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Journal Articles

Adaptation for knowledge management to nuclear research fields

Taruta, Yasuyoshi; Yanagihara, Satoshi*; Iguchi, Yukihiro; Kitamura, Koichi; Tezuka, Masashi; Koda, Yuya

Chishiki Kyoso (Internet), 8, p.IV2_1 - IV2_12, 2018/08

no abstracts in English

Journal Articles

Research concept of decommissioning knowledge management for the Fugen NPP

Taruta, Yasuyoshi; Yanagihara, Satoshi*; Iguchi, Yukihiro; Kitamura, Koichi; Tezuka, Masashi; Koda, Yuya

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07

The IAEA are developed the discussion for those situations and pointed out the importance of nuclear knowledge management. The nuclear knowledge management is developing a database as nuclear knowledge management. In recent years, the IAEA has also advanced knowledge taxonomies on nuclear accidents. These studies are attempts to appropriately arrange and utilize huge amounts of information. Even in nuclear facilities in Japan, it is pointed out that veteran staff aging and loss of knowledge and skill caused by retirement. Therefore, we created a prototype database system to utilize past knowledge and information for ATR Fugen. Now, there are few cases of past decommissioning that can be utilized. This study of pilot model concept revealed that it is not sufficient to just prepare a past data and information. This is what information other than the construction report requires the decommissioning and what kind of information should be gathered.

JAEA Reports

A Study on optimization of dismantling scenarios in Fugen decommissioning project; Preliminary evaluation of dismantling scenario of the heat exchangers, etc.

Koda, Yuya; Tezuka, Masashi; Yanagihara, Satoshi*

JAEA-Technology 2015-050, 74 Pages, 2016/03

JAEA-Technology-2015-050.pdf:3.43MB

The implementation of the decommissioning work is accompanied by long-term period and considerable expense, so it is important that we make the most optimized work scenario in consideration of safety or the work and effectiveness. For this reason, we are studying selection method of the optimal work scenarios as a management index of the manpower and dose etc., in dismantling work for Fugen. In this report, results of a study shows the method of selecting the best scenarios for the heat exchangers of the reactor coolant purification system by evaluating execution multiple work scenarios, as well as evaluating the manpower and dose, etc., moreover by setting the importance of each evaluation item.

Journal Articles

Waste management scenario in the hot cell and waste storage for DEMO

Someya, Yoji; Tobita, Kenji; Yanagihara, Satoshi*; Kondo, Masatoshi*; Uto, Hiroyasu; Asakura, Nobuyuki; Hoshino, Kazuo; Nakamura, Makoto; Sakamoto, Yoshiteru

Fusion Engineering and Design, 89(9-10), p.2033 - 2037, 2014/10

 Times Cited Count:4 Percentile:54.43(Nuclear Science & Technology)

In the replacement period of a fusion power reactor, the assembly of blanket or divertor modules need to be removed from the reactor in order to minimize remote maintenance in the vacuum vessel and to attain a reasonable plant availability. In the hot cell, the modules will be removed from the backplate of the assembly. Here, note that the active cooling must be done by a way that does not cause contamination of the hot cell environment due to dispersion of tritium and tungsten dust. In this sense, the cooling scenario is adopted that the existing pipe of cooling water in the assembly is connected to a different cooling water system in the hot cell. In this scenario, the temperature of the assembly is maintained about 40-100$$^{circ}$$C. On the other hand, the structural material (RAFM) of the blanket and divertor is not recycled due to its high contact dose rate. It should be crushed into small pieces to reduce volume of the waste and required storage space. Here, the decay heat must be removed by natural convection to keep the temperature below 65$$^{circ}$$C for preventing water evaporation from the mortar. The RAFM is kept in the interim storage during 12 years until the required temperature conditions for mortar are ensured and then is disposed of.

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

What is decommissioning of nuclear facilities?; Technology necessary for decommissioning

Yanagihara, Satoshi

Enerugi Rebyu, 30(10), p.54 - 55, 2010/10

Decommissioning work is conducted by using various technologies. In the decommissioning process, it should be necessary to consider safety of public and workers from radiological and industrial aspects, and that lowing environmental burden by minimizing radioactive waste arising as well as optimizing decommissioning costs by rational implementation of the practices. The technology necessary for decommissioning are roughly grouped into the areas such as facility characterization, dismantling, decontamination, radioactive waste treatment/disposal. In addition, project management including decommissioning planning where project parameters are evaluated in terms of resource, costs, schedule, risk, etc. This article will describe the technologies mentioned above briefly.

Journal Articles

Method for determining the number of samples in clearance verification by measurement and evaluation

Ishigami, Tsutomu; Tachibana, Mitsuo; Yanagihara, Satoshi

Nippon 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.

JAEA Reports

The Second Studsvik AB-JAEA Meeting for Cooperation in Nuclear Energy Research and Development; September 14-18, 2009, Studsvik-Sweden

Ishihara, Masahiro; Yanagihara, Satoshi; Karlsson, M.*; Stenmark, A.*

JAEA-Review 2009-057, 149 Pages, 2010/03

JAEA-Review-2009-057.pdf:27.7MB

The second annual meeting was held at Studsvik AB in Sweden to exchange information on radioactive waste treatment technology including recycling of materials and technical developments for the neutron irradiation experiments in materials testing reactors. The information exchange meeting was held on the basis of the implemental agreement between the Studsvik AB and the Japan Atomic Energy Agency (JAEA) for cooperation in nuclear energy research and development. The major items of the information exchange were the present status of waste treatment in both organizations including acceptance criteria of wastes in Studsvik facilities, experience and current status of RI production technology in both organizations as well as the sensor development. The future plan in cooperative program was also discussed. This report describes contents of the information exchange and discussions in two cooperation areas.

Journal Articles

Twenty five years passed from starting OECD/NEA decommissioning cooperative program

Yanagihara, Satoshi

Dekomisshoningu Giho, (41), P. 1, 2010/03

Twenty five years have passed since starting the OECD/NEA decommissioning cooperative program. During these terms, the decommissioning programs of Shipping Port and Neideraichbach Power Plants have been completed successfully. Both WAGR and BR-3 decommissioning programs are in final stage at this moment. In addition, US DOE Environmental Management program has been actively conducted for more than 20 years. The cleanup programs of Mound, Fernald and Rocky Flats have been completed so far. It may need relatively long time to complete decommissioning and cleanup activities. By being informed of the successful results of WAGR and BR-3 and some of EM programs, I thought of that it might be important to continue these programs with persistence on long term perspective.

JAEA Reports

The First Studsvik AB - JAEA meeting for cooperation in nuclear energy research and development; July 18, 2008, JAEA-Oarai

Ishihara, Masahiro; Yanagihara, Satoshi; Karlsson, M.*; Stenmark, A.*

JAEA-Review 2008-059, 81 Pages, 2009/01

JAEA-Review-2008-059.pdf:13.68MB

Based on the implemental agreement between the Studsvik AB and the Japan Atomic Energy Agency (JAEA) for cooperation in nuclear energy research and development, the first annual meeting was held at Oarai Research and Development Center, Japan Atomic Energy Agency. In this meeting, information exchange on two cooperation areas, "Radioactive waste treatment technology including recycling of materials" and "Technical developments for the neutron irradiation experiments in materials testing reactors", was carried out, and future plan in cooperation was discussed. This report describes contents of information exchange and discussions in two cooperation areas.

JAEA Reports

Study of decommissioning cost evaluation technique for nuclear reactor dismantlement; Calculation of decommissioning cost by COSMARD

Oshima, Soichiro; Shiraishi, Kunio; Shimada, Taro; Sukegawa, Takenori; Yanagihara, Satoshi

JAERI-Tech 2005-046, 46 Pages, 2005/09

JAERI-Tech-2005-046.pdf:3.43MB

A model for estimating decommissioning costs consisting of labor cost, device cost and expense, was developed for items which OECD/NEA had standardized, and was installed into the computer system for planning and management of reactor decommissioning (COSMARD). Input data files and databases for the decommissioning of JPDR were prepared, and the decommissioning cost was calculated with COSMARD. In addition, the decommissioning cost for a large scale BWR power plant was also calculated on the assumption of the advantage of scale. The calculations have shown that it is useful and efficient for studying the decommissioning costs for nuclear reactors to apply the COSMARD with database for cost estimation to the decommissioning cost calculation.

Journal Articles

Development of public dose assessment code for decommissioning of nuclear reactors (DecDose)

Shimada, Taro; Oshima, Soichiro; Ishigami, Tsutomu; Yanagihara, Satoshi

Proceedings of 10th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '05) (CD-ROM), 8 Pages, 2005/09

In order to review an operator's "Decommissioning Plan" applied to the regulatory body for approval accurately and quickly, Public Dose Assessment Code for Decommissioning of Nuclear Reactors (DecDose) was developed. It evaluates public exposure doses for each year during dismantling activities in accordance with the "Decommissioning Plan". DecDose takes account of various exposure pathways such as cloudshine, surface ground deposition, ingestion of seafood, and direct and skyshine radiation based on the quantity of radionuclides discharged to the environment, and containers stored in the facility in consideration of cutting and storage of components and structures. Example evaluations with DecDose have shown that it is a useful tool for assessing public dose during decommissioning of nuclear reactors.

Journal Articles

Development of automated measurement device for low-level radioactive contamination on building surfaces

Tachibana, Mitsuo; Ito, Hirokuni*; Hatakeyama, Mutsuo*; Yanagihara, Satoshi

Nippon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.120 - 127, 2004/03

The RAPID-1600 was developed to measure a low-level radioactive contamination on building surfaces automatically. The double layered detectors are structured by two gas flow type detectors with a $$beta$$ rays shielding plate between the two detectors and it is horizontally positioned. The lower counter measures $$beta$$ and $$gamma$$ rays and the upper counter measures $$gamma$$ rays. The $$beta$$ rays counting rates are derived by subtracting $$gamma$$ rays counting rates of the upper counter from $$gamma$$ and $$beta$$ rays counting rates of the lower counter. This mechanism results in sensitive to $$beta$$ rays against to low background radiation conditions. The driving unit can move omnidirectionally by controlling two driving wheels individually, and has a capability to correct its position if an orbital error is detected by the self-position identification system. The RAPID-1600 was successfully applied to the actual measurement in the radioisotope production facilities. The RAPID-1600 is expected to be a useful tool for measurement of radioactivity in decommissioning nuclear facilities.

Journal Articles

Development of remote surveillance squads for nuclear emergency

Yanagihara, Satoshi; Kobayashi, Tadayoshi; Miyajima, Kazutoshi; Tanaka, Mitsugu

International Journal of Robotics and Automation, 18(4), p.160 - 165, 2003/12

no abstracts in English

Journal Articles

Recent activities related to decommissioning in nuclear energy agency of OECD

Yanagihara, Satoshi

Dekomisshoningu Giho, (28), p.2 - 9, 2003/10

Decommissioning of nuclear facilities has been actively progressed in the major member countries participating to OECD/NEA. The NEA has recognized necessity of studying various issues related to decommissioning nuclear facilities and it has made an approach to solve the issues from various ways. In the cooperative program for decommissioning (CPD), information on decommissioning projects has been exchanged among the member countries. In the working party on decommissioning and dismantling (WPDD), recent issues have been studied in terms of regulation, implementation of decommissioning projects and research and development on technologies. Decommissioning cost and regulatory practices were also studies and the reports were published, which will be useful for understanding the present issues on decommissioning in the world. The NEA's activity on decommissioning will be valuable for us to implement decommissioning projects in safe and economical manner in Japan. This report deals with the recent NEA activities on decommissioning.

JAEA Reports

Development of measuring device for inner surfaces of embedded piping (Contract research)

Ito, Hirokuni*; Hatakeyama, Mutsuo*; Tachibana, Mitsuo; Yanagihara, Satoshi

JAERI-Tech 2003-012, 34 Pages, 2003/03

JAERI-Tech-2003-012.pdf:2.87MB

The MISE was developed to evaluate low-level radiological contaminations of inner surfaces of piping. The MISE consists of a cylindrically-formed double layered type detector and a piping crawling robot, which were designed and manufactured separately. In measurements of the contaminations, an outer cylindrical detector close to the surface of piping measures $$beta$$-rays and $$gamma$$-rays and an inner cylindrical detector set after a shielding plate for shield of $$beta$$-rays measures $$gamma$$-rays. The $$beta$$-ray counting rates are derived by subtracting $$gamma$$-ray counts measured by the inner detector from $$gamma$$- and $$beta$$-ray counts measured by the outer detector. The robot transports the double layered type detector with observing inner surfaces of piping. The detection limit for the contamination of $$^{60}$$Co was found to be about 0.17Bq/cm$$^{2}$$ with measurement time of 30 seconds. It is expected that 0.2Bq/cm$$^{2}$$ corresponding to clearance level of $$^{60}$$Co (0.4Bq/g) can be evaluated with measurement time of 2 seconds, which is equal to measurement speed of 54m/h.

Journal Articles

Decommissioning project feedback experience in the Japan Atomic Energy Research Institute

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.

Journal Articles

Development of computer systems for planning and management of reactor decommissioing

Yanagihara, Satoshi

Nippon Genshiryoku Gakkai-Shi, 44(10), p.734 - 737, 2002/10

no abstracts in English

Journal Articles

Magnitude of the decommissioning task in south and east Asia and Oceania

Tanaka, Mitsugu; Yanagihara, Satoshi

Safe Decommissioning for Nuclear Activities, p.65 - 75, 2002/10

no abstracts in English

118 (Records 1-20 displayed on this page)