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Journal Articles

Development of high-performance monitoring system under severe accident condition

Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Komanome, Hirohisa*; Miura, Kuniaki*; Ishihara, Masahiro

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04

After the accident at the Fukushima Dai-ichi (1F) Nuclear Power Plant (NPP), the Japanese Government referred to "Enhancement of instrumentation to identify the status of the reactors and PCVs", in the report of Japanese government to the IAEA ministerial conference in June 2011. In response to these provisions, a research and development of a monitoring system for NPPs situations during severe accidents started in November 2012. The objectives of the R&D are composed of radiation-resistant monitoring camera, radiation-resistant in-water transmission system, and heat-resistant signal cable. For all the three objectives, the elemental technologies have been already developed and now trial system are being fabricated and tested under simulated conditions of severe accidents. The results will enable us to determine the basic specifications of the systems and to provide the information about application limits for users.

Journal Articles

R&D of high-temperature resistance type mineral insulated cable for sever accident

Miura, Kuniaki*; Shibata, Hiroshi; Onizawa, Tatsuya*; Nakano, Hiroko; Takeno, Naofumi*; Takeuchi, Tomoaki; Tsuchiya, Kunihiko

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.387 - 390, 2016/07

no abstracts in English

Journal Articles

Status of R&D of high-performance monitoring system under sever accident

Tsuchiya, Kunihiko; Takeuchi, Tomoaki; Komanome, Hirohisa*; Miura, Kuniaki*; Araki, Masanori; Ishihara, Masahiro

Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.375 - 378, 2016/07

no abstracts in English

JAEA Reports

Development of heater-and-thermocouple-type water level sensor

Shibata, Akira; Miura, Kuniaki*; Takeuchi, Tomoaki; Otsuka, Noriaki; Nakamura, Jinichi; Tsuchiya, Kunihiko

JAEA-Technology 2013-024, 21 Pages, 2013/10

JAEA-Technology-2013-024.pdf:12.62MB

In the Fukushima-Daiichi Nuclear Power Plant Accident, the measurements of water level in pressure vessel and spent fuel pool were impossible due to station blackout, and it resulted in difficulty for countermeasures against the accidents and for understanding of the situations of reactor core after accidents. Therefore, we started to develop a new water level sensor for l with high reliability, which works with small electric power. This report describes reviews of conventional water level sensor and design and production of new water level sensor. After production of the sensor, performance tests were performed between room temperature and about 95 $$^{circ}$$C, and the it was confirmed that the sensor is able to measure water level with the accuracy of $$pm$$ 20 mm. As the results, a perspective to use the new water level sensor as water level indicator for spent fuel pools and reactor vessels after severe accident.

Journal Articles

Development of instruments for improved safety measure for LWRs

Takeuchi, Tomoaki; Shibata, Akira; Nagata, Hiroshi; Miura, Kuniaki*; Sano, Tadafumi*; Kimura, Nobuaki; Otsuka, Noriaki; Saito, Takashi; Nakamura, Jinichi; Tsuchiya, Kunihiko

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 8 Pages, 2012/10

In-pile instrumentation systems in present LWR's are indispensable to monitor all situations during reactor operation and reactor shut down. However, those systems did not work sufficiently under the conditions of the severe accident at the Fukushima Dai-ichi (F1) Nuclear Power Plant. Based on instrumentation and irradiation experiences accumulated in JMTR, the developments of reactor instrumentation systems to prevent severe core damage accident in advance have been started. The development objects are water level gauge utilizing $$gamma$$ heating, self-powered $$gamma$$-ray detector, hydrogen concentration gauge, and analysis system for imaging and quantification of in-reactor information using Cherenkov light.

Journal Articles

Development of reactor water level sensor for extreme conditions

Miura, Kuniaki*; Shibata, Akira; Nakamura, Jinichi; Ogasawara, Toshihiko*; Saito, Takashi; Tsuchiya, Kunihiko

JAEA-Conf 2011-003, p.193 - 195, 2012/03

In the Fukushima accident, measurement failure of water level was one of the most important factors which caused this serious situation. The differential pressure type water level indicators are widely used in various place of nuclear plant but after the accident of TMI-2, the need of other reliable method has been demanded. And the BICOTH type and the TRICOTH type water level indicator for light water power reactors had been developed for in-pile water level indicator but currently those are not adopted to a nuclear power plant. In this study, the development of new type water level indicator which composed of thermocouple and heater, and the demonstration test and characteristic evaluation of the water level indicator were described.

JAEA Reports

Conceptual design of multipurpose compact research reactor; Annual report FY2010 (Joint research)

Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.

JAEA-Technology 2011-031, 123 Pages, 2012/01

JAEA-Technology-2011-031.pdf:16.08MB

The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.

Journal Articles

Lead-bismuth eutectic compatibility with materials in the concept of spallation target for ADS

Kikuchi, Kenji; Saito, Shigeru; Kurata, Yuji; Futakawa, Masatoshi; Sasa, Toshinobu; Oigawa, Hiroyuki; Wakai, Eiichi; Umeno, Makoto*; Mizubayashi, Hiroshi*; Miura, Kuniaki*

JSME International Journal, Series B, 47(2), p.332 - 339, 2004/05

Lead bismuth eutectic (LBE) is favored by spallation neutron sources and coolant in the sub-critical reactor at the accelerator driven nuclear transmutation system (ADS). Technical issues of ADS are material technology of how to compromise with flowing lead bismuth, high-energy proton accelerator technology and a sub-critical reactor system technology. This paper describes LBE technology developed at JAERI. First a scenario in order to realize the ADS is shown. The concept of spallation target test facility is introduced with a target design of thermo-fluid dynamics. Base data of flow rate and temperature of Pb-Bi during LBE circulation are described. The results of LBE loop operation under the flowing conditions of target design concept are reported. The stagnant corrosion tests were done to know the controlling parameters among the various steels. The tube-type oxygen sensor with having the solid electrolyte was studied. Cleaning techniques were developed to remove LBE from materials.

Journal Articles

Corrosion-erosion test of SS316 in flowing Pb-Bi

Kikuchi, Kenji; Kurata, Yuji; Saito, Shigeru; Futakawa, Masatoshi; Sasa, Toshinobu; Oigawa, Hiroyuki; Wakai, Eiichi; Miura, Kuniaki*

Journal of Nuclear Materials, 318(1-3), p.348 - 354, 2003/05

 Times Cited Count:25 Percentile:84.36(Materials Science, Multidisciplinary)

Corrosion test of austenitic stainless tube was done under the flowing Pb-Bi condition during 3000 hrs at 450$$^{circ}$$C. Specimen is 316SS produced as a tubing form with 13.8 mm outer diameter, 2 mm thickness and 40 cm length. During the operation, maximum temperature, temperature difference and flow velocity of Pb-Bi at the specimen were kept at 450$$^{circ}$$C, 50$$^{circ}$$C, and 1m/s, respectively. After the test, specimen and components of the loop were cut and examined by optical microscope, SEM, EDX, WDX and X-ray diffraction. Pb-Bi adhered on the surface of the specimen even after Pb-Bi was drained out to the storage tank from the circulating loop. Different results from a stagnant corrosion test were that the specimen surface became rough and the corrosion rate was maximally 0.1mm/3000hrs. And mass transfer from the high temperature to the lower temperature area was observed: crystals of Fe-Cr were found on the tube surface in low-temperature part. The size of crystal was 0.1 $$sim$$ 0.2 mm. The depositing crystal was ferrite grain and the chemical composition ratio (mass%) of Fe to Cr was 9:1.

Journal Articles

Corrosion-erosion of SS316 under flowing Pb-Bi

Kikuchi, Kenji; Kurata, Yuji; Saito, Shigeru; Futakawa, Masatoshi; Sasa, Toshinobu; Oigawa, Hiroyuki; Miura, Kuniaki*

Nihon Kikai Gakkai 2002-Nendo Nenji Taikai Koen Rombunshu, p.273 - 274, 2002/09

Corrosion-erosion properties of type 316 austenitic stainless steel were investigated at 450oC. The study aims at developing ADS, accelerator driven system, for nuclear transmutation of long lived activated nuclei to shorter ones. After 3000 hrs flow of eutectic 45Pb-55Bi loop tubes were cut and analyzed by optical microscope, SEM, EDX, WDX and TEM. It is concluded that corrosion-erosion depth is maximally 0.1mm per 3000 hrs and Cr-Fe crystals were precipitated in the lower temperature of flowing channel. Further more inspection results of Electro Magnetic Pump, Electro Magnetic Flow meter and controlling valve were also reported. Output signal from EMF was stable after certain time duration. In this experiment oxygen content in Pb-Bi was not actively controlled but Pb-Bi was covered by 4N Argon gas.

Oral presentation

Output test of new oxygen probe in flowing PbBi

Kikuchi, Kenji; Tezuka, Masao*; Saito, Shigeru; Onizawa, Tatsuya*; Abe, Yuji*; Miura, Kuniaki*

no journal, , 

Solid-electrolyte oxygen-probe was developed for measurement of oxygen concentration in lead bismuth eutectic. The difference of the probe from conventional ones is that first reference electrolyte is iron oxide, secondly it is a cassette type model that can be a part of circulating pipe, and thirdly measuring temperature is below 400 $$^{circ}$$C. Proto type probe was attached in the circulating PbBi loop of JAEA and measurement rest was done during about 8000 hrs. Oxygen concentration of the loop, with non-active oxygen control but PbBi was shielded from the air by high purity argon gas, was evaluated to be 1E-5 to 1E-2 wppm.

Oral presentation

Conceptual design of next generation MTR

Nagata, Hiroshi; Yamaura, Takayuki; Naka, Michihiro; Kawamata, Kazuo; Izumo, Hironobu; Hori, Naohiko; Nagao, Yoshiharu; Kusunoki, Tsuyoshi; Kaminaga, Masanori; Komori, Yoshihiro; et al.

no journal, , 

Conceptual design of the high-performance and low-cost next generation materials testing reactor which will be assumed to introduce to the nuclear power plant introduction country started from 2010 in the JAEA. Japanese atomic energy-related companies participate in this project, and this activity role as the environmental management and nuclear human resource development for the new research reactor designs. 10 MW thermal power by plate type fuel elements and swimming pool type was assumed as a design base. High safety, high cost performance, high reactor operation rate, high technology irradiation are targets of this conceptual design.

Oral presentation

Calibration tests of self-powered $$gamma$$-ray detector with Pb emitter

Otsuka, Noriaki; Takeuchi, Tomoaki; Shibata, Akira; Nagata, Hiroshi; Tsuchiya, Kunihiko; Miura, Kuniaki*

no journal, , 

no abstracts in English

Oral presentation

Effect of emitter shape on output current of self-powered $$gamma$$-ray detector

Otsuka, Noriaki; Takeuchi, Tomoaki; Shibata, Akira; Nagata, Hiroshi; Tsuchiya, Kunihiko; Miura, Kuniaki*

no journal, , 

no abstracts in English

Oral presentation

Research and development of high-performance monitoring systems for safety measures of LWRs, 6; Effect on electrical properties of high temperature-typed mineral insulated cables

Shibata, Hiroshi; Takeuchi, Tomoaki; Uehara, Toshiaki; Matsui, Yoshinori; Tsuchiya, Kunihiko; Yamamura, Chiaki*; Miura, Kuniaki*

no journal, , 

no abstracts in English

Oral presentation

Remote technology development for function advancement of research base-development of small, 6; Diameter self-powered critical monitoring sensor

Usami, Hiroshi; Kawamura, Hiroshi; Ooka, Makoto; Miura, Kuniaki*; Onizawa, Tatsuya*

no journal, , 

no abstracts in English

Oral presentation

Development of monitoring system under severe accident at LWRs

Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Ishihara, Masahiro; Komanome, Hirohisa*; Miura, Kuniaki*

no journal, , 

no abstracts in English

Oral presentation

Effect on electrical properties of high-temperature typed MI cables under gamma irradiation

Shibata, Hiroshi; Onizawa, Tatsuya*; Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Takeno, Naofumi*; Miura, Kuniaki*; Tsuchiya, Kunihiko

no journal, , 

no abstracts in English

18 (Records 1-18 displayed on this page)
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