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Hidaka, Akihide
Journal of Nuclear Science and Technology, 56(9-10), p.831 - 841, 2019/09
Times Cited Count：12 Percentile：80.27(Nuclear Science & Technology)The insoluble Cs particles (Type A) were firstly observed in Tsukuba-city on the morning of March 15. The particles have been considered to be generated in RPV of Unit 2 by evaporation/condensation based on the measured 
Cs/
Cs ratio and the core temperatures of each unit. However, the Type A particles with smaller diameter than the Type B particles of Unit 1 origin, are covered by almost pure silicate glass and have a trace of the quenching. This indicates that the particles could have been generated due to the melting of the HEPA filter in SGTS by the fire of H
detonation at Unit 3, and atomization followed by quenching of the molten materials by air blast of the explosion. Although the particles were mostly dispersed to the sea because of the wind direction, some of them deposited onto the lower elevation of R/B at Unit 3, could have been subsequently re-suspended and released into the environment, by the steam flow in the R/B caused by restart of the Unit 3 core cooling water injection at 2:30 of March 15.
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.
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.
Hatano, Takahiro
Physical Review Letters, 92(1), p.015503_1 - 015503_4, 2004/01
Times Cited Count：45 Percentile：82.67(Physics, Multidisciplinary)Molecular dynamics simulations on a three dimensional defective Lennard-Jones solid containing a void are performed in order to investigate detailed properties of hot spot generation. In addition to the temperature, I monitor the number of energetically colliding particles per unit volume which characterizes the intensity of shock-enhanced chemistry. The quantity is found to saturate for nanoscale voids and to be maximized after voids have completely collapsed. It makes an apparent comparison to the temperature which requires much larger void for the enhancement and becomes maximum during the early stage of the collapse. It is also found that the average velocity and the temperature of ejected molecules inside a cubic void are enhanced during the collapse because of the focusing of momentum and energy towards the center line of a void.
Inaba, Yoshitomo; Nishihara, Tetsuo; Moriyama, Koichi*; Nakamura, Masashi*
JAERI-Data/Code 2002-014, 255 Pages, 2002/07
JAERI-Data-Code-2002-014.pdf:21.69MB
One of the most important safety design issues for an HTGR hydrogen production system is to ensure reactor safety against fire and explosion accidents in the hydrogen production plant because a large amount of combustible fluid is dealt with in the system. JAERI has the demonstration test plan to connect the hydrogen production system with the HTTR. In the plan, we considered effective measures against the fire and explosion accidents in the HTTR hydrogen production system, which were applicable to the HTGR hydrogen production system of a commercial base, and also developed the P2A code system to analyze event sequences and consequences in detail, on assumed fire and explosion accidents in the HTGR hydrogen production system and the HTTR hydrogen production system. The P2A can analyze the process of leakage, dispersion, ignition, and combustion including deflagration and detonation of the combustible fluid in the internal and external area of the reactor building. In this report, we describe the outline and the usage of the P2A, and the results of preliminary calculations.
Inaba, Yoshitomo; Nishihara, Tetsuo; Inagaki, Yoshiyuki
Proceedings of 14th Hydrogen Energy Conference (WHEC 2002) (CD-ROM), 9 Pages, 2002/06
The Japan Atomic Energy Research Institute (JAERI) has the demonstration test plan to connect a hydrogen production system by steam reforming of methane with the High Temperature engineering Test Reactor (HTTR). One of the most important safety design issues for the HTTR hydrogen production system is to ensure reactor safety against fire and explosion accidents. Therefore, we developed the P2A code system to analyze event sequences and consequences in detail, on assumed fire and explosion accidents in the HTTR hydrogen production system. It is possible that the P2A analyzes the process of leakage, dispersion and combustion including deflagration and detonation of the combustible fluid in the internal and external area of the reactor building. This paper describes the outline of the P2A and the results of preliminary calculations.
; Abe, Yutaka*; *; *; Yamano, N.; Sugimoto, Jun
JAERI-Research 96-032, 152 Pages, 1996/06
JAERI-Research-96-032.pdf:4.05MB
no abstracts in English
