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Ikenoue, Tsubasa; Tani, Takashi*; Kawamura, Hideyuki; Sato, Yuhi*
Environmental Science & Technology, 59(38), p.20588 - 20594, 2025/09
Times Cited Count：1 Percentile：47.55(Engineering, Environmental)Since 2023, ALPS-treated water containing tritium from the Fukushima Daiichi Nuclear Power Plant (1F) accident has been released into the ocean. Monitoring of seafood collected near the Fukushima coast has shown negligible increases in the tritium concentration. However, this monitoring has limitations, including delayed data release and a limited sample size. Therefore, a predictive estimation is necessary to assess the potential for high tritium accumulation in seafood. This study estimated tritium concentrations in Japanese flounder near the Fukushima coast using numerical simulations. The estimation combined an oceanic dispersion model for tritiated water (HTO) with a tritium transfer model for the marine food web. Tritium accumulation was evaluated as organically bound tritium (OBT), the long-retaining chemical form of tritium in organisms. First, the dispersion model's ability to reproduce HTO concentrations in seawater was validated using actual measurement data from the Fukushima coast, showing good agreement. Subsequently, the OBT concentrations in flounder were estimated under the hypothetical maximum release scenario of the treated water. The estimation suggested that even within 100 km of 1F, the maximum concentration of the OBT was comparable with natural levels of tritium in environmental waters. Additionally, the maximum concentration in the flounder remained at a negligible level for internal radiation exposure through consumption.
Tagami, Hirotaka*; Okano, Yasushi; Yamano, Hidemasa
Proceedings of 21st International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-21) (Internet), 12 Pages, 2025/08
Toyota, Kodai; Imagawa, Yuya; Onizawa, Takashi; Suzuki, Akihiro*
Proceedings of the ASME 2025 Pressure Vessels & Piping Conference (PVP2025) (Internet), 8 Pages, 2025/07
Shimada, Asako; Hemmi, Ko; Ohira, Saki; Iida, Yoshihisa
Analytical Sciences, 41, p.1383 - 1391, 2025/06
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)Kinoshita, Junichi; Sakamoto, Yu; Suzuki, Ichiro; Nakajima, Ryota; Morita, Yusuke; Irie, Hirobumi
JAEA-Technology 2024-027, 55 Pages, 2025/05
JAEA-Technology-2024-027.pdf:8.49MB
The Waste Treatment Facility No.2 has equipment that can process solid waste with relatively high radioactive levels generated within the Japan Atomic Energy Agency. This facility had been constructed under the old Building Standards Act. Seismic evaluation based on a new regulatory requirements enforced in December 2013 was executed, thereby, it was found that the seismic resistance requirements was insufficient according to the current Building Standards Act. Therefore, seismic reinforcement works was carried out from November 2018 to February 2020. In this report, seismic reinforcement design, works, test and inspection was complied.
Aihara, Jun; Ueta, Shohei; Honda, Masaki*; Kasahara, Seiji; Okamoto, Koji*
JAEA-Research 2024-012, 98 Pages, 2025/02
JAEA-Research-2024-012.pdf:32.24MB
Concept of Pu-burner high temperature gas-cooled reactor (HTGR) was proposed for the purpose of more safely reducing amount of recovered Pu. In Pu-burner HTGR concept, coated fuel particle (CFP), with ZrC coated yttria stabilized zirconia (YSZ) containing PuO
(PuO-YSZ) small particle and with tri-structural isotropic (TRISO) coating, is employed for very high burn-up and high nuclear proliferation resistance. ZrC layer is oxygen getter. In research project of Pu-burner HTGR carried out from fiscal year of 2014 to fiscal year of 2017, simulated CFPs were fabricated using Ce to simulate Pu. Moreover, simulated fuel compacts were fabricated using fabricated simulated CFPs. In this report, results of microstructural observation of CeO-YSZ and ZrC layer at each fabrication step are reported.
Gubarevich, A.*; Kubo, Ryotaro*; Arisaka, Makoto; Osugi, Takeshi; Yoshida, Katsumi*; Takeshita, Kenji*
Journal of Nuclear Science and Technology, 10 Pages, 2025/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)To immobilize and solidify carbonate-based Advanced Liquid Processing System (ALPS) sediment wastes, this study introduces a chemical transformation process that converts these wastes into calcium and magnesium phosphate phases, followed by densification using a novel cold sintering press (CSP) technique. Simulated calcium-magnesium carbonate slurries were treated with phosphoric acid to synthesize calcium and magnesium phosphates, which were then sintered at 300-500
C using CSP. The effects of the calcium-to-magnesium ratio, strontium incorporation, and sodium chloride addition on phase composition and CSP densification were investigated. Dense bulk samples were successfully fabricated and characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and the Archimedes method. The results showed that the chemical transformation process led to the formation of whitlockite and newberyite, with the calcium-to-magnesium ratio determining the relative proportions of these phases. Strontium was effectively incorporated into the whitlockite crystal structure, while newberyite enhanced densification through a dehydration-driven process. Sodium chloride had no effect on chemical transformation and was not found in the final solid product. These results show that direct conversion of calcium-magnesium carbonate slurries to whitlockite-based phosphate ceramics, followed by CSP, enables stable solidification, making this method promising for ALPS sediment waste management.
Mikhail, M. A. G.*; Kin, Tadahiro*; Eto, Taisei*; Tsukada, Kazuaki
Scientific Reports (Internet), 14, p.27132_1 - 27132_10, 2024/11
Times Cited Count：0 Percentile：0.00(Multidisciplinary Sciences)We have studied a straightforward and robust single-step cation exchange separation method to isolate medical copper radioisotopes 
Cu and 
Cu produced in the 
Zn(n, x) reaction with an accelerator neutrons technique. This study revealed the key role of a phosphate buffer pre-treatment of the cation exchange column in the separation process. It was found that incorporating the phosphate buffer into the column pre-treatment markedly enhances the retention of copper isotopes within the column throughout the separation procedure. This approach yields a high-purity radioactive copper sample with a high extraction efficiency of 94.4% of the initially produced copper, all within a relatively short experimental time frame of approximately 5 h for 100 g of starting material.
Terasaka, Yuta; Iimoto, Takeshi*; Saso, Michitaka*; Fujita, Reiko*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 66(4), p.203 - 207, 2024/04
no abstracts in English
Yamashita, Kiyoto; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2023-023, 97 Pages, 2024/03
JAEA-Technology-2023-023.pdf:8.21MB
The incinerator adopted to incineration room, Plutonium Waste Treatment Facility had been demonstrated since 2002 for developing technologies to reduce the volume of fire-resistant wastes such as vinyl chloride (represented by Polyvinyl chloride bags) and rubber gloves for Radio Isotope among radioactive solid wastes generated by the production of mixed oxide fuels. The incinerator, cooling tower, and processing pipes were replaced with a suspension period from 2018 to 2022, which fireproof materials on the inner wall of the incinerator was cracked and grown caused by hydrogen chloride generated when disposing of fire-resistant wastes. This facility consists of the waste feed process, the incineration process, the waste gas treatment process, and the ash removal process. We replaced the cooling tower in the waste gas treatment process from March 2020 to March 2021, and the incinerator in the incineration process from January 2021 to February 2022. In addition, samples were collected from the incinerator and the cooling tower during the removing and dismantling of the replaced devices, observed by Scanning Electron Microscope and X-ray microanalyzer, and analyzed by X-ray diffraction to investigate the corrosion and deterioration of them. This report describes the method of setting up the green house, the procedure for replacing them, and the results from analysis in corrosion and deterioration of the cooling tower and incinerator.
Bess, J. D.*; Chipman, A. S.*; Pope, C. L.*; Jensen, C. B.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato*
Nuclear Science and Engineering, 197(8), p.1845 - 1872, 2023/08
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Pretransient characterization was performed for the EBR-II MOX fuel pellets from the SPA-2/-2B Operational Reliability Testing collaboration between Japan and US. The continued collaboration will investigate the transient performance of these rods in TREAT at Idaho National Laboratory. The results will fill a gap in existing transient performance data for MOX as these rods have a peak burnup of ~134.4 GWd/t in the EBR-II. Fuel pellet properties were gathered from available resources and their irradiation and decay history evaluated. Further reactor physics calculations were performed to support the experiment design, reactor operations, and safety analyses necessary to enable the programmatic success. Of the three irradiated fuel pins, two will undergo transient testing, and all three will undergo post-irradiation examination.
Ota, Hirokazu*; Ogata, Takanari*; Yamano, Hidemasa; Futagami, Satoshi; Shimada, Sadae*; Yamada, Yumi*
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 8 Pages, 2023/05
Hirooka, Shun; Nakamichi, Shinya; Matsumoto, Taku; Tsuchimochi, Ryota; Murakami, Tatsutoshi
Frontiers in Nuclear Engineering (Internet), 2, p.1119567_1 - 1119567_7, 2023/03
Storage of plutonium (Pu)-containing materials requires extremely strict attention in terms of physical safety and material accounting. Despite the emphasized importance of storage management, only a few reports are available in the public, e.g., experience in PuO storage in the UK and safety standards in the storage of Pu-containing materials in the US. Japan also stores more U-Pu mixed oxide (MOX) mostly in powder form. Adopting an appropriate storage management is necessary depending on the characteristics of MOX items such as raw powder obtained by reprocessing of spent Light Water Reactor fuels, research and development on the remains of fuel fabrication, which can contain organic materials, and dry-recycled powder during fuel fabrication. Stagnation in fuel fabrications and experience in degradation of MOX containers during extended period of storage have led to the review of the storage method in the Plutonium Fuel Development Center in Japan Atomic Energy Agency. The present work discusses the various nuclear materials, storage methods, experience in degradation of containers that occur during storage, and strategies for future long-term storage.
Yoshida, Yukihiko
IL Nuovo Cimento, 46(2), p.33_1 - 33_8, 2023/03
Wang, Y.*; Tomota, Yo*; Omura, Takahito*; Gong, W.; Harjo, S.
Materialia, 27, p.101685_1 - 101685_9, 2023/03
Maamoun, I.; Rushdi, M.*; Falyouna, O.*; Eljamal, R.*; Eljamal, O.*
Separation and Purification Technology, 308, p.122863_1 - 122863_16, 2023/03
Times Cited Count：13 Percentile：48.79(Engineering, Chemical)
removal from aqueous solutions; Cost-effectiveness & parametric effectsMaamoun, I.; Eljamal, R.*; Eljamal, O.*
Chemosphere, 312, Part 1, p.137176_1 - 137176_11, 2023/01
Times Cited Count：32 Percentile：85.84(Environmental Sciences)
and nano zero-valent ironIslam, M. S.*; Maamoun, I.; Falyouna, O.*; Eljamal, O.*; Saha, B. B.*
Journal of Molecular Liquids, 370, p.121005_1 - 121005_11, 2023/01
Times Cited Count：60 Percentile：98.70(Chemistry, Physical)Idham, M. F.*; Falyouna, O.*; Eljamal, R.*; Maamoun, I.; Eljamal, O.*
Journal of Water Process Engineering (Internet), 50, p.103289_1 - 103289_16, 2022/12
Times Cited Count：38 Percentile：92.71(Engineering, Environmental)Yamashita, Kiyoto; Yokoyama, Aya*; Takagai, Yoshitaka*; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2022-020, 106 Pages, 2022/10
JAEA-Technology-2022-020.pdf:4.77MB
Radioactive solid wastes generated by Fukushima Daiichi Nuclear Power Station disaster may contain high levels of salt from the tsunami and seawater deliberately released into the area. It is assumed that polyvinyl chloride (PVC) products may be used for decommissioning work and for containment of radioactive wastes in the future. Among the method of handling them, incineration is one method that needs to be investigated as it is good method for reduction and stabilization of wastes. But in order to dispose of Trans-Uranic (TRU) solid waste containing chlorides, it is necessary to select the structure and materials of the facility based on the information such as the movement of nuclides and chlorides in the waste gas treating system and the corrosion of equipment due to chlorides. Therefore, we decided to get various data necessary to design a study of the incineration facilities. And we decided to examine the transfer behavior of chlorides to the waste gas treatment system, the corrosion-resistance of materials in the incineration facilities, and the distribution survey of plutonium in them obtained using the Plutonium-contaminated Waste Treatment Facility (PWTF), Nuclear Fuel Cycle Engineering Laboratories, which is a unique incinerating facility in Japan. This report describes the transfer behavior of chlorides in the waste gas treatment system, the evaluation of corrosion-resistance materials and the distribution survey of plutonium in the incineration facilities obtained by these tests using the Plutonium-contaminated Waste Treatment Facility, Nuclear Fuel Cycle Engineering Laboratories.
