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Komuro, Michiyasu; Kanazawa, Hiroyuki; Kokusen, Junya; Shimizu, Osamu; Honda, Junichi; Harada, Katsuya; Otobe, Haruyoshi; Nakada, Masami; Inagawa, Jun
JAEA-Technology 2021-042, 197 Pages, 2022/03
JAEA-Technology-2021-042.pdf:16.87MB
Plutonium Research Building No.1 was constructed in 1960 for the purpose of establishing plutonium handling technology and studying its basic physical properties. Radiochemical research, physicochemical research and analytical chemistry regarding solutions and solid plutonium compounds had been doing for the research program in Japan Atomic Energy Agency (JAEA). In 1964, the laboratory building was expanded and started the researching plutonium-uranium mixed fuel and reprocessing of plutonium-based fuel, playing an advanced role in plutonium-related research in Japan. Since then, the research target has been expanded to include transplutonium elements, and it has functioned as a basic research facility for actinides. The laboratory is constructed by concrete structure and it has the second floor, equipped with 15 glove boxes and 4 chemical hoods. Plutonium Research Building No.1 was decided as one of the facilities to be decommissioned by Japan Atomic Energy Agency Reform Plan in September 2014. So far, the contamination survey of the radioactive materials in the controlled area, the decontamination of glove boxes, and the consideration of the equipment dismantling procedure have been performed as planned. The radioisotope and nuclear fuel materials used in the facility have been transfer to the other facilities in JAEA. The decommissioning of the facility is proceeding with the goal of completing by decommissioning the radiation controlled area in 2026. In this report, the details of the decommissioning plan and the past achievements are reported with the several data.
Tamura, Koji*; Toyama, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 62(5), p.268 - 271, 2020/05
The laser cutting technology is expected to be a promising candidate for the decommissioning measure of nuclear facilities, because it has a lot of advantage such as its high controllability and excellent suitability to remote handling by robot arm, etcetera. This report describes the recent result from laser cutting technology development for thick steel materials summarizing the cutting demonstration of 300 mm thick steels and dummy pressure vessel, the analysis of cutting condition of thick steel cutting, the observation of cutting process, remote controlled cutting system, the cutting in pile of steels by the system, and countermeasure for fume produce by cutting process.
Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.
JAEA-Review 2016-008, 98 Pages, 2016/07
JAEA-Review-2016-008.pdf:11.73MB
Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.
Iwai, Hiroki; Nakamura, Yasuyuki; Mizui, Hiroyuki; Sano, Kazuya; Morishita, Yoshitsugu
Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08
The reactor of FUGEN is characterized by its tube-cluster construction that contains 224 channels arranging both the pressure and the calandria tubes coaxially in each channel. And the periphery part of the core has the laminated structure of up to 150 mm thickness of carbon steel for radiation shielding. Method for dismantling the reactor core is also being studied with considering processes of dismantlement by remote-handling devices under the water for the radiation shielding. In order to shorten the term of the reactor dismantlement work and reduce the secondary waste, some cutting tests and literature research for various cutting methods had been carried out. As the result, the laser cutting method, which has feature of the narrow cutting kerf and the fast cutting velocity, was mainly selected for dismantling the reactor. In this presentation, current activities of FUGEN decommissioning and R&D of laser cutting tests are introduced.
Mimura, Ryuji; Muraguchi, Yoshinori; Nakashio, Nobuyuki; Nemoto, Koichi; Shiraishi, Kunio
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05
The JAERI's Reprocessing Test Facility (JRTF) was the first engineering-scale reprocessing facility constructed in Japan. The JRTF was operated from 1968 to 1969 to reprocess spent fuels from the Japan Research Reactor No.3 (JRR-3). As a result of the operation (total 3 runs) by PUREX process, 200 g of highly purified plutonium (Pu) were extracted. In this operation, about 70 m
of liquid waste was generated and part of this waste, which including Pu, with relatively high radioactivity, was stored in six large tanks. After shutdown of the facility, the JRTF decommissioning program was started in 1990 to develop decommissioning technologies and to obtain experiences and data on dismantling of fuel cycle facilities. Liquid waste in the tanks was treated from 1982 to 1998. Dismantling of tanks started in 2002. The tanks were installed in narrow concrete cells and inside of the cell was high dose area. Dismantling method for the tank is important factor to decide manpower and time for dismantlement. In this paper, in-situ dismantling of the liquid waste storage tank and its preparation work are discussed.
Mizukoshi, Seiji; Oshima, Soichiro; Shimada, Taro
JAERI-Tech 2005-011, 122 Pages, 2005/03
JAERI-Tech-2005-011.pdf:13.25MB
The radiological and physical characteristic on decommissioning, such as component and structure weights and radioactivity of the 1.1 MWe class reference nuclear power plants summarized in the NUREG reports of the US NRC were classified,arranged and compared with the domestic commercial nuclear power plants and JPDR from a view point of dismantling plan and waste management for decommissioning. As the results, it was found that the radioactive component and structure weights was about 28,000ton、and non-radioactive structure weights was about 124,000ton less than the domestic commercial BWR. And it was found that this differences has mainly influenced dismantling costs for decommissioning. Farther, it was found that the concrete element composition rates of B, Ni, Nb and so were differerence of one or more figures btween the reference nuclear power plants and the domestic commercial PWR or JPDR.Also,it was found that the this difference became about two or three times by radioactivity concentration and has mainly influenced transport and disposal costs for decommissioning.
Akutsu, Atsushi; Kishimoto, Katsumi; Sukegawa, Takenori; Shimada, Taro
JAERI-Tech 2003-090, 75 Pages, 2004/01
JAERI-Tech-2003-090.pdf:6.83MB
The Japan Research Reactor No.1 (JRR-1) that was constructed first in Japan was permanently shut down after operation from 1957 to 1968. At present, the reactor part is in safe store conditions. The JRR-1 facility is being used as an exhibition room for the time being, and will be dismantled in the future. In consideration of future dismantling of the facility, the radioactive inventory in reactor part was calculated using computer codes that are Two-Dimensional Discrete Ordinates Transport Code (DORT) and Oak Ridge Isotope Generation and Depletion Code (ORIGEN-MD). The average concentration of radioactivity is estimated to be 6.40
Bq/g in the core tank as of April, 2002. It is also expected that the low level waste (LLW) weights approximately 400kg and very low level waste (VLLW) weights approximately 14,000kg, and the waste which doesn't need to deal as a radioactive material weights approximately 250,000kg.
Yanagihara, Satoshi; Tachibana, Mitsuo; Miyajima, Kazutoshi
Proceedings of International Conference; Decommissioning Challenges (CD-ROM), 8 Pages, 2003/00
Several decommissioning projects are on going and studies on decommissioning issues are in progress in JAERI. The JPDR and JRTF decommissioning projects have been set up as demonstration programs for future decommissioning large nuclear facilities. Therefore, efforts have been made not only to dismantle the facilities but also to collect data and lessons learnt on dismantling activities. The data and lessons learnt have been analyzed to produce the database for future decommissioning projects by categorizing into manpower expenditure, radiation dose and waste generation in project data, and safety aspect, waste management, work efficiency considerations in lessons learnt. respectively. The feedback experience has been effectively contributed to various areas on decommissioning such as studies on regulatory systems and planning of other dismantling projects. This paper deals with decommissioning experience and lessons learned in JAERI.
Tachibana, Mitsuo; Shimada, Taro; Yanagihara, Satoshi
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.489 - 492, 2002/06
A remote dismantling robot was developed for decommissioning in nuclear facilities. The remote dismantling robot consists of two electrical powered manipulators, end-effectors and a control system. To realize stable dismantling operation remotely, the remote dismantling robot is designed from view point of proper control in coping with different activity conditioning by feedback of image and of force to the control system. The image feedback was considered to obtain accurate positioning of the end-effectors and the force feedback was considered to supply proper force for direct interaction with an object. Motion tests were performed to verify the remote dismantling robot and its control system. As a result, it was confirmed that the remote dismantling activities such as cutting, radioactivity measurement, decontamination were conducted efficiently by using the image feedback and the force feedback.
Nakamura, Hisashi; Nakashima, Mikio
JAERI-Tech 2002-006, 58 Pages, 2002/03
JAERI-Tech-2002-006.pdf:2.56MB
Radiation exposure was estimated on production and utilization of recycled items using dismantling waste by assuming that their usage are restricted to nuclear facilities. The radiation exposure attributed to production of a steel-plate cast iron waste container, a receptacle for slag, and a drum reinforcement was calculated to be in the range of several 
Sv to several tens of Sv even in recycling contaminated metal waste of which radioactivity concentration of Co-60 is higher than the clearance level by a factor of two figures. It is also elucidated that casting of a multiple casting waste package meets the standards of dose equivalent rate for the transport of a radioactive package and the weight of the package will be able to kept around 20 tons for the convenience of the handling, in case of disposal of metal waste less than 37MBq/g with the steel-plate cast iron waste container. As the results, from the radiological exposure's point of view, it should be possible to use slightly contaminated metal for recycled items in waste management.
Yanagihara, Satoshi
Dekomisshoningu Giho, (25), p.2 - 11, 2002/03
no abstracts in English
Kimura, Masanori; Myodo, Masato; Okane, Shogo; Miyajima, Kazutoshi
Proceeding of International Waste Management Symposium 2002 (WM '02) (CD-ROM), 14 Pages, 2002/00
no abstracts in English
Shiraishi, Kunio; Sukegawa, Takenori; Yanagihara, Satoshi
JAERI-Data/Code 2001-028, 86 Pages, 2001/11
JAERI-Data-Code-2001-028.pdf:6.31MB
The data on worker dose in dismantling of the Japan Power Demonstration Reactor (JPDR) was analyzed to characterize its features. It was appeared from the study that the collective dose to the workers was 306 man-mSv, in which maximum individual dose was 8.5 mSv, almost all doses were received in the activities for dismantling of reactor internals, the reactor pressure vessel and the biological shield, and that the worker dose distribution was similar to that in the maintenanee of the facilities which was characterized by the hybrid log normal distribution model. Farthermore, it was found that the dismantling activities were categorized into three groups depending on dose rates in workplaces, then contribution factors for radiation exposure in terms of dose rates in different groups were derived based on the analysis. The study would be useful for estimation of worker dose in future decommissioning of commercial nuclear power plants in Japan.
Yanagihara, Satoshi; Oshima, Soichiro; Sukegawa, Takenori; Tanabe, Norio*; Takaya, Junichi*; Kiuchi, Yoshio*; Yokota, Shuichi*
Nihon Genshiryoku Gakkai-Shi, 43(5), p.493 - 502, 2001/05
Times Cited Count：1 Percentile：12.01(Nuclear Science & Technology)no abstracts in English
Tachibana, Mitsuo; Shiraishi, Kunio; Yanagihara, Satoshi
JAERI-Tech 2001-014, 42 Pages, 2001/03
In the JPDR dismantling demonstration project, the dismantling activities were conducted for the purpose of verification of remote dismantling machines and collection of various kinds of data on work activities. These lessons were categorized into safety consideration, waste treatment and work efficiency by analyzing the data on work activities. Exemplified are necessities of facility information, efficiency of mock-up tests for evaluation of remote dismantling procedures. There will be useful for implementing other decommissioning projects in safe and efficiency. This report describes the measure taken for remote dismantling activities and the lessons learned from the dismantling activities.
Yanagihara, Satoshi; Sukegawa, Takenori; Shiraishi, Kunio
Journal of Nuclear Science and Technology, 38(3), p.193 - 202, 2001/03
no abstracts in English
Tachibana, Mitsuo; Shimada, Taro; Yanagihara, Satoshi
Proceedings of International Waste Management Symposium '00 (Waste Manegement '00) (CD-ROM), 9 Pages, 2000/02
no abstracts in English
Shiraishi, Kunio; Sukegawa, Takenori; Yanagihara, Satoshi
JAERI-Data/Code 99-050, p.113 - 0, 2000/01
JAERI-Data-Code-99-050.pdf:5.95MB
no abstracts in English
Kobayashi, Makoto
Hoken Butsuri, 34(4), p.412 - 414, 1999/12
no abstracts in English
Tachibana, Mitsuo; Hatakeyama, Mutsuo; Yanagihara, Satoshi
Nihon Genshiryoku Gakkai-Shi, 41(6), p.677 - 685, 1999/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
