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Iguchi, Satoshi; Yoshida, Masato; Hirano, Hiroshi*; Kitamura, Akihiro
Nuclear Technology, 15 Pages, 2026/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The size reduced materials resulting from the dismantling of the plutonium-contaminated gloveboxes are eventually packed into the containers as radioactive waste. Conventionally, the execution of this task has been entrusted to workers equipped with air-fed suits, a practice that carries inherent risks, including potential suit damage and inhalation hazards. Moreover, in order to mitigate these risks, the size reduced materials are covered with rags or plastic to enhance safety for workers. However, this approach entails the separation of non-flammable waste and flammable waste during the disposal process. To circumvent these issues, we have designed a glove operation compartment that enables waste handling and packing activities through glove operations instead of air-fed suits. This reduces the risks associated with air-fed suit operations and eliminates the need to cover size reduced materials with rags and plastic. The procedure involves packing the size reduced materials into metal cans, weighing the cans, and storing them in the containers. We tested these operations using the compartment's test bed and modified them through mock-up experiments to ensure feasibility. This report presents the features of the glove operation compartment, the assumed handling procedures, and the insights obtained from the test results.
Nagai, Yuya; Kimura, Yasuhisa; Takeuchi, Kentaro; Shuji, Yoshiyuki; Kawasaki, Takeshi; Hirano, Koji*; Tomiyama, Noboru*; Usui, Yasuhiro*; Nidaira, Seiichiro*; Shinozaki, Tomohiro*; et al.
JAEA-Technology 2025-003, 110 Pages, 2025/10
JAEA-Technology-2025-003.pdf:11.5MB
Japan Atomic Energy Agency (JAEA) manages wide range of nuclear facilities. Many of these facilities are required to be performed adjustment with the aging and complement with the new regulatory standards and the earthquake resistant, since the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident. It is therefore desirable to promote decommissioning of facilities that have reached the end of their productive life in order to reduce risk and maintenance costs. However, the progress of facility decommissioning require large amount of money and radioactive waste storage space. In order to address these issues, JAEA has formulated a "The Medium/Long-Term Management Plan of JAEA Facilities" with three pillars: (1) consolidation and prioritization of facilities, (2) assurance of facility safety, and (3) back-end countermeasures. In this plan, Plutonium Fuel Fabrication Facility has been selected as primary decommissioned facility, and dismantling of equipment in the facilities have been underway. The following gloveboxes were dismantled between March 2020 and March 2022: Glovebox No. W-4, which houses the roasting furnace, washing and dewatering tank, and washing waste tank; Glovebox No. W-5, which houses the weighing tank; Glovebox No. W-6-1, which houses the flocculation-sedimentation tank, slurry-receiving tank, neutralization tank, and receiving tank; and Glovebox No. W-6-2, which houses the adjustment tank, adjustment liquid agitator, adsorption tower, discharge tank, discharge tank agitator, and adsorption tower. This report summarizes the results of the work and the findings obtained through the dismantling of these gloveboxes.
Iguchi, Satoshi; Yoshida, Masato; Hirano, Hiroshi*; Wada, Masaomi*; Mori, Yoshihito*; Kitamura, Akihiro
Journal of Robotics and Mechatronics, 37(4), p.973 - 983, 2025/08
In nuclear fuel fabrication facilities, gloveboxes are typically dismantled manually. The integration of remotely controlled equipment, comprising a robot arm and a size reduction tool, can enhance work efficiency and mitigate radiation exposure risks in dismantling operations. The hydraulic cutter is regarded as a highly effective tool for reducing the size of steel frame structures, which are commonly composed of gloveboxes. However, when an object is severed by a hydraulic cutter fixed to a robot arm, the resultant reaction force may compromise the integrity of the robot arm or nearby structures. Consequently, in this study, we designed and manufactured a buffer device that can loosely hold the cutter to automatically align the object and absorb the reaction force. Furthermore, a visual support system was developed to assist the operator in performing remote dismantling operations. This system utilized a 3D viewer to project the robot arm, the buffer device, and the working environment. The functionality of the buffer device and 3D viewer was evaluated for the glovebox test bed. The experimental results satisfactorily confirmed the functionality of the buffer device to self-align the object and absorb sudden movements of the hydraulic cutter. Moreover, the 3D viewer provided the robot arm operator with an unobstructed perspective of the work environment, thereby confirming the efficacy of the visual support system in facilitating remote dismantling operations.
Asakawa, Jun; Kimura, Yasuhisa; Hirano, Hiroshi*; Kitamura, Akihiro
Hoken Butsuri (Internet), 60(1), p.63 - 73, 2025/04
Yoshida, Masato; Iguchi, Satoshi; Hirano, Hiroshi*; Kitamura, Akihiro
Nuclear Engineering and Design, 431, p.113691_1 - 113691_16, 2025/01
Times Cited Count：3 Percentile：51.35(Nuclear Science & Technology)The Plutonium Fuel Fabrication Facility is currently in the decommissioning phase, with glovebox dismantling operations ongoing since 2010. During conventional glovebox dismantling operations, the glovebox to be dismantled is enclosed within plastic tents to contain contamination. The glovebox is then dismantled by workers wearing air-fed suits with thermal or mechanical cutting tools, which typically generate dross or sparks in the form of radioactive aerosols during cutting. Despite the longevity and meticulous organization of this manual method, the workload remains considerable, while the allowable working time is limited. In addition, the potential for inhalation exposure to plutonium is elevated in the event of an accident given the contamination of the work area. To overcome disadvantages associated with conventional glovebox dismantling methods, new methods are currently being developed. The primary objective is to reduce the reliance on operation based on air-fed suits and enhance worker safety by introducing remote equipment and a new floor-reinforcing panel. Another objective is to suppress waste generation by reusing all equipment on multiple occasions which is achieved by developing a containment system that have a large open port with a pallet for the storage and reuse of equipment for successive operations. Furthermore, a glove operation compartment is designed and tested for the manual handling of dismantled materials as an additional strategy to reduce work based on air-fed suits and mitigate secondary waste generation.
Nagai, Yuya; Kimura, Yasuhisa; Hirano, Hiroshi*; Kitamura, Akihiro
Hoken Butsuri (Internet), 59(4), p.168 - 181, 2024/12
We have dismantled one glovebox that stood very near at the wall of a controlled room and a part of one transfer tunnel that penetrated walls of control rooms. We have developed new containment boundaries because conventional tent enclosure cannot be applied to these objects. In this report, we present the features of new containment boundaries and dismantlement procedures we have developed and the details of the dismantlement activities we have implemented.
Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.
Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02
Times Cited Count：13 Percentile：75.01(Multidisciplinary Sciences)Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C
fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which 
-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).
Kitamura, Akihiro; Hirano, Hiroshi*; Yoshida, Masato
Nuclear Engineering and Design, 411, p.112435_1 - 112435_14, 2023/09
Times Cited Count：5 Percentile：57.44(Nuclear Science & Technology)This study presents the features and brief history of the glovebox dismantling facility and the primary dismantlement results. Subsequently, we evaluate the novelties of the facility from operational experiences in manual and remote glovebox dismantlement methods and discuss their characteristics. Furthermore, we evaluate the worker exposure dose based on the obtained data. Finally, we show how these experiences are effectively fed back to the technological dismantlement development for our decommissioning project.
Shibanuma, Tomohiro; Hirano, Hiroshi*; Kimura, Yasuhisa; Aita, Takahiro; Yoshida, Masato; Nagai, Yuya; Kitamura, Akihiro
Hoken Butsuri (Internet), 58(2), p.91 - 98, 2023/08
We developed new containment tents that are more easily assembled and effectively functioned, by improving and refurbishing the shortcomings of the conventional tents. The new tents have been already tested in the real airborne contamination situation occurred at the plutonium fuel fabricating facility. The tents appropriately functioned for intended use but other shortcomings emerged and therefore we had modified the structure of the tents further.
Kitamura, Akihiro; Hirano, Hiroshi*; Yoshida, Masato; Takeuchi, Kentaro
Hoken Butsuri (Internet), 58(2), p.76 - 90, 2023/08
The alpha contaminated gloveboxes have been dismantled for over 20 years in Plutonium Fuel Fabrication Facility. The so called wet recovery equipment gloveboxes, which recover plutonium and uranium from scrap fuel by dissolving and extracting processes, were chosen as the priority gloveboxes to be dismantled. These gloveboxes and other gloveboxes in the same room were size reduced and removed up until 2022. Also, non-radioactive ancillary facility and non-radioactive giant glovebox were removed from 2007 to 2010 for ease of glovebox dismantling activities that follows and for making waste storage spaces. Several incidents were occurred and recidivism prevention measures were implemented on each occasion. In this report, glovebox dismantling activities we conducted in the past 20 years are reviewed and lessons we have learned are summarized.
Nagai, Yuya; Shuji, Yoshiyuki; Kawasaki, Takeshi; Aita, Takahiro; Kimura, Yasuhisa; Nemoto, Yasunori*; Onuma, Takeshi*; Tomiyama, Noboru*; Hirano, Koji*; Usui, Yasuhiro*; et al.
JAEA-Technology 2022-039, 117 Pages, 2023/06
JAEA-Technology-2022-039.pdf:11.96MB
Japan Atomic Energy Agency (JAEA) manages wide range of nuclear facilities. Many of these facilities are required to be performed adjustment with the aging and complement with the new regulatory standards and the earthquake resistant, since the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident. It is therefore desirable to promote decommissioning of facilities that have reached the end of their productive life in order to reduce risk and maintenance costs. However, the progress of facility decommissioning require large amount of money and radioactive waste storage space. In order to address these issues, JAEA has formulated a "The Medium/Long-Term Management Plan of JAEA Facilities" with three pillars: (1) consolidation and prioritization of facilities, (2) assurance of facility safety, and (3) back-end countermeasures. In this plan, Plutonium Fuel Fabrication Facility has been selected as primary decommissioned facility, and dismantling of equipment in the facilities have been underway. In this report, size reduction activities of the glove box W-9 and a part of tunnel F-1, which was connected to W-9, are presented, and the obtained findings are highlighted. The glovebox W-9 had oxidation & reduction furnace, and pellet crushing machine as equipment interior. The duration of activity took six years from February 2014 to February 2020, including suspended period of 4 years due to the enhanced authorization approval process.
Asakawa, Jun; Hirano, Hiroshi*; Nagai, Yuya; Aita, Takahiro; Shibanuma, Tomohiro; Kimura, Yasuhisa
Hoken Butsuri (Internet), 57(2), p.93 - 101, 2022/09
In the dismantling work of glove boxes (GBs) contaminated with radioactive materials at the nuclear fuel facilities, plastic tents are constructed around the entire GBs, and workers putting on air-fed suits (AFS) (hereinafter referred to as AFS worker) dismantle the GBs and interior equipment by using cutting tools. If an AFS worker suddenly feels sick during the work and the worker is unable to move independently, it will be necessary to exit in the shortest time from the viewpoint of respecting human life. In this case, a lot of radioactive materials may be brought into the contamination control room, thus the room and the equipment of the workers may be contaminated. Consequently, until the decontamination work is completed, the other AFS workers will have to put on AFS and wait for long time, which puts a strain on the workers. In this report, the plastic enclosure tents for body decontamination developed in JAEA were used as a new contamination control room replaced the contaminated one, and the procedure to quickly exit the remaining AFS workers was proposed. As a result, we confirmed that it was possible to greatly reduce the waiting time of the other AFS workers who is forced to wait in the dismantling area.
Kikuchi, Haruka; Hirano, Hiroshi*; Kitamura, Akihiro
Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(1), p.50 - 63, 2022/03
The air fed suit is a kind of personal protective equipment that provides purified air through a hose and that protects a worker from radiation hazards. In the Nuclear Fuel Cycle Engineering Laboratories of the JAEA, the suit is used for size reduction and dismantlement of radioactively contaminated, in particular with plutonium, gloveboxes and equipment. Although the suit has been widely adopted in the similar activities, there still exist potential hazards due to the limiting features of the suit itself and its supplemental system. In fact, we had faced with several unexpected problems regarding such restricted aspects during the dismantling activities. To address these failure potentials, we have implemented various countermeasures and improvements to enhance the workers safety. We describe the disadvantages of the air fed suit system and positive feedbacks we have implemented.
Amekura, Hiroshi*; Toulemonde, M.*; Narumi, Kazumasa*; Li, R.*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Ishikawa, Norito; Okubo, Nariaki; et al.
Scientific Reports (Internet), 11, p.185_1 - 185_11, 2021/01
Times Cited Count：17 Percentile：65.30(Multidisciplinary Sciences)We report the track formation of 10 nm in diameter in silicon irradiated with 6 MeV C, i.e., much lower energy than the previously reported energy threshold.
and 200 MeV Xe ion irradiationLi, R.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yu*; Tsuya, Daiju*; Yamamoto, Shunya*; Saito, Yuichi*; Okubo, Nariaki; Ishikawa, Norito; Pang, C.*; et al.
Nanotechnology, 31(26), p.265606_1 - 265606_9, 2020/06
Times Cited Count：8 Percentile：32.86(Nanoscience & Nanotechnology)We report the elongation of embedded Au nanoparticles (NPs) in three different matrices under irradiations of 4 MeV C ions and 200 MeV Xe ions. Large elongation of Au NPs was observed for crystalline indium tin oxide (ITO) under both 4 MeV C and 200 MeV Xe irradiation. The ITO layer preserved the crystallinity even after large elongation was induced. This is the first report of the elongation of metal NPs in a crystalline matrix.
Kimura, Yasuhisa; Hirano, Hiroshi; Watahiki, Masatoshi; Kuba, Meiji; Ishikawa, Shinichiro
Dekomisshoningu Giho, (52), p.45 - 54, 2015/09
The Plutonium Fuel Fabrication Facility (PFFF) of the Japan Atomic Energy Agency is now in its decommissioning phase. In the PFFF, terminated gloveboxes have been dismantled. Gloveboxes to be dismantled are surrounded by a plastic enclosure to prevent contamination from being spread into process room. Dismantling operations for gloveboxes are performed manually by workers, each wearing an air-feed suit. However, the mental and physical loads placed on workers wearing the air-feed suits are intensively high. Therefore, R&Ds on new dismantling technologies including utilization of heavy machines covered with plastic enclosure for anti-contamination have been started to reduce the potential risks associated with workers and decommissioning costs. In this paper, the status of decommissioning of the PFFF and the overview of developed dismantling technologies for 
-tight gloveboxes are described.
Sekio, Yoshihiro; Yoshimochi, Hiroshi; Kosaka, Ichiro; Hirano, Hiroyasu; Koyama, Tomozo; Kawamura, Hiroshi
Proceedings of 52nd Annual Meeting of Hot Laboratories and Remote Handling Working Group (HOTLAB 2015) (Internet), 8 Pages, 2015/09
Due to the Fukushima Daiichi Nuclear Power Plant accident in March 2011, the safe and secure implementations of the decommissioning for Fukushima Daiichi Nuclear Power Plant has been positioned as the urgent tasks in Japan. Japan Atomic Energy Agency has a critical mission of analysing radioactive wastes having generated by the accident for long-term storage and disposal methods. This will be performed in two hot laboratories to be constructed in Okuma Analysis and Research Center at Fukushima Daiichi Nuclear Power Plant site. In one laboratory, radioactive wastes such as rubbles and secondary wastes will be treated, whereas debris such as fuel debris and high dose structural materials will be handled in the other laboratory. The detail considerations for advanced techniques and experimental apparatus to be installed are underway.
Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.
Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12
Times Cited Count：8 Percentile：47.19(Physics, Nuclear)We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.
Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Kuba, Meiji; Watahiki, Masatoshi; Hirano, Hiroshi; Ishikawa, Shinichiro; Sato, Hisato
Proceedings of International Waste Management Symposia 2014 (WM2014) (Internet), 12 Pages, 2014/05
Plutonium Fuel Fabrication Facility is now in a decommissioning phase. In the facility, stabilizing activities of nuclear material residuals remained and the gloveboxes dismantling activities have been carried out simultaneously. Glovebox dismantling activities are performed manually by a worker wearing air-feed suit with mechanical tools in a plastic enclosure which is constructed around the glove boxes for preventing spread of contamination. However, the mental load and physical load of the worker are intensively high. Therefore, worker's safely issue still exists and need to be resolved. Moreover, occupational time for the worker is restricted to only one hour per day, which in turn make shortening schedule and cost savings almost impossible. R&D of new dismantling methods including application of heavy equipment with anti-contamination measure to strengthen the work performance in the plastic enclosures has been started to reduce the above mentioned potential risks and costs.
