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Hidaka, Akihide
Journal of Radioanalytical and Nuclear Chemistry, 332, p.1607 - 1623, 2023/03
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)no abstracts in English
Hidaka, Akihide
Nuclear Technology, 208(2), p.318 - 334, 2022/02
Times Cited Count：6 Percentile：69.63(Nuclear Science & Technology)The author previously proposed that the Cs bearing microparticle (Type A) may have been formed by melting and atomization of glass fibers (GF) of the HEPA filter in the SGTS due to flame and blast during the hydrogen explosion in Unit 3. If this hypothesis is correct, the Type A could contain or accompany carbon (C), that ignites spontaneously above 623 K, because of the limited time to be heated up, inclusion of C in the binder applied on the GF surface and closely located charcoal filter. As the previous studies did not focus on C, the present analyses were performed with EPMA whether the Type A contains C. The results showed that the Type A contained C originating from the binder, and non-spherical particles accompanied by the Type A and the film surrounding the Type A contained more C, which is thought to originate from the charcoal filter. These results cannot be explained by the other mechanisms proposed so far, and can be explained consistently by the author proposed hypothesis.
Hidaka, Akihide
Journal of Nuclear Science and Technology, 56(9-10), p.831 - 841, 2019/09
Times Cited Count：12 Percentile：79.16(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.
Kinuhata, Hiroshi*; Yamamoto, Masahiko; Taguchi, Shigeo; Surugaya, Naoki; Sato, Soichi; Kodama, Takashi*; Tamauchi, Yoshikazu*; Shibata, Yuki*; Anzai, Kiyoshi*; Matsuoka, Shingo*
Nuclear Technology, 192(2), p.155 - 159, 2015/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Experiments using a small-scale apparatus with 30 ml actual high-level liquid waste from the Tokai Reprocessing Plant were carried out to show that the hydrogen concentration in the gas phase reaches a steady-state value of much less than 4% (lower explosive limit) in the absence of sweeping-air. The H concentration reached a steady-state value as was expected and it was compared with a value predicted from an equation with parameters which had been obtained using the simulated solution. Satisfactory agreement showed that the Pd-ion catalytic H consumption reaction previously found in the simulated solution proceeded equally well in the actual solution.
Inaba, Yoshitomo; Nishihara, Tetsuo
JAERI-Tech 2005-033, 206 Pages, 2005/07
JAERI-Tech-2005-033.pdf:34.71MB
In this report, we investigated the effects of jet for the dispersion and explosion analysis of leaked gas, obstacles, position of an ignition point and cell size for the gas explosion analysis, and atmospheric stability for the dispersion analysis of the leaked gas, with PHOENICS, AutoReaGas, and AUTODYN. Then, we carried out two accident analyses about combustible fluid leakage based on the investigation results of these effects. As a result, it was shown that important buildings related to safety was hardly affected by the explosion of the leaked gas.
Inaba, Yoshitomo; Nishihara, Tetsuo; Nitta, Yoshikazu*
Nuclear Technology, 146(1), p.49 - 57, 2004/04
Times Cited Count：4 Percentile：29.17(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.
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.
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
Sugimoto, Jun
Dennetsu Kenkyu, 34(133), p.52 - 59, 1995/04
no abstracts in English
; ; Murao, Yoshio; ; ; ; ; ; ; Ueda, Shuzo; et al.
JAERI-M 82-039, 201 Pages, 1982/05
no abstracts in English
