Radiocarbon measurement of a small-scale sample with a cementite target at JAEA-AMS-TONO

南谷 史菜; 西尾 智博; 藤田 奈津子; 前田 祐輔; 三宅 正恭*; 松原 章浩*; 神野 智史; 小北 康弘; 渡邊 隆広

Nuclear Instruments and Methods in Physics Research B, 579, p.166245_1 - 166245_7, 2026/10

https://doi.org/10.1016/j.nimb.2026.166245

東濃地科学センターでは、セメンタイトによる放射性炭素の微量分析の構築に着手した。セメンタイトは均質なターゲット合成と安定した測定が特徴であり、高精度かつ低バックグラウンドで測定が可能である。本センターで最適なセメンタイト調製法を確立するため、鉄の種類や使用条件・反応収率・測定の再現性・バックグラウンドを検討した。試料調製では、鉄触媒の使用条件を工夫することで、高い収率でのターゲット生成に成功した。測定条件は検討段階であるが、測定に十分なビーム強度をもち、比較的高い確度をもつことがわかった。本発表では、本センターでのセメンタイトによる微量分析の特徴について報告する。

Nanoplastics reprogram fungal metabolism to reshape extracellular microenvironments and manganese biomineralization

Wu, C.*; Qiu, X.*; 田中 万也; 谷 幸則*; Lloyd, J. R.*; Yu, Q.*

Bioresource Technology, 456, p.134916_1 - 134916_9, 2026/09

https://doi.org/10.1016/j.biortech.2026.134916

マンガン酸化菌は環境中においてMn(II)を酸化することでMn(IV)酸化物を形成する。こうしたバイオミネラリゼーションにより形成するMn(IV)酸化物は環境中の放射性核種の挙動に影響を与える。近年、環境中での人為的なナノプラスチック(NP)の汚染が進んでおり、本研究ではNPがバイオミネラリゼーションに与える影響を調べた。その結果、低濃度NPは形成するMn(IV)酸化物の結晶性に影響を与え、高濃度NPではMn(II)酸化が阻害されることが分かった。こうしたNPによるバイオミネラリゼーションへの影響は、環境中での金属元素や放射性核種の挙動に影響を与える可能性がある。

異性材料マイクロ球状ゲル製造装置の開発

丸藤 崇人; 植田 祥平; 川口 浩一; 渡部 雅; Yan, X.

JAEA-Technology 2026-011, 22 Pages, 2026/08

JAEA-Technology-2026-011.pdf:1.84MB

燃料核を予め密封する新たな二重成膜技術を適用したマイクロカプセル製造では、要求液滴径が従来よりも大きいことから、最適製造条件を改めて検討する必要がある。一方、従来装置では複数の操作パラメータが連動して変化するため、各パラメータの影響を分離して評価することが難しく、最適条件の明確化が困難であった。また、実用化に際しては装置の経済性も重要な課題である。以上を踏まえ、本研究では、各パラメータを独立に設定・評価可能であり、かつ低コスト化を図った新規装置を開発した。

Applicability of subcritical water treatment for degradation of spent tannin-based uranium adsorbent; Fundamental research

岩本 敏広; 大森 康平; 荒井 陽一; 船越 智雅; 渡部 創; 中村 雅弘; 渡邉 賢*

Mechanical Engineering Journal (Internet), 13(4-S1), p.25-00391_1 - 25-00391_8, 2026/08

https://doi.org/10.1299/mej.25-00391

TANNIX loaded with uranium and nitric acid ions has accumulated as a secondary waste of radioactive water decontamination. Establishment of treatment procedure of the spent TANNIX is an important issue for facility management. In this study, applicability of the subcritical water treatment for the spent TANNIX decomposition was experimentally examined. As the results, temperature conditions contributed significantly to the decomposition efficiency, and the solid-liquid ratio had a limited effect. The decomposition rate tends to decrease as the test time increases, suggesting that decomposition preferentially occurs around at functional groups. These experimental results showed that most of the TANNIX could be decomposed at high temperatures and longer reaction times. This study demonstrated that hydrothermal reactions can be used both to recover uranium from TANNIX and to decompose it.

Operational challenges of positive pressure systems for radiation protection in medical facilities

松本 智紘*; 田邊 翔太*; 山本 知佳*; Zhao, T.*; 澤野 豊明*; 野中 沙織*; 加藤 秀之*; 山口 文恵; 高原 省五; 田中 知明*; et al.

Journal of Radiological Protection, 46(3), p.032501_1 - 032501_10, 2026/07

https://doi.org/10.1088/1361-6498/ae80d3

During nuclear disasters, shelter-in-place (SIP) is often a safer alternative to evacuation for patients in medical facilities who may be particularly vulnerable. In Japan, medical institutions located near nuclear facilities have been equipped with positive-pressure systems (PPS), designed specifically for radiation protection. However, operational protocols to execute and manage SIP and PPS remain poorly defined. This study aimed to investigate the challenges in implementing SIP at the time of nuclear catastrophe while maintaining essential clinical functions. A case study was conducted at the Matsue Red Cross Hospital, located within an urgent protective action planning zone. Data were gathered through participation in the hospital's nuclear disaster countermeasures committee and through analysis of meeting minutes, facility documents, and technical specifications. The findings revealed a fundamental conflict between the technical requirements of PPS and the continuity of clinical services. Four critical sub-challenges were identified: (1) the unavoidable presence of certain staff and patients in non-protected zones within the hospital; (2) the potential inability to maintain sufficient positive pressure in protected zones during active clinical service; (3) the difficulty in regulating indoor temperature and humidity as a consequence of PPS operation; and (4) the increased risk of external radiation exposure in the vicinity of PPS units when outdoor ambient dose rates are elevated. For facilities that already have PPS installed, further investigations into PPS operations and the development of countermeasures are necessary. Furthermore, when installing PPS in the future, it is desirable for the government, hospitals, and installation companies to thoroughly discuss operations and design systems to minimise the impact on hospital functions.

東濃地科学センターにおける微量試料の放射性炭素年代測定法の開発; JAEA-AMS-TONOの最適な条件検討

南谷 史菜; 西尾 智博; 藤田 奈津子; 前田 祐輔; 三宅 正恭*; 松原 章浩*; 北野 敏彦*; 神野 智史; 渡邊 隆広

第26回AMSシンポジウム報告集(インターネット), p.11 - 16, 2026/06

東濃地科学センターでは、微量試料の放射性炭素年代測定を実用化するため、セメンタイトをAMSターゲットとする微量分析法の構築に着手した。2024年度、試料調製の条件を最適化し85%の高収率での試料調製を可能にしたが、AMS測定ではC値の精度が低く、Cのばらつきも大きくなった。そこで、ビーム電流値の制御に焦点を当て、センターのAMS装置を用いて最適なイオン源設定条件を検討した。カソード電圧、エキストラクタ電圧、イマージョンレンズ電圧などを調整し、最適な電流値を評価することで、C値とCのばらつきが最も小さくなる条件を検討した。本発表では、その検討結果を報告する。

Pulsed-neutron imaging study of a naginata from the Edo Period and spears from the Muromachi Period

及川 健一; 松本 吉弘*; 佐藤 博隆*; 渡辺 賢一*; Parker, J. D.*; 篠原 武尚; 鬼柳 善明*

JPS Conference Proceedings (Internet), 45, p.011047_1 - 011047_8, 2026/06

https://doi.org/10.7566/JPSCP.45.011047

Our Japanese sword research team is attempting to gain insight into the secrets of sword-making techniques by conducting systematic nondestructive study from the viewpoint of crystallographic structure, mainly using the energy-resolved neutron imaging system, RADEN at J-PARC. In particular, the manufacturing process of old swords 'Koto' up to the end of the 16th century is not well understood because there are few written records of the sword making process, and it would be an important clue to clarify how the crystallographic structure differs compared to after the 16th century. With the cooperation of NITROPLUS Co., Ltd., we have started the neutron imaging experiment of swords of known provenance and era from 2021. So far, they have provided us with a total of ten exhibition-class swords. In this presentation, we will report on the analysis results of Bragg-edge imaging and neutron tomography of these swords, Naginata and spear, which are sword-related weapons closely related to the Japanese sword but made in different ways.

Large spontaneous Hall effect arising from collinear antiferromagnetism in CePtGe

松田 駿汰*; 日比野 瑠央*; 田端 千紘; 金子 耕士; 比嘉 野乃花*; 鬼丸 孝博*; 田中 裕斗*; 藤 秀樹*; 菅原 仁*; 林 純一*; et al.

Physical Review B, 113(19), p.195116_1 - 195116_8, 2026/05

https://doi.org/10.1103/4x23-wbc6

The spontaneous Hall effect, corresponding to a zero-field anomalous Hall effect (AHE), is induced by symmetry breaking associated with ferromagnetism. Studies in recent years, however, have revealed that antiferromagnetic (AFM) states characterized by magnetic point groups that allow ferromagnetism can also break the relevant symmetries and induce AHE without a large net magnetization. Here, we report that the AFM system CePtGe exhibits a pronounced spontaneous Hall effect. Single-crystal neutron scattering experiments demonstrate that CePtGe exhibits a collinear AFM structure with a propagation vector = 0. The small net magnetization indicates that the observed AHE arises from symmetry breaking inherent to its AFM structure. The anomalous Hall conductivity (AHC) reaches 300 cm, which exceeds the intrinsic AHC of related compounds such as CeCuGe and CePdGe. This large AHC, most likely attributed to the large spin-orbit coupling of the Pt atoms, provides a platform for understanding the interplay between the Berry curvatures and localized f-moments with an AFM configuration.

Construction of a Compton camera-equipped robotic system capable of moving autonomously towards the radiation source

佐藤 優樹; 角藤 壮*; 田中 孝幸*; 嶋野 寛之*

European Physical Journal; Special Topics, 235(4), p.949 - 958, 2026/04

https://doi.org/10.1140/epjs/s11734-025-01483-5

In decommissioning the Fukushima Daiichi Nuclear Power Station, understanding the distribution of radioactive substances is crucial to developing detailed decontamination plans and minimizing worker exposure. In this study, an autonomous mobile radiation source detection system based on a mecanum wheel robot equipped with a Compton camera was constructed. The Compton camera visualizes the radiation source, and software embedded in the robot system reads the results to recognize the radiation source and move the robot toward it. If the robot's depth camera detects an obstacle while moving, it changes direction, visualizes the radiation source again using the Compton camera, and repeats moving the robot toward the radiation source. Furthermore, two demonstration tests were conducted in the laboratory using a Cs radiation source to confirm that the robot can reach it where there are obstacles or a narrow region. We have also summarized issues that must be identified to apply this system to actual decommissioning sites.

Impact of detailed depletion chains and cross-section treatments on nuclide inventory using SWAT-X

渡邉 友章; 多田 健一; 山本 章夫*

Proceedings of International Conference on the Physics of Reactors (PHYSOR 2026) (Internet), 8 Pages, 2026/04

https://doi.org/10.5281/zenodo.20803523

This study investigates the impact of detailed depletion-chain and cross-section treatments on burnup calculation results using SWAT-X, which is a Monte Carlo burnup code currently under development by the authors. In this work, a new capability to construct arbitral depletion chains based on ENDF-6 formatted nuclear data libraries has been implemented in SWAT-X. Detailed depletion chains consisting of 4,070 nuclides were constructed using decay and fission yield data from JENDL-5. Using these depletion chains, burnup calculations for a UO pin-cell model assuming a PWR were performed with different cross-section treatments. Cross sections for 226 major nuclides were treated in continuous energy in the Monte Carlo calculations for all cases, whereas those for the remaining nuclides in the depletion chain were treated differently, either in continuous energy or multi-group with different structures, to evaluate their impact on the calculated nuclide inventories. The results indicate that the effect of the cross-section treatment is small, suggesting that a simplified approach with multi-group cross sections is sufficient. In this study, the impact of cross-section coverage in the depletion chain was also examined by extending the data to include a total of 2,697 nuclides using TENDL-2023. As a result, some changes and new generations of nuclides were observed, although their overall impact on the nuclide inventory was limited.