Tachibana, Mitsuo; Murata, Masato; Tasaki, Tadayuki; Usui, Hideo; Kubota, Shintaro
Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1987 - 1996, 2015/09
230 various types of nuclear facilities were constructed in JAEA's R&D Institutes or Center until the establishment of the JAEA in 2005. The JAEA has efficiently and systematically decommissioned nuclear facilities that would no longer be required after the establishment of the JAEA. Decommissioning of nuclear facilities in each JAEA's R&D Institutes or Center was continued based on the second midterm plan of the JAEA from FY2010 to FY2014. Decommissioning of 2 nuclear facilities was completed during the second midterm. This report describes current status of decommissioning activities in the JAEA during the second midterm and outline of the decommissioning plan in the third midterm.
Tachibana, Mitsuo; Kishimoto, Katsumi; Shiraishi, Kunio
International Nuclear Safety Journal (Internet), 3(4), p.16 - 24, 2014/11
Three research reactors were permanently shut down in the Nuclear Science Research Institute (NSRI) of the Japan Atomic Energy Agency (JAEA) as of October 2014. Safe storage or one-piece removal method was applied to decommissioning of these research reactors depending on decommissioning cost and utilization of facilities and so on. Various kinds of data and experiences were obtained through decommissioning of these research reactors. This report shows data and experiences on the research reactors decommissioning in the NSRI of the JAEA.
Izumo, Sari; Usui, Hideo; Kubota, Shintaro; Tachibana, Mitsuo; Kawagoshi, Hiroshi; Takahashi, Nobuo; Morimoto, Yasuyuki; Tokuyasu, Takashi; Tanaka, Yoshio; Sugitsue, Noritake
JAEA-Technology 2014-021, 79 Pages, 2014/07
Japan Atomic Energy Agency has developed PROject management data evaluation code for DIsmantling Activities (PRODIA) to make an efficient decommissioning for nuclear facilities. PRODIA is a source code which provides estimated value such as manpower needs, costs, etc., for dismantling by evaluation formulas according to the type of nuclear facility. Evaluation formulas of manpower needs for dismantling of equipments about reprocessed uranium conversion in Uranium Refining and Conversion Plant are developed in this report. In the result, 7 formulas for prepare process, 24 formulas for dismantling process and 8 formulas for clean-up process are derived. It is confirmed that an unified evaluation formula can be used instead of 8 formulas about dismantling process of steel equipment for uranium conversion process, and 3 types of simplified formula can be used for preparation process and clean-up process respectively.
Shibahara, Yuji; Usui, Hideo; Izumo, Sari; Izumi, Masanori; Tezuka, Masashi; Morishita, Yoshitsugu; Kiyota, Shiko; Tachibana, Mitsuo
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(3), p.197 - 210, 2013/09
As the first step of the applicability inspection of PRODIA Code for dismantling activities in the decommissioning of FUGEN, manpower needs for dismantling activities in FUGEN conducted in 2008 were calculated with conventional calculation formulas which were made by data obtained from JPDR decommissioning program. Since the conventional calculation formula for dismantling of feedwater heater has no applicability, the new calculation formula was constructed by reflecting the work description of dismantling of feedwater heater in FUGEN. It was found that the calculation results with this new formula showed the good agreement with the actual data both of 3rd feedwater heater and 4th one. Based on this discussion, some case studies for dismantling of feedwater heater were conducted.
Izumo, Sari; Usui, Hideo; Tachibana, Mitsuo; Morimoto, Yasuyuki; Takahashi, Nobuo; Tokuyasu, Takashi; Tanaka, Yoshio; Sugitsue, Noritake
Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 9 Pages, 2013/09
Tachibana, Mitsuo; Izumo, Sari; Sugitsue, Noritake; Park, S.-K.*
DYNATOM (Internet), 2013(4), p.31 - 35, 2013/04
JAEA has the Uranium Refining & Conversion Plant. KAERI has the Uranium Conversion Plant. These CFs have been under decommissioning after their missions completed. Each organization has been developing decommissioning engineering systems to develop effective decommissioning plans and to implement dismantling activities effectively. Therefore, benchmark tests were started in order to verify mutual decommissioning engineering systems. Each organization compared mutual decommissioning engineering system, and compared specification and dismantling procedure of the rotary kiln and management data for dismantling the rotary kiln. Management data for dismantling the rotary kiln in KAERI was calculated by using DENESYS of JAEA. This report describes results of comparisons of dismantling activities of the rotary kiln in JAEA and KAERI, and calculated results by JAEA.
Muraguchi, Yoshinori; Kanayama, Fumihiko; Usui, Hideo; Izumo, Sari; Tachibana, Mitsuo
JAEA-Technology 2012-035, 69 Pages, 2012/12
Dismantling activities of equipment in JAEA's Reprocessing Test Facility (JRTF) used for wet reprocessing test started from 1996. Glove boxes and hoods installed in the main building were dismantled preferentially for securing temporary place of dismantled waste and dismantling tools by dismantling activities. Of these, 8 glove boxes (glove box group) were installed in room 232 of the main building. The glove box group was dismantled by setting up a large plastic enclosure (greenhouse) for work efficiency. In this report, dismantling procedure and actual data obtained from dismantling activity were arranged about dismantling activity of glove box group of room 232 in 1996. About dismantling activity of glove box group, manpower of the basic work items extracted by classifying into common work items and independent work items were analyzed. In addition, calculation equation was examined concerning dismantling of glove boxes.
Tachibana, Mitsuo; Izumo, Sari; Sugitsue, Noritake; Park, S.-K.*
Proceedings of American Nuclear Society Embedded Topical on Decommissioning, Decontamination and Reutilization and Technology Expo (DD&R 2012) (DVD-ROM), p.107 - 110, 2012/06
JAEA has the Uranium Refining & Conversion Plant. KAERI has the Uranium Conversion Plant. These facilities have been under decommissioning after their missions completed. Each organization has been developing decommissioning engineering systems to develop effective decommissioning plans and to implement dismantling activities effectively. Therefore, benchmark tests were started in order to verify mutual decommissioning engineering systems. This report describes results of comparisons of dismantling activities of the rotary kiln in JAEA and KAERI, and calculated results by JAEA.
Wada, Ken*; Hyodo, Toshio*; Yagishita, Akira*; Ikeda, Mitsuo*; Osawa, Satoshi*; Shidara, Tetsuo*; Michishio, Koji*; Tachibana, Takayuki*; Nagashima, Yasuyuki*; Fukaya, Yuki; et al.
European Physical Journal D, 66(2), p.37 - 40, 2012/02
no abstracts in English
Usui, Hideo; Izumo, Sari; Shibahara, Yuji; Morimoto, Yasuyuki; Tokuyasu, Takashi; Takahashi, Nobuo; Tanaka, Yoshio; Sugitsue, Noritake; Tachibana, Mitsuo
Proceedings of International Waste Management Symposia 2012 (WM 2012) (CD-ROM), 13 Pages, 2012/02
Dismantling of dry conversion facility in the uranium refining and conversion plant at Ningyo-toge began in 2008. During dismantling activities, project management data have been collected. Establishment of the calculation formula for dismantling of each kind of equipment makes it possible to evaluate manpower for dismantling the whole facility. However, it is not easy to prepare calculation formula for all kinds of equipment in the facility. Therefore, a simpler evaluation method was considered to calculate manpower based on facility characteristics. The results showed promise for evaluating dismantling manpower with respect to each chemical process. To create an effective dismantling plan, it is necessary to carefully consider use of a GH preliminarily. Thus, an evaluation method of project management data such as manpower and secondary waste generation was considered. The results showed promise for evaluating project management data of GH by using established calculation formula.
Shibahara, Yuji; Tachibana, Mitsuo; Izumi, Masanori; Nanko, Takashi
JAEA-Technology 2011-010, 44 Pages, 2011/06
Manpower needs for the preparation and clean-up process on the dismantling of equipments in FUGEN 3rd/4th feedwater heater room conducted in 2008 was calculated with the management data evaluation system: PRODIA Code, and it was inspected whether the conventional evaluation model had the applicability for large nuclear facilities such as FUGEN or not. It was confirmed that the conventional evaluation model had no applicability for FUGEN causing by the difference in the plant scale between JPDR and FUGEN bringing the expanding of working area. The difference between the actual data and the calculated value was improved by the reviewing of the evaluation model, and this reviewing process also brought the new evaluation model.
Nakayama, Shinichi; Okoshi, Minoru; Shimada, Taro; Tachibana, Mitsuo; Momma, Toshiyuki; Niibori, Yuichi*; Nagasaki, Shinya*; Ahn, J.*
Genshiryoku Kyokasho "Hoshasei Haikibutsu No Kogaku", 235 Pages, 2011/01
This book is designed to provide everyone with an interest in radioactive waste issues, including students and individuals involved in engineering and public administration, with a graduate-level understanding of radioactive wastes from the scientific foundations that support radioactive waste management covering radioactive waste generation including decommissioning of nuclear facilities, treatment, disposal, clearance and their safety assessment. This book is the one volume of the English translation of the text series "An Advanced Course in Nuclear Engineering" lectured in the University of Tokyo.
Shibahara, Yuji; Tachibana, Mitsuo; Ishigami, Tsutomu; Izumi, Masanori; Nanko, Takashi
JAEA-Technology 2010-033, 42 Pages, 2010/10
Manpower needs for the dismantling process in FUGEN 3rd/4th feedwater heater room was calculated with the evaluation system (PRODIA Code), and it was inspected whether the conventional evaluation model had applicability for FUGEN or not. It was confirmed that the conventional evaluation model for feedwater heater had no applicability. In comparison of the calculated value with the actual data, we found two difference: (1) the evaluated manpower were significantly larger than the actual data, (2) the manpower need for the dismantling of 3rd feedwater heater was twice larger than that of 4th feedwater heater, though these equipments were almost same weight. It was found that these were brought (1) by the difference in the work descriptions of dismantling between JPDR and FUGEN, and (2) by that in the cutting number between 3rd feedwater heater and 4th one. The manpower needs for the dismantling of both feedwater heaters were calculated with a new calculation equation reflecting the descriptions of dismantling, and it was found that these results showed the good agreement with the actual data.
Shibahara, Yuji; Izumi, Masanori; Nanko, Takashi; Tachibana, Mitsuo; Ishigami, Tsutomu
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.347 - 353, 2010/10
Tachibana, Mitsuo; Shiraishi, Kunio; Ishigami, Tsutomu
Nihon Genshiryoku Gakkai Wabun Rombunshi, 9(3), p.271 - 278, 2010/09
DECOST code was developed in consideration of the features and structures of nuclear facilities and the similarity of dismantling methods. DECOST code could calculate 8 items of decommissioning cost. Actual data of dismantling activities was evaluated. Unit conversion factors of general components could be classified into three kinds. The weights of components in the facility and of structures of the facility were necessary for the calculation of the manpower. Methods for evaluating weight of components and structures of the facility were studied. The weight of components in the facility was proportional to weight of structures of the facility. The weight of structures of the facility was proportional to total area of floors in the facility. Decommissioning costs of 7 nuclear facilities are calculated. Outline of DECOST code, evaluation results of unit conversion factors, evaluation method of weight of components and structures were described.
Tachibana, Mitsuo; Ishigami, Tsutomu; Satoyama, Tomonori; Yoshimori, Michiro
Proceedings of 2010 ANS Topical Meeting on Decommissioning, Decontamination and Reutilization & Technology Expo (DD&R 2010) (CD-ROM), p.341 - 344, 2010/08
The clearance level verification evaluation system (CLEVES) has been developed to execute clearance activities efficiently. The SNM which is one of programs of the CLEVES was fabricated for selecting nuclides for measurement and assessment (NMA) based on evaluation of relative importance measure (RIM: nuclide activity divided by clearance level) for nuclides. In addition, case study was carried out by using the SNM based on data concerning clearance activities for concrete generated from the JRR-3. In this report, outline of the CLEVES, a method for selecting NMAs in the SNM, and calculated results of case study are described.
Tachibana, Mitsuo; Fukushima, Tadashi*; Ishigami, Tsutomu
JAEA-Testing 2010-001, 43 Pages, 2010/07
The DENESYS has been developed to support examination of decommissioning plan aiming to use management data and experiences obtained through decommissioning of nuclear facilities effectively. In the development of the DENESYS, it is important efficiently to collect, and to analyze management data obtained from actual decommissioning of nuclear facilities. Then, collecting items of management data needed to examine decommissioning plan were extracted. And en efficient collecting method of the extracted collecting items was examined based on the JPDR decommissioning project. As a result, collecting items are work management data, waste management data. These data would be collected by suing daily work management report, waste record, and secondary record data in each JAEA site. In this report outline of collecting items and collecting method for decommissioning of nuclear facilities were described. And manual for collecting management data was introduced.
Ishigami, Tsutomu; Tachibana, Mitsuo; Yanagihara, Satoshi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 9(2), p.199 - 206, 2010/06
To release some materials in considerably low radioactive concentration arising from decommissioning activities of nuclear installations, it is required to confirm that the sum of D/C is lower than the reference value by measurement and evaluation of radioactive concentration. When the radioactive concentration is evaluated by using a statistical method where samples are taken from the material, two points should be taken into account; (1) a conservative evaluation that prevents underestimation to be caused by statistical uncertainties, (2) an error that may lead to a wrong decision where the material is not released due to the conservative evaluation. This paper proposes a method to determine the number of samples required for clearance verification based on a statistical theory in a consistent manner, where uncertainties in the sum of D/C is taken into account.
Tachibana, Mitsuo; Ishigami, Tsutomu
JAEA-Data/Code 2009-019, 52 Pages, 2010/02
Clearance activities for a large amount of waste with decommissioning of nuclear reactor facilities have been planned in the JAEA. To improve efficiency of clearance activities, the CLEVES has been developed to support safe and secure clearance of wastes. Program for selection of nuclides for meas. and assessment was fabricated for selecting nuclides to be evaluated based on relative importance measure for nuclides according to contamination source or contamination property of clearance objects. In addition, case studies ware carried out by using the program based on data concerning actual clearance activities in the JAEA. As a result, it has been found to be able to select nuclides for meas. and assessment safely by the individual method which evaluates relative importance measure of each contamination source, when it is difficult to analyze evaluated activity of nuclide. In this report, outline of the program was described.
Satoyama, Tomonori; Kishimoto, Katsumi; Takaizumi, Hirohide; Hoshi, Akiko; Okoshi, Minoru; Tachibana, Mitsuo
JAEA-Technology 2009-060, 42 Pages, 2010/01
In the modification activities of JRR-3, a large volume of extremely low-level radioactive concrete debris were generated from dismantling of concrete structure around reactor body during one-piece removal of reactor body. These concrete debris are stored in the waste storage facility NL of the Nuclear Science Research Institute. The applicability of clearance to concrete debris generated from the modification activities of JRR-3 was examined as waste measures in the Nuclear Science Research Institute. First, generated place, amount of volume and radioactivity of concrete debris in the waste storage facility NL were surveyed from records in the modification of JRR-3 and data sheets of radioactive waste stored in the waste storage facility. Next, the radioactivity of samples taken from concrete debris stored in the waste storage facility NL was measured, and distribution of those radioactivity concentration was investigated to evaluate the contamination situation. In addition, activated contamination situation of concrete structure was evaluated by activated calculation. As a result, radioactivity of concrete debris was enough lower than clearance levels, so it was found that concrete debris in the waste storage facility NL was able to treat as clearance materials.