurement, called "nuclear data activity") rather than a "place for examination" that can be felt from the sense of the word "committee". At present, the AESJ's Investigation Committee of Nuclear Data and the JAEA's JENDL Committee are working independently, and the JENDL Committee has taken over the actual work of producing nuclear data files. On the occasion of the 60th anniversary of the Sigma Committee, we have reviewed its progress and historical description so far given in the references.
Collaborative Laboratories for Advanced Decommissioning Science; Shinshu University*
JAEA-Review 2022-067, 98 Pages, 2023/03
JAEA-Review-2022-067.pdf:3.72MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Development of environmental mitigation technology with novel water purification agents" conducted in FY2021. The present study aims to develop a reusable adsorbent for strontium ions through joint research between Japan and the United Kingdom, and to reduce the amount of used adsorbent generated through the decontamination process. This fiscal year, the preparation method of materials was improved based on the results obtained in the first year of the project. Moreover, various metal salts were added as additives to see the influence on the yield and adsorption performance. Structural analyses were conducted by observing the resulting materials with SEM, and theoretical analyses were performed by combining ...
Tada, Kenichi; Yamamoto, Akio*; Kunieda, Satoshi; Nagaya, Yasunobu
JAEA-Data/Code 2022-009, 208 Pages, 2023/02
JAEA-Data-Code-2022-009.pdf:3.87MB
The nuclear data processing code has an important role to connect evaluated nuclear data libraries and neutronics calculation codes. Japan Atomic Energy Agency (JAEA) has developed the nuclear data processing code FRENDY since 2013 to generate cross section files from evaluated nuclear data libraries, such as JENDL, ENDF/B, JEFF, and TENDL. The first version of FRENDY was released in 2019. FRENDY version 1 generates ACE files which are used for continuous energy Monte Carlo codes such as PHITS, Serpent, and MCNP. FRENDY version 2 generates multi-group neutron cross-section files from ACE files. The other major improvements are as follows: (1) uncertainty quantification for the probability tables of the unresolved resonance cross-section; (2) perturbation of the ACE file for the uncertainty quantification using a continuous Monte Carlo code; (3) modification of the ENDF-6 formatted nuclear data file. This report describes an overview of the nuclear data processing methods and input instructions for FRENDY.
Fukahori, Tokio
Kaku Deta Nyusu (Internet), (134), p.34 - 45, 2023/02
On the occasion of the 60th anniversary of the founding of the Sigma Committee in the Atomic Energy Society of Japan, we will attempt to record and preserve its history as a reference for future activities.
Maekawa, Fujio
JAEA-Conf 2022-001, p.7 - 13, 2022/11
The partitioning and transmutation (P-T) technology has promising potential for volume reduction and mitigation of degree of harmfulness of high-level radioactive waste. JAEA is developing the P-T technology combined with accelerator driven systems (ADS). One of critical issues affecting the feasibility of ADS is the proton beam window (PBW) which functions as a boundary between the accelerator and the sub-critical reactor core. The PBW is damaged by a high-intensity proton beam and spallation neutrons produced in the target, and also by flowing high-temperature liquid lead bismuth eutectic alloy which is corrosive to steel materials. To study the materials damage under the ADS environment, J-PARC is proposing a plan of proton irradiation facility which equips with a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam. The facility is also open for versatile purposes such as soft error testing of semi-conductor devises, RI production, materials irradiation for fission and fusion reactors, and so on. Application to nuclear data research with using the proton beam and spallation neutrons is also one of such versatile purposes, and we welcome unique ideas from the nuclear data community.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
JAEA-Conf 2022-001, p.129 - 133, 2022/11
For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.
Fukahori, Tokio; Nakayama, Shinsuke; Katabuchi, Tatsuya*; Shigyo, Nobuhiro*
Nihon Genshiryoku Gakkai-Shi ATOMO, 64(7), p.413 - 414, 2022/07
The Investigation Advisory Committee on Nuclear Data monitors global nuclear research and development trends, and conducts collaborative nuclear data activities with domestic and foreign academic institutions in a wide range of fields. The aims are to contact, to exchange information, and to build an interdisciplinary cooperation system. Reported are the activities on the request list site, human resources development, and roadmap creation regarding nuclear data directly related to future nuclear data research activities, among the main activities in the 2019-2020 period.
Okita, Shoichiro; Fukaya, Yuji; Sakon, Atsushi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
Proceedings of International Conference on Physics of Reactors 2022 (PHYSOR 2022) (Internet), 9 Pages, 2022/05
Horiguchi, Naoki; Yoshida, Hiroyuki; Yamamura, Sota*; Fujiwara, Kota*; Kaneko, Akiko*; Abe, Yutaka*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 14 Pages, 2022/03
Collaborative Laboratories for Advanced Decommissioning Science; Shinshu University*
JAEA-Review 2021-051, 81 Pages, 2022/01
JAEA-Review-2021-051.pdf:4.03MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Development of environmental mitigation technology with novel water purification agents" conducted in FY2020. The present study aims to develop a reusable adsorbent for strontium ions through joint research between Japan and the United Kingdom, and to reduce the amount of used adsorbent generated through the decontamination process. The basic strategy of this research is to produce adsorbents and examine their Sr adsorption performance at Shinshu University. The structural analyses of the adsorbents are conducted by the Institute for Molecular Science (IMS) and the UK teams.
Sato, Ikken
Nuclear Engineering and Design, 383, p.111426_1 - 111426_19, 2021/11
Times Cited Count：5 Percentile：65.59(Nuclear Science & Technology)Fujimoto, Nozomu*; Tada, Kenichi; Ho, H. Q.; Hamamoto, Shimpei; Nagasumi, Satoru; Ishitsuka, Etsuo
Annals of Nuclear Energy, 158, p.108270_1 - 108270_8, 2021/08
Times Cited Count：3 Percentile：45.99(Nuclear Science & Technology)Yokoyama, Kenji; Ishikawa, Makoto*
Annals of Nuclear Energy, 154, p.108100_1 - 108100_11, 2021/05
Times Cited Count：1 Percentile：16.35(Nuclear Science & Technology)In the design of innovative nuclear reactors such as fast reactors, the improvement of the prediction accuracies for neutronics properties is an important task. The nuclear data adjustment is a promising methodology for this issue. The idea of the nuclear data adjustment was first proposed in 1964. Toward its practical application, however, a great deal of study has been conducted over a long time. While it took about 10 years to establish the theoretical formulation, the research and development for its practical application has been conducted for more than half a century. Researches in this field are still active, and the fact suggests that the improvement of the prediction accuracies is indispensable for the development of new types of nuclear reactors. Massimo Salvatores, who passed away in March 2020, was one of the first proposers to develop the nuclear data adjustment technique, as well as one of the great contributors to its practical application. Reviewing his long-time works in this area is almost the same as reviewing the history of the nuclear data adjustment methodology. The authors intend that this review would suggest what should be done in the future toward the next development in this area. The present review consists of two parts: a) the establishment of the nuclear data adjustment methodology and b) the achievements related to practical applications. Furthermore, the former is divided into two aspects: the study on the nuclear data adjustment theory and the numerical solution for sensitivity coefficient that is requisite for the nuclear data adjustment. The latter is separated to three categories: the use of integral experimental data, the uncertainty quantification and design target accuracy evaluation, and the promotion of nuclear data covariance development.
