Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 134

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

JAEA Reports

Review of research on advanced computational science in FY2020

Center for Computational Science & e-Systems

JAEA-Evaluation 2021-001, 66 Pages, 2021/11

JAEA-Evaluation-2021-001.pdf:1.66MB

Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid- and long-term goal of the Japan Atomic Energy Agency", has been performed by Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of external experts and authorities which does research evaluation and advice for the assistance of the future research and development. This report summarizes the results of the R&D performed by CCSE in FY2020 (April 1st, 2020 - March 31st, 2021), the results expected at the end of the 3rd mid and long-term goal period, and the evaluation by the committee on them.

JAEA Reports

Review of research on advanced computational science in FY2019

Center for Computational Science & e-Systems

JAEA-Evaluation 2020-002, 37 Pages, 2020/12

JAEA-Evaluation-2020-002.pdf:1.59MB

Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid and long term goal of the Japan Atomic Energy Agency", has been performed at Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of outside experts and authorities which does research evaluation and advice for the assistance of the future research and development. This report summarizes the results of the R&D performed at CCSE in FY2019 (April 1st, 2019 - March 31st, 2020) and the evaluation by the committee on them.

Journal Articles

MPI/OpenMP hybrid parallelization of a Monte Carlo neutron/photon transport code MVP

Nagaya, Yasunobu; Adachi, Masaaki*

Proceedings of International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering (M&C 2017) (USB Flash Drive), 6 Pages, 2017/04

MVP is a general-purpose Monte Carlo code for neutron and photon transport calculations based on the continuous-energy method. To speed up the MVP code, hybrid parallelization is applied with a message passing interface library MPI and a shared-memory multiprocessing library OpenMP. The performance test has been done for an eigenvalue calculation of a fast reactor subassembly, a fixed-source calculation of a neutron/photon coupled problem and a PWR full core model. Comparisons has been made for MPI only with 4 processes and hybrid parallelism with 4 processes $$times$$ 3 threads. As a result, the hybrid parallelism yields the reduction of elapsed time by 16% to 34% and the used memories are almost the same.

Journal Articles

Sorption of Eu$$^{3+}$$ on Na-montmorillonite studied by time-resolved laser fluorescence spectroscopy and surface complexation modeling

Sasaki, Takayuki*; Ueda, Kenyo*; Saito, Takumi; Aoyagi, Noboru; Kobayashi, Taishi*; Takagi, Ikuji*; Kimura, Takaumi; Tachi, Yukio

Journal of Nuclear Science and Technology, 53(4), p.592 - 601, 2016/04

 Times Cited Count:12 Percentile:80.58(Nuclear Science & Technology)

The influences of pH and the concentrations of Eu$$^{3+}$$ and NaNO$$_{3}$$ on the sorption of Eu$$^{3+}$$ to Na-montmorillonite were investigated through batch sorption measurements and time-resolved laser fluorescence spectroscopy (TRLFS). The pH had a little effect on the distribution coefficients (Kd) in 0.01 M NaNO$$_{3}$$, whereas the Kd strongly depended on pH at 1 M NaNO$$_{3}$$. A cation exchange model combined with a one-site non-electrostatic surface complexation model was successfully applied to the measured Kd. The TRLFS spectra of Eu$$^{3+}$$ sorbed were processed by parallel factor analysis (PARAFAC), which corresponded to one outer-sphere (factor A) and two inner-sphere (factor B and C) complexes. It turned out that factors A and B correspond to Eu$$^{3+}$$ sorbed by ion exchange sites and inner-sphere complexation with hydroxyl groups of the edge faces, respectively. Factor C became dominant at relatively high pH and ionic strength and likely correspond to the precipitation of Eu(OH)$$_{3}$$ on the surface.

Journal Articles

Parallel computing with Particle and Heavy Ion Transport code System (PHITS)

Furuta, Takuya; Sato, Tatsuhiko; Ogawa, Tatsuhiko; Niita, Koji*; Ishikawa, Kenichi*; Noda, Shigeho*; Takagi, Shu*; Maeyama, Takuya*; Fukunishi, Nobuhisa*; Fukasaku, Kazuaki*; et al.

Proceedings of Joint International Conference on Mathematics and Computation, Supercomputing in Nuclear Applications and the Monte Carlo Method (M&C + SNA + MC 2015) (CD-ROM), 9 Pages, 2015/04

In Particle and Heavy Ion Transport code System PHITS, two parallel computing functions are prepared to reduce the computational time. One is the distributed-memory parallelization using message passing interface (MPI) and the other is the shared-memory parallelization using OpenMP directives. Each function has advantages and disadvantages, and thus, by adopting both functions in PHITS, it is possible to conduct parallel computing suited for needs of users. It is also possible to conduct the hybrid parallelization by the intra-node OpenMP parallelization and the inter-node MPI parallelization in supercomputer systems. Each parallelization functions were explained together with some application results obtained using a workstation and a supercomputer system, K computer at RIKEN.

Journal Articles

Medical application of the PHITS code, 2; Acceleration by parallel computing

Furuta, Takuya; Sato, Tatsuhiko

Igaku Butsuri, 35(3), p.264 - 268, 2015/00

Time-consuming Monte Carlo dose calculation becomes feasible owing to the development of computer technology. However, the recent development is due to emergence of the multi-core high performance computers. Therefore, parallel computing becomes a key to achieve good performance of software programs. A Monte Carlo simulation code PHITS contains two parallel computing functions, the distributed-memory parallelization using protocols of MPI and the shared-memory parallelization using OpenMP directives. Users can choose the two functions according to their needs. This paper gives the explanation of the two functions with their advantages and disadvantages. Some test applications are also provided to show their performance using a typical multi-core high performance workstation.

Journal Articles

Nonlinear acceleration of the electron inertia-dominated magnetohydrodynamic modes due to electron parallel compressibility

Matsumoto, Taro; Naito, Hiroshi*; Tokuda, Shinji; Kishimoto, Yasuaki

Physics of Plasmas, 12(9), p.092505_1 - 092505_7, 2005/09

 Times Cited Count:2 Percentile:7.19(Physics, Fluids & Plasmas)

The behavior of the collisionless magnetohydrodynamics modes is investigated by the gyro-kinetic particle simulation in a cylindrical tokamak plasma in the parameter region where the effects of electron inertia and electron parallel compressibility are competitive for magnetic reconnection. Although the linear growth of the $$m=1$$ internal kink-tearing mode is dominated by the electron inertia, it is found that the growth rate can be nonlinearly accelerated due to the electron parallel compressibility proportional to the ion sound Larmor radius $$rho_s$$. It is also found that, as decreasing the electron skin depth $$delta_e$$, the maximum growth rate before the internal collapse saturates independently of the microscopic scales such as $$delta_e$$ and $$rho_s$$. The acceleration of growth rate is also observed in the nonlinear phase of the $$m=2$$ double tearing mode.

JAEA Reports

MVP/GMVP 2; General purpose Monte Carlo codes for neutron and photon transport calculations based on continuous energy and multigroup methods

Nagaya, Yasunobu; Okumura, Keisuke; Mori, Takamasa; Nakagawa, Masayuki

JAERI 1348, 388 Pages, 2005/06

JAERI-1348.pdf:2.02MB

To realize fast and accurate Monte Carlo simulation of neutron and photon transport problems, two vectorized Monte Carlo codes MVP and GMVP have been developed at JAERI. MVP is based on the continuous energy model and GMVP is on the multigroup model. Compared with conventional scalar codes, these codes achieve higher computation speed by a factor of 10 or more on vector supercomputers. Both codes have sufficient functions for production use by adopting accurate physics model, geometry description capability and variance reduction techniques. The first version of the codes was released in 1994. They have been extensively improved and new functions have been implemented. The major improvements and new functions are (1) capability to treat the scattering model expressed with File 6 of the ENDF-6 format, (2) time-dependent tallies, (3) reaction rate calculation with the pointwise response function, (4) flexible source specification, etc. This report describes the physical model, geometry description method used in the codes, new functions and how to use them.

JAEA Reports

Radiation monitoring data of the HTTR rise-to-power test; Results up to 30MW operation on the high-temperature test operation mode

Ashikagaya, Yoshinobu; Kawasaki, Tomokatsu; Yoshino, Toshiaki; Ishida, Keiichi

JAERI-Tech 2005-010, 81 Pages, 2005/03

JAERI-Tech-2005-010.pdf:16.65MB

no abstracts in English

Journal Articles

Parallel volume rendering on immersive projection technology

Nakajima, Norihiro; Ono, Nobuaki*; Suzuki, Yoshio*; Kureta, Masatoshi*

Denki Gakkai Rombunshi, C, 124(10), p.2197 - 2198, 2004/10

Our research interest is to implement volume rendering on CAVE system at enough frame rate. It can be implemented on CAVE easily using texture mapping but there are some defects; for example frame rate declines when the view point is close to the data and images projected to the screens become big. Thus we try to find another way to implement it on CAVE. Considering that Onyx300 is a parallel computer and there are some algorisms of volume rendering which improve the frame rate, we make the program that draws stereo images through two of the algorisms and by parallel computing, and displays only two images on CAVE. And we confirm that this program works well and draws stereo images at sufficient frame rates.

Journal Articles

In the case of Japan Atomic Energy Research Institute

Azumi, Masafumi

Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.378 - 381, 2004/05

Progress of large scale scientific simulation environment in JAERI is briefly described. The expansion of fusion simulation science have been played a key role in the increasing performances of super computers and computer network system in JAERI. Both scalar parallel and vector parallel computer systems are now working in Naka and Tokai sites respectively and, particle and fluid simulation codes developed under the fusion simulation project, NEXT, are running on each system. The storage grid system has been also successfully developed for the effective visualization analysis by remote users. Fusion research is going to enter the new phase of ITER, and the need for the super computer system with higher performance are increasing more than as ever along with the development of reliable simulation models.

JAEA Reports

Proceedings of Conferences on the Large Data Management; January 29-31, 2003, Advanced Photon Research Center, Kyoto

Advanced Photon Research Center; Center for Promotion of Computational Science and Engineering

JAERI-Conf 2004-002, 81 Pages, 2004/03

JAERI-Conf-2004-002.pdf:7.77MB

no abstracts in English

JAEA Reports

New method for model coupling using Stampi; Application to the coupling of Atmosphere Model (MM5) and Land-Surface Model (SOLVEG)

Nagai, Haruyasu

JAERI-Data/Code 2003-021, 36 Pages, 2003/12

JAERI-Data-Code-2003-021.pdf:1.73MB

A new method to couple atmosphere and land-surface models using the massage passing interface (MPI) was proposed to develop a atmosphere-land model for studies on heat, water, and material exchanges at around the land surface. A non-hydrostatic atmospheric dynamic model of Pennsylvania State University and National Center for Atmospheric Research (PUS/NCAR-MM5) and a detailed land surface model (SOLVEG) including the surface-layer atmosphere, soil, and vegetation developed at Japan Atomic Energy Research Institute (JAERI) are used as the atmosphere and land-surface models, respectively. Concerning the MPI, a message passing library named Stampi developed at JAERI that can be used between different parallel computers is used. The models are coupled by exchanging calculation results by using MPI on their independent parallel calculations.

Journal Articles

Proposal and implementation of a fluid-Structure coupled simulation system with parallel commercial codes

Guo, Z.; Hazama, Osamu; Yamagiwa, Mitsuru; Hirayama, Toshio; Matsuzawa, Teruo*

Advances in computational & experimental engineering & sciences (CD-ROM), 6 Pages, 2003/07

no abstracts in English

Journal Articles

Multiple time and spatial scale plasma simulation; Prospect based on current status

Kishimoto, Yasuaki

Purazuma, Kaku Yugo Gakkai-Shi, 79(5), p.460 - 463, 2003/05

This is a collection of review article related to the "Multiple Time and Spatial Scale Plasma Simulation" of various fields including fundamental research area of self-organization, magnetic and laser fusion field, space and astrophysics field where a plasma plays an essential roles.

Journal Articles

Global gyrokinetic simulation of ion temperature gradient driven turbulence in plasmas using a canonical Maxwellian distribution

Idomura, Yasuhiro; Tokuda, Shinji; Kishimoto, Yasuaki

Nuclear Fusion, 43(4), p.234 - 243, 2003/04

 Times Cited Count:114 Percentile:95.12(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Parallel implementation of the solver for the one-dimensional Vlasov-Poisson equation based on the DA-CIP method

Utsumi, Takayuki*; Koga, J. K.; Kunugi, Tomoaki*

Parallel Computational Fluid Dynamics; New Frontiers and Multi-Disciplinary Applications, p.539 - 546, 2003/00

no abstracts in English

JAEA Reports

Radiation monitoring data of the HTTR rise-to-power test; Results up to 30 MW operation on the rated operation mode

Ashikagaya, Yoshinobu; Yoshino, Toshiaki; Yasu, Katsuji; Kurosawa, Yoshiaki; Sawa, Kazuhiro

JAERI-Tech 2002-094, 80 Pages, 2002/12

JAERI-Tech-2002-094.pdf:12.8MB

no abstracts in English

Journal Articles

Nonlocal transport related to dynamics along magnetic field line

Takizuka, Tomonori; Hojo, Hitoshi*; Hatori, Tadatsugu*

Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.857 - 912, 2002/09

Transport along field lines in magnetic confinement plasmas is reviewed. Collisionless and collisional-diffusive transports are discussed. Because of their fast transport, features of plasmas along field lines are apt to behave nonlocally. A nonlocal phenomenon of scrape-off layer (SOL) and divertor plasmas in a tokamak is introduced, whose asymmetry along field lines is induced by the thermoelectric instability related to the SOL current. A local phenomenon called MARFE can be brought by the strong radiation cooling. The "snake" with nonlocal feature along field lines but with local structure perpendicular to the field is observed in a tokamak core plasma. For mirror-confined plasmas, axial particle losses from the mirror ends, especially pitch-angle-sattering losses into the loss cone and nondiabatic losses due to the breakdown of adiabaticity of the magnetic moment, are also discussed in the relation to nonlocal axial transport.

134 (Records 1-20 displayed on this page)