Experiences in dismantlement of gloveboxes for wet recovery and other use that are contaminated with nuclear fuel materials

Kitamura, Akihiro; Hirano, Hiroshi*; Yoshida, Masato; Takeuchi, Kentaro

Hoken Butsuri (Internet), 58(2), p.76 - 90, 2023/08

https://doi.org/10.5453/jhps.58.76

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.

Decommissioning state of Plutonium Fuel Fabrication Facility; Dismantling the glove box W-9 and equipment interior, and a part of tunnel F1

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

Safety improvements in demolition and removal activities with air-fed suit for Plutonium Fuel Facility Decommissioning

Kikuchi, Haruka; Hirano, Hiroshi*; Kitamura, Akihiro

Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(1), p.50 - 63, 2022/03

https://doi.org/10.3327/taesj.J20.035

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.

Status and future plan of decommissioning of the Plutonium Fuel Fabrication Facility

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.

Waste handling activities in glovebox dismantling facility

Kitamura, Akihiro; Okada, Takashi; Kashiro, Kashio; Yoshino, Masanori*; Hirano, Hiroshi*

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.531 - 536, 2007/09

We present our waste handling activities in glovebox dismantling facility, installed in Plutonium Fuel Production Facility, Nuclear Fuel Cycle Engineering Laboratories, JAEA. In this facility, we treat only one size gloveboxes (3m3m1m), but for the future waste treatment, we segregate waste into material categories. We analyzed the data collected for the future decommissioning, waste treatment and waste disposal. We also present the improvements which are already made and will be made in the near future.

Development of plastic enclosure tents for body contamination

Aita, Takahiro; Hirano, Hiroshi*; Kimura, Yasuhisa; Shibanuma, Tomohiro; Yoshida, Masato; Nagai, Yuya; Asakawa, Jun; Shuji, Yoshiyuki

no journal, , 

The newly developed Plastic enclosure tents have reliable airtightness and can be set up in a short time with the small number of persons. Also, in order to prevent the spread of contamination, the exhaust device secures the internal airflow line, and the radiation management device measures the concentration of radioactive materials in the air are in real time. Furthermore, by setting up a multiple of evacuation routes, the decontamination time is shortened even when there are many contaminated persons. Therefore, it is possible to quickly evacuate the contaminated person by having both radiation safety and setting up that can quickly respond to a large-scale body contamination accident.

物品搬出入システム及び物品搬出入方法

吉田 将冬; 周治 愛之; 川崎 猛; 木村 泰久; 平野 宏志

not registered

JP, 2018-170691  Patent licensing information  Patent publication (In Japanese)

【課題】汚染雰囲気に曝される物を最小限に抑えて、汚染雰囲気に対して物品を安全に搬出入可能な物品搬出入システムを提供する。 【解決手段】物品搬出入システムは、汚染雰囲気を囲って非汚染雰囲気から隔離すると共に、汚染雰囲気及び非汚染雰囲気を連通させる開口が形成されたポートを有する建屋と、物品が載置される載置部、及び把持可能な把持部を有する載置台と、可撓性を有する材料で構成されており、開放された両端部のうち、一方側端部が前記開口を囲むようにポートに接続され、他方側端部が載置部を囲むように載置台に接続される筒状部材と、筒状部材から露出した把持部を把持して、ポートを通じて載置台を建屋に搬入し、さらに建屋から搬出する搬出入装置と、載置台が建屋から搬出された後に、ポートと載置台との間で筒状部材をシールするシール装置とを備えることを特徴とする。

接続テント及び接続テントの組立方法

平野 宏志; 木村 泰久; 柴沼 智博; 會田 貴洋; 永井 佑哉; 浅川 潤; 吉田 将冬; 周治 愛之

南 明則*

JP, 2019-238397  Patent licensing information  Patent publication (In Japanese)

【課題】迅速に組み立て可能な接続テントを提供する。 【解決手段】接続テント(1)は、一対の第1側面フレーム(11、12)及び第1天面フレーム(13)を有する門型フレーム(10)と、第2側面フレーム(21)及び第2天面フレーム(22)を有するL型フレーム(20)と、門型フレーム(10)及びL型フレーム(20)で囲まれた内部空間に収容可能であり、開閉可能な複数の出入口が側面に形成された箱型の部屋テントとを備え、複数の出入口それぞれは、門型フレーム(10)及びL型フレーム(20)の側面に形成された複数の開口のいずれかに対面している。

保持装置

小野 洋輔; 周治 愛之; 平野 宏志; 立原 丈二; 庄司 博行; 田村 健

南 明則*

JP, 2022-000568  Patent licensing information

【課題】全面マスク内で対象物を保持する保持装置において、全面マスクの気密性の維持と、使用者の視界の確保とを両立する技術を提供する。 【解決手段】保持装置(10)は、磁力によって互いに引き合う第1磁性体(11)及び第2磁性体(12)と、対象物を着脱可能に保持する保持部(15)と、第2磁性体(12)から保持部(15)を吊り下げる吊下部(16)とを備える。