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Journal Articles

Off-gas processing system operations for mercury target vessel replacement at J-PARC

Kai, Tetsuya; Uchida, Toshitsugu; Kinoshita, Hidetaka; Seki, Masakazu; Oi, Motoki; Wakui, Takashi; Haga, Katsuhiro; Kasugai, Yoshimi; Takada, Hiroshi

Journal of Physics; Conference Series, 1021(1), p.012042_1 - 012042_4, 2018/06

JAEA Reports

Mock-up test of the modified STACY (Performance check of water feed and drain system)

Seki, Masakazu; Maekawa, Tomoyuki; Izawa, Kazuhiko; Sono, Hiroki

JAEA-Technology 2017-038, 52 Pages, 2018/03


The Japan Atomic Energy Agency is conducting a reactor modification project of the Static Experiment Critical Facility (STACY). In the modification, STACY is to be converted from a thermal reactor using solution fuel into that using fuel rods and light water moderator. Reactivity of the modified STACY core is controlled by the water level fed in the core tank as well as the present STACY. In order to verify the basic design of the water feed and drain system of the modified STACY, we constructed a mockup test apparatus with almost the same structure and specifications as the modified STACY. In the mockup test, performance checks were pursued regarding limitation of maximum flow of water feeding, adjustment of the flow rate of water feeding, stop of water feeding and others. This report describes the outline and results of the mock-up test of the water feed and drain system of the modified STACY.

JAEA Reports

Mock-up test of the modified STACY (Accuracy verification of water-feed- stop switch detector)

Seki, Masakazu; Izawa, Kazuhiko; Sono, Hiroki

JAEA-Technology 2014-047, 22 Pages, 2015/03


The Japan Atomic Energy Agency is conducting a reactor modification project of the Static Experiment Critical Facility (STACY). In the modification, STACY is to be converted from a thermal reactor using solution fuel into that using fuel rods and light water moderator. Reactivity of the modified STACY is controlled by the water level fed in the core tank as well as the present STACY. Regarding water level detection, however, a float-type water-feed-stop switch is adopted in the modified STACY because the electro-conductivity-type switch of the present STACY for uranyl nitrate solution cannot detect demineralized water used in the modified STACY. For safety operation of the modified STACY, the float-type switch needs accurate and reliable detection of water level at any temperature. This report describes a mock-up test on accuracy verification of the float-type water-feed-stop switch in whole range of water temperature (room temperature $$sim$$70$$^{circ}$$C) in the modified STACY operation.

JAEA Reports

Operation databook of the fuel treatment system of the Static Experiment Critical Facility (STACY) and the Transient Experiment Critical Facility (TRACY); JFY 2004 to JFY 2008

Kokusen, Junya; Sumiya, Masato; Seki, Masakazu; Kobayashi, Fuyumi; Ishii, Junichi; Umeda, Miki

JAEA-Technology 2012-041, 32 Pages, 2013/02


Uranyl nitrate solution fuel used in the STACY and the TRACY is adjusted in the Fuel Treatment System, in which such parameters are varied as concentration of uranium, free nitric acid, soluble neutron poison, and so on. Operations for concentration and denitration of the solution fuel were carried out with an evaporator from JFY 2004 to JFY 2008 in order to adjust the fuel to the experimental condition of the STACY and the TRACY. In parallel, the solution fuel in which some kinds of soluble neutron poison were doped was also adjusted in JFY 2005 and JFY 2006 for the purpose of the STACY experiments to determine neutron absorption effects brought by fission products, etc. After these experiments in the STACY, a part of the solution fuel including the soluble neutron poison was purified by the solvent extraction method with mixer-settlers in JFY 2006 and JFY 2007. This report summarizes operation data of the Fuel Treatment System from JFY 2004 to JFY 2008.

JAEA Reports

Maintenance of used components in spallation neutron source; Moderator $$cdot$$ reflector and proton beam window

Teshigawara, Makoto; Kinoshita, Hidetaka; Wakui, Takashi; Meigo, Shinichiro; Seki, Masakazu; Harada, Masahide; Ito, Manabu; Suzuki, Toru; Ikezaki, Kiyomi; Maekawa, Fujio; et al.

JAEA-Technology 2012-024, 303 Pages, 2012/07


3 GeV Protons with 1 MW beam power are irradiated to mercury target of spallation neutron source in Materials and Life science Facility (MLF), which is one of facilities of J-PARC. Irradiated components, such as target container, moderator, reflector and proton beam window, are needed to replace periodically due to irradiation damage of high energy protons and neutrons. These used components are replaced remotely because of highly activated. Maintenance scenario was settled so as to handle these components. Required remote handling machines were designed and installed in hot cell and other room of the MLF. We performed remote handling tests by using actual components to confirm the design. We report results, such as replacement procedure, trouble and its solution, etc., for moderator, reflector and proton beam window in order to provide the handling of actual used components.

JAEA Reports

Result of study on storage plan for irradiated components generated at MLF in J-PARC

Kinoshita, Hidetaka; Wakui, Takashi; Matsui, Hiroki; Maekawa, Fujio; Kasugai, Yoshimi; Haga, Katsuhiro; Teshigawara, Makoto; Meigo, Shinichiro; Seki, Masakazu; Sakamoto, Shinichi; et al.

JAEA-Technology 2011-040, 154 Pages, 2012/03


In the MLF, relatively high level irradiated components will be generated. Therefore, these components can not be kept in standard facilities. For the irradiated components at the MLF, the storage plan using the facilities in the Nuclear Science Research Institute has been studied, but the concrete plan is not decided yet. In this report, outline of the components, prehistory of the studying for storage, schedule of the component generation and status of the possible facility, which is a hot laboratory, are described. Resulting from the comparison between the generation schedule and the plan of the hot laboratory, the difference is very large. Present status of the hot laboratory and the cost estimation of the modification to use for storage of the MLF components were studied. Using the hot laboratory seems not to have advantage from the view point of cost and modification method. Therefore, the study on a new storage facility construction will be started as soon as possible.

JAEA Reports

Influence of Great East Japan Earthquake on neutron source station in J-PARC

Sakai, Kenji; Sakamoto, Shinichi; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Kasugai, Yoshimi; Tatsumoto, Hideki; et al.

JAEA-Technology 2011-039, 121 Pages, 2012/03


This report investigates the behavior, damage and restoration of a neutron source station of the MLF at the Great East Japan Earthquake and verified the safety design for emergency accidents in the neutron source station. In the MLF, after an occurrence of the Earthquake, strong quakes were detected at the instruments, the external power supply was lost, all of the circulators shut down automatically, and the hydrogen gas was released. The leakages of mercury, hydrogen and radio-activation gases did not occur. While, the quakes made gaps between the shield blocks and ruptured external pipe lines by subsidence around the building. But significant damages to the components were not found though the pressure drop of compressed air lines influenced on a target trolley lock system and so on. These results substantiated the validity of the safety design for emergency accidents in the source station, and suggested several points of improvement.

Journal Articles

Influence of Great East Japan Earthquake on neutron target station in J-PARC

Sakai, Kenji; Futakawa, Masatoshi; Takada, Hiroshi; Sakamoto, Shinichi; Maekawa, Fujio; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; et al.

Proceedings of 20th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-20) (USB Flash Drive), 6 Pages, 2012/03

This report investigates behaviors and damages of each component in a neutron target station of the MLF at the J-PARC at the time of the Great East Japan Earthquake (GEJE). At the date of the GEJE, in the MLF, strong quakes were detected at several instruments, an external power supply were lost, all of the circulation systems were shut down automatically, and a hydrogen gas was released as planned. Leakage of activation liquids and gases did not occur. While, the quakes made gaps between shield blocks and ruptured external pipe lines for air and water by subsidence. But significant damages on the components of the target station were not found though a loss of compressed air supply affected lock systems with air cylinders and pneumatic operation values. These results substantiated a validity of safety design on the target station for emergency accidents.

Journal Articles

Fabrication of nanowires by varying energy microbeam lithography using heavy ions at the TIARA

Kamiya, Tomihiro; Takano, Katsuyoshi; Ishii, Yasuyuki; Sato, Takahiro; Oikawa, Masakazu*; Okubo, Takeru; Haga, Junji*; Nishikawa, Hiroyuki*; Furuta, Yusuke*; Uchiya, Naoyuki*; et al.

Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2317 - 2320, 2009/06

 Times Cited Count:5 Percentile:56.05(Instruments & Instrumentation)

Journal Articles

Neutronics experimental study on tritium production in solid breeder blanket mockup with neutron reflector

Sato, Satoshi; Verzilov, Y.*; Ochiai, Kentaro; Wada, Masayuki*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Seki, Masakazu; Oginuma, Yoshikazu*; Kawabe, Masaru*; et al.

Journal of Nuclear Science and Technology, 44(4), p.657 - 663, 2007/04

 Times Cited Count:5 Percentile:56.65(Nuclear Science & Technology)

Neutronics experiments have been performed for the solid breeder blanket using a DT neutron source at the FNS facility in JAEA. We have applied the blanket mockup composed of two enriched Li$$_{2}$$TiO$$_{3}$$ and three beryllium layers, and measured the detailed spatial distribution of the tritium production rate (TPR) using enriched Li$$_{2}$$CO$$_{3}$$ pellets. TPRs in the pellets have been measured by a liquid scintillation counter. Experiments have been done under a condition with a neutron reflector surrounding the DT neutron source. Numerical simulations have been performed using the MCNP-4C with the FENDL-2.0 and JENDL-3.3. The ranges of ratios of calculation results to experimental ones (C/Es) are 0.97-1.17 concerning with local TPR, and 1.04-1.09 for the integrated tritium production. It is found that the total integrated tritium production, which corresponds to tritium breeding ratio, can be predicted within uncertainty of 10% using the Monte Carlo calculation code and latest nuclear data libraries.

Journal Articles

1-D crosslinked polymer nanowires prepared by single particle nanofabrication techniques

Seki, Shuhei*; Tsukuda, Satoshi*; Tagawa, Seiichi*; Sugimoto, Masaki; Sato, Takahiro; Oikawa, Masakazu*; Sakai, Takuro

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 145, 2007/02

no abstracts in English

JAEA Reports

Editing of the environmental report; Environmental concerning activity at JAERI and JNC in the first half fiscal year of 2005

Narita, Osamu; Iwata, Noboru; Isobe, Yoshihiro; Seki, Masakazu; Kadosaka, Hidetake; Ninomiya, Kazushige; Sato, Osamu

JAEA-Technology 2006-037, 102 Pages, 2006/06


We edited and published the Environmental Report according to the law on Promotion of the Environmental Concerning Activity by means of the Publish of Environmental Concerning Data. The report included the environmental concerning activity at the Japan Atomic Energy Research Institute (JAERI) and the Japan Nuclear Fuel Cycle Development Institute (JNC) in the first half year of 2005. This report is the first one which is regulated and obligated by the law. We have made much effort for gathering the data and gained a lot of experience on editing the report. We hope this paper is useful not only for the back data of our environmental report, but also for the organization which is planning to publish the similar environmental report.

Journal Articles

Operation and management of STACY experiment using Pseudo-FPs-doped fuel

Izawa, Kazuhiko; Seki, Masakazu; Hirose, Hideyuki; Kaminaga, Jota; Aoyama, Yasuo; Yoshida, Hiroshi; Sono, Hiroki; Ogawa, Kazuhiko; Sakuraba, Koichi

UTNL-R-0453, p.9_1 - 9_10, 2006/03

no abstracts in English

JAEA Reports

Report on the fuel treatment facility operation

Kokusen, Junya; Seki, Masakazu; Abe, Masayuki; Nakazaki, Masato; Kida, Takashi; Umeda, Miki; Kihara, Takehiro; Sugikawa, Susumu

JAERI-Tech 2005-004, 53 Pages, 2005/03


This report presents operating records of dissolution of uranium dioxide and concentration of uranyl nitrate solution and acid removal, which have been performed from 1994 through 2003, for the purpose of feeding 10% and 6% enriched uranyl nitrate solution fuel to Static Experimental Critical Facility(STACY) and Transient Experimental Critical Facility(TRACY) in Nuclear Fuel Safety Engineering Facility(NUCEF).

Journal Articles

Tritium distribution measurement of FNS tritium targets by imaging plate

Kutsukake, Chuzo; Seki, Masakazu; Tanaka, Shigeru; Oginuma, Yoshikazu*; Abe, Yuichi; Yamauchi, Michinori*

Fusion Science and Technology, 41(3), p.555 - 559, 2002/05

no abstracts in English

Journal Articles

Development of high intensity deuteron ion source for fusion intense neutron source

Kinsho, Michikazu; Sugimoto, Masayoshi; Seki, Masakazu; Oguri, Hidetomo; Okumura, Yoshikazu

Review of Scientific Instruments, 71(2), p.963 - 965, 2000/02

 Percentile:100(Instruments & Instrumentation)

no abstracts in English

JAEA Reports

Development of a bucket type ion source for FNS

Miyamoto, Naoki*; Seki, Masakazu; Kinsho, Michikazu; Oguri, Hidetomo; Okumura, Yoshikazu

JAERI-Tech 99-010, 27 Pages, 1999/02


no abstracts in English

Oral presentation

ITER/TBM neutronics experiments at FNS, 1; Experiment

Ochiai, Kentaro; Sato, Satoshi; Takakura, Kosuke; Yamauchi, Michinori*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Seki, Masakazu; Kawabe, Masaru*; Konno, Chikara; et al.

no journal, , 

The test blanket module (TBM), water cooled pebble bed type, which is to be installed in ITER has been designed in JAEA. The TBM is made up of water cooling system with a kind of low activation ferrite, beryllium as neutron breeder, $$^{6}$$Li enriched Li$$_{2}$$TiO$$_{3}$$ or Li$$_{2}$$O pebble as tritium breeding material. To evaluate the nuclear properties, we have carried out some DT neutronics experiments with TBM mock up assemblies in the Fusion Neutronics Source (FNS) and one of the TBM nuclear properties, the tritium production rate (TPR), in the Li$$_{2}$$TiO$$_{3}$$ layer has been clarified by means of a liquid scintillation counter method with Li$$_{2}$$CO$$_{3}$$ pellets or Li$$_{2}$$O pebbles.

Oral presentation

Reactor physics on STACY heterogeneous core with light water moderator, 3; Evaluation of kinetics in reactivity insertion events

Aoyama, Yasuo; Komuro, Michiyasu; Seki, Masakazu; Izawa, Kazuhiko; Sono, Hiroki; Ogawa, Kazuhiko; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

no journal, , 

no abstracts in English

Oral presentation

Damage measurement of mercury target vessel and replacement to new target

Haga, Katsuhiro; Wakui, Takashi; Naoe, Takashi; Kogawa, Hiroyuki; Kinoshita, Hidetaka; Teshigawara, Makoto; Kasugai, Yoshimi; Seki, Masakazu; Hanano, Kohei; Suzuki, Toru; et al.

no journal, , 

Pitting damage of the target vessel wall is the crucial issue for the development of the high power mercury target. The damage is affected by the target vessel structure and the proton beam condition. In order to improve the evaluation accuracy of the pitting depth, the data of the pitting damage in the J-PARC mercury target was indispensable. Because the first target vessel of J-PARC was damaged by the earthquake, the preparations for cutting out specimens were carried out in advance. The surface dose rate is more than 10micro Sv/h. Then, we developed the cutting machine using hole saw, and we succeeded in cutting out specimens of the outer diameter of 50 mm. A spot which seems the cavitation damage was found by visual observation. The target replacement was also successfully finished. The radioactive gas release was more than the expectation, and it roused the necessity of reconsider the off-gas treatment system.

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