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Journal Articles

The Progress and achievement of the ATR Fugen

Morishita, Yoshitsugu; Yanagisawa, Tsutomu*

Wagakuni Shorai Sedai No Enerugi O Ninau Kakunenryo Saikuru; Datsu Tanso Shakai No Enerugi Anzen Hosho; NSA/Commentaries, No.24, p.119 - 126, 2019/03

no abstracts in English

Journal Articles

Efforts in the "Fugen"; The History of up to termination of operation and Efforts of decommissioning measures

Morishita, Yoshitsugu

Denki Hyoron, 101(11), p.24 - 29, 2016/11

no abstracts in English

Journal Articles

The Study on application of laser technology for the reactor core dismantling

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.

Journal Articles

Study on dismantling scenario for large equipment in decommissioning of nuclear facilities; Utilization of validation result of applicability of project management data evaluation code to decommissioning project of FUGEN

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.

JAEA Reports

Research on decommissioning of nuclear facilities, 2; Study on optimum scenario using the AHP (Joint research)

Shibahara, Yuji; Ishigami, Tsutomu; Morishita, Yoshitsugu; Yanagihara, Satoshi*; Arita, Yuji*

JAEA-Technology 2012-038, 72 Pages, 2013/01

JAEA-Technology-2012-038.pdf:3.68MB

To implement a decommissioning project reasonably, it is necessary and important to beforehand evaluate project management data as well as to select an optimum dismantling scenario among various scenarios postulated. Little study on the subject of selecting an optimum scenario has been carried out, and it is one of the most important subjects in terms of decision making. In FY 2009, Japan Atomic Energy Agency and University of Fukui launched the joint research of a decision making method which is important to determine a decommissioning plan. The purpose of this research is to construct a methodology for selecting an optimum dismantling scenario among various scenarios postulated based on calculated results of project management data for FUGEN. Project management data for several dismantling scenarios postulated at FUGEN were evaluated based on actual dismantling work for feedwater heater at FUGEN, and an optimum scenario was discussed using the AHP, one of Multi-Criteria Decision Analysis Method. This report describes the results of the joint research in FY 2010.

JAEA Reports

Research on decommissioning of nuclear facilities (Joint research)

Shibahara, Yuji; Ishigami, Tsutomu; Morishita, Yoshitsugu; Yanagihara, Satoshi; Arita, Yuji*

JAEA-Technology 2011-021, 35 Pages, 2011/07

JAEA-Technology-2011-021.pdf:4.52MB

To implement reasonable decommissioning of nuclear facilities, it is necessary and important to beforehand evaluate project management data as well as to select optimum dismantling scenario among various scenarios postulated. Little study on the subject of selecting an optimum scenario has been carried out, and it is one of the most important subjects in terms of decision making. In FY2009, Japan Atomic Energy Agency and University of Fukui launched the joint research of a decision making method which is important to determine a decommissioning plan. The purpose of the research is to construct a methodology for selecting optimum dismantling scenario among various scenarios postulated based on calculated results of project management data for Fugen. Project management data for several dismantling scenarios postulated at Fugen were evaluated based on actual dismantling work for feed water heater at Fugen, and an optimum scenario was discussed using the multi-criteria decision analysis. This report describes the results of the joint research in FY2009.

Journal Articles

The Study on abrasive water jet for predicting the cutting performance and monitoring the cutting situation in the water

Nakamura, Yasuyuki; Sano, Kazuya; Morishita, Yoshitsugu; Maruyama, Shinichiro*; Tezuka, Shinichi*; Ogane, Daisuke*; Takashima, Yuji*

Journal of Engineering for Gas Turbines and Power, 133(6), p.064501_1 - 064501_3, 2011/06

 Times Cited Count:0 Percentile:0.01(Engineering, Mechanical)

Abrasive water jet (AWJ), is to shoot the abrasive mixed with high-pressure water to the material for cutting, can cut most materials like metals and concretes in water with long stand-off means the length from the cutting head to the material for cutting. On the other hand, AWJ is required to reduce an amount of the abrasive because it becomes the waste. It is also difficult to monitor the cutting condition by any visual methods like a TV camera in the water becoming cloudy by both used abrasive and cut metal grit. For solving these issues, some cutting tests were conducted and (1) It was possible to predict an optimal supply rate of abrasive by considering the conservation of momentum between the water jet and the abrasive. (2) It was also possible to judge whether the material could be cut successfully or not by detecting the change in the frequency characteristics of vibration or sound caused during the cutting process.

Journal Articles

Decommissioning program of FUGEN and current activities

Tezuka, Masashi; Mizui, Hiroyuki; Matsushima, Akira; Nakamura, Yasuyuki; Hayashi, Hirokazu; Sano, Kazuya; Nanko, Takashi; Morishita, Yoshitsugu

Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.2815 - 2821, 2009/09

FUGEN is a proto-type heavy water moderated, boiling light water cooled, pressure tube type reactor with 165MWe and has been shut downed on Mar. 2003. Following the approval of decommissioning program in 2008, stage of FUGEN was changed to the decommissioning of the facilities. The program consists of following four periods; (1) Spent fuel transportation, (2) Periphery facilities dismantlement, (3) Reactor dismantlement and (4) Building demolition. It is expected that the whole decommissioning will be completed until 2028. As a part of the work in the spent fuel transportation period, the main steam system and the feeder water system etc. are being dismantled in the turbine building. The remaining tritium in the heavy water system is also being removed for facilitating the dismantlement of the heavy water system. Moreover, method on dismantlement of the reactor core is being studied with considering the process under the water for the radiation shielding and the dust suppression.

Journal Articles

Experimental study on the applicability of the abrasive water jet for dismantling the reactor core of Fugen

Nakamura, Yasuyuki; Iwai, Hiroki; Sano, Kazuya; Morishita, Yoshitsugu; Maruyama, Shinichiro*; Tezuka, Shinichi*; Ogane, Daisuke*; Takashima, Yuji*

Dekomisshoningu Giho, (38), p.43 - 52, 2008/11

The advanced thermal reactor (Fugen) at Fugen Decommissioning Engineering Center is characterized by its tube-cluster construction. As a part of the study of dismantling, we are considering the abrasive water jet (AWJ) technique that could be used for the dismantlement techniques of double-tubes (pressure tube and calandria tube) as one of possible methods. As a part of tests, we confirmed the possibility of abrasive recycle for cutting and the applicability of cutting monitoring technique for reducing the volume of secondary wastes and developing the cutting monitoring technique in the water.

Journal Articles

Decommissioning program for ATR-FUGEN nuclear power station

Sano, Kazuya; Kitamura, Koichi; Tezuka, Masashi; Mizui, Hiroyuki; Kiyota, Shiko; Morishita, Yoshitsugu

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

The operation of Advanced Thermal Reactor Fugen was terminated on Mar. 29th, 2003. After the operation, the preparative works and R&D have been conducted strenuously for the planning of the rational and safe decommissioning. The decommissioning program for Fugen was planed, based on the results of above works and R&D, and was applied to the government as a first case under the revised nuclear reactor regulation law. As a result, the program was approved on Feb. 12th, 2008. In this paper, the decommissioning program for Fugen was outlined, which are the dismantling process consists of four periods; (1) Spent fuel transportation, (2) Periphery facilities dismantlement, (3) Reactor dismantlement and (4) Building demolition, the amount of radioactive waste, the safety assessment etc.

Journal Articles

Basic policy for decommissioning of nuclear power plant in Japan and the decommissioning of Fugen

Morishita, Yoshitsugu

Proceedings of International Symposium on Advanced Mechanical and Power Engineering 2008 (ISAMPE 2008), p.211 - 217, 2008/10

The basic policy for the decommissioning of the nuclear reactor in Japan was shaped in the 1990s. In the policy, it is premised that the nuclear power stations will be dismantled and removed after the safe store of the reactor from 5 to 10 years. Fugen, is the proto-type heavy water moderated, light water cooled, pressure tube type reactor with 165 MWe and has been shut downed 25 years operation. The program for decommissioning of Fugen had been prepared, and it was approved on Feb. of this year. Following the approval, we initiated to dismantle part of the facilities. It is expected that the whole decommissioning will be completed until 2028. In this paper, the basic policy for the decommissioning in Japan is outlined. The decommissioning program of FUGEN and relating R&D are also described.

Journal Articles

Evaluation of radioactive inventory for Fugen's decommissioning

Kitamura, Koichi; Hayashi, Hirokazu; Morishita, Yoshitsugu; Tanji, Kazuhiro*

Hoshasen, 34(1), p.53 - 63, 2008/01

It is very important to evaluate radioactive inventory and an amount of radioactive waste accurately for both the planning and the safety assessment on Fugen's decommissioning. Fugen had carried out various radioactive inventory investigations, activation evaluations by materials sampling, neutron measurements, contamination evaluation by investigation of radiation control records, etc. since operation period because Fugen uses heavy water as moderator and its core structure is different from that of LWR. And then, radioactive inventory was evaluated using those investigation data. Moreover, an amount of radioactive waste was estimated by the classification for the radioactive waste disposal based on the evaluated radioactive inventory results. This paper is intended to introduce the evaluation methods and results of the radioactive inventory and estimation of an amount of radioactive waste for Fugen.

Journal Articles

Development of a tracking method for augmented reality applied to NPP maintenance work and its experimental evaluation

Bian, Z.*; Ishii, Hirotake*; Shimoda, Hiroshi*; Yoshikawa, Hidekazu*; Morishita, Yoshitsugu; Kanehira, Yoshiki; Izumi, Masanori

IEICE Transactions on Information and Systems, E90-D(6), p.963 - 974, 2007/06

 Times Cited Count:4 Percentile:34.46(Computer Science, Information Systems)

This study designed linecode marker, a new type of paper-based marker and proposed recognition, tracking algorithm for it in order to resolve these problems. In comparison of the conventional paper-based markers, such as square markers, circle markers, the linecode marker is not only just easier to set up in complex industrial environment, but also makes it possible to use AR in industrial plant. In order to evaluate the tracking accuracy, trackable distance of the proposed tracking method, an evaluation experiment was conducted in a large room. The experiment results show that: comparing with traditional marker-based tracking method, tracking possible distance extends extremely; tracking accuracy improved to a level of 20cm in 10m distance.

Journal Articles

Quantum beam applications in nuclear energy industries

Minehara, Eisuke; Morishita, Yoshitsugu; Mizuki, Junichiro

Enerugi Rebyu, 26(8), p.15 - 18, 2006/08

The advanced quantum beam technologies (synchrotron orbital radiation and laser) are applied to the nuclear energy industrial one and many other fields, and solving various actual difficulties and acquiring much new knowledge in Quantum Beam Science Directorate, Japanese Atomic Energy Agency. Here, we would like to introduce and to explain three ones from such activities stated just above. In the text, we would like to explain in details (1) the high power laser cutting with narrow-gap in decommissioning the nuclear power reactor plants, (2) complete removing of RI (radio-isotope) contaminated surface components using non-thermal laser ablation, and (3) the discovery of the high temperature superconductor working mechanism using synchrotron-orbital-radiation beam as three typical examples.

Journal Articles

Applicability examination and evaluation of reactor dismantlement technology in the Fugen; Examination of double tubes cutting by abrasive water jet

Nakamura, Yasuyuki; Kikuchi, Koichi; Morishita, Yoshitsugu; Usui, Tatsuo*; Ogane, Daisuke*

Proceedings of 14th International Conference on Nuclear Engineering (ICONE-14) (CD-ROM), 9 Pages, 2006/07

It is necessary to clarify the dismantlement method of 224 double tubes arranging both pressure and calandria tubes concentrically in the reactor as a peculiar problem of Fugen, in the case of phased dismantlement of the reactor. The machine type cutting is desirable, considering the influence on the atmospheres because the double tubes consist of the zirconium alloy and zircalloy material radio activated highly. Besides, Cutting method has long standoff to cut the double tubes at a time for to be short the term of dismantlement. is desirable. Therefore, it was examined to confirm the applicability to the double tubes cutting by abrasive water jet (hereinafter referred to as AWJ) as the machine type cutting method that can take the standoff comparatively longer. As a result, We confirmed for possibility of cutting the double tubes at a time from inside and outside tube, and cutting thick slab by abrasive water jet. Besides, We confirmed for relationship of abrasive supply and cutting velocity, properties of secondly waste.

Journal Articles

Decommissioning of ATR Fugen

Morishita, Yoshitsugu

Dai-17-Kai Genshiryoku Shisetsu Dekomisshoningu Gijutsu Koza Tekisuto, p.55 - 80, 2006/02

no abstracts in English

Oral presentation

Applicability of Monte-Carlo code to radioactivity evaluation for FUGEN

Kitamura, Koichi; Tanji, Kazuhiro*; Morishita, Yoshitsugu; Hayashi, Hirokazu; Azekura, Kazuo*; Naito, Yoshitaka*

no journal, , 

no abstracts in English

Oral presentation

Evaluation of radioactivity inventory in the Fugen, 12; Development of activation activity evolution system (ORIGEN-2) for Fugen

Kitamura, Koichi; Tanji, Kazuhiro*; Morishita, Yoshitsugu; Hayashi, Hirokazu; Yamaguchi, Katsuyoshi*; Saito, Kuniyoshi*

no journal, , 

no abstracts in English

Oral presentation

Applicability examination and evaluation of nuclear reactor dismantlement technology in the Fugen; Examination of simulation material cutting by abrasive water jet, 1

Nakamura, Yasuyuki; Kikuchi, Koichi; Morishita, Yoshitsugu; Ogane, Daisuke*; Usui, Tatsuo*

no journal, , 

no abstracts in English

Oral presentation

Applicability of Monte-Carlo code to radioactivity evaluation for FUGEN, 2

Kitamura, Koichi; Morishita, Yoshitsugu; Hayashi, Hirokazu; Tanji, Kazuhiro*; Azekura, Kazuo*; Naito, Yoshitaka*

no journal, , 

no abstracts in English

57 (Records 1-20 displayed on this page)