A Model intercomparison of atmospheric Cs concentrations from the Fukushima Daiichi Nuclear Power Plant accident, phase III; Simulation with an identical source term and meteorological field at 1-km resolution

Sato, Yosuke*; Sekiyama, Tsuyoshi*; Fang, S.*; Kajino, Mizuo*; Qurel, A.*; Qulo, D.*; Kondo, Hiroaki*; Terada, Hiroaki; Kadowaki, Masanao; Takigawa, Masayuki*; et al.

Atmospheric Environment; X (Internet), 7, p.100086_1 - 100086_12, 2020/10

https://doi.org/10.1016/j.aeaoa.2020.100086

The third model intercomparison project for investigating the atmospheric behavior of Cs emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident (FDNPP-MIP) was conducted. A finer horizontal grid spacing (1 km) was used than in the previous FDNPP-MIP. Nine of the models used in the previous FDNPP-MIP were also used, and all models used identical source terms and meteorological fields. Our analyses indicated that most of the observed high atmospheric Cs concentrations were well simulated, and the good performance of some models improved the performance of the multi-model ensemble. The analyses also confirmed that the use of a finer grid resolution resulted in the meteorological field near FDNPP being better reproduced. The good representation of the wind field resulted in the reasonable simulation of the narrow distribution of high deposition amount to the northwest of FDNPP and the reduction of the overestimation over the area to the south of FDNPP. In contrast, the performance of the models in simulating plumes observed over the Nakadori area, the northern part of Gunma, and the Tokyo metropolitan area was slightly worse.

Model intercomparison of atmospheric Cs from the Fukushima Daiichi Nuclear Power Plant accident; Simulations based on identical input data

Sato, Yosuke*; Takigawa, Masayuki*; Sekiyama, Tsuyoshi*; Kajino, Mizuo*; Terada, Hiroaki; Nagai, Haruyasu; Kondo, Hiroaki*; Uchida, Junya*; Goto, Daisuke*; Qulo, D.*; et al.

Journal of Geophysical Research; Atmospheres, 123(20), p.11748 - 11765, 2018/10

https://doi.org/10.1029/2018JD029144

A model intercomparison of the atmospheric dispersion of Cs emitted following the Fukushima Daiichi Nuclear Power Plant accident was conducted by 12 models to understand the behavior of Cs in the atmosphere. The same meteorological data, horizontal grid resolution, and an emission inventory were applied to all the models to focus on the model variability originating from the processes included in each model. The multi-model ensemble captured 40% of the observed Cs events, and the figure-of-merit in space for the total deposition of Cs exceeded 80. Our analyses indicated that the meteorological data were most critical for reproducing the Cs events. The results also revealed that the differences among the models were originated from the deposition and diffusion processes when the meteorological field was simulated well. However, the models with strong diffusion tended to overestimate the Cs concentrations.

Stress corrosion cracking behavior of type 304 stainless steel irradiated under different neutron dose rates at JMTR

Kaji, Yoshiyuki; Kondo, Keietsu; Aoyagi, Yoshiteru; Kato, Yoshiaki; Taguchi, Taketoshi; Takada, Fumiki; Nakano, Junichi; Ugachi, Hirokazu; Tsukada, Takashi; Takakura, Kenichi*; et al.

Proceedings of 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors (CD-ROM), p.1203 - 1216, 2011/08

In order to investigate the effect of neutron dose rate on tensile property and irradiation assisted stress corrosion cracking (IASCC) growth behavior, the crack growth rate (CGR) test, tensile test and microstructure observation have been conducted with type 304 stainless steel specimens. The specimens were irradiated in high temperature water simulating the temperature of boiling water reactor (BWR) up to about 1dpa with two different dose rates at the Japan Materials Testing Reactor (JMTR). The radiation hardening increased with the dose rate, but there was little effect on CGR. Increase of the yield strength of specimens irradiated with the low dose rate condition was caused by the increase of number density of frank loops. Little difference of radiation-induced segregation at grain boundaries was observed in specimens irradiated by different dose rates. Furthermore, there was little effect on local plastic deformation behavior near crack tip in the crystal plasticity simulation.

Induction of mutations by the ion beam irradiation to the bulb-scales of cv. Acapulco.

Kondo, Masayoshi*; Koike, Yosuke*; Hase, Yoshihiro; Yokota, Yuichiro; Kobayashi, Hitoshi*

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 75, 2008/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2007-060.pdf

no abstracts in English

A Migration analysis of (Horvth) (Homoptera: Delphacidae) using hourly catches and a three-dimensional simulation model

Otsuka, Akira*; Watanabe, Tomonari*; Suzuki, Yoshito*; Matsumura, Masaya*; Furuno, Akiko; Chino, Masamichi; Kondo, Tomoya*; Kamimuro, Tsuyoshi*

Agricultural and Forest Entomology, 8(1), p.35 - 47, 2006/02

https://doi.org/10.1111/j.1461-9555.2006.00284.x

1 Migration of Sogatella furcifera captured in Japan in the 2003 season were analyzed using hourly catches and a simulation model.2. The catch data showed several clear migration peaks, with average durations of 4 h. The peaks were separated from each other by approximately 12 h, corresponding to the observed fact that planthoppers take off at dusk and dawn.3. The simulation model, together with the hourly catches, enabled an estimation of migration source regions.4. Possible migration sources during our hourly observation period were located in the coastal area of Fujian province in China, as well as Taiwan.

SIMMER-III: A Computer Program for LMFR Core Disruptive Accident Analysis; Version 3.A Model Summary and Program Description

Yamano, Hidemasa; Fujita, Satoshi; Tobita, Yoshiharu; Kamiyama, Kenji; Kondo, Satoru; Morita, Koji*; Fischer, E. A.; Brear, D. J.; Shirakawa, Noriyuki*; Cao, X.; et al.

JNC TN9400 2003-071, 340 Pages, 2003/08

JNC-TN9400-2003-071.pdf:1.54MB

An advanced safety analysis computer code, SIMMER-III, has been developed to investigate postulated core disruptive accidents in liquid-metal fast reactors (LMFRs). SIMMER-III is a two-dimensional, three-velocity-field, multiphase, multicomponent, Eulerian, fluid-dynamics code coupled with a space-dependent neutron kinetics model. By completing and integrating all the physical models originally intended at the beginning of this code development project, SIMMER-III is now applicable to integral reactor calculations and other complex multiphase flow problems. A systematic code assessment program, conducted in collaboration with European research organizations, has shown that the advanced features of the code have resolved many of the limitations and problem areas in the previous SIMMER-II code. In this report, the models, numerical algorithms and code features of SIMMER-III Version 3.A are described along with detailed program description. Areas which require future model refinement are also discussed. SIMMER-III Version 3.A, a coupled fluid-dynamics and neutronics code system, is expected to significantly improve the flexibility and reliability of LMFR safety analyses.

Development of pulsed MeV positron beam line

Maekawa, Masaki; Masuno, Shinichi*; Hirano, Takeshi*; Kondo, Masakazu*; Kawasuso, Atsuo; Ito, Hisayoshi; Okada, Sohei

JAERI-Tech 2003-039, 52 Pages, 2003/03

JAERI-Tech-2003-039.pdf:5.14MB

no abstracts in English

Noninductive current drive and steady-state operation in JT-60U

Ushigusa, Kenkichi; Ide, Shunsuke; Oikawa, Toshihiro; Suzuki, Takahiro; Kamada, Yutaka; Fujita, Takaaki; Ikeda, Yoshitaka; Naito, Osamu; Matsuoka, Mamoru*; Kondoh, Takashi; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.255 - 277, 2002/09

https://doi.org/10.13182/FST02-A228

Studies on non-inductive current drive and development of an integrated steady-state high performance operation in JT-60 are reviewed. Experiments on lower hybrid current drive in JT-60 haven shown a large non-inductive current up to 3.5MA, high current drive efficiency of 3.6x1019m-2A/W. Basic studies on LH waves in JT-60 have contributed to understand current drive physics. Significant progress in neutral beam current drive has been made in JT-60 by testing the performance of negative ion based NBI (N-NBI). The CD efficiency of ~1.5x1019m-2A /W, and N-NB driven current of ~1MA have been demonstrated in N-NBCD. Strongly localized driven current by electron cyclotron current drive was identified with a fundamental O-mode scheme. Efficiency of 0.5x1019m-2A/W and EC driven current of 0.2MA were achieved and suppression of neo-classical tearing mode was demonstrated. Based on these developments, two integrated steady-state operation scenarios were developed in JT-60, which are reversed magnetic shear (R/S) plasmas and high bp ELMy H-mode. In these operation regimes, discharges have been sustained near the steady-state current profile under full non-inductive current drive. High performance plasmas with a high nDotETio and at high normalized density were also produced under fully non-inductive condition in high bp ELMy H-mode and R/S mode.

SIMMER-IV: A Three-Dimensional Computer Program for LMFR Core Disruptive Accident Analysis - Version 1.B Model Summary and Program Description -

kondo, Satoru; Yamano, Hidemasa; Tobita, Yoshiharu; Fujita, Satoshi; Morita, Koji*; Mizuno, Masahiro*;

JNC TN9400 2001-003, 307 Pages, 2000/11

JNC-TN9400-2001-003.pdf:8.33MB

An advanced safety analysis computer code, SIMMER-III, has been developed at Japan Nuclear Cycle Development Institute (JNC) to more realistically investigate postulated core disruptive accidents in liquid-metal fast reactors. The two-dimensional framework of SIMMER-III fluid dynamics has been extended to three dimensions to a new code, SIMMER-IV, which is currently (in Version 1) coupled with the existing two-dimensional neutronics model. With the completion of the first SIMMER-IV version, the applicability of the code is further enhanced and the many of the known limitations in SIMMER-III are eliminated. The sample calculations demonstrated the general validity of SIMMER-IV. This report describes SIMMER-IV version 1.B, by documenting the models, numerical algorithms and code features, along with the program description and input and output information to aid the users. Further extension of the code is planned to couple the three-dimensional neutronics in the future.

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; ; ; ; Kurosawa, A.; ; Maki, Akira

JNC TN8410 99-022, 136 Pages, 1999/07

JNC-TN8410-99-022.pdf:46.42MB

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