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Journal Articles

Research on activation assessment of a reactor structural materials for decommissioning

Seki, Misaki; Ishikawa, Koji*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Hanakawa, Hiroki; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2018, P. 257, 2019/08

no abstracts in English

Journal Articles

Status of decommissioning of FUGEN Decommissioning Engineering Center

Takiya, Hiroaki; Aratani, Kenta; Awatani, Yuto; Ishiyama, Masahiro; Tezuka, Masashi; Mizui, Hiroyuki

Dekomisshoningu Giho, (59), p.2 - 12, 2019/03

FUGEN Decommissioning Engineering Center received the approval of the decommissioning program in 2008, and we have been progressing the decommissioning. The first phase of decommissioning (Heavy Water and Other system Decontamination Period) finished in May 2018, and FUGEN has entered into the second phase of decommissioning (Reactor Periphery Facilities Dismantling Period). This report outlines the results obtained in the first phase of decommissioning of FUGEN.

Journal Articles

Development of program for improving generativity of staffs in nuclear power plant

Zhao, Q.*; Taruta, Yasuyoshi; Kobayashi, Shigeto*; Hashimoto, Takashi*

Chishiki Kyoso (Internet), 8, p.V13_1 - V13_2, 2018/08

no abstracts in English

JAEA Reports

The User manual of the simplified decommissioning cost estimation code for nuclear facilities "DECOST"

Takahashi, Nobuo; Suekane, Yurika; Sakaba, Ryosuke*; Kurosawa, Takuya*; Sato, Koichi; Meguro, Yoshihiro

JAEA-Testing 2018-002, 45 Pages, 2018/07


The Japan Atomic Energy Agency has many nuclear facilities such as research reactors, nuclear fuel facilities and research facilities. Although these facilities will be decommissioned due to the termination of the purpose of use of the facility and aging, it is necessary to evaluate the decommissioning cost of these facilities prior to the decommissioning. We have developed an evaluation method called DECOST code that can efficiently calculate the decommissioning cost in a short time based on factors such as features, similarity, and dismantling methods. This report is as a manual of the DECOST code prepared for improving convenience. Here, the evaluation formulae used for DECOST are presented and the method of using them is explained for each kind of nuclear facilities to be evaluated. In addition, the preparation method of facility information and dismantled waste amount that are need for evaluation is also shown.

Journal Articles

Challenge to decommissioning of Fukushima Daiichi Nuclear Power Station by applying VR technology

Horiguchi, Kenichi

Gijutsushi, 30(4), p.8 - 11, 2018/04

The verification activity and training of operation in the Fukushima-Daiichi Nuclear Power Station are more important than another Nuclear Power Station. At the JAEA Naraha Remote Technology Development Center, it has being carried out the development work to apply to the decommissioning work by using the full sized mock up and VR system which is built based on location surveying data of inside the reactor building. It is able to contribute to the decommissioning more reliably and efficiently.

Journal Articles

Outline of decommissioning plan of Tokai Reprocessing Plant

Okano, Masanori; Akiyama, Kazuki; Taguchi, Katsuya; Nagasato, Yoshihiko; Omori, Eiichi

Dekomisshoningu Giho, (57), p.53 - 64, 2018/03

The construction of Tokai Reprocessing Plant (TRP) was initiated in June 1971, and its hot test using spent fuel started in September 1977. Thereafter TRP had been operated to reprocess 1,140 tons of spent fuel for approximately 30 years until May 2007, according to the reprocessing contract with domestic electric power companies. JAEA announced a policy of TRP in report of JAEA reform plan published in September 2014. The policy shows that TRP will shift to a decommissioning stage by economic reasons. Based on the policy, application of approval for TRP decommissioning plan was submitted to Nuclear Regulation Authority (NRA) in June 2017. This plan provides basic guidelines such as procedures for decommissioning and specific activities for risk reduction, and implementation divisions of decommissioning, management of spent fuels and radioactive wastes, decommissioning budget, and decommissioning schedule. The process of TRP decommissioning is planned to continue for approximately 70 years until the release of controlled areas of approximately 30 facilities.

Journal Articles

Advanced non-destructive analysis technique capable of rapidly determining uranium mass contained in waste drum with high accuracy

Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi

Nippon Genshiryoku Gakkai-Shi, 59(12), p.700 - 704, 2017/12

no abstracts in English

Journal Articles

Report on OPIC Laser Solutions for Space and the Earth (LSSE 2017)

Ebisuzaki, Toshikazu*; Wada, Satoshi*; Saito, Norihito*; Fujii, Takashi*; Nishimura, Akihiko

Reza Kenkyu, 45(10), p.664 - 665, 2017/10

no abstracts in English

JAEA Reports

Preliminary missions for the decommissioning of the laboratory building No.1 for the plutonium research program

Segawa, Yukari; Horita, Takuma; Kitatsuji, Yoshihiro; Kumagai, Yuta; Aoyagi, Noboru; Nakada, Masami; Otobe, Haruyoshi; Tamura, Yukito*; Okamoto, Hisato; Otomo, Takashi; et al.

JAEA-Technology 2016-039, 64 Pages, 2017/03


The laboratory building No.1 for the plutonium research program (Bldg. Pu1) was chosen as one of the facilities to decommission by Japan Atomic Energy Agency Reform in September, 2013. The research groups, users of Bldg. Pu1, were driven by necessity to remove used equipment and transport nuclear fuel to other facilities from Bldg. Pu1. Research Group for Radiochemistry proactively established the Used Equipment Removal Team for the smooth operation of the removal in April, 2015. The team classified six types of work into the nature of the operation, removal of used equipment, disposal of chemicals, stabilization of mercury, stabilization of nuclear fuel, transportation of nuclear fuel and radioisotope, and survey of contamination status inside the glove boxes. These works were completed in December, 2015. This report circumstantially shows six works process, with the exception of the approval of the changes on the usage of nuclear fuel in Bldg. Pu1 to help prospective decommission.

JAEA Reports

Handbook of advanced nuclear hydrogen safety (1st Edition)

Hino, Ryutaro; Takegami, Hiroaki; Yamazaki, Yukie; Ogawa, Toru

JAEA-Review 2016-038, 294 Pages, 2017/03


In the aftermath of the Fukushima nuclear accident, safety measures against hydrogen in severe accident have been recognized as a serious technical problem in Japan. Therefore, efforts have begun to form a common knowledge base between nuclear engineers and experts on combustion and explosion, and to secure and improve future nuclear energy safety. As one of such activities, we have prepared the "Handbook of Advanced Nuclear Hydrogen Safety" under the Advanced Nuclear Hydrogen Safety Research Program funded by the Agency for Natural Resources and Energy of the Ministry of Economy, Trade and Industry. The concepts of the handbook are as follows: to show advanced nuclear hydrogen safety technologies that nuclear engineers should understand, to show hydrogen safety points to make combustion-explosion experts cooperate with nuclear engineers, to expand information on water radiolysis considering the situation from just after the Fukushima accidents and to the waste management necessary for decommissioning after the accident, etc.

JAEA Reports

Enforcement management system for decommissioning project in Ningyo-toge Environmental Engineering Center; Results of activities in fiscal year 2015

Ema, Akira; Ishimori, Yuu

JAEA-Review 2016-034, 84 Pages, 2017/03


The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency has managed the decommissioning projects since 2013. In 2015, Enforcement Management System (EMS) was established to enforce the project management systematically. The project management based on EMS was started in 2015. This report summarized the state of management activities in FY 2015.

Journal Articles

The Outline of Japan Atomic Energy Agency's Okuma Analysis and Research Center, 1; The Total progress of Labolatory-1 and Labolatory-2

Inoue, Toshihiko; Ogawa, Miho; Sakazume, Yoshinori; Yoshimochi, Hiroshi; Sato, Soichi; Koyama, Shinichi; Koyama, Tomozo; Nakayama, Shinichi

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 7 Pages, 2017/00

Decommissioning of TEPCO's 1F is in progress according to the Roadmap. The Roadmap assigned the construction of a hot laboratory and analysis to the JAEA. The hot laboratory, Okuma Analysis and Research Center consists of the three buildings; Administrative building, the Laboratory-1 and Laboratory-2. The Laboratory-1 and Laboratory-2 are hot laboratories. Laboratory-1 is for radiometric analysis of low and medium level radioactive rubble and secondary wastes. The license of the Laboratory-1's implementation was approved by The Secretariat of the Nuclear Regulation Authority and the construction started in April 2017 and plans an operational start in 2020. Laboratory-2 provides concrete cells, steel cells for the analysis of the fuel debris and high level radioactive rubble. The Laboratory-2's major analysis items is reviewed by review meeting organized of cognoscente.

Journal Articles

Radiochemical analysis of rubble collected from Fukushima Daiichi Nuclear Power Station

Sato, Yoshiyuki; Tanaka, Kiwamu; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

Hoken Butsuri, 51(4), p.209 - 217, 2016/12

A large amount of contaminated rubbles were generated by the accident at the Fukushima Daiichi Nuclear Power Station (F1NPS). For safe decommissioning of F1NPS, it is important to evaluate the composition and concentration of radionuclides in the rubbles. In this paper, to characterize the rubbles collected at F1NPS in Unit-1, Unit-2 and Unit-3, radiochemical analysis was operated. As a result of radiochemical analysis, $$gamma$$-ray-emitting nuclides $$^{60}$$Co, $$^{137}$$Cs and $$^{152,154}$$Eu, $$beta$$-ray-emitting nuclides $$^{3}$$H, $$^{14}$$C, $$^{90}$$Sr and $$^{99}$$Tc, and $$alpha$$-particle-emitting nuclides $$^{238,239+240}$$Pu, $$^{241}$$Am and $$^{244}$$Cm were detected. In contrast, $$^{94}$$Nb and $$^{152}$$Eu concentrations were below the detection limit. Measured radioactive concentrations implied that $$^{3}$$H, $$^{14}$$C, $$^{60}$$Co and $$^{90}$$Sr concentrations depended on $$^{137}$$Cs concentration respectively. This analysis was characterized the radioactivity concentrations of the rubbles.

Journal Articles

Development of air cooling performance evaluation method for fuel debris on retrieval of Fukushima Daiichi NPS by dry method, 1; Outline of research project

Yoshida, Hiroyuki; Uesawa, Shinichiro; Yamashita, Susumu; Nagase, Fumihisa

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11

Journal Articles

Full operation of JAEA Naraha Remote Technology Development Center

Daido, Hiroyuki

Hozengaku, 15(3), p.20 - 25, 2016/10

Naraha Remote Technology Development Center is open for various users to contribute to recovery of the coast area of Fukushima as well as the decommissioning of Fukushima Daiichi Nuclear Power Station. The center is located within a distance of 20 km from the Fukushima Daiichi station. This is the first development center funded by the Government near the Fukushima Daiichi. Many people expect that the center plays a significant role to contribute to the decommissioning of Fukushima Daiichi and recovery of Fukushima area from the hazards. The author describe details of the facility and our plan.

Journal Articles

Activation cross-section file for decommissioning of LWRs

Shibata, Keiichi; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Iwamoto, Osamu

JAEA-Conf 2016-004, p.47 - 52, 2016/09

It is required to estimate radioactive products accurately for the decommissioning of LWRs. We have developed the neutron-induced activation cross-section file for this purpose. The products consist of 227 nuclides with half-lives larger than 30 days and 12 nuclides with very long half-lives. Target nuclei were selected by considering possible paths leading to the required products. The activation cross sections of these targets were taken from JENDL-4.0, JENDL/A-96 and the post JENDL-4.0 evaluations. As a result, we produced the activation cross-section file with 302 nuclides. Comparing with other evaluations, there exists a large difference especially for the capture cross sections leading to meta-stable states. The data will be released in FY2016 after achieving further improvements.

Journal Articles

Tritium decontamination of contaminated system with tritiated heavy water by drying treatment

Kadowaki, Haruhiko; Matsushima, Akira; Nakajima, Yoshiaki

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 6 Pages, 2016/06

Advanced thermal reactor "FUGEN" is a heavy water-moderated boiling light water-cooled pressure tube-type reactor. Because tritium had been generated in the heavy water during the reactor operation, the heavy water system and helium system were contaminated by tritium. The chemical form of the tritium was water molecule in FUGEN. Air-through drying and vacuum drying were applied to the system drying, and it was demonstrated that both methods were effective for drying treatment of heavy water in system. Helium system, low-contamination and non inclusion, could finish the vacuum drying rapidly. However, Heavy water purification system needed long period for drying treatment. The result showed that it needed long period to dry up if the objects include the adsorbent of water such as alumina pellet, resin and silica gel. But it can be accelerated by replacement absorbed heavy water to light water from the result of drying treatment of the rotary type dehumidifier.

JAEA Reports

Enforcement management system for decommissioning project in Ningyo-toge Environmental Engineering Center; Results of activities in fiscal year 2014

Ema, Akira; Miyagawa, Hiroshi; Ishimori, Yuu

JAEA-Review 2016-006, 88 Pages, 2016/03


The Ningyo-toge Environmental Engineering Center of the Japan Atomic Energy Agency had managed the decommissioning project based on the Quality Management System and the Environmental Management System, but found that these systems were unsuitable for project management from several viewpoints. In order to solve these problems, the Task Team for Enforcement Backend Project temporarily managed the decommissioning project in 2013. To enforce the project management systematically, the Research and Development Promotion Section was organized newly in the Environmental Research and Development Department in April 2014, and started the project management. On the other hand, to establish the primary and secondary documents related to the new system, until April 2015 the section has been developing the Enforcement Management System (EMS) to separate from the Quality Management System or the Environmental Management System. This report summarizes the state of these activities in the FY 2014.

JAEA Reports

Current status of a decommissioning project in the Enrichment Engineering Facilities; Results in the first-half of the fiscal year of 2014

Matsumoto, Takashi; Morimoto, Yasuyuki; Takahashi, Nobuo; Takata, Masaharu; Yoshida, Hideaki; Nakashima, Shinichi; Ishimori, Yuu

JAEA-Technology 2015-036, 60 Pages, 2016/01


The Enrichment Engineering Facilities of the Ningyo-toge Environmental Engineering Center was constructed in order to establish the technical basis of the uranium enrichment plant in Japan. Uranium enrichment tests, using natural and reprocessed uranium, were carried out from 1979 to 1990 at two types of plants in the facilities. UF$$_{6}$$ handling equipment and Supplemental equipment in these plants are intended to be dismantled by 2019 in order to make places for future projects, for example, inventory investigation, precipitation treatment, etc. This report shows the basic plan of this decommissioning project and presents the current state of dismantling in the first-half of the fiscal year of 2014, with indicating its schedule, procedure, situation, results, and so on. The dismantled materials generated amounted to 37 mesh containers and 199 drums, and the secondary waste generated amounted to 271.4 kg.

JAEA Reports

Development of ESRAD2 program for estimation of spatial radioactivity distribution based on kriging; User's manual

Ishigami, Tsutomu; Shimada, Taro; Seki, Masaya; Mukai, Masayuki

JAEA-Data/Code 2015-019, 122 Pages, 2015/12


In ensuring compliance with the criterion of site release as the final stage of termination of decommissioning of nuclear facilities, it is supposed to confirm the radioactivity concentration obtained by measurement in the site is less than or equal to the concentration corresponding to the criterion. It is needed to estimate the distribution and mean of radioactivity concentration in the evaluation unit using a number of measured data. It is further needed to compare the estimated result with the concentration corresponding to the criterion of site release and to decide if the evaluation unit should comply with the criterion. The estimated result exhibits uncertainty depending on the number of measurement points, which results in a certain probability of the occurrence of decision error according to the uncertainty. It is important to decide the number of measurement points required by revealing a relationship of the error probability to the number of measurement points for site security. We have developed the ESRAD2 (Estimation of Spatial RadioActivity Distribution program version 2), which is an extended version of the existing ESRAD, for estimating the mean of radioactivity concentration and calculating the number of measurement points required according to the error probability. This report describes a method for ensuring compliance with the criterion of site release, structure and functions, input file format, output examples, execution method of ESRAD2, and sample run with ESRAD2.

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