Improvement in legal compliance activities of nuclear security in JAEA

Hirata, Tomohiro; Hanawa, Kazutaka; Shibata, Ryodai; Yamada, Hiroyuki; Yamazaki, Katsuyuki

Dai-46-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2025/12

no abstracts in English

Three-dimensional resistivity structure and its relationship to the rupture of the 1997 Kagoshima earthquake doublet (Mw 6.1 and 6.0), Japan

Matsunaga, Keita*; Aizawa, Koki*; Asamori, Koichi; Ogawa, Hiroki*; Utsugi, Mitsuru*; Yoshimura, Ryokei*; Yamazaki, Kenichi*; Uchida, Kazunari*; Matsushima, Takeshi*; Inoue, Tomohiro*; et al.

Tectonophysics, 915, p.230880_1 - 230880_11, 2025/11

https://doi.org/10.1016/j.tecto.2025.230880

Comparative study of the multistep thermal dehydration/decomposition of geopolymer pastes prepared using different active fillers

Shindo, Manami*; Ueoku, Aya*; Okamura, Wakana*; Kikuchi, Shin; Yamazaki, Atsushi*; Koga, Nobuyoshi*

Thermochimica Acta, 749, p.180021_1 - 180021_14, 2025/07

https://doi.org/10.1016/j.tca.2025.180021

Neutron optics design of a neutron magnetic microscope using Wolter type I supermirror

Soyama, Kazuhiko; Hayashida, Hirotoshi*; Maruyama, Ryuji; Yamazaki, Dai; Goto, Yoshiki*; Kobayashi, Yuki*; Arakawa, Shohei*; Yamamoto, Yugo*; Suba, Kenta*; Yamamura, Kazuya*

JAEA-Research 2024-006, 15 Pages, 2024/10

JAEA-Research-2024-006.pdf:1.51MB

A neutron optics design has been conducted for a neutron magnetic microscope that utilize a Wolter type I multilayer supermirror for the purpose of magnetic fields imaging in magnetic materials. Ray trace simulation was performed for a magnifying imaging optical system with a magnification rate of 12.5 times. Based on classical model of Lamor precession, depolarization due to magnetic domains was simulated, and the effect of slope errors on the Wolter mirror created by the replica method on the spatial resolution of the microscope was investigated. As a result, reference data about the shape error required to obtain spatial resolution on the order of micrometers was obtained.

Multistep kinetics of the thermal dehydration/decomposition of metakaolin-based geopolymer paste

Shindo, Manami*; Ueoku, Aya*; Okamura, Wakana*; Kikuchi, Shin; Yamazaki, Atsushi*; Koga, Nobuyoshi*

Thermochimica Acta, 738, p.179801_1 - 179801_12, 2024/08

https://doi.org/10.1016/j.tca.2024.179801

Exhumation history of the Kurobe area, Hida Range, based on solidification ages and depths of the Pliocene-Quaternary plutons

Sueoka, Shigeru; Kawakami, Tetsuo*; Suzuki, Kota*; Kagami, Saya; Yokoyama, Tatsunori; Shibazaki, Bunichiro*; Nagata, Mitsuhiro; Yamazaki, Ayu*; Higashino, Fumiko*; King, G. E.*; et al.

Fuisshon, Torakku Nyusureta, (36), p.1 - 3, 2023/12

https://ftrgj.org/FTNLs/FTNL36/FTNL36ALL.pdf

no abstracts in English

Case study activities for nuclear security culture development in JAEA

Amano, Tsukasa; Shibata, Ryodai; Sato, Yoshiharu; Yamazaki, Katsuyuki; Shiromo, Hideo; Nakamura, Hironobu

Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 6 Pages, 2023/05

In Japan, about 10 years have passed since the law obligated nuclear operators to develop and maintain a nuclear security culture. During this period, the global nuclear situation has changed significantly, and it is becoming important to maintain a stance that emphasizes compliance with regulations and nuclear security culture. In JAEA, the policy of legal compliance and developing nuclear security culture is determined by the president of JAEA. For legal compliance and developing nuclear security culture, many activities are carried out based on that policy. Finally, these activities are evaluated and improved it every year. Case study is the one of activities that can obtain skills for legal compliance and developing nuclear security culture, such as sensitivity of nuclear security risks, correct understanding of the laws. The procedure for the case study was created with reference to a method called KY-Training which is often applied to safety training program in Japan. KY-Training is a training that participants (groups) can reach the conclusion how to respond to cases through four questions. Firstly, participants are given illustrations and descriptions which has potential of nuclear security risks. Then, participants make discussion according to four questions. Consequently, participants can effectively become aware of nuclear security risks. In the 2022 case study, we prepared 23 cases so that they can select choose freely according to role of participants such as in charge of nuclear security, guards, general employees. Finally, participants are asked to fill a questionnaire to evaluate effectiveness of case study. The result of questionnaires indicated that the case study was able to lead to improvement sensitivity of nuclear security risks and correct understanding of the laws. Overall, case study results suggested that JAEA's efforts were implying sufficiently to develop and maintain a nuclear security culture.

Improve long periodic ground motion evaluation with the epicenter on the border between Fukushima and Ibaraki prefectures in seismic design of nuclear facilities

Kirita, Fumio; Tominaga, Masahiro; Yamazaki, Toshihiko; Seshimo, Kazuyoshi; Uryu, Mitsuru

JAEA-Research 2022-006, 61 Pages, 2023/02

JAEA-Research-2022-006.pdf:6.24MB

Nuclear Fuel Cycle Engineering Laboratories (NCL) has been observing ground motion for a long time. On the border from northern Ibaraki prefecture to Fukushima prefecture, inland crustal earthquakes occur less frequently until the 2011 off the Pacific coast of Tohoku Earthquake (hereinafter referred to as Tohoku Earthquake). After Tohoku Earthquake, aftershocks have become more frequent in this area, and in the Hamadori region of Fukushima earthquake that a remarkable long periodic component was observed in the NCL seismic observation record. Until now there were no such things that long periodic components were observed at the observation points near the epicenter of April 2011 Fukushima earthquake, but it was thought basin structure in deep basement around the NCL affected the propagation process to NCL by reflection survey result. As basement structure of NCL affected the seismic wave propagation process, the seismic wave repeatedly reflects and refracts. For that reason, long periodic components of seismic waves may be possibly amplified. In this study, in order to refine the long periodic ground motion evaluation, using a three dimensional ground structure model (3D model) that can reflect the shape of the deep basement structure around the NCL. When modeling 3D ground structure which has a width of about 80km and a length of about 110km and ranges from the epicenter area of April 2011 Fukushima earthquake to the northern coastal area of Ibaraki prefecture modeled, improved the optimum ground structure model using multiple observation records and performed simulation analysis.

Results of 1-MW operation in J-PARC 3 GeV rapid cycling synchrotron, 2

Yamamoto, Kazami; Yamamoto, Masanobu; Yamazaki, Yoshio; Nomura, Masahiro; Suganuma, Kazuaki; Fujirai, Kosuke; Kamiya, Junichiro; Nakanoya, Takamitsu; Hatakeyama, Shuichiro; Yoshimoto, Masahiro; et al.

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.277 - 281, 2023/01

https://www.pasj.jp/web_publish/pasj2022/proceedings/PDF/TUP0/TUP004.pdf

The J-PARC 3GeV Rapid Cycling Synchrotron (RCS) is aiming to provide the proton beam of very high power for neutron experiments and the main ring synchrotron. We have continued the beam commissioning and the output power from RCS have been increasing. In recent years, we have been trying continuous supply of 1-MW high-intensity beam, which is the design value, to a neutron target. We tried to operate continuously for over 40 hours in June 2020. However, some trouble occurred and the operation was frequently suspended. In June 2021, we tried again 1-MW operation but it was suspended due to deterioration of the cooling water performance. Last summer shutdown period, we recovered performance of the cooling water system and retried in this June. In the final case, the outside temperature became extremely high. We could not keep 1-MW power, whereas 600 kW beam was delivered in stable.

Legal compliance activities and nuclear security culture development activities in JAEA

Amano, Tsukasa; Sato, Yoshiharu; Shibata, Ryodai; Yamazaki, Katsuyuki; Shiromo, Hideo; Nakamura, Hironobu

Dai-43-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2022/11

About ten years have passed since the introduction of nuclear security compliance and security culture development activities. While there have been changes in domestic and international situations, it is essential for nuclear security that the entire organization maintains an attitude that emphasizes compliance with laws and regulations and nuclear security. JAEA has been effectively implementing various activities with evaluation and improvement. Especially, e-learning which combines education and awareness, case studies, and internal audits are considered effective in maintaining nuclear security compliance and security culture development activities.