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Journal Articles

Study on vortex cavitation in scaled upper plenum model of Japan Sodium-cooled Fast Reactor, 2; Investigation of effective cavitation suppressor

Hagiwara, Hiroyuki*; Ezure, Toshiki; Ito, Kei; Kamide, Hideki

Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 7 Pages, 2014/11

Journal Articles

Experimental study on vortex cavitation in scaled upper plenum model of Japan Sodium-cooled Fast Reactor, 1; Evaluation of circulation and vortex cavitation occurrences using vortex model

Ezure, Toshiki; Ito, Kei; Kameyama, Yuri*; Hagiwara, Hiroyuki*; Kamide, Hideki

Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 7 Pages, 2014/11

JAEA Reports

Experimental study on thermal stratification phenomena in compact reactor vessel of sodium cooled fast reactor; Evaluation on stratification interface behavior under natural circulation condition

Hagiwara, Hiroyuki; Kimura, Nobuyuki*; Onojima, Takamitsu; Nagasawa, Kazuyoshi*; Kamide, Hideki; Tanaka, Masaaki

JAEA-Research 2014-014, 178 Pages, 2014/09

JAEA-Research-2014-014.pdf:53.12MB

Thermal stratification in the upper plenum is one of the most important issues of a reactor vessel in sodium cooled fast reactor. The steep temperature gradient across the stratification interface may cause the thermal load against the reactor vessel wall. In this study, the water experiment was carried out using the 1/11 scale upper plenum model of the Japan sodium-cooled fast reactor (JSFR) in order to evaluate the thermal stratification under the natural circulation condition and a direct heat exchanger (DHX) operation condition. The temperature gradient under the natural circulation condition was approximately 1/3 times smaller than that under the forced circulation condition. In the DHX operation case, the steep temperature gradient occurred in the lower region of upper plenum due to the cold fluid from the outlet of DHX.

JAEA Reports

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2011

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; et al.

JAEA-Review 2013-018, 169 Pages, 2013/09

JAEA-Review-2013-018.pdf:15.71MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in 2011 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2011, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.

Journal Articles

Thermal-hydraulic studies on self actuated shutdown system for Japan Sodium-cooled Fast Reactor

Hagiwara, Hiroyuki; Yamada, Yumi*; Eto, Masao*; Oyama, Kazuhiro*; Watanabe, Osamu*; Yamano, Hidemasa

Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 8 Pages, 2012/12

The self-actuated shutdown system (SASS), which is selected for Japan Sodium-cooled Fast Reactor (JSFR), is a passive reactor shutdown system utilizing a Curie point electromagnet (CPEM). With CPEM, an excessive fuel outlet temperature rise is sensed and the control rods are released into the core, and the reactor can be shutdown. Therefore it is important for feasibility of SASS to be established by assuring a quick response of CPEM to the coolant temperature rise. In this paper, a device named "flow collector", which collects flows discharged from six fuel subassemblies surrounding CPEM backup control rods, has been proposed to ensure a shorter response time.

Journal Articles

Experimental study for the proposal of design measures against cover gas entrainment and vortex cavitation with 1/11th scale reactor upper sodium plenum model of Japan Sodium-cooled Fast Reactor

Yoshida, Kazuhiro*; Sakata, Hideyuki*; Sago, Hiromi*; Shiraishi, Tadashi*; Oyama, Kazuhiro*; Hagiwara, Hiroyuki*; Yamano, Hidemasa; Yamamoto, Tomohiko

Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 9 Pages, 2012/12

To prevent the vortex cavitations, asymmetric flow in the upper plenum due to the radial slit with upper internal structure (UIS) has been mitigated by installing a cylindrical structure named as dummy plug instead of the fuel handling machine only used for refueling period. In this study, the extended brim and the division plate at the slit of UIS have been proposed in order to improve flow pattern in upper plenum for the purpose of the vortex cavitation prevention.

JAEA Reports

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2010

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Ueno, Takashi; Tokuyasu, Shingo; Daimaru, Shuji; Takeuchi, Ryuji; et al.

JAEA-Review 2012-020, 178 Pages, 2012/06

JAEA-Review-2012-020.pdf:33.16MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II. And Phase III started in 2010 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2010, as a part of the Phase II based on the MIU Master Plan updated in 2002.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 3; Neutron spectrum measurements in intense pulsed neutron fields of the 120-GeV proton facility using a current Bonner sphere technique

Hagiwara, Masayuki*; Sanami, Toshiya*; Iwamoto, Yosuke; Arakawa, Hiroyuki*; Shigyo, Nobuhiro*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; Nakamura, Takashi*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.52 - 56, 2011/02

In pbar target station, the pulsed proton beam with the power of around 75 kW and the time structure of 1.6 $$mu$$s pulse width and 2.2 s cycle time bombards the pbar production target and produces high instantaneous intensity neutron (burst neutron) fields. The duration of the burst neutrons, which is less than $$mu$$s, is very severe condition to measure neutron spectra with a conventional Bonner sphere technique with pulse readout electronics because of signal pile-up problem. In this study, we have developed a current readout Bonner sphere technique to measure neutron spectra in a burst neutron field. We have measured the neutron spectra on the pbar target and graphite dump. The neutron spectra obtained with the present technique show generally good agreements with the calculation results using MARS code except difference of the thermal neutron flux due to the geometrical problem.

JAEA Reports

Hydrochemical investigation at the Mizunami Underground Research Laboratory; Compilation of groundwater chemistry in the Mizunami group and Toki granite area (April, 2004 - March, 2008)

Sai, Masataka; Hagiwara, Hiroki; Matsushima, Hiroyuki*; Noda, Masatoshi*; Noda, Masaru*; Ando, Kenichi*; Tanaka, Tatsuya*; Ueda, Tadashi*; Honda, Yuko*; Mizuno, Takashi

JAEA-Data/Code 2010-010, 75 Pages, 2010/09

JAEA-Data-Code-2010-010.pdf:2.5MB

This report compiles data set of the groundwater chemistry obtained at Mizunami Underground Research Laboratory (MIU) between the fiscal year 2004 and the fiscal year 2007. These data includes groundwater chemistry of inflow in the shafts and sampled groundwater in the boreholes, which drilled from sub-stages of MIU and from surface (MSB-2, MSB-4, and MIZ-1). Basic information (e.g. sampling location, sampling date, sampling method, analytical method) are also described in terms of quality control and traceability.

Journal Articles

Experimental studies of shielding and irradiation effects at high energy accelerator facilities

Nakashima, Hiroshi; Sakamoto, Yukio; Iwamoto, Yosuke; Matsuda, Norihiro; Kasugai, Yoshimi; Nakane, Yoshihiro; Masukawa, Fumihiro; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; et al.

Nuclear Technology, 168(2), p.482 - 486, 2009/11

BB2007-3640.pdf:0.22MB

 Times Cited Count:7 Percentile:47.42(Nuclear Science & Technology)

Experimental studies of shielding and radiation effects have been started using 120-GeV proton synchrotron at Fermi National Accelerator Laboratory (FNAL) under collaboration between FNAL and Japan. The first campaign of the experiment was carried out at the Pbar target station and Numi experimental station at FNAL, using antiproton and neutrino production targets irradiated by 120-GeV protons. The generated secondary particles passing through steel, concrete and rock were measured by activation methods as well as by other detectors such as scintillator with a veto counter, phoswich detector and a Bonner ball counter on trial. Preliminary experimental results are presented.

Journal Articles

Preparation of polymer electrolyte membranes consisting of alkyl sulfonic acid for a fuel cell using radiation grafting and subsequent substitution/elimination reactions

Takahashi, Shuichi*; Okonogi, Hiroyuki*; Hagiwara, Tokio*; Maekawa, Yasunari

Journal of Membrane Science, 324(1-2), p.173 - 180, 2008/10

 Times Cited Count:36 Percentile:74.23(Engineering, Chemical)

Polymer electrolyte membranes (PEM) consisting of alkylsulfonic acid were successfully synthesized by radiation-induced graft polymerization of methyl acrylate (MA) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film, followed by sulfonation at an $$alpha$$-carbonyl carbon of the MA units in the grafting chain using an equimolar complex of chlorosulfonic acid and dioxane (ClSO$$_{3}$$H-Complex). The ion exchange capacity and ion conductivity of the MA-grafted PEM were controlled in the respective ranges of 0.54-1.47 mmol/g and 0.014-0.14 S/cm by changing the grafting degree. It has been confirmed by titrimetric and gravimetric analyses of sulfonic and carboxylic acids in the film that the sulfonation reaction is accompanied with decarboxylation of the MA units equimolar to the substituted sulfonic acids (substitution of carboxylic acid with sulfonic acid), that the sulfonation degree was about 30%.

Journal Articles

Tomonaga-Luttinger liquid in a quasi-one-dimensional $$S$$ = 1 antiferromagnet observed by specific heat measurements

Hagiwara, Masayuki*; Tsujii, Hiroyuki*; Rotundu, C. R.*; Andraka, B.*; Takano, Yasumasa*; Tateiwa, Naoyuki; Kobayashi, Tatsuo*; Suzuki, Takafumi*; Suga, Seiichiro*

Physical Review Letters, 96(14), p.147203_1 - 147203_4, 2006/04

 Times Cited Count:18 Percentile:68.26(Physics, Multidisciplinary)

Specific-heat experiments on single crystals of the $$S$$ = 1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C$$_9$$H$$_{24}$$N$$_4$$)(NO$$_2$$)(ClO$$_4$$) (NTENP) have been performed in magnetic fields applied both parallel and perpendicular to the spin chains. We have found for the parallel field configuration that the magnetic specific heat ($$C_{rm mag}$$) is proportional to temperature ($$T$$) above a critical field $$H_c$$, at which the energy gap vanishes, in a temperature region above that of the long-range ordered state. The ratio $$C_{rm mag}$$ = $$T$$ increases as the magnetic field approaches $$H_c$$ from above. The data are in good quantitative agreement with the prediction of the $$c$$=1 conformal field theory in conjunction with the velocity of the excitations calculated by a numerical diagonalization, providing conclusive evidence for a Tomonaga-Luttinger liquid.

Oral presentation

Novel electrolyte membranes synthesized by radiation graft polymerization and polymeric transformation of functional groups

Takahashi, Shuichi; Maekawa, Yasunari; Hagiwara, Tokio*; Okonogi, Hiroyuki*

no journal, , 

Aliphatic vinyl monomers, like acrylatic acid derivatives or vinyl ketones, were grafted by $$gamma$$-ray irradiation on a poly(ethylene-co-tetrafluoroethylene) (ETFE) film. Then, novel electrolyte membranes, which possess alkyl sulfonic acids on grafted chain, were synthesized by polymeric transformation of functional groups. The electrolyte membranes prepared by the above approach showed higher heat-stability in the wet condition compared to the electrolyte membranes with sulfonated styrene grafted membranes.

Oral presentation

Characterization of graft-type PEM prepared with the help of polymeric transformation of functional groups

Takahashi, Shuichi; Maekawa, Yasunari; Hagiwara, Tokio*; Okonogi, Hiroyuki*

no journal, , 

Methyl acrylate monomer was grafted by $$gamma$$-ray irradiation on a poly(ethylene-co-tetrafluoroethylene)(ETFE) film. Then, the novel polymer electrolyte membranes (PEM), which possess alkyl sulfonic acids on grafted chain, were synthesized by polymeric transformation of functional groups. The PEM prepared by the above approach were analyzed structurally and characterized well.

Oral presentation

Polymer electrolyte membranes consisting of alkyl sulfonic acid for fuel cells, synthesized by radiation-induced graft polymerization and subsequent chemical transformation

Maekawa, Yasunari; Takahashi, Shuichi; Hanh, T. T.*; Okonogi, Hiroyuki*; Hagiwara, Tokio*

no journal, , 

Polymer electrolyte membranes (PEMs) consisting of alkylsulfonic acid in grafting chains can be prepared by radiation-induced graft polymerization of methyl acrylate (MA) onto a poly(ethylene-co-tetrafluoroethylene) (ETFE) film, followed by the sulfonation of MA units in the grafting chains using an equimolar complex of chlorosulfonic acid and dioxane. The sulfonation reaction accompanied equimolar decarboxylation of the MA unit (substitution of carboxylic acid with sulfonic acid) to give the PEMs with conductivity of 0.01-0.11 S/cm. Furthermore, the replacement of the MA unit with methyl metacrylate (MMA) as a comonomer in grafting chains enhances the stability of the PEM at higher temperatures.

Oral presentation

Shielding experiments at high energy accelerators of FERMI, 6; Measurement of reaction products

Matsumura, Hiroshi*; Kasugai, Yoshimi; Yashima, Hiroshi*; Iwase, Hiroshi*; Matsuda, Norihiro; Kinoshita, Norikazu*; Sanami, Toshiya*; Hagiwara, Masayuki*; Shigyo, Nobuhiro*; Arakawa, Hiroyuki*; et al.

no journal, , 

A gold activation detector was studied as a high energy neutron detector at high radiation field in a series of shielding experiment at Fermi National Accelerator Laboratory. We could measure spallation residual nuclei with wide threshold energy by using a combination method with radiological chemical separation and X-X-$$gamma$$ coincidence detection methods. It was shown the detector was effective for high energy neutron detector.

Oral presentation

Current status of JASMIN: Japanese-American study of muon interactions and neutron detection

Nakashima, Hiroshi; Mokhov, N.*; Iwamoto, Yosuke; Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; Sanami, Toshiya*; et al.

no journal, , 

Several multi-purpose high-energy radiation transport codes are used in many research fields such as high-energy physics as well as accelerator facility shielding designs. The codes are benchmarked against experimental data on a regular basis. To promote this to a higher level and to a hardly explored field of neutron radiation induced by energetic muons, a JASMIN collaboration (Japanese-American Study of Muon Interaction and Neutron detection), has been created with several Laboratories and Universities of Japan and U.S.A. The collaboration has performed a series of experiments at the Pbar target station and NuMI facility at Fermi National Accelerator Laboratory, using irradiation of targets with 120 GeV protons for antiproton and neutrino production. This paper reviews recent activities and results.

Oral presentation

Experimental study for the proposal of design measures against cover gas entrainment and vortex cavitation with 1/11 scale reactor upper sodium plenum model of Japan Sodium-cooled Fast Reactor

Yoshida, Kazuhiro*; Sakata, Hideyuki*; Sago, Hiromi*; Shiraishi, Tadashi*; Oyama, Kazuhiro*; Hagiwara, Hiroyuki*; Yamano, Hidemasa; Yamamoto, Tomohiko

no journal, , 

no abstracts in English

Oral presentation

Analysis of temperature response characteristics for coolant around SASS sensitive alloy in demonstration FBR

Hagiwara, Hiroyuki*; Oyama, Kazuhiro*; Watanabe, Osamu*; Eto, Masao*; Yamano, Hidemasa

no journal, , 

Fast Reactor Cycle Technology Development Project (FaCT) adopts Self-Actuated Shutdown System (SASS). SASS is the system dropping the control rod to shutdown by sensing the core outlet temperature rise from Anticipated Transient Without Scram (ATWS) of abnormal transition. Hence, coolant flow velocity around the SASS sensing alloy improves temperature response time constant. Especially, accelerating the coolant flow velocity in the slit installed at the SASS sensing alloy. This study aims at flow acceleration and considers proposed structure of incorporating flow collector surrounding six SASS auxiliary assembly. The result of the effectiveness evaluation by three-dimensional thermal hydraulic analyses is presented.

Oral presentation

Thermal-hydraulic experiments for structural soundness of sodium-cooled fast reactor, 1; Confirmation test of countermeasure against vortex cavitation

Hagiwara, Hiroyuki; Kimura, Nobuyuki; Aizawa, Kosuke; Kobayashi, Jun; Kamide, Hideki

no journal, , 

Water test has been carried out to evaluate vortex cavitation which may occur near the entrance of hot-leg in Japan sodium-cooled fast reactor. It has been confirmed that flow splitter, which is a partition plate installed on reactor vessel wall near the hot-leg, has a preventive effect on vortex cavitation.

23 (Records 1-20 displayed on this page)