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Tashiro, Shinsuke; Ono, Takuya; Amano, Yuki; Yoshida, Ryoichiro; Watanabe, Koji*; Abe, Hitoshi
Nuclear Technology, 208(10), p.1553 - 1561, 2022/10
Times Cited Count：1 Percentile：0.01(Nuclear Science & Technology)To contribute to the confinement safety evaluation of the radioactive materials in the Glove box (GB) fire accident, combustion tests with the Polymethyl methacrylate (PMMA) and the Polycarbonate (PC) as typical panel materials for the GB have been conducted with a relatively large scale apparatus. As the important data for evaluating confinement safety, the release ratio and the particle size distribution of the soot generated from the burned materials were obtained. Furthermore, the rise of the differential pressure (
P) of the high efficiency particle air (HEPA) filter by the soot loading was also investigated. As results, the release ratio of the soot from the PC was about seven times as large as the PMMA. In addition, it was found that the behavior of the rise of the P with soot loading could be represented uniformly regardless of kinds of combustion materials by considering effect of the loading volume of the soot particle in the relatively low loading region.
Amano, Yuki; Watanabe, Koji; Tashiro, Shinsuke; Yamane, Yuichi; Ishikawa, Jun; Yoshida, Kazuo; Uchiyama, Gunzo; Abe, Hitoshi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(2), p.86 - 94, 2015/06
Radioactive materials could be released into air due to the accidental boiling of high active liquid waste (HALW) in reprocessing plants. Volatile radioactive nuclides, such as ruthenium, are released from the tanks into the atmosphere. Nitrogen oxides (NOx) are also released due to the thermal decomposition of metal nitrates in HALW. The released NOx transport volatile ruthenium and cause redox reactions associated with the composition or decomposition of volatile ruthenium. In this study, NOx release data were obtained by heating simulated HALW up to 600
C. As a result, the release of NOx from the simulated HALW was observed from 200C to 600C, and the main release of NOx was observed at about 340C. All the lanthanide nitrates were found to decompose in the simulated HALW, and the thermal decomposition temperature of the lanthanide nitrates decreased after the addition of ruthenium dioxide to the mixed lanthanide nitrates solution.
ray irradiation on pyrolysis properties of glove-box panel materialsAbe, Hitoshi; Watanabe, Koji; Uchiyama, Gunzo
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(4), p.136 - 144, 2014/12
The glove box (GB) is the equipment with some kinds of plastic components which is used for the containment of the radioactive material. In the MOX fuel fabrication facility, MOX is also handled in the GB. Since the plastic panel, which has the largest area of the GB, is used in the long period, it is exposed to high dose from MOX continuously. In this study, to confirm that containment capability of GB can be maintained even under external thermal stress, effect of the -ray irradiation with 
Co on the pyrolysis properties of the common panel materials which were obtained by TG-DTA has been investigated. As a result, polymethylmethacrylate showed the large peak of mass loss rate at about 260 degrees under the non-irradiation and air condition but it separated into lower and higher temperature sides above 25 kGy. The effect was not observed up to 10 kGy for polymethylmethacrylate, and up to 880 kGy for polycarbonate. By comparing with the estimated total dose of which GB panel would be irradiated in the operation period, it was found that the irradiation from MOX does not have significant effect on the pyrolysis properties of GB panel in the actual facility.
Abe, Hitoshi; Tashiro, Shinsuke; Watanabe, Koji; Uchiyama, Gunzo
JAEA-Research 2012-035, 26 Pages, 2013/01
JAEA-Research-2012-035.pdf:1.94MB
To contribute on confirmation of safety of fuel cycle facilities, an evaluation method for soundness of confinement capability of the facilities under fire accident has been investigated. Organic extraction solvents, zinc stearate, which is added into MOX powder in MOX fuel preparation process, and typical lubricating oil were considered to be examination objects as the representative combustible materials in the facilities. Combustion property data, such as mass loss rate and soot release fraction, of them and clogging property data of HEPA filter with combustion of the organic extraction solvents were measured. As the results, it was found that soot release fraction from burning 30%TBP/70%dodecane was larger than that of the other materials including dodecane and very rapid rise of differential pressure of HEPA filter, which has not been reported, would be induced in the last stage of combustion of 30%TBP/70%dodecane. Furthermore, it was confirmed that zinc stearate, of which combustibility has not been considered, burned continuously in the condition which was heated from outside.
Abe, Hitoshi; Watanabe, Koji; Tashiro, Shinsuke; Uchiyama, Gunzo
JAEA-Research 2007-075, 50 Pages, 2007/11
JAEA-Research-2007-075.pdf:6.35MB
In the MOX fuel fabrication facility, MOX is required to be handled in Grove-box to sustain containment of MOX into the facility. In case of fire in the facility, the containment capability of Grove-box may be deteriorated by pyrolysis or combustion of the plastic materials as components of Grove-box caused by thermal stress from flame. The purpose of this study is to examine pyrolysis and combustion properties of the materials for applying quantitative evaluation method for the containment capability of Grove-box under fire. This report summarize experimental results about the properties under the Air condition and investigation of evaluation model for estimating time-course of deteriorating containment capability of Grove-box under fire.
Abe, Hitoshi; Watanabe, Koji; Tashiro, Shinsuke; Uchiyama, Gunzo
JAEA-Research 2006-054, 39 Pages, 2006/09
JAEA-Research-2006-054.pdf:2.91MB
no abstracts in English
Koike, Tadao; Nishio, Gunji; Takada, Junichi; Tsukamoto, Michio; Miyata, Teijiro; *
JAERI-Tech 95-005, 84 Pages, 1995/02
no abstracts in English
Abe, Hitoshi; Watanabe, Koji; Tashiro, Shinsuke; Tsuchino, Susumu*; Umetsu, Hiroyuki*
no journal, ,
no abstracts in English
Watanabe, Koji; Abe, Hitoshi; Tashiro, Shinsuke; Uchiyama, Gunzo; Tsuchino, Susumu*; Umetsu, Hiroyuki*
no journal, ,
no abstracts in English
Abe, Hitoshi; Watanabe, Koji; Tashiro, Shinsuke; Uchiyama, Gunzo; Tsuchino, Susumu*; Umetsu, Hiroyuki*
no journal, ,
no abstracts in English
Amano, Yuki; Watanabe, Koji; Abe, Hitoshi; Ishikawa, Jun; Tashiro, Shinsuke; Yamane, Yuichi; Uchiyama, Gunzo
no journal, ,
no abstracts in English
Amano, Yuki; Watanabe, Koji; Ishikawa, Jun; Tashiro, Shinsuke; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo; Uchiyama, Gunzo
no journal, ,
Combinating thermal decomposition data of nitrates which consist of high level liquid waste (HLLW), we tried simulating thermal decomposition behavior of HLLW and NOx emission behavior. Simulation of thermal decomposition behavior was similar to experimental data, but simulation of NOx emission behavior was not similar to experimental data. We believe that the difference between simulation and experiment was caused by the composition of complex oxides after denitration under condition consisted of a number of nitrates.
Abe, Hitoshi; Masaki, Tomoo; Watanabe, Koji; Suzuki, Shinya; Tashiro, Shinsuke; Amano, Yuki; Yamane, Yuichi; Yoshida, Kazuo; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.
no journal, ,
The release and transport characteristics of radioactive materials under the boiling and desiccating accident of the high active liquid waste in a reprocessing plant have been studied. Ruthenium is one of the important nuclides for evaluating public dose from the volatile viewpoint. By using apparatus which can control the experimental condition of temperature and atmosphere composition in the gas phase, the transport characteristics data of RuO
which is chemical form of Ru with volatility was acquired. As the results, it was found that RuO would transport in the gas phase without thermal decomposition and deposition onto the inner wall of glass under the experimental condition with nitric acid vapor.
Amano, Yuki; Watanabe, Koji; Suzuki, Shinya; Tashiro, Shinsuke; Yamane, Yuichi; Abe, Hitoshi; Yoshida, Kazuo; Uchiyama, Gunzo
no journal, ,
no abstracts in English
Abe, Hitoshi; Masaki, Tomoo; Watanabe, Koji; Tashiro, Shinsuke; Yamane, Yuichi; Amano, Yuki; Yoshida, Kazuo; Uchiyama, Gunzo
no journal, ,
The release and transport characteristics of radioactive materials under the boiling and drying accident of the high active liquid waste (HALW) in a reprocessing plant have been studied. It has been reported that Ru, which is one of the important nuclides for evaluating public dose from the volatile viewpoint, is released mainly with progressing dryness of HALW. In this work, to grasp the release behavior of Ru, release ratio of Ru with thermal decomposition of Ru nitrate, which would be in the dried HALW, was measured and release rate constant of Ru from the nitrate was estimated. It was found that the calculation result of release rate of Ru from the nitrate with rise of temperature by using the constant could well simulate the result acquired from the beaker-scale experiment.
