Achievements and status of the STRAD project for radioactive liquid waste management

荒井 陽一; 渡部 創; 中原 将海; 船越 智雅; 星野 貴紀; 高畠 容子; 坂本 淳志; 粟飯原 はるか; 長谷川 健太; 吉田 稔生; et al.

Progress in Nuclear Science and Technology (Internet), 7, p.168 - 174, 2025/05

https://doi.org/10.15669/pnst.7.168

STRADプロジェクトの進捗に係る報告として、CPFホットセルの処理状況とともに、新たなターゲットに係る研究計画と最新のトピックスについて報告する。

Using X-ray absorption near edge structure to evaluate adsorption properties of rare earths and nitrogen by difference of their interactions

箕輪 一希*; 渡部 創; 中瀬 正彦*; 高畠 容子; 宮崎 康典; 伴 康俊; 松浦 治明*

Nuclear Instruments and Methods in Physics Research B, 556, p.165496_1 - 165496_6, 2024/11

https://doi.org/10.1016/j.nimb.2024.165496

X線吸収端構造(XANES)分析とカラム試験により希土類のアルキルジアミドアミン(ADAAM)含浸吸着材への選択性を考察した。さらに高レベル放射性廃液に含まれるマイナーアクチノイド(MA)の模擬物質として希土類を実験に利用する蓋然性の高さを、ADAAMの窒素原子と希土類イオンの相互作用により証明した。LaとCeはADAAM中のアミンの窒素原子と相互に作用することを証明し、N-K端におけるXANESスペクトルにて検討に供した希土類においてピークシフトが観察されたことから、ソフトな相互作用が希土類の選択性に関与することを明らかにした。また、ADAAM含浸吸着材において希土類の選択性に関する要因はMAのそれと同じであることから、希土類がMAの模擬物質として適していることを示した。

Overview of development program for engineering scale extraction chromatography MA(III) recovery system

渡部 創; 高畠 容子; 長谷川 健太; 後藤 一郎*; 宮崎 康典; 渡部 雅之; 佐野 雄一; 竹内 正行

Mechanical Engineering Journal (Internet), 11(2), p.23-00461_1 - 23-00461_10, 2024/04

https://doi.org/10.1299/mej.23-00461

Japan Atomic Energy Agency is developing extraction chromatography technology to recover MA(III) from spent nuclear fuel. Developments in the extraction chromatography system especially focusing on safety and stable operation are required for practical application of the technology. This paper discusses the main tasks that have to be challenged preferentially based on achievements obtained by previous studies and potential MA(III) recovery process flow.

Decontamination and solidification treatment on spent liquid scintillation cocktail

渡部 創; 高畠 容子; 小木 浩通*; 大杉 武史; 谷口 拓海; 佐藤 淳也; 新井 剛*; 梶並 昭彦*

Journal of Nuclear Materials, 585, p.154610_1 - 154610_6, 2023/11

https://doi.org/10.1016/j.jnucmat.2023.154610

Treatment of spent scintillation cocktail generated by analysis of radioactivity is one of important tasks for management of nuclear laboratories. This study proposed a procedure consists of adsorption of radioactivity and solidification of residual liquid wastes, and fundamental performance of each step was experimentally tested. Batch-wise adsorption showed excellent adsorption performance of Ni onto silica-based adsorbent, and chelate reaction was suggested as the adsorption mechanism by EXAFS analysis. Alkaline activate material successfully solidified the liquid waste, and TG/DTA and XRD analyses revealed that the organic compounds exist inside the matrix. Only 1% of the loaded organic compounds were leaked from the matrix by a leaching test, and most of the organic compounds should be stably kept inside the matrix.

Treatment of U contaminated waste generated from nuclear fuel fabrication process, 1; Ce(IV) recovery by temperature swing extraction with monoamides

岩本 敏広; 齋藤 まどか*; 高畠 容子; 渡部 創; 渡部 雅之; 成瀬 惇喜*; 塚原 剛彦*

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05

モノアミド抽出剤と温度応答性ポリマーを用いたゲル化抽出技術のウラン廃棄物処理への適用性の検討を行った。異なる構造を有する3種類のモノアミド抽出剤を用いた模擬溶液の分離試験により、溶液中のCe(IV)をゲル化抽出法により選択的に回収されることが示された。これらの試験結果をもとに、ゲル化抽出法に適したモノアミド抽出剤を選定した。

Development of engineering scale extraction chromatography separation system, 1; Overview of developments in engineering scale system

渡部 創; 高畠 容子; 長谷川 健太; 後藤 一郎*; 宮崎 康典; 渡部 雅之; 佐野 雄一; 竹内 正行

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05

Japan Atomic Energy Agency is developing extraction chromatography technology for MA(III) recovery from spent nuclear fuel. Developments in the extraction chromatography system especially focusing on safety and stable operation are required for practical application of the technology. In this paper, main tasks which have to be challenged preferentially are discussed based on achievements obtained by previous studies and potential MA(III) recovery process flow.

Structural characterization by X-ray analytical techniques of calcium aluminate cement modified with sodium polyphosphate containing cesium chloride

高畠 容子; 渡部 創; 入澤 啓太; 塩飽 秀啓; 渡部 雅之

Journal of Nuclear Materials, 556, p.153170_1 - 153170_7, 2021/12

https://doi.org/10.1016/j.jnucmat.2021.153170

The long-time experimental activities on pyroprocessing have generated waste eutectic salts contaminated with nuclear materials. After reprocessing tests, waste salts should be appropriately treated, with a focus on Cl disposal considering its corrosive nature. It is important to construct Cl confinement for the waste salts. Chlorapatite (Ca(PO)Cl) has great potential for Cl confinement due to Ca and P. The chemical reactivity of Cl will be drastically reduced if chlorapatite can be synthesized in calcium aluminate cement modified with sodium polyphosphate (CAP) containing CsCl. This study confirms the chemical state of Cl and metal elements in the cement by XRD, XPS, and XANES in the CAP containing CsCl. The analyses results suggest the existence of the Ca-Cl-Cs and Al-Cl-Cs bonds in CAP containing CsCl. The formation of the chemical bonds of Cl with metal elements might be one of important factors for the chlorapatite formation from the CAP containing CsCl.

STRAD project for systematic treatments of radioactive liquid wastes generated in nuclear facilities

渡部 創; 小木 浩通*; 荒井 陽一; 粟飯原 はるか; 高畠 容子; 柴田 淳広; 野村 和則; 神谷 裕一*; 浅沼 徳子*; 松浦 治明*; et al.

Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11

AA2019-0193.pdf:1.29MB

https://doi.org/10.1016/j.pnucene.2019.103090

A new collaborative research project for systematic treatments of radioactive liquid wastes containing various reagents generating in nuclear facilities was started from 2018 initiated by Japan Atomic Energy Agency. The project was named as STRAD (Systematic Treatments of RAdioactive liquid wastes for Decommissioning) project. Tentative targets to be studied under the project are aqueous and organic liquid wastes which have been generated by experiments and analyses in a reprocessing experimental laboratory of JAEA. Currently fundamental studies for treatments of the liquid wastes with complicated compositions are underway. In the STRAD project, process flow for treatment of ammonium ion involved in aqueous waste was designed though the inactive experiments, and decomposition of ammonium ion using catalysis will be carried out soon. Adsorbents for recovery of U and Pu from spent solvent were also developed. Demonstration experiments on genuine spent solvent is under planning.

Investigation of the contamination on the operation floor of unit 2 based on the radiochemical analysis data

高畠 容子; 駒 義和

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05

Radioactive nuclides contaminated F1NPS on the severe accident. It is necessary to discuss about radioactive waste processing and disposal. To investigate contamination process for the waste is important to establish methodologies for their management. Operation floor of unit 2 reactor building was highly contaminated, and boring cores of floor and ceiling were radiochemicaly analyzed. Comparing with distribution of Cs and dose rate indicated the difference of degree of contamination between the floor and ceiling. Contamination with Pu, Am and Cm was higher at the floor above the reactor shield plug, where is considered that the contaminated gas leaked. Degree of contamination of H, Co, Tc, Am and Cm were highest at the point of the opposite side of the blow out panel among several sampling point of the ceiling. From the activity ratio of U to U with samples, the origin of uranium was the damaged fuel.

再処理構造材料の腐食挙動に及ぼすRu化学形態の影響に関する研究

佐野 雄一; 安倍 弘; 高畠 容子

あいちシンクロトロン光センター2017年度公共等利用成果報告書(インターネット), 1 Pages, 2018/00

再処理工程での腐食機構の解明及び腐食抑制方法の提案を目的として、海水成分を含む硝酸溶液中におけるRuの存在形態に共存物質が及ぼす影響について評価を行った。Ruを対象としたXAFS測定の結果、塩化物イオンとの相互作用に起因すると推定されるRu近傍の構造変化が観測され、硝酸溶液中におけるRuの腐食促進作用に何らかの影響を及ぼすことが示唆された。