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Kondo, Hiroo*; Kanemura, Takuji*; Hirakawa, Yasushi; Furukawa, Tomohiro
Fusion Engineering and Design, 136(Part A), p.24 - 28, 2018/11
Times Cited Count：1 Percentile：0.01(Nuclear Science & Technology)In the IFMIF-EVEDA project, we designed and constructed the IFMIF-EVEDA Li Test Loop (ELTL), and we performed experiments to validate the stability of the Li target. This project required a diagnostic tool to be developed in order to examine the Li target; as such, we developed a unique laser-based method that we call the laser-probe method; this method combines a high-precision laser distance meter with a statistical data analysis method. Following the successful development of the laser-probe method, we proposes a long-distance-measurement of the laser probe method (long-distance LP method) as a diagnostics tool in off-beam conditions for IFMIF or the relevant neutron sources. In this study, the measurement uncertainty resulting from coherency of the laser in a long-distance-measurement has been verified by using stationary objects and a water jet simulating the liquid Li target.
Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-11) (USB Flash Drive), 8 Pages, 2016/10
In order to evaluate the distance for fragmentation of molten core material discharged into the lower sodium plenum during core disruptive accidents in sodium-cooled fast reactors, experiments with simulated molten materials and coolants (water, sodium) was carried out, where an empirical correlation of the distance for fragmentation was developed. The empirical correlation developed by this study showed a good agreement with the measurement results obtained by the present experiments. It was found that in order to well-predict the distance for fragmentation in sodium, thermal phenomena, such as sodium boiling and resultant vapor expansion, needed to be considered.
Watanabe, Fumitaka; Okuno, Hiroshi
Proceedings of 18th International Symposium on the Packaging and Transport of Radioactive Materials (PATRAM 2016) (DVD-ROM), 9 Pages, 2016/09
This paper shows our calculations on the effects of a radiological release by assuming a severe accident in nuclear material transportation. Following recalculations of safe distance from the point of a severe accident during transportation of a transportation cask TN12 typically used in France containing spent nuclear fuel, and calculations to replicate the "Regulatory Guide: Emergency Preparedness for Nuclear Facilities", a similar calculation was made for a spent fuel transportation cask NFT-14P that was typically utilized in Japan instead of TN12. The safe distance was calculated to be about 30 m. The above calculations were made with the HotSpot codes which adopted the Gauss plume model and had been developed by the USA. Some additional calculations were made with EyesAct, which was developed and used in Japan, adopting also the Gauss plume model, to compare calculation results.
Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Tobita, Yoshiharu
Journal of Nuclear Science and Technology, 53(5), p.707 - 712, 2016/05
Times Cited Count：17 Percentile：82.69(Nuclear Science & Technology)In order to develop an evaluation method of the distance for fragmentation of molten core material discharged into the sodium plenum, a sodium experiment with visual observation was conducted using an X-ray imaging system. In the current experiments, 0.9 kg of molten aluminum (initial temperature: around 1473 K) was discharged into a sodium pool (initial temperature: 673 K) through a nozzle (inner diameter: 20 mm). Based on the experimental results, the distance for fragmentation of the liquid column was estimated to be 100 mm in the experiments. Through the sodium experiment, useful knowledge was obtained for the future development of an evaluation method of the distance for fragmentation of molten core material. As a next step, sodium experiments using higher-density molten materials will be conducted to enrich the experimental knowledge. Besides, a new semi-empirical correlation will be developed to evaluate more appropriately the distance for fragmentation under CDA conditions.
Kato, Takaaki*; Takahara, Shogo; Homma, Toshimitsu
Journal of Disaster Research, 10(4), p.627 - 634, 2015/08
Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 7 Pages, 2014/12
In order to develop an evaluation method of the distance for fragmentation of molten core material discharged into the sodium plenum, a sodium experiment with visual observation was conducted using an X-ray imaging system. In the current experiments, 0.9 kg of molten aluminum (initial temperature: around 1473 K) was discharged into a sodium pool (initial temperature: 673 K) through a nozzle (inner diameter: 20 mm). Based on the experimental results, the distance for fragmentation of the liquid column was estimated to be 100 mm in the experiments. Through the sodium experiment, useful knowledge was obtained for the future development of an evaluation method of the distance for fragmentation of molten core material. As a next step, sodium experiments using higher-density molten materials will be conducted to enrich the experimental knowledge. Besides, a new semi-empirical correlation will be developed to evaluate more appropriately the distance for fragmentation under CDA conditions.
Inaba, Yoshitomo; Kotchourko, A.*; Breitung, W.*
JAERI-Tech 2005-053, 24 Pages, 2005/09
The Flow and Combustion Engineering Division at the Forschungszentrum Karlsruhe carried out the explosion experiments of hydrogen-oxygen mixtures in a smooth tube made of stainless steel after two radiolysis gas explosion accidents occurred in Japanese and German BWRs. In these experiments, stoichiometric hydrogen-oxygen mixtures with different initial pressures were used. The pressure in the tube and the strain of the tube were measured, and then the structural response during the detonation and the Deflagration-to-Detonation Transition (DDT) process were investigated. In the present study, a numerical analysis was performed to simulate one of the experiments by the use of the 3-dimensional turbulent combustion analysis code COM3D, which has been developed in FZK, and a DDT process was calculated. The COM3D code contains a reaction rate constant, which must be obtained empirically from experimental results. In the present calculation, the reaction rate constant was assumed to be an exponential function. As a result, it was found that the COM3D code can simulate the DDT process.
(Horv
th) (Homoptera: Delphacidae) and 
(St
l), using an advanced weather forecast modelOtsuka, Akira*; Dudhia, J.*; Watanabe, Tomonari*; Furuno, Akiko
Agricultural and Forest Entomology, 7(1), p.1 - 9, 2005/02
Times Cited Count：43 Percentile：83.63(Entomology)A new method of backward trajectory analysis for planthopper migration is presented. The method consists of two components: an advanced weather forecast model, MM5, for weather simulation, and a migration model for trajectory calculation. Although the landing process is not considered in the modeling, it is shown that the method is able to precisely simulate the migration and accurately estimate various parameters. This study also shows the importance of high quality weather simulation.
Inaba, Yoshitomo; Nishihara, Tetsuo; Nitta, Yoshikazu*
Nuclear Technology, 146(1), p.49 - 57, 2004/04
Times Cited Count：4 Percentile：29.26(Nuclear Science & Technology)One of the most important safety design issues for a hydrogen production system coupling with a High Temperature Gas-cooled Reactor (HTGR) is to ensure reactor safety against fire and explosion accidents because a large amount of combustible fluid is dealt with in the system. The Japan Atomic Energy Research Institute (JAERI) has a demonstration test plan of a hydrogen production system by steam reforming of methane coupling with the High Temperature engineering Test Reactor (HTTR). In the plan, we developed the P2A code system to analyze event sequences and consequences in detail on the fire and explosion accidents assumed in the HTGR or HTTR hydrogen production system. This paper described the three accident scenarios assumed in the system, the structure of P2A, the analysis procedure with P2A and the results of the numerical analyses based on the accident scenarios, and it was showed that P2A was a useful tool for the accident analysis in the system.
Oka, Kiyoshi; Hiyama, Masayuki*
Keisoku Jido Seigyo Gakkai Rombunshu, 40(1), p.109 - 116, 2004/01
Remote maintenance technology is essential to realize ITER since the reactor components are activated by 14-MeV neutrons and have to be maintained remotely. For this purpose, the JAERI has been conducting remote handling technology development mainly for in-vessel components. On the other hand, a critical accident at the JCO occurred in September 1999, which was the most serious nuclear accident in Japan. Therefore, the JAERI has developed a Radiation-proof Robot (called RaBOT) operating under high radiation field. Under such a background, a variable baseline type distance sensor has been developed for use under the severe conditions such as gamma radiation. The aim of the sensor is to be used for the measurement of the distance between a robot and an object under the severe conditions of the maintenance for fusion plants and atomic disaster. This report describes the outline of the variable baseline type distance sensor and the results of the basic performance test.
Hiramatsu, Yoichi*; Shimada, Taihei*; Miyahara, Yoshikazu*
JAERI-Tech 99-082, p.274 - 0, 1999/12
no abstracts in English
Nishihara, Tetsuo; Hada, Kazuhiko; Shiozawa, Shusaku
JAERI-Research 97-022, 110 Pages, 1997/03
JAERI-Research-97-022.pdf:4.1MB
no abstracts in English
Yanagihara, Satoshi; ; Nakamura, Hisashi
Nuclear Technology, 86, p.159 - 167, 1989/08
Times Cited Count：3 Percentile：41.87(Nuclear Science & Technology)no abstracts in English
; ; ; ;
JAERI-M 8497, 27 Pages, 1979/10
no abstracts in English
Yaita, Tsuyoshi
no journal, ,
