Introduction to dismantling and decommissioning chemistry

Sato, Nobuaki*; Kameo, Yutaka; Sato, Soichi; Kumagai, Yuta; Sato, Tomonori; Yamamoto, Masahiro*; Watanabe, Yutaka*; Nagai, Takayuki; Niibori, Yuichi*; Watanabe, Masayuki; et al.

Introduction to Dismantling and Decommissioning Chemistry, 251 Pages, 2024/09

This book focuses on the dismantling and decommissioning of nuclear facilities and reactors that have suffered severe accidents. In Part 1, we introduce basic aspects ranging from fuel chemistry, analytical chemistry, radiation chemistry, corrosion, and decontamination chemistry to waste treatment and disposal. Then, Part 2 covers the chemistry involved in the decommissioning of various nuclear facilities, and discusses what chemical approaches are necessary and possible for the decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Plants, how decommissioning should be carried out, and what kind of research and development and also human resource development are required for this.

Progress status and future issues of development of analysis and estimation technology for fuel debris characterization, 3; Activities toward enhanced analysis accuracy of fuel debris

Ikeuchi, Hirotomo; Koyama, Shinichi

Nihon Genshiryoku Gakkai-Shi ATOMO, 66(2), p.74 - 78, 2024/02

https://doi.org/10.3327/jaesjb.66.2_74

For the steady removal of fuel debris from the TEPCO's Fukushima Daiichi Nuclear Power Station (1F), it is an urgent issue to establish analysis technology and systems for fuel debris samples with unknown properties (unknown samples). For this purpose, through analysis tests using samples with known properties (simulated fuel debris) and discussions among experts, the validity of analysis results and the factors that cause errors has been identified. In addition to knowing the current level of analysis accuracy, studies are being conducted to understand and improve the influencing factors. This paper introduces a part of the development of infrastructure for analysis and evaluation technology of "nuclides and element content."

Summary results of subsidy program for the "Project of Decommissioning, Contaminated Water and Treated Water Management (Development of Analysis and Estimation Technologies for Characterization of Fuel Debris (Development of Estimation Technologies of RPV Damaged Condition, etc.) in 2022JFY

Yamashita, Takuya; Shimomura, Kenta; Nagae, Yuji; Yamaji, Akifumi*; Mizokami, Shinya; Mitsugi, Takeshi; Koyama, Shinichi

Hairo, Osensui, Shorisui Taisaku Jigyo Jimukyoku Homu Peji (Internet), 53 Pages, 2023/10

https://dccc-program.jp/5835

JAEA performed the subsidy program for the "Project of Decommissioning, Contaminated Water and Treated Water Management (Development of Analysis and Estimation Technologies for Characterization of Fuel Debris (Development of Estimation Technologies of RPV Damaged Condition, etc.) in 2022JFY. This presentation summarized briefly the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning, Contaminated Water and Treated Water Management.

Weyl-Kondo semimetal behavior in the chiral structure phase of CeRhSn

Iwasa, Kazuaki*; Suyama, Kazuya*; Kawamura, Seiko; Nakajima, Kenji; Raymond, S.*; Steffens, P.*; Yamada, Akira*; Matsuda, Tatsuma*; Aoki, Yuji*; Kawasaki, Ikuto; et al.

Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014201

Accomplishment of OECD/NEA, PreADES (Preparatory Study on Analysis of Fuel debris) project

Nakayoshi, Akira; Koyama, Shinichi; Washiya, Tadahiro

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR2022) (Internet), 4 Pages, 2022/10

The activity of the PreADES project was carried out under the collaboration with many international organizations, and accumulated useful expertise. Following project tasks were discussed: (1) the Characteristic table that clarified characteristics of fuel debris for 1F, TMI2, and Chernobyl from various analyses and experiments, (2) Compiling informative tables for fuel debris analysis (the Analytical table, the Major issue and methodology table; the Hot testing analysis capabilities table). The first one identified analysis data to be obtained, and the last one indicated practical appropriate and optimal methodologies for fuel debris handling, (3) future international R&D framework. Through these activities with many discussions, project partners re-realized that important aspects for the success of future collaborative initiative was to implement conditions for fluid dialogue and information exchange between involved organizations. Currently, post-PreADES project, "Fukushima Daiichi Nuclear Power Station Accident Information Collection and Evaluation (FACE)" project has been launched and discussion is ongoing enthusiastically.

Step-by-step challenge of debris characterization for the decommissioning of Fukushima-Daiichi Nuclear Power Station (FDNPS)

Kurata, Masaki; Okuzumi, Naoaki*; Nakayoshi, Akira; Ikeuchi, Hirotomo; Koyama, Shinichi

Journal of Nuclear Science and Technology, 59(7), p.807 - 834, 2022/07

https://doi.org/10.1080/00223131.2022.2040393

Immediately after the 1F-accident, various attempts have been made to evaluate the fuel debris characteristics toward the decommissioning of 1F. The present review outlines those attempts. In the years immediately following the 1F-accident, the knowledge obtained from the 1F-site (especially from the damaged reactors of Units 1, 2 and 3) was extremely limited. The approximate location of fuel debris was investigated by muon tomography, and its characteristics were roughly estimated based on the past findings such as the results of the Three Mile Island-II accident investigation in the United States, which gave us information of prototypical accident scenarios and debris characteristics for pressurized water reactor accident. After that, various internal investigation robots were developed, and from 2017, investigation of the inside of the reactor containment vessel was started using these robots. Consequently, these three units were found to have core damage status and debris distribution that were rather different from what had been expected based on the typical accident scenario of a pressurized water reactor. In parallel, a small amount of U-bearing particle was recovered from the smear samples of these robots. The analysis of these particles is ongoing to get information relevant to fuel debrsi body. Furthermore, international collaboration is ongoing mainly under OECD/NEA, including accident analysis and debris characterization. From now on, one need to further understand 1F-accident scenario and progress debris characterization based on these 1F-site information.

High-spin states in S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

https://doi.org/10.1103/PhysRevC.103.034327

Adsorption behavior of cesium on hybrid microcapsules in spent fuel solution

Onishi, Takashi; Koyama, Shinichi; Mimura, Hitoshi*

Nihon Ion Kokan Gakkai-Shi, 31(3), p.43 - 49, 2020/10

https://doi.org/10.5182/jaie.31.43

How different is the core of F from O ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

https://doi.org/10.1103/PhysRevLett.124.212502

The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

https://doi.org/10.1038/s42005-019-0165-1

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.