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Journal Articles

Development of on-site measurement technique of retained austenite volume fraction by compact neutron source RANS

Ikeda, Yoshimasa*; Takamura, Masato*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Kumagai, Masayoshi*; Suzuki, Hiroshi

Tetsu To Hagane, 104(3), p.138 - 144, 2018/03

 Times Cited Count:0 Percentile:100(Metallurgy & Metallurgical Engineering)

Neutron engineering diffraction is a powerful technique which provides the information of the micro structure of steels in bulk-average, while X-ray diffraction or Electron backscatter diffraction can provide information only from the surface layer. However, such measurement using neutron diffraction is typically performed in a large facility such as a reactor and a synchrotron, while a compact neutron source has never been used for this purpose. Authors have recently developed a neutron diffractometer installed in Riken Accelerator driven compact Neutron Source (RANS) and succeeded in the measurement of texture evolution of a steel sheet. In this study, we made an attempt to measure the volume fraction of retained austenite by RANS. Background noise was carefully eliminated in order to detect as many diffraction peaks as possible with low flux neutrons. The volume fraction was estimated by Rietveld analysis. The accuracy of the measurement result was discussed by comparing with those obtained by a large neutron facility (J-PARC TAKUMI). The volume fraction obtained by RANS with reasonable measurement time, i.e. 30 to 300 min, showed only 1 to 2 % discrepancies with those obtained in J-PARC. These comparisons suggest that neutron diffraction by RANS is capable of quantitative analysis of the volume fraction of crystal phases, showing the possibility of practical use of an in-house compact neutron source in the industry.

Journal Articles

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

Ikeda, Yoshimasa*; Taketani, Atsushi*; Takamura, Masato*; Sunaga, Hideyuki*; Kumagai, Masayoshi*; Oba, Yojiro*; Otake, Yoshie*; Suzuki, Hiroshi

Nuclear Instruments and Methods in Physics Research A, 833, p.61 - 67, 2016/10

 Times Cited Count:20 Percentile:1.93(Instruments & Instrumentation)

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by the large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 minutes. The minimum resolution of the 110 reflection for RANS is approximately 2.5 % at 8 $$mu$$s of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 $$mu$$s, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenite phase was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS was proved to be capable for neutron engineering diffraction aiming for the easy access measurement of the texture and the amount of retained austenite.

Journal Articles

Non-destructive texture measurement of steel sheets with compact neutron source "RANS"

Takamura, Masato*; Ikeda, Yoshimasa*; Sunaga, Hideyuki*; Taketani, Atsushi*; Otake, Yoshie*; Suzuki, Hiroshi; Kumagai, Masayoshi*; Hama, Takayuki*; Oba, Yojiro*

Journal of Physics; Conference Series, 734(Part B), p.032047_1 - 032047_4, 2016/08

 Times Cited Count:1 Percentile:37.31

Neutron diffraction is well known to be a useful technique for measuring a bulk texture of metallic materials taking advantage of a large penetration depth of the neutron beam. However, this technique has not been widely utilized for the texture measurement because large facilities like a reactor or a large accelerator are required in general. In contrast, RANS (Riken Accelerator-driven Compact Neutron Source) has been developed as a neutron source which can be used easily in laboratories. In this study, texture evolution in steel sheets with plastic deformation was successfully measured using RANS. The results show the capability of the compact neutron source for the analysis of the crystal structure of metallic materials, which leads us to a better understanding of plastic deformation behavior.

Journal Articles

Status of decommissioning of the Plutonium Fuel Fabrication Facility and R&Ds of dismantling technologies for gloveboxes

Kimura, Yasuhisa; Hirano, Hiroshi; Watahiki, Masatoshi; Kuba, Meiji; Ishikawa, Shinichiro

Dekomisshoningu Giho, (52), p.45 - 54, 2015/09

The Plutonium Fuel Fabrication Facility (PFFF) of the Japan Atomic Energy Agency is now in its decommissioning phase. In the PFFF, terminated gloveboxes have been dismantled. Gloveboxes to be dismantled are surrounded by a plastic enclosure to prevent contamination from being spread into process room. Dismantling operations for gloveboxes are performed manually by workers, each wearing an air-feed suit. However, the mental and physical loads placed on workers wearing the air-feed suits are intensively high. Therefore, R&Ds on new dismantling technologies including utilization of heavy machines covered with plastic enclosure for anti-contamination have been started to reduce the potential risks associated with workers and decommissioning costs. In this paper, the status of decommissioning of the PFFF and the overview of developed dismantling technologies for $$alpha$$-tight gloveboxes are described.

Journal Articles

Prospect of compact accelerator based on breakthrough technologies

Arakawa, Kazuo

Genshiryoku Nenkan 2006-Nen Ban, p.125 - 126, 2005/10

no abstracts in English

JAEA Reports

Examination of a distributed small reactor system with the social acceptability; The District heat supply small reactor system using deep underground cave

Nakajima, Nobuya; Takahashi, Hiroki; Kusunoki, Tsuyoshi; Mitomo, Nobuo

JAERI-Tech 2005-057, 54 Pages, 2005/09


Availability using small reactor sited in deep underground cave was examined as a district heat supply system.From the viewpoint of a social acceptability, the contact points with a distributed small reactor system were examined to resolve a social structure-subject of a big city through investigation of the city environmental issue and city calamity. In order to estimate the scale of the heat source of a district heat supply system, a virtual city model was set up about 100,000 populations. It became clear that the heat can be supplied by installing two reactors with thermal-power 100MWt (MR-100G) in caves. Moreover, it turns out that the system will also function effectively for more than 40 years. The economic efficiency of this system was compared with the natural-gas boiler, and we confirmed that the district heat supply system by the small reactor is excellent especially for the case of long-term system operation.

JAEA Reports

Studies on applications of detectors for marine radioactivity and methodologies for data analysis (Joint Research)

Ito, Toshimichi; Kinoshita, Masataka*; Saito, Saneatsu*; Machiyama, Hideaki*; Shima, Shigeki*; Gasa, Shinichi*; Togawa, Orihiko; Okano, Masaharu*

JAERI-Research 2005-028, 121 Pages, 2005/09


no abstracts in English

Journal Articles

Design of small reduced-moderation water reactor

Okubo, Tsutomu; Iwamura, Takamichi; Takeda, Renzo*; Moriya, Kumiaki*; Yamauchi, Toyoaki*; Aritomi, Masanori*

Nippon Kikai Gakkai 2003-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.245 - 246, 2003/08

A design study on a 300MWe class small Reduced-Moderation Water Reactor (RMWR) has been performed, based on the experienced LWR technology. The core can be cooled by the natural circulation and can achieve a conversion ratio of 1.01, a negative void reactivity coefficient, a core average burn-up of 65 GWd/t and a cycle length of 25 months. The system has been simplified as much as possible by introducing the passive safety components, in order to reduce the construction cost per electric power output overcoming “the scale demerit" for a small reactor comparing with the large one. The results show a 1.35 times higher cost than for the ABWR case, but suggest the possible lower cost when the effects such as the mass production are taken into account.

JAEA Reports

Study on the thermal output scale of a very small reactor for district-heat-and-cooling system

Takahashi, Hiroki; Nakajima, Nobuya; Kusunoki, Tsuyoshi

JAERI-Tech 2003-052, 59 Pages, 2003/06


The feasibility study of a distributed small reactor system has been performed in JAERI for the utilization of the heat source for public welfare, especially for air-conditioning and hot water supply, from the view point of use expansion of nuclear energy. In this report, the optimization of heat supply system including the set up and analysis of the model city are studied for the prediction of short and long term heat demand in the heat supply area. It is important process for understanding the whole system image to estimate the suitable heat source scale for the heat demand of the heat supply area, which is within a 5-km radius from heat supply source. From the analysis, it is clear that two or more set of the nuclear reactors based on 100 MW thermal power are suitable. Furthermore, it is indicated that the introduced reactor system can be utilized for more than 30 year and the heat reserve system is indispensable. This results show the feasibility of a small reactor system for district heat-and cooling supply.

JAEA Reports

Development of in-vessel type control rod drive mechanism for a innovative small reactor (Contract research)

Yoritsune, Tsutomu; Ishida, Toshihisa

JAERI-Tech 2003-022, 118 Pages, 2003/03


no abstracts in English

JAEA Reports

Summary of the 5th Workshop on the Reduced Moderation Water Reactor; March 8, 2002, JAERI, Toaki

Nakano, Yoshihiro; Ishikawa, Nobuyuki; Nakatsuka, Toru; Iwamura, Takamichi

JAERI-Conf 2002-012, 219 Pages, 2002/12


no abstracts in English

Journal Articles

In-vessel type control rod drive mechanism using magnetic force latching for a very small reactor

Yoritsune, Tsutomu; Ishida, Toshihisa; Imayoshi, Sho*

Journal of Nuclear Science and Technology, 39(8), p.913 - 922, 2002/08

 Times Cited Count:2 Percentile:81.08(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Super safe fast reactor RAPID with full automatic operation; Application to lunar base and distributed electric power plant on earth

Kobe, Mitsuru*; Tsunoda, Hirokazu*; Mishima, Kaichiro*; Kawasaki, Akira*; Iwamura, Takamichi

Genshiryoku eye, 48(1), p.23 - 28, 2002/01

no abstracts in English

Journal Articles

Development of a micro gas chromatograph for the analysis of hydrogen isotope gas mixtures in the fusion fuel cycle

Kawamura, Yoshinori; Konishi, Satoshi; Nishi, Masataka

Fusion Engineering and Design, 58-59, p.389 - 394, 2001/11

 Times Cited Count:23 Percentile:14.62

no abstracts in English

Journal Articles

Passively safe small reactor for distributed energy system, PSRD

Ochiai, Masaaki

Nippon Genshiryoku Gakkai-Shi, 43(11), p.1070 - 1074, 2001/11

no abstracts in English

JAEA Reports

Neutronic study of a very small reactor MR-1G core for exclusive use of heat supply

Odano, Naoteru; Ishida, Toshihisa; Ochiai, Masaaki

JAERI-Research 2001-044, 53 Pages, 2001/10


A very small reactor, MR-1G with a thermal output of 1 MW, is the integral-pressurized type reactor to be used for heat supply to an office building in a city. Neutronic study has been carried out for design of the MR-1G, the core of which could achieve continuous long-term operation without refueling for 10 years assuming a load factor of the core of 44 %. In the present study, arrangement of fuel rods and $$^{235}$$U enrichment of UO$$_{2}$$ fuel rods were surveyed as design parameters. The $$^{235}$$U enrichment was determined to be 8.5 wt% to satisfy design requirement. Reactor physics parameters including reactivity coefficients and power distributions were evaluated for the determined core specifications. Reactor physics parameters related to core safety were also analyzed. Results of the safety analysis indicated that the determined core specifications satisfied design conditions. Reactor shutdown performance by dropping the reflector, which was adopted as a passive reactor shutdown system, was analyzed and confirmed it's availability from a viewpoint of reactor physics.

JAEA Reports

Manufacture of ultrasonic thickness measurement apparatus

Oba, Toshihiro; Yanagihara, Takao; Kato, Chiaki; Hamada, Shozo

JAERI-Tech 2001-059, 36 Pages, 2001/09


The demonstration test for evaluating reliability of the acid recovery evaporator at Rokkasho Reprocessing Plant has been carried out at JAERI. For the nondestructive mesurement of the thickness of heat transfer tubes in the acid recovery evaporator and short tubes used in corrosion test, we have developed ultra sonic thickness measuring apparatus using immersion method with high resolution. This apparatus can measure and record tube thickness automatically with a personal computer. The results obtained by this apparatus are coincident with the results obtained by a destructive method using an optical microscope.

JAEA Reports

Neutronic study of DRX (Deep Sea Rector X) core for deep sea research vessel

Odano, Naoteru; Ishida, Toshihisa

JAERI-Research 2001-004, 36 Pages, 2001/03


no abstracts in English

Journal Articles

Activities of design studies on innovative small and medium LWRs in JAERI

Iwamura, Takamichi; Ochiai, Masaaki

Proceedings of 1st Asian Specialist Meeting of Future Small-Sized LWR Development, p.7_1 - 7_9, 2001/00

JAERI has developed two types of small and medium size Light Water Reactors to meet the goals of innovative nuclear reactors such as sustainability and diversification of energy utilization. One is the Reduced-Moderation light Water Reactor (RMWR) with passive safety features. The reactor core consists of MOX fuel assemblies with tight lattice arrangement to increase the conversion ratio by reducing the moderation of neutron energy. The core design of 330MWe output with the operational cycle of 26 months was accomplished. A breeding ratio of 1.01, negative void coefficient and natural circulation cooling of the core were realized under the discharged burn-up of 60GWd/t. The other is the Passive Safe small Reactor for Distributed energy systems (PSRD) to diversify the nuclear energy utilization. An innovative advanced marine reactor (MRX) is used to supply the small grid electricity or electricity and heat co-supply by installing it on a barge. A small integral LWR for underground deployment is also studied for exclusive use of heat supply to household or office.

Journal Articles

Design study of a district-heating reactor installed in the basement of building

Kusunoki, Tsuyoshi; Odano, Naoteru; Nakajima, Nobuya; Fukuhara, Yoshifumi*; Ochiai, Masaaki

Nippon Genshiryoku Gakkai-Shi, 42(11), p.1195 - 1203, 2000/11

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

70 (Records 1-20 displayed on this page)