Design and characterisation of different characteristics of metakaolin-based geopolymer for fuel debris removal (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2025-041, 79 Pages, 2025/12

JAEA-Review-2025-041.pdf:9.8MB

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 FY2023, this report summarizes the research results of the "Design and characterisation of different characteristics of metakaolin-based geopolymer for fuel debris removal" conducted in FY2023. This study aims to demonstrate the potential of metakaolin-based geopolymer, which has high fluidity and confinement performance, and incorporates neutron absorption capability through boron addition, for the stabilization and solidification of radioactive waste from fuel debris and contaminated water treatment. In this year, the research focused on the design and evaluation of metakaolin geopolymer with and without boron, the interaction between metakaolin-based geopolymer and Fe2O3 colloids, the characterization of geopolymer, and the property evaluation of simulated waste solidification samples. The influence of metakaolin's particle size and firing temperature on its leaching rate, and fluidity, hardening properties of geopolymer was investigated in detail. Additionally, the effects of boron addition in alkaline solution properties and extended hardening time were confirmed. In the interaction with colloids, the confinement of colloids and dimensional changes within the geopolymer were evaluated. Furthermore, solidification samples with simulated waste were prepared, and viscosity changes during the curing process were measured. Hardening time and temperature changes during curing were measured. Compression strength measurements and -ray irradiation tests were also conducted, and through the measurement of hydrogen generation, important basic data on the properties of the solidified bodies were obtained. In research promotion, collaboration with Hokkaido University, JAEA, Sobueclay Co. Ltd., and the University of Sheffield was strengthened through regular meetings and data sharing, and plans for the following years were finalized. Additionally, a human resource development program was launched.

Development of evaluation method for diffusion and filtration behavior of colloid in compacted bentonites using dendrimers

Endo, Takashi*; Tachi, Yukio; Ishidera, Takamitsu; Terashima, Motoki

Nihon Genshiryoku Gakkai Wabun Rombunshi, 20(1), p.9 - 22, 2021/03

https://doi.org/10.3327/taesj.J20.001

Evaluation method of colloid diffusion and filtration in compacted bentonites was developed using dendrimers. Diffusion and filtration behavior of PAMAM dendrimers with the size of 5.77.2nm was investigated by the through-diffusion experiment in bentonite compacted to 0.8 Mg/m and saturated with 0.0050.5mol/L NaCl. Effective diffusivities (De) and filtration ratios (Rf) of dendrimers were determined from the breakthrough curves and the depth profiles in compacted bentonite, respectively. The De values of negatively charged dendrimer increased when porewater salinity increased and dendrimer size decreased as influenced by anion exclusion effect in negatively charged clay surfaces. The Rf values increased when porewater salinity decreased and dendrimer size increased, demonstrating significant fractions of dendrimer were filtered by narrow pores in complex pore networks. These trends consistent with the previous studies emphasize the validity of the evaluation method using dendrimer.

Association of dissolved radionuclides released by the Chernobyl accident with colloidal materials in surface water

Matsunaga, Takeshi; Nagao, Seiya*; Ueno, Takashi; Takeda, Seiji; Amano, Hikaru; Tkachenko, Y.*

Applied Geochemistry, 19(10), p.1581 - 1599, 2004/10

https://doi.org/10.1016/j.apgeochem.2004.02.002

The association of dissolved Sr, Pu and Am with natural colloids was investigated in surface waters in the Chernobyl nuclear accident area by means of ultrafiltration. Results suggest that Pu and Am isotopes were preferentially associated with dissolved humic substances (HS) of high molecular size. A model calculation of the complexation of Pu and Am with HS also supported the above. This study has expanded our understanding of the general role of natural organic colloids in dictating the chemical form of actinides in the surface aquatic environment.

RBS/channeling, XRD and optical characterization of deep ion implantation into single crystalline SiO

Dai, Z.*; Yamamoto, Shunya; Naramoto, Hiroshi; Narumi, Kazumasa; Miyashita, Atsumi

1998 International Conference on Ion Implantation Technology Proceedings, Vol.2, p.1159 - 1162, 1998/06

https://doi.org/10.1109/IIT.1998.813889

no abstracts in English

Preparation of ThO sols suitable for gelation into microspheres in CCl-ammonia media

;

Journal of Nuclear Science and Technology, 22(11), p.915 - 921, 1985/00

https://doi.org/10.3327/jnst.22.915

no abstracts in English

On the particle size distribution of hydrolyzed plutonium(IV) polymer

;

Journal of Radioanalytical and Nuclear Chemistry, 84(2), p.269 - 275, 1984/00

https://doi.org/10.1007/BF02036966

no abstracts in English

Sol Production Apparatus of pH Control Type

; ; Shiba, Koreyuki

JAERI-M 9477, 26 Pages, 1981/05

JAERI-M-9477.pdf:1.05MB

no abstracts in English

Studies on the behavior of carrier-free radioisotopes, 8; On the problem of radiocolloidal silver in aqueous solution

;

Radiochimica Acta, 24(1), P. 49, 1977/01

no abstracts in English

Colloidal Li metal in neutron-irradiated LiF crystals

Journal of the Physical Society of Japan, 18(11), p.1703 - 1703, 1963/00

https://doi.org/10.1143/JPSJ.18.1703

no abstracts in English

Groundwater colloid properties in sedimentary rocks; Preliminary results from the Horonobe URL

Sasamoto, Hiroshi; Ohara, Shigeru*

no journal, , 

In the present study, a non-destructive technique using Particle Tracking Analysis (PTA) has been tested to determine size distribution and concentration of colloids in groundwater. The groundwaters were sampled from water-rings (4 samples) located in the vertical shafts and boreholes (6 samples) drilled in the drifts of the Horonobe URL. Results suggest that colloid particle concentrations range from 9.110 to 7.810 particle/mL (pt/mL) and the estimated colloid mass concentrations range from 3.410 to 4.2 mg/L for the diameter of 1 to 1000 nm, respectively. Colloid concentrations of groundwater sampled from water-rings are generally higher than those sampled from boreholes due to differences in groundwater sampling conditions. For sizes 100 nm of particles, colloid stability was evaluated on the basis of DLVO theory. DLVO theory predicts that particle sizes 100 nm would be unstable (i.e., coagulation could occur). Particle and mass colloid concentrations in the groundwater were therefore reevaluated to obtain the reliable colloid particle concentrations range from 5.810 to 3.010 pt/mL and colloid mass concentrations range from 2.010 to 1.310 mg/L for the diameter range 100 nm, respectively. Furthermore, the reevaluated results indicate a negative correlation between colloid concentrations and IS of groundwater.