Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2025-004, 186 Pages, 2025/07

JAEA-Review-2025-004.pdf:11.9MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2023. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies" conducted from FY2021 to FY2023. The present study aims to develop an evaluation method necessary to obtain a perspective on the longterm structural soundness of accident-damaged reactor buildings, where accessibility to work sites is extremely limited due to high radiation dose rate and high contamination. In FY2023, the final year of the three-year project, experimental and analytical research activities were performed to develop, (1) Method for evaluating the building by monitoring the response to earthquakes and other disturbances, (2) Damage detection technology for concrete structures using electromagnetic waves, (3) Evaluation method for concrete materials and structures based on damage detection information, (4) Comprehensive soundness evaluation method and a long-term maintenance plan, (5) Promotion of the research. Expected results and final goals are achieved based on the outcomes including achievements up to FY2022.

Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2022-071, 123 Pages, 2023/03

JAEA-Review-2022-071.pdf:6.07MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies" conducted in FY2021. The present study aims to develop an evaluation method necessary to obtain a perspective on the long-term structural soundness of accident-damaged reactor buildings, where accessibility to work sites is extremely limited due to high radiation dose rate and high contamination. In FY2021, the first year of the three-year plan, the following research items were undertaken by clarifying specific research methods, setting research directions, making necessary preparations, and conducting some tests and other activities.

Computer Simulation of Isotope-Selective Dissociation of Lithium Chloride Molecules in the Rotational Temperature of 70 K by Terahertz Optical Pulses

Ichihara, Akira; Matsuoka, Leo*

no journal, , 

Separation of long-lived fission products from other isotopes is important for the research of nuclear transmutation. Recently, we proposed an isotope separation method applicable to diatomic molecules in the gas phase. In this method, two kinds of terahertz (THz) optical fields are utilized to dissociate the selected isotope molecule. In this study, we investigated the isotope-selective dissociation using the LiCl and LiCl molecules in the rotational temperature of 70 K, where LiCl was employed as a substitute of CsI which is formed in nuclear reactors. The molecular wave-packet (WP) computation was carried out to demonstrate that the LiCl molecules can be dissociated selectively by using the THz optical pulses. The obtained dissociation probabilities were 20 % for LiCl, and 0.5 % for LiCl, respectively. We expect that this method is applicable to other diatomic molecular ensembles whose rotational states are in the thermal distribution.