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Collaborative Laboratories for Advanced Decommissioning Science; Japan Agency for Marine-Earth Science and Technology*
JAEA-Review 2026-013, 86 Pages, 2026/07
JAEA-Review-2026-013.pdf:5.3MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), has been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") from FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), 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 FY2024, this report summarizes the research results of the "Data-driven on-site diagnostic technology: predicting microbiologically influenced corrosion risk for ensuring long-term integrity" conducted in FY2024. The present study aims to establish an innovative on-site diagnostic protocol capable of predicting microbiologically influenced corrosion (MIC) risks with high accuracy. To achieve this, we combined high-throughput analytical methods, simulated field experiments, and data-driven statistical analyses. Environmental samples were collected in Fukushima Prefecture to characterize microbial community structures and to develop key technologies for on-site genetic diagnostics. Using these samples, we evaluated the iron-corroding potential under various culture conditions and designed experimental systems simulating 1F environment. A high-throughput testing framework was validated for its ability to measure actual iron corrosion. In parallel, statistical approaches integrating microbial community profiles with MIC activity data were applied, yielding useful insights into both their applicability and limitations. Further, fixation methods for microbial observation in corrosion samples were examined, and optimal conditions were identified. Overall, the project provided valuable information on environmental microbial communities, cultivation of corrosion-associated microorganisms, and data-driven statistical approaches. These results lay the groundwork for the development of biomarker-based, ubiquitous diagnostic technologies for MIC applicable to diverse field environments, including those around 1F site.
Hori, Junichi*; Kimura, Atsushi; Terada, Kazushi*
JAEA-Conf 2026-001, 165 Pages, 2026/06
The 2024 Symposium on Nuclear Data was held at Kumatori Town Community Center "Smiles Rengakan" in Kumatori Town on November 14-15, 2024. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan (AESJ) and the Institute for Integrated Radiation and Nuclear Science, Kyoto University in cooperation with the Investigation Committee on Nuclear Data in AESJ, Nuclear Science and Engineering Center of Japan Atomic Energy Agency, and High Energy Accelerator Research Organization. The symposium consisted of six oral presentation sessions and a poster session, with 17 talks and 29 posters presented. The total number of participants was 80. Each oral and poster presentation was followed by an active question and answer session. This report consists of a total of 27 papers including 8 oral and 19 poster presentations.
Tada, Kenichi
Kaku Deta Nyusu (Internet), (144), p.17 - 29, 2026/06
This document provides an overview of the international conference on reactor physics, Physor2026, and explains research presentations related to nuclear data for the Japanese nuclear data community.
Furuta, Takuya; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Tanimura, Yoshihiko
Nuclear Instruments and Methods in Physics Research A, 1086, p.171320_1 - 171320_8, 2026/06
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A new function to incorporate nuclear data libraries with outgoing particles plus residual nuclei in specific excitation states for neutron-induced reactions has been implemented in a Monte Carlo simulation code, Particle and Heavy Ion Transport code System (PHITS). With this function, accurate predictions of outgoing particle spectra and angular distributions according to the nuclear data libraries become possible, while accounting for production of residual nuclei and de-excitation gammas, conserving total energy and momentum in each event. This feature allows users to perform high-precision simulations of detector responses and radiation damage in materials.
Group for Fukushima Mapping Project
JAEA-Technology 2025-013, 206 Pages, 2026/03
JAEA-Technology-2025-013.pdf:34.64MB
This report presents results of the investigations on the distribution-mapping project of radioactive substances conducted in FY2024. Car-borne and walk surveys, a measurement using survey meters, and an unmanned helicopter survey were carried out to obtain air dose rate data on land to create their distribution maps, and temporal changes of those air dose rates were analyzed. In order to confirm the applicability of unmanned aircraft to monitoring in mountainous areas, a basic performance of unmanned aircraft was investigated in mountainous areas. Surveys on depth profile of radiocesium and in-situ measurements as for radiocesium deposition were performed. These measurement results were published on the WEB site. Based on these measurement results, effective half-lives of the temporal changes in the air dose rates and the deposition were evaluated. Using the Bayesian hierarchical modeling approach, we obtained maps that integrated air dose rate distribution data acquired through surveys such as car-borne and walk surveys. Radiation monitoring and analysis of environmental samples owing to the comprehensive radiation monitoring plan were carried out. Representative life patterns that can be expected after the return to the evacuation-designated restricted area were set, and the cumulative exposure doses were evaluated for the local governments and residents in the area. Score maps to classify the importance of the measurement points were created, and the temporal changes in the score were analyzed. A system to report the tritium concentration level in seawater to the Nuclear Regulation Authority was operated, and the variation of tritium concentration before and after the discharge of ALPS treated water to the ocean was analyzed. Monitoring data in coastal area performed owing to the comprehensive radiation monitoring plan until FY2024 was analyzed.
Maruyama, Shuhei; Yamamoto, Akio*; Endo, Tomohiro*
Journal of Nuclear Science and Technology, 63(1), p.31 - 44, 2026/01
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Woloszczuk, K.*; Maik, P.*; Safronov, A.*; Wieczorek, A.*; Morishita, Yuki; Sanada, Yukihisa; Szklarski, L.*
Zeszyty Naukowe SGSP, 2(96), p.105 - 121, 2025/12
Fukahori, Tokio
JAEA-Conf 2024-002, p.6 - 11, 2024/11
The author has been keeping relationship with Japanese Evaluated Nuclear Data Library for around 38 years. During this period, he has been contributing code developments, for example, Preequilibrium Nuclear Reaction Calculation Code (ALICE-F) and Particle and Heavy Ion Transport Code System (PHITS). The author has also been assisting for EXFOR activities and promoting Evaluated Nuclear Data Processing Code (FRENDY) and Multiphase Multicomponent Detailed Thermal Fluid Analysis Code (JUPITER). In this paper, introduced are the outline of the author's works. Also reported are the author's perspective and challenge for the future form of nuclear data.
Kawabata, Kuniaki; Imabuchi, Takashi; Shirasaki, Norihito*; Suzuki, Soichiro; Ito, Rintaro; Aoki, Yuto; Omori, Takazumi
ROBOMECH Journal (Internet), 11, p.11_1 - 11_11, 2024/09
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：2 Percentile：25.59(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：0.00(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：2 Percentile：18.91(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：0.00(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.
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.
