Project plan of HTTR heat application test facility; Safety design and Safety analysis

青木 健; 長谷川 武史; 倉林 薫; 野本 恭信; 清水 厚志; 佐藤 博之; 坂場 成昭

Proceedings of 11th International Topical Meeting on High Temperature Reactor Technology (HTR 2024), 6 Pages, 2024/10

原子力機構はHTTR(高温工学試験研究炉)及び水素製造施設を接続するHTTR-熱利用試験を計画している。本研究は、HTTR-熱利用試験施設の安全設計及び安全解析の成果を報告する。安全設計では、期待する安全機能に基づき構築物・系統及び機器の安全重要度分類を定めた。予備安全解析では、RELAP5コードを用いた熱流動解析を行った。予備安全解析は、蒸気発生器の伝熱管破損を除くHTTR-熱利用試験で新たに想定される事象が既設のHTTRの許認可ベース事象に包絡されること、並びに、新たな許認可ベース事象の候補は安全解析の判断基準を満足することを明らかにした。

1F廃炉に向けた放射線源逆推定及び線源対策に係るデジタル技術の研究開発; 3D-ADRES-Indoor FrontEnd: 廃炉現場で用いるファストデジタルツイン技術

町田 昌彦; 山田 進; Kim, M.; 田中 伶詞*; 飛田 康弘*; 岩田 亜矢子*; 青木 勇斗; 青木 和久; 柳澤 憲一*; 山口 隆司; et al.

RIST News, (70), p.3 - 22, 2024/09

福島第一原子力発電所(1F)建屋内には、原子炉内から漏洩した放射性物質の汚染により高い放射線量を示す地点が多数存在し、廃炉作業を円滑に進める上での大きな障害となっている。日本原子力研究開発機構(JAEA)は、この課題解決に貢献するため、経済産業省の廃炉・汚染水対策事業費補助金「原子炉建屋内の環境改善のための技術開発(被ばく低減のための環境・線源分布のデジタル化技術の高機能化開発)」を受託し、令和(R)5年度4月より、廃炉屋内の放射線環境改善に係るデジタル技術の研究開発事業を進めている。本事業では、前期事業(R34年度実施)にて開発した3 D-ADRES-Indoor(プロトタイプ)を発展させ、現場で活用可能な高速デジタルツイン技術より成るFrontEnd、1F新事務本館等の居室で詳細解析を行うPro、そして、収集したデータ及び解析したデータを集中管理するデータベースの役割を果たすBackEndの3つの連携システムの開発を目標としている。本報告では、この3つの連携システムの中でも現場で活用するシステムとして、点群測定後、迅速に3Dメッシュモデルを作成し、線量率の計測結果から線源を逆推定し、その推定線源の位置や強度を更に高精度化する計算技術(再観測指示と再逆推定)を有するFrontEndを中心に、その開発状況について報告し、その検証結果として5号機での試験結果を示す。また、簡単に当該事業の今後の研究開発の計画も報告する。

Universal access to water-compatible and nanostructured materials via the self-assembly of cationic alternating copolymers

筋田 涼太*; 青木 裕之; 竹中 幹人*; 大内 誠*; 寺島 崇矢*

ACS Macro Letters (Internet), 13(6), p.747 - 753, 2024/06

https://doi.org/10.1021/acsmacrolett.4c00173

Herein, we report the water-assisted self-assembly of alternating copolymers bearing imidazolium cations and hydrophobic groups to create water-compatible and nanostructured materials. The copolymers efficiently absorbed water into the cationic segments from the outer environments, depending on the relative humidity. The absorbed water serves as hydrophilic molecules to modulate the weight fraction of hydrophilic/hydrophobic units in the samples. Thus, the morphologies and domain spacing of the nanostructures can be controlled by not only the side chains, but also the amount of absorbed water. The self-assembly of the cationic copolymers, developed herein, afforded universal access to various morphologies, including lamella, gyroid, and cylinder, in addition to the precision control of the domain spacing at the 0.01 nm level.

Lamellar microphase separation and phase transition of hydrogen-bonding/crystalline statistical copolymers; Amide functionalization at the interface

Ikami, Takaya*; 青木 裕之; 寺島 崇矢*

ACS Macro Letters (Internet), 13(4), p.446 - 452, 2024/04

https://doi.org/10.1021/acsmacrolett.3c00743

Microphase separation of random copolymers, as well as that of high ; low N block copolymers, is promising to construct sub-10-nm structures into materials. Herein, we designed statistical copolymers consisting of 2-hydroxyethyl acrylate (HEA) and N-octadecylacrylamide (ODAAm) to produce crystallization and hydrogen bond-assisted lamellar structure materials. The copolymers not only formed a crystalline lamellar structure with 3-4 nm domain spacing but also maintained an amorphous lamellar structure via phase transition above the melting temperature up to approximately 100 C. The key is to introduce hydrogen-bonding amide junctions between the octadecyl groups and the polymer backbones, by which the polymer chains are physically fixed at the interface of lamellar structures even above the melting temperature. The stabilization of the lamellar structure by the amide units is also supported by the fact that the lamellar structure of all-acrylate random copolymers bearing hydroxyethyl and crystalline octadecyl groups is disordered above the melting temperature. By spin-coating on a silicon substrate, the HEA/ODAAm copolymer formed a multilayered lamellar thin film consisting of a hydrophilic hydroxyethyl/main chain phase and a hydrophobic octadecyl phase. The structure and order-disorder transition were analyzed by neutron reflectivity.

Synthesis of heat-resistant living polymer particles by one-step reversible addition-fragmentation chain transfer precipitation polymerization of styrene and -phenylmaleimide

山崎 駿*; 金子 直矢*; 加藤 敦也*; 渡邉 航平*; 青木 大輔*; 谷口 竜王*; 唐津 孝*; 上田 祐生; 元川 竜平; 大倉 滉生*; et al.

Polymer, 298, p.126846_1 - 126846_11, 2024/04

https://doi.org/10.1016/j.polymer.2024.126846

Synthesis of heat-resistant, living polymer particles via one-step reversible addition-fragmentation chain transfer precipitation polymerization (RAFTPP) of styrene and -phenylmaleimide is reported. Gel permeation chromatography and nuclear magnetic resonance spectroscopy confirmed that the polymerization proceeded in a living manner. The scanning electron microscopy results showed that the monodisperse P(St-PhMI) RAFTPP particles with a diameter of 1.88 micrometer were successfully synthesized. The P(St-PhMI) RAFTPP showed excellent thermal stability with a high glass transition temperature and a 5 percent weight loss temperature. The surface concentration of the RAFT groups was determined to be 0.181 groups/square-nanometer due to fragmentation of the RAFT groups exposed on the particles. The small-angle neutron scattering measurements showed the particle formation mechanism, in which the swollen, growing polymer chains were consumed for particle formation. The introduction of grafted chains by surface-initiated RAFT polymerization demonstrated the possibility of further functionalization of P(St-PhMI) RAFTPP particles by exploiting their living nature.

Development of a DO/HO vapor generator for contrast-variation neutron scattering

有馬 寛*; 高田 慎一; 笠井 聡*; 大内 啓一*; 森川 利明*; 宮田 登*; 宮崎 司*; 青木 裕之; 岩瀬 裕希*; 廣井 孝介; et al.

Journal of Applied Crystallography, 56(6), p.1802 - 1812, 2023/12

https://doi.org/10.1107/S1600576723009780

The contrast-variation technique in neutron scattering experiments plays a pivotal role in distinguishing partial structures within multi-component complexes, facilitating the elucidation of distinct sample constituents. This differentiation is achieved using different isotopes, namely hydrogen and deuterium, which possess varying neutron scattering characteristics. This study presents a novel vapor generator designed for neutron scattering experiments, enabling continuous control of the DO/HO ratio of the vapor. This feature is especially useful for contrast-variation studies. The generator features two saturators and four mass flow controllers, allowing for the rapid and independent generation of DO/HO vapors. Additionally, the incorporation of the two-temperature method ensures accurate dew point control within a margin of 0.2Cdp. This setup proves useful for conducting time-resolved experiments and can accelerate research on functional polymers, such as polymer electrolyte membranes for fuel cells, where water potential assumes critical importance.

Impact of the Ce states in the electronic structure of the intermediate-valence superconductor CeIr

藤森 伸一; 川崎 郁斗; 竹田 幸治; 山上 浩志; 雀部 矩正*; 佐藤 芳樹*; 清水 悠晴*; 仲村 愛*; Maruya, A.*; 本間 佳哉*; et al.

Electronic Structure (Internet), 5(4), p.045009_1 - 045009_7, 2023/11

https://doi.org/10.1088/2516-1075/ad0a3d

The electronic structure of the -based superconductor was studied by photoelectron spectroscopy. The energy distribution of the state was revealed by the resonant photoelectron spectroscopy. The state was mostly distributed in the vicinity of the Fermi energy, suggesting the itinerant character of the state. The contribution of the state to the density of states (DOS) at the Fermi energy was estimated to be nearly half of that of the states, implying that the state has aconsiderable contribution to the DOS at the Fermi energy. The core-level and X-ray absorption spectra were analyzed based on a single-impurity Anderson model. The number of the state in the ground state was estimated to be 0.8-0.9, which is much larger than the values obtained in the previous studies (i.e., 0-0.4).

Strain-induced crystallization and phase separation used for fabricating a tough and stiff slide-ring solid polymer electrolyte

橋本 慧*; 塩飽 透*; 青木 裕之; 横山 英明*; 眞弓 皓一*; 伊藤 耕三*

Science Advances (Internet), 9(47), p.eadi8505_1 - eadi8505_8, 2023/11

https://doi.org/10.1126/sciadv.adi8505

The demand for mechanically robust polymer-based electrolytes is increasing for applications to wearable devices. Young's modulus and breaking energy are essential parameters for describing the mechanical reliability of electrolytes. The former plays a vital role in suppressing the short circuit during charge-discharge, while the latter indicates crack propagation resistance. However, polymer electrolytes with high Young's moduli are generally brittle. In this study, a tough slide-ring solid polymer electrolyte (SR-SPE) breaking through this trade-off between stiffness and toughness is designed on the basis of strain-induced crystallization (SIC) and phase separation. SIC makes the material highly tough (breaking energy, 80 to 100 megajoules per cubic meter). Phase separation in the polymer enhanced stiffness (Young's modulus, 10 to 70 megapascals). The combined effect of phase separation and SIC made SR-SPE tough and stiff, while these mechanisms do not impair ionic conductivity. This SIC strategy could be combined with other toughening mechanisms to design tough polymer gel materials.

もんじゅ燃料体取出し作業報告書; 第1段階「燃料体取出し」作業

塩田 祐揮; 工藤 淳貴; 津野 大海; 竹内 遼太郎; 有吉 秀夫; 塩濱 保貴; 浜野 知治; 高木 剛彦; 長沖 吉弘

JAEA-Technology 2023-002, 87 Pages, 2023/06

JAEA-Technology-2023-002.pdf:8.53MB

高速増殖原型炉もんじゅは、2018年から廃止措置に移行し、約30年を経て廃止措置を完了する予定である。なお、廃止措置は4段階に分けて実施する計画である。もんじゅは、原子炉容器及び炉外燃料貯蔵槽(EVST)に多量のナトリウムを保有し、大規模なナトリウム火災との重畳による燃料破損という残留リスクがあった。このため、もんじゅ廃止措置計画の第1段階では約5.5年をかけて「燃料体取出し」作業を実施し、速やかにこれらの燃料体を全て燃料池に貯蔵し残留リスクを排除することとした。燃料体取出し作業では、炉心の燃料体を燃料池に移送し貯蔵することを目的に、炉外燃料貯蔵槽に貯蔵中の燃料体を洗浄し、燃料池に貯蔵する「燃料体の処理」、炉心にある燃料体を模擬燃料体等と交換し、炉外燃料貯蔵槽に貯蔵する「燃料体の取出し」を交互に行い、4キャンペーンに分け炉心に存在する燃料体370体と炉外燃料貯蔵槽に貯蔵されている燃料体160体の計530体の燃料体を全て安全かつ計画通りに燃料池への貯蔵を完了した。本報告書は、第1段階での燃料体取出し作業の総括として、作業の進め方、事前の機器・設備点検やリスク評価といった作業前の準備、キャンペーン内での運転や点検等の作業の実績、作業の評価について取り纏めたものである。

Development plan for coupling technology between high temperature gas-cooled reactor HTTR and hydrogen production facility, 1; Overview of the HTTR heat application test plan to establish high safety coupling technology

野本 恭信; 水田 直紀; 守田 圭介; 青木 健; 沖田 将一朗; 石井 克典; 倉林 薫; 安田 貴則; 田中 真人; 井坂 和義; et al.

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05

JAEA initiated an HTTR heat application test plan to develop for coupling technology between HTGR and hydrogen production facility. The principal objective of this test plan is to establish the high safety coupling technology for coupling a hydrogen production facility to HTGR through the demonstration of a hydrogen production by the proven technology of methane steam reforming method utilizing the HTTR as a high temperature heat source. The other objective is to develop for coupling equipment such as a high temperature isolation valve, a helium gas circulator and a high temperature insulation pipe. This paper describes the overview of an HTTR heat application test plan such as a draft test schedule and test targets for the demonstration of a hydrogen production. This paper also presents basic specifications of an HTTR heat application test facility such as the HTTR modification strategy, overall system configuration and heat and mass balance at rated test operation for the demonstration of a hydrogen production. Furthermore, the operation plan during the normal start-up and shut-down processes is proposed.