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Journal Articles

Verification of fuel assembly bowing analysis model for core deformation reactivity evaluation

Doda, Norihiro; Uwaba, Tomoyuki; Ohgama, Kazuya; Yoshimura, Kazuo; Nemoto, Toshiyuki*; Tanaka, Masaaki; Yamano, Hidemasa

Nihon Kikai Gakkai Kanto Shibu Dai-29-Ki Sokai, Koenkai Koen Rombunshu (Internet), 5 Pages, 2023/03

An evaluation method for reactivity feedback due to core deformation during reactor power increase in sodium-cooled fast reactors is being developed for realistic core design evaluation. In this evaluation method, fuel assembly bowing was modeled with a beam element of the finite element method, and the assembly's pad contact between adjacent assemblies was modeled with a dedicated element which could consider the wrapper tube cross-sectional distortion and the pad stiffness depending on pad contact conditions. This fuel assembly bowing analysis model was verified for thermal bowing of a single assembly and assembly pad contact between adjacent assemblies in a core as past benchmark problems. The calculation results by this model showed good agreement with those of reference solutions of theoretical solutions or results by participating institutions in the benchmark. This study confirmed that the analysis model was able to calculate thermal assembly bowing appropriately.

Journal Articles

Development of evaluation method for core deformation reactivity feedback in sodium-cooled fast reactor by coupled analysis approach

Doda, Norihiro; Uwaba, Tomoyuki; Yokoyama, Kenji; Nemoto, Toshiyuki*; Tanaka, Masaaki

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 14 Pages, 2022/03

In sodium-cooled fast reactors, reactivity feedback is generated by thermal deformation of the core fuel assembly during core temperature rise. To utilize the core deformation reactivity as an inherent safety characteristic and to eliminate excessive conservativeness of core design in the safety evaluation, an evaluation method by coupling analyses of neutronics, thermal-hydraulics, and structural deformation has been developed. An experiment of unprotected loss-of-flow event in the experimental fast breeder reactor EBR-II was analyzed. The analysis results show that the core deformation reactivity has a negative feedback effect, and that the deformation reactivity is affected not only by the fuel movement but also by the movement of reflectors around the fuel. As a result, the availability of the evaluation method for core deformation reactivity feedback by coupled analysis approach is confirmed.

Journal Articles

Development of neutronics, thermal-hydraulics, and structure mechanics coupled analysis method on integrated numerical analysis for design optimization support in fast reactor

Doda, Norihiro; Uwaba, Tomoyuki; Nemoto, Toshiyuki*; Yokoyama, Kenji; Tanaka, Masaaki

Keisan Kogaku Koenkai Rombunshu (CD-ROM), 26, 4 Pages, 2021/05

For design optimization of fast reactors, in order to consider the feedback reactivity due to thermal deformation of the core when the core temperature rises, which could not be considered in the conventional design analysis, a neutronics, thermal-hydraulics, and structure mechanics coupled analysis method has been developed. Neutronics code, plant dynamics code, and structural mechanics code are coupled by a control module in python script. This paper outlines the coupling method of analysis codes and the results of its application to an experiment in an actual plant.

Journal Articles

Complementary characterization of radioactivity produced by repetitive laser-driven proton beam using shot-to-shot proton spectral measurement and direct activation measurement

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Yogo, Akifumi; Nishiuchi, Mamiko; Orimo, Satoshi; Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.

Japanese Journal of Applied Physics, 51(4), p.048003_1 - 048003_2, 2012/04

 Times Cited Count:2 Percentile:8.97(Physics, Applied)

A proton beam driven by a repetitive high-intensity-laser is utilized to induce a $$^{7}$$Li(p,n)$$^{7}$$Be nuclear reaction. The total activity of $$^{7}$$Be are evaluated by two different methods. The activity obtained measuring the decay $$gamma$$-rays after 1912 shots at 1 Hz is 1.7$$pm$$0.2 Bq. This is in good agreement with 1.6$$pm$$0.3 Bq evaluated from the proton energy distribution measured using a time-of-flight detector and the nuclear reaction cross-sections. We conclude that the production of activity can be monitored in real time using the time-of-flight-detector placed inside a diverging proton beam coupled with a high-speed signal processing system.

Journal Articles

A Possible overestimation of the effect of acetylation on lysin residues in KQ mutant analysis

Fujimoto, Hirofumi*; Higuchi, Mariko; Koike, Manabu*; Ode, Hirotaka*; Pinak, M.; Kotulic Bunta, J.*; Nemoto, Toshiyuki*; Sakudo, Takashi*; Honda, Naoko*; Maekawa, Hideaki*; et al.

Journal of Computational Chemistry, 33(3), p.239 - 246, 2012/01

 Times Cited Count:30 Percentile:64.16(Chemistry, Multidisciplinary)

Lysine acetylation is one of the most common protein post transcriptional modifications. The acetylation effects of lysine residues on Ku protein were examined herein applying several computer simulation techniques. Acetylation of the lysine residues did not reduce the affinity between Ku and its substrate, DNA, in spite of the fact that the substitution of lysine with glutamine (KQ mutant) reduced the affinity of Ku for DNA, or the substitution of lysine with arginine (KR mutant) did not reduce it, as previously reported in experimental studies. These results suggest that the effects of in vivo acetylation may be overestimated when the KQ mutant is employed in mimicry of the acetylated protein.

JAEA Reports

Evaluation of fundamental performance of JAEA's new supercomputer system

Sakamoto, Kensaku; Shimizu, Futoshi; Tsuruoka, Takuya*; Nemoto, Toshiyuki*; Ishikawa, Naota*

JAEA-Testing 2011-005, 88 Pages, 2011/11

JAEA-Testing-2011-005.pdf:5.16MB

A new supercomputer system was deployed at JAEA in March 2010. The system is mainly composed of a large scale Linux cluster system (PRIMERGY BX900: 200Tflops) and a lead off system of RIKEN's K computer (FX1: 12Tflops), whose purposes are to deliver a high-performance parallel computing environment and application code development environment for the K computer, respectively. In this report, we present results of the evaluation of fundamental performance of the system.

Journal Articles

Proton-induced nuclear reactions using compact high-contrast high-intensity laser

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Yogo, Akifumi; Nishiuchi, Mamiko; Orimo, Satoshi; Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.

Applied Physics Express, 2(6), p.066001_1 - 066001_3, 2009/05

 Times Cited Count:14 Percentile:49.88(Physics, Applied)

Protons with energies up to 3.5 MeV have been generated by a 10 Hz compact laser with an intensity of about 10$$^{20}$$ W/cm$$^{2}$$, focused on a 7.5 mm thick polyimide target. These protons were used to induce a nuclear reaction of $$^{11}$$B(p,n)$$^{11}$$C. A total activity of 11.1 Bq was created after 60-shot laser irradiation. The possibility of thin layer activation (TLA) using a high-intensity ultra-short pulsed laser is discussed.

Journal Articles

DNA strand break; Structural and electrostatic properties studied by molecular dynamics simulation

Kotulic Bunta, J.*; Laaksonen, A.*; Pinak, M.; Nemoto, Toshiyuki*

Computational Biology and Chemistry, 30(2), p.112 - 119, 2006/04

 Times Cited Count:3 Percentile:21.79(Biology)

Due to their lethal consequences, single and double strand breaks are among the most important and dangerous DNA lesions. This work defines and analyzes a DNA with single strand break as a template study for future complex analyses of biologically serious double strand break damage and its enzymatic repair mechanisms. Besides a non-damaged DNA serving as a reference system, system with open valences of the atoms at the strand break ends as well as a system with filled valences was simulated. As for the results, the system with open valences is partly disrupted, and the system with filled valences is stabilized by forming new hydrogen bonds between two strand endings.

Journal Articles

Molecular dynamics simulation of clustered DNA damage sites containing 8-oxoguanine and abasic site

Fujimoto, Hirofumi*; Pinak, M.; Nemoto, Toshiyuki*; O'Neill, P.*; Kume, Etsuo; Saito, Kimiaki; Maekawa, Hideaki*

Journal of Computational Chemistry, 26(8), p.788 - 798, 2005/06

 Times Cited Count:23 Percentile:57.6(Chemistry, Multidisciplinary)

Clustered DNA damage sites induced by ionizing radiation have been suggested to have serious consequences to organisms. In this study, approaches based on molecular dynamics (MD) simulation have been applied to examine conformational changes and energetic properties of DNA molecules containing clustered damage sites consisting of 2 lesioned sites, 8-oxoG and AP site. After 1 nanosecond of MD simulation, one of the 6 DNA molecules containing a clustered damage site develop specific characteristic features: sharp bending at the lesioned site and weakening or complete loss of electrostatic interaction energy between 8-oxoG and bases locating on the complementary strand. From these results it is suggested that these changes would make it difficult for the repair enzyme to bind to the lesions within the clustered damage site and thereby result in a reduction of its repair capacity.

Journal Articles

Molecular dynamics of 8-oxoguanine lesioned B-DNA molecule; Structure and energy analysis

Pinak, M.; O'Neill, P.*; Fujimoto, Hirofumi; Nemoto, Toshiyuki*

AIP Conference Proceedings 708, p.310 - 313, 2004/05

The multiple nanosecond molecular dynamics simulations of DNA mutagenic oxidative lesion - 7,8-dihydro-8-oxoguanine (8-oxoG), complexed with the repair enzyme - human oxoguanine glycosylase 1 (hOGG1) in a physiological aqueous environment, were performed in order to describe the structural and energy changes in DNA and the dynamical process of DNA-enzyme complex formation. In complex the N-terminus of arginine 324 was found located close to the phosphodiester bond of the nucleotide with 8-oxoG enabling chemical reaction(s) between the amino acid and the lesion. The recognition of lesion on DNA, its recognition by repair enzyme and the formation of stable DNA-enzyme complex are necessary conditions for the onset of the successful enzymatic repair process.

Journal Articles

Large scale MD simulation of 8-oxoguanine and AP site multiple lesioned DNA molecule combined with biomolecular visualization software

Fujimoto, Hirofumi; Pinak, M.; Nemoto, Toshiyuki*; Sakamoto, Kiyotaka*; Yamada, Kazuyuki*; Hoshi, Yoshiyuki*; Kume, Etsuo

Journal of Molecular Structure; THEOCHEM, 681(1-3), p.1 - 8, 2004/01

We developed the novel system, Fujitsu Bio Molecular Visualization System (F-BMVS), that enables to produce real pictures and an animation by arranging them along a time series of a large scale simulation of biomolecules associated with a molecular dynamics (MD) simulation program. This animation system is used to study the results of molecular dynamics code, AMBER, in order to find structural differences on the lesioned DNA comparing with non-damaged DNA. These structural differences would be a factor that guides a repair enzyme to discriminate a lesion from non-damaged DNA region.

JAEA Reports

Vectorization, parallelization and porting of nuclear codes; 2001

Akiyama, Mitsunaga*; Katakura, Fumishige*; Kawasaki, Nobuo*; Nemoto, Toshiyuki*; Tsuruoka, Takuya*; Adachi, Masaaki*; Ishizuki, Shigeru*; Kume, Etsuo

JAERI-Data/Code 2003-009, 307 Pages, 2003/07

JAERI-Data-Code-2003-009.pdf:10.37MB

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the supar computer system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 10 codes in fiscal 2001. In this report, the parallelization of Newtron Radiography for 3 dimensional CT code NR3DCT, the vectorization of Unsteady-state heat conduction code THERMO3D, the porting of initial program of MHD simulation, the tuning of Heat And Mass Balance Analysis Code HAMBAC, the porting and parallelization of Monte Carlo N-Particle transport code MCNP4C3, the porting and parallelization of Monte Carlo N-Particle Transport code system MCNPX2.1.5, the porting of code CINAC-V4, the porting of Assisted Model Building with Energy Refinement Amber5 code system, the part of additional VisLink library Multidimensional Two-fluid model code ACD3D and the porting of experiment data processing code for GS8500 to SR8000 are described.

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization); Progress report fiscal 1999

Adachi, Masaaki*; Ishizuki, Shigeru*; Ogasawara, Shinobu*; Kume, Etsuo; Yatake, Yoichi*; Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Kawai, Wataru*

JAERI-Data/Code 2000-043, 220 Pages, 2001/02

JAERI-Data-Code-2000-043.pdf:7.39MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (Porting); Progress report fiscal 1999

Kawasaki, Nobuo*; Nemoto, Toshiyuki*; Kawai, Wataru*; Ogasawara, Shinobu*; Ishizuki, Shigeru*; Kume, Etsuo; Yatake, Yoichi*; Adachi, Masaaki*

JAERI-Data/Code 2000-039, 134 Pages, 2001/01

JAERI-Data-Code-2000-039.pdf:4.32MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (Parallelization on scalar processors); Progress report fiscal 1999

Yatake, Yoichi*; Kume, Etsuo; Kawai, Wataru*; Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Adachi, Masaaki*; Ishizuki, Shigeru*; Ogasawara, Shinobu*

JAERI-Data/Code 2000-038, 57 Pages, 2000/12

JAERI-Data-Code-2000-038.pdf:2.3MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (Vectorization and parallelization); Progress report fiscal 1998

Ishizuki, Shigeru*; Ogasawara, Shinobu*; Kawai, Wataru*; Nemoto, Toshiyuki*; Kume, Etsuo; Adachi, Masaaki*; Kawasaki, Nobuo*; Yatake, Yoichi*

JAERI-Data/Code 2000-018, p.217 - 0, 2000/03

JAERI-Data-Code-2000-018.pdf:6.35MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (Porting); Progress report fiscal 1998

Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Kume, Etsuo; Kawai, Wataru*; Adachi, Masaaki*; Ishizuki, Shigeru*; Yatake, Yoichi*; Ogasawara, Shinobu*

JAERI-Data/Code 2000-017, p.99 - 0, 2000/03

JAERI-Data-Code-2000-017.pdf:3.31MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes (Parallerization on scalar processors); Progress report fiscal 1998

Yatake, Yoichi*; Adachi, Masaaki*; Kume, Etsuo; Kawai, Wataru*; Kawasaki, Nobuo*; Nemoto, Toshiyuki*; Ishizuki, Shigeru*; Ogasawara, Shinobu*

JAERI-Data/Code 2000-016, p.43 - 0, 2000/03

JAERI-Data-Code-2000-016.pdf:1.36MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes on the VPP500 system (Porting); Progress report fiscal 1997

*; *; *; *; *; Adachi, Masaaki*; Ogasawara, Shinobu*; *; Kume, Etsuo

JAERI-Data/Code 99-027, 39 Pages, 1999/05

JAERI-Data-Code-99-027.pdf:1.21MB

no abstracts in English

JAEA Reports

Vectorization, parallelization and porting of nuclear codes on the VPP500 system (Vectorization); Progress report fiscal 1997

*; *; *; *; *; Ogasawara, Shinobu*; Adachi, Masaaki*; *; Kume, Etsuo

JAERI-Data/Code 99-026, 91 Pages, 1999/05

JAERI-Data-Code-99-026.pdf:2.9MB

no abstracts in English

40 (Records 1-20 displayed on this page)