Study on water stopping, repair and stabilization of lower PCV by geopolymer, etc. (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2022-062, 121 Pages, 2023/03

JAEA-Review-2022-062.pdf:4.78MB

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 "Study on water stopping, repair and stabilization of lower PCV by geopolymer, etc." conducted in FY2021. The present study aims to propose a construction method to stop jet deflectors by improved geopolymer and ultra-heavy muddy water, and to repair the lower part of the dry well. In addition, in order to increase the options for on-site construction in unknown situations such as deposition conditions, we will examine a wide range of construction outside the pedestal, and evaluate the feasibility of the construction method by the latest thermal flow simulation method. When widely constructed, fuel debris and deposits discharged out of the pedestal are coated with water stop and repair materials and become waste ...

Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2022-050, 116 Pages, 2023/01

JAEA-Review-2022-050.pdf:11.41MB

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 (1F), 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 FY2019, this report summarizes the research results of the "Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. The present study aims to explore alkali activated materials with high anionic nuclide retention and flowability and their recipes for safe storage and disposal of iron flocculant from the water treatment facility at 1F, and to propose a design of a solidification device that is feasible as an actual plant. In order to achieve these objectives, the following five items were carried out in this study.

Geopolymer and ordinary Portland cement interface analyzed by micro-Raman and SEM

Cantarel, V.; Yamagishi, Isao

Journal of Nuclear Science and Technology, 59(7), p.888 - 897, 2022/07

https://doi.org/10.1080/00223131.2021.2016510

Microparticles with diverse sizes and morphologies from mechanical and laser cutting of fuel debris simulants and geopolymer as a covering material

Zhou, Q.*; Saito, Takumi*; Suzuki, Seiya; Yano, Kimihiko; Suzuki, Shunichi*

Journal of Nuclear Science and Technology, 58(4), p.461 - 472, 2021/04

https://doi.org/10.1080/00223131.2020.1869623

Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2020-043, 116 Pages, 2021/01

JAEA-Review-2020-043.pdf:7.74MB

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 FY2019. 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 FY2018, this report summarizes the research results of the "Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval" conducted in FY2019. In this study, a technique to effectively suppress the scattering of fine particles has been developed, and as a result of experiments, a method of spraying with water mist was found to be an effective and applicable method for improving aerosol removal efficiency and removal rate. As a method of solidifying fuel debris to suppress fine particle scattering during cutting, geopolymer was evaluated for its strength, thermal conductivity and cutting powder. In addition, flow status of geopolymer and the temperature distribution inside RPV covered by geopolymer were simulated.

Development of technology to prevent scattering of radioactive materials in fuel debris retrieval (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2019-037, 90 Pages, 2020/03

JAEA-Review-2019-037.pdf:7.0MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. 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 FY2018, this report summarizes the research results of the "Development of Technology to Prevent Scattering of Radioactive Materials in Fuel Debris Retrieval". The objective of the present study is to clarify the behavior of microparticles in gas and liquid phases in order to steadily confine radioactive microparticles at the time of debris retrieval in Fukushima Daiichi Nuclear Power Station. In addition, as measures to prevent scattering, we will evaluate and develop methods by experiments and simulation as to; (1) a method to suppress the scattering with minimum amount of water utilizing water spray etc., and (2) a method to suppress the scattering by solidifying fuel debris.

3D X Ray micro-tomography as a tool to formulate metakaolin-based geopolymer-oil emulsions

Lambertin, D.*; Davy, C. A.*; Hauss, G.*; Planel, B.*; Marchand, B.*; Cantarel, V.

Proceedings of 1st International Conference on Innovation in Low-Carbon Cement and Concrete Technology (ILCCC 2019) (USB Flash Drive), 4 Pages, 2019/06

Composite materials made of geopolymer (GP) cement and organic liquids are useful to synthetize porosity-controlled media, for the management of radioactive organic liquid waste, or as phase change materials (PCM). Indeed, GP cements are able to integrate huge amounts of organic oils by direct emulsion in the fresh paste. The emulsion (GEOIL) remains stable during GP hardening. In this contribution, by using 3D X Ray micro Computed Tomography (micro CT) with a voxel size of 1 micron, we investigate the effect of formulation parameters (oil proportion, Si/Al molar ratio, surfactant) on the 3D oil droplet structure of GEOIL pastes. Samples are emulsified in the fresh state, and imaged in the hardened state. Porosity, oil droplet size distribution and mean distance between droplets are all determined quantitatively. It is observed that the presence of surfactant provides significantly smaller oil droplets. The increase in Si/Al ratio also decreases the oil droplet sizes, but to a lesser extent.

Scale up effect on geopolymer H production under gamma irradiation

Cantarel, V.; Arisaka, Makoto; Yamagishi, Isao

no journal, , 

The present study aimed at completing previous results on geopolymer H production under irradiation, taking into account physical phenomena such as gas diffusion. Experimental data showed the consumption of hydrogen by the wasteform itself under irradiation provided hydrogen diffusion was slow enough or the sample large enough. Sample with the same water content and same internal chemistry were shown to have very different effective radiolytic yield by modification of the sample dimensions (100 times smaller for a 40 cm long cylinder compared to the powder of the same sample). A simple model taking in account only hydrogen gas diffusion in the sample, its production and a pseudo first order reaction for the H consumption allowed to predict correctly the effective experimental hydrogen production. A strong dependency between H production, wasteform dimensions and sample permeation properties was highlighted and understood. This difference in our vision of hydrogen production opens new horizons for active waste immobilization.

Investigation of the interface between cement and geopolymer

Cantarel, V.; Yamagishi, Isao

no journal, ,