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Journal Articles

Standard for prevention of gas entrainment phenomena in fast reactors, 1; Validations of CFD methods for reproducibilities of gas entrainment phenomena

Ohshima, Hiroyuki; Tanaka, Nobuatsu*; Eguchi, Yuzuru*; Nishimura, Motohiko*; Kunugi, Tomoaki*; Uchibori, Akihiro; Ito, Kei; Sakai, Takaaki

Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(4), p.316 - 328, 2012/12

It is of importance for stable operations of sodium-cooled fast reactors (SFRs) to prevent gas entrainment (GE) phenomena due to free surface vortices. Therefore, the authors have been developing an evaluation method for GE based on computational fluid dynamics (CFD) methods. In this study, we determine the suitable CFD method for GE phenomena from several candidates through some numerical benchmarks. As the results, we obtain the following guideline for the vortex-induced gas entrainment. Free vortex flow around the vortex core can be correctly evaluated by using the appropriate numerical models such as enough mesh resolution, suitable advection solver, suitable turbulence and free surface modeling.

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.

JAEA Reports

Description of "Design guideline for gas entrainment prevention using CFD method" (Cooperative research)

Ohshima, Hiroyuki; Sakai, Takaaki; Kamide, Hideki; Kimura, Nobuyuki; Ezure, Toshiki; Uchibori, Akihiro; Ito, Kei; Kunugi, Tomoaki*; Okamoto, Koji*; Tanaka, Nobuatsu*; et al.

JAEA-Research 2008-049, 44 Pages, 2008/06

JAEA-Research-2008-049.pdf:42.3MB

Japan Atomic Energy Agency has conducted a conceptional design study of a sodium-cooled fast reactor in a frame work of the FBR feasibility study. The plant system concept for a commercial step is intended to minimize a vessel diameter to achieve an economical competitiveness. Therefore, the coolant in the vessel has relatively higher velocity and gas entrainment (GE) prevention from a liquid surface in the reactor vessel becomes one of important issues for the thermal-hydraulic design. In order to establish a design criteria for the GE prevention, the GE from vortex dimples at the liquid surface was investigated by a working group. The 1st proposal of "Design Guideline for Gas Entrainment Prevention Using CFD Method" was established based on the knowledge gained from the working group activities. This report introduces each study in the working group to clarify the basis of the design guideline.

JAEA Reports

CFD Simulation of trasient phenomena on gas entrainment

Nishimura, Motohiko*; Nonaka, Yoshiharu*; Maekawa, Isamu*

JNC-TJ9400 2005-002, 55 Pages, 2005/07

JNC-TJ9400-2005-002.pdf:74.29MB

Sodium cooled FBR reactor in a feasibility study on commercialized fast reactor system has been designed so compact that flow velocity is much higher in the reactor than in the reactors so far. This design requires an evaluation method for gas entrainment from reactor free surface and effective countermeasures. Focusing on the establishment of gas entrainment evaluation method based on CFD, CFD simulation has been carried out with analyses of an existing gas entrainment experiment. In the analyses, four turbulence models such as standard k-e, RNG k-e, non-linear k-e and k-w have been applied and evaluated for their analytical capability in addition to laminar model. Main results have been obtained as follows;1) Laminar model shows faster vortices behavior accompanied with strong flow and pressure fluctuations including random variations than any other turbulence models. RNG model shows the solutions more similar to the laminar model than the other turbulence models.2) k-w, non-linear k-e and Standard k-e models show milder vortices behavior in this order due to excess turbulence viscosity.3) Main characteristics of major turbulence models have been obtained when they are applied to gas entrainment analysis.

JAEA Reports

JAEA Reports

Numerical Study on Plant Dynamic Characteristics of Helium Gas Cooled Fast Reactor

Sato, Manabu*; Nishimura, Motohiko; Ohshima, Hiroyuki

JNC-TN9400 2003-100, 66 Pages, 2003/08

JNC-TN9400-2003-100.pdf:2.67MB

This report describes a new program for the plant dynamic response analysis of helium gas cooled fast reactors, which has the following calculation functions as point reactor kinetics, multi-dimensional reactor vessel thermal-hydraulics, volume junction gas turbine system dynamics and these interactions, and its application to the analysis of a particle-fuel-type helium gas cooled fast reactor design that was proposed in 2002 fiscal year to clarify plant dynamic characteristics under several accident conditions.

JAEA Reports

JAEA Reports

None

; ; ; ; ; *; *

JNC-TJ6400 2001-014, 39 Pages, 2002/02

JNC-TJ6400-2001-014.pdf:1.46MB

None

JAEA Reports

None

Shimakawa, T.*; *

JNC-TJ9420 2001-008, 82 Pages, 2001/03

JNC-TJ9420-2001-008.pdf:1.99MB

None

JAEA Reports

JASPER Experimental data book (VII); Gap streaming Experiment

Takemura, Morio*

JNC-TJ9450 2000-002, 112 Pages, 2000/03

JNC-TJ9450-2000-002.pdf:2.55MB

This report is intended to make it easier to apply the measured data obtained from the Gap Streaming Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about two months beginning at the start of March, 1992 as the sixth one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Gap Streaming Experiment was planned to obtain the data of neutron streaming characteristics in the inclosure system above the core of an advanced fast reactor for verification and improvement of the analysis method to be applied to the shielding design. A iron-lined solid or slit concrete assembly was placed, with or without a spectrum modifier forming soft incident neutron spectrum, behind the TSR-II reactor of Tower Shielding Facility. Inserting central cylinders and cylindrical sleeves gave various gap width and offset in the slit concrete assembly. Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured on radial traverse and on the axis behind the concrete assembly in almost all configurations. Neutron spectrum and fine radial distribution in high energy region was measured further in case of hard incident neutron spectrum, Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12140. "Measurements for the JASPER Program Gap Streaming Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

JASPER Experimental data book (VI); Special materials experiment

Mori, Tomoaki*; Takemura, Morio*

JNC-TJ9450 2000-001, 96 Pages, 2000/03

JNC-TJ9450-2000-001.pdf:2.04MB

This report is intended to make it easier to apply the measured data obtained from the Special Materials Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about a month beginning at the end of June, 1992 as the last one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Special Materials Experiment was planned to obtain the data of neutron attenuation characteristics of selected shielding materials for use in advanced fast reactors. The material of particular interest for the experiment was zirconium hydride that is rich in hydrogen. The mockup slabs for the special materials were preceded by the spectrum modifier behind the TSR-II reactor of Tower Shielding Facility. The layer of zirconium hydride was simulated with a combination of zirconium and polyethylene slabs. The thick layer of polyethylene with no zirconium was installed in some configurations.Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured in eight configurations and neutron spectrum in high energy region was measured also in almost all configurations. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12277. "Measurements for the JASPER Program Special Materials Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Revise of a basic data base for shielding design

*; Takemura, Morio*

JNC-TJ9440 2000-005, 157 Pages, 2000/03

JNC-TJ9440-2000-005.pdf:3.7MB

With use of the two-dimensional discrete ordinates code DORT and the standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the representative configurations in the Radial Shield Attenuation Experiment of the JASPER were performed. The results were compared with those obtained with use of traditional method DOT3.5/JSDJ2 for the previous JASPER experimetal analyses. In general, the change of the cross section library gives higher results and the change of the transport code gives lower results. Finally the new analysis method gives better agreement with the experimental results and also less deviations of calculational errors between various detectors. Experimental analyses for the thick concrete configulation in the Gap Streaming Experiment of the JASPER was also performed with the new analysis method, after solving the poor agreement found in last year with the original JASPER experimental analyses. The same tendency due to the library change was confirmed with the above mentioned analyses of the Radial Shield Attenuation Experiment. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments were continued through the above-mentioned experimental analyses and related informations were added for repletion of the database preserved in a computer disk holding previously accumulated data. Input data descriptions were made for auxiliary routines needed for the experimental analyses and their sample data were compiled and stored in the database.

JAEA Reports

None

Shimakawa, T.*; *; *

JNC-TJ9440 99-018, 77 Pages, 1999/03

JNC-TJ9440-99-018.pdf:1.88MB

None

JAEA Reports

Preparation of a covariance processing system for the evaluated nuclear data file, JENDL, (III)

*; *

JNC-TJ9440 99-003, 114 Pages, 1999/03

JNC-TJ9440-99-003.pdf:5.52MB

In the Japanese Nuclear Data Committee, Japan Atomic Energy Research Institute, the evaluation work of covariance data for the Japanese evaluated nuclear data file JENDL is now inprogress. Preparation of a covariance processing code system for JENDL is necessary for using its evaluated covariance data. Therefore, a covariance processing code ERRORJ was improved for processes of resonance parameters, average cosine of elastic scattering, and fission energy spectrum. Two types of utility programs were produced to treat multigroup covariance file with the COVERX format. 14 nuclides ($$^{10}$$B, $$^{11}$$B, $$^{16}$$O, $$^{23}$$Na, Cr, $$^{55}$$Mn, Fe, Ni, $$^{233}$$U, $$^{235}$$U, $$^{238}$$U, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Pu) including the evaluated covariance data for JENDL-3.2 were processed by the ERRORJ code and produced the JENDL-3.2 multigroup covariance file with the COVERX format.

JAEA Reports

Preparation of a basic data base for shielding design (IV)

*; Takemura, Morio*

JNC-TJ9440 99-002, 141 Pages, 1999/03

JNC-TJ9440-99-002.pdf:3.13MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the JASPER experiments were performed. In order to verify the new version of JSSTDL, whose cross setions of thermal energy region was updated, the polyethylene transmission experiments of the Special Materials Experiment was analysed again, and also zirconium transmission experiment of the Experiment was newly analysed. JSSTDL was applied to the analysis of neutron multiplicative region of the in-vessel fuel storage mockup configulations in the IVS Experiment. Also it was applied to the analyses of neutron streaming effect through the mockup of sodium window in B$$_{4}$$C shield in the Flux Monitor Experiment and also the mockup of narrow gaps in thick concrete shield in the Gap Streaming Experiment. The results were compared with those obtained by the same analysis method and input data using the JSDJ2 library that had been applied consistently to the JASPER experiment analyses. Although the analysis with the new version of JSSTDL resulted in a little reduction of overestimation in the polyethylene transmission configulation, the results obtained with JSSTDL are, in general, higher than those with JSDJ2 as had been found in analyses in preceding years for the Radial Shield Attenuation Experiment, the Axial Shield Experiment, the Intermediate Heat Exchager Experiment and so on. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected at the first stage of this study, were continued and new data were added into the computer disk holding previously accumulated data.

JAEA Reports

JASPER Experimental data Book (IX); Axial shield re-measurement experiment

*; Takemura, Morio*

JNC-TJ9440 99-001, 104 Pages, 1999/03

JNC-TJ9440-99-001.pdf:2.12MB

This report is intended to make it easier to apply the measured data obtained from the Axial Shield Re-Measurement Experiment, which was conducted at the Oak Ridge National Laboratory(ORNL) during about one month beginning at the start of August, 1992 as the last one of a series of experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason, the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system, and daily-basis records of measurements. Axial Shield Experiment was performed in 1990, to study the neutron attenuation characteristics of the axial shield of liquid metal fast reactor (LMR) which is designed in the fuel assembly to reduce the neutron fluence in regions above the core. However, the investigation of the experimental results showed the capability of the influence to the streaming characteristics by the scattered neutrons from the concrete region surrounding the mockup of axial shield region. So, the Axial Shield Re-Measurement Experiment was newly planned and performed, in which the concrete region was covered by lithium-paraffin layer at the front surface. A spectrum modifier was placed behind the TSR-II reactor of Tower Shielding Facility to mockup the leakage neutron spectrum typical to LMRs. Neutron flux was measured behind the experimental configurations with various types of detectors. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12276, "Measurements for the JASPER Program Axial Shield Re-Measurement Experiment") Additional information reported by the assignee is utilized also.

JAEA Reports

JASPER Experimental data book (VIII); Flux monitor experiment

Takemura, Morio*

PNC-TJ9055 98-003, 89 Pages, 1998/03

PNC-TJ9055-98-003.pdf:1.89MB

This report is intended to make it easier to apply the measured data obtained from the Flux Monitor Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about two months beginning at the start of May, 1992 as the seventh one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason, the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system, and daily-basis records of measurements. The Flux Monitor Experiment was planned to examine the shielding concerns and neutron transport characteristics pertaining to the neutron instrumentation systems (NIS) designed to monitor neutron flux within the reactor vessel of an advanced fast reactor, for verification and improvement of the analysis method to be applied to the shielding design. A spectrum modifier and a mockup around NIS was placed, with or without a in-vessel fuel storage region, behind the TSR-II reactor of Tower Shielding Facility. Neutron flux was measured behind the configurations or in situ with various types of detectors. The integral neutron flux in wide energy region was measured with Bonner ball detectors on the axis and on radial traverse in almost all configurations. Fast neutron spectrum was further measured with spectrometors and also radial distribution of low energy neutron with fission chambers. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12171, "Measurements for the JASPER Program Flux Monitor Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Preparation of a basic data base for shielding design (III)

Takemura, Morio*

PNC-TJ9055 98-002, 111 Pages, 1998/03

PNC-TJ9055-98-002.pdf:2.21MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the In-vessel Fuel Storage (IVS) Experiment and the Intermediate Heat Exchanger (IHX) Experiment were performed. The results were compared with those obtained by the same analysis method and input data using the JSDJ2 library that had been applied consistently to the JASPER experiment analyses. In general, the results obtained with JSSTDL are higher than those with JSDJ2 as were found in analyses in last two years for the Radial Shield Attenuation Experiment and the Special Materials Experiment and also the Axial Shield Experiment. The calculation-to-experiment ratios of the fast neutron flux just behind deep penetration in sodium were obtained first by these IVS and lHX experimental analyses with the JSSTDL library. However, it was confirmed not to be easy to evaluate the accuracy of sodium cross section because of its dependency on how to model the swelled sodium slabs and tanks. The analyses with the JSSTDL library were verified by comparison with other analyses with another library based on JENDL-3.2. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected at the first stage of this study, were continued and new data were added into the computer disk holding previously accumulated data.

JAEA Reports

None

*; Shimakawa, T.*

PNC-TJ9055 97-005, 35 Pages, 1997/03

PNC-TJ9055-97-005.pdf:1.67MB

None

JAEA Reports

None

*; Yano, Kazutaka*; *

PNC-TJ9055 97-003, 94 Pages, 1997/03

PNC-TJ9055-97-003.pdf:2.52MB

None

65 (Records 1-20 displayed on this page)