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Journal Articles

Numerical analysis for FP speciation in VERDON-2 experiment; Chemical re-vaporization of iodine in air ingress condition

Shiotsu, Hiroyuki; Ito, Hiroto*; Sugiyama, Tomoyuki; Maruyama, Yu

Annals of Nuclear Energy, 163, p.108587_1 - 108587_9, 2021/12

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Journal Articles

Analysis of transport behaviors of cesium and iodine in VERDON-2 experiment for chemical model validation

Shiotsu, Hiroyuki; Ito, Hiroto*; Ishikawa, Jun; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 6 Pages, 2018/11

JAEA Reports

CHEMKEq; Evaluation code for chemical composition based on partial mixed model with Chemical Equilibrium and Reaction Kinetics (Contract research)

Ito, Hiroto*; Shiotsu, Hiroyuki; Tanaka, Yoichi*; Nishihara, Satomichi*; Sugiyama, Tomoyuki; Maruyama, Yu

JAEA-Data/Code 2018-012, 42 Pages, 2018/10

JAEA-Data-Code-2018-012.pdf:4.93MB

Chemical composition of fission products transported in nuclear facilities in severe accidents is controlled by slower chemical reaction rates, therefore, it could be different from that evaluated on the chemical equilibrium assumption. Hence, it is necessary to evaluate the chemical composition with reaction kinetics. On the other hand, databases applicable to the analysis of nuclear facilities have not been constructed because knowledge of reaction rates of complex chemical reactions in severe accidents is currently limited. Accordingly, we have developed the CHEMKEq code based on a partial mixed model with chemical equilibrium and reaction kinetics to decrease uncertainties of the chemical composition caused by the reaction rate. The CHEMKEq code, under mass conservation law, firstly evaluates chemical species obeying the chemical equilibrium model, and then, relatively slow reactions are solved by the reaction kinetics model. Moreover, the CHEMKEq code has a multiplicity of use in evaluations of chemical composition because general chemical equilibrium and reaction kinetics models are also available and databases required to calculation are external file formats. This report is the user's guide of the CHEMKEq code, showing models, solution methods, structure of the code and calculation examples. And information to run the CHEMKEq code is summarized in appendixes.

Journal Articles

Evaluation of chemical speciation of iodine and cesium considering fission product chemistry in reactor coolant system

Ishikawa, Jun; Zheng, X.; Shiotsu, Hiroyuki; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of Asian Symposium on Risk Assessment and Management 2018 (ASRAM 2018) (USB Flash Drive), 6 Pages, 2018/10

Journal Articles

Influence of chemical speciation in reactor cooling system on pH of suppression pool during BWR severe accident

Shiotsu, Hiroyuki; Ishikawa, Jun; Sugiyama, Tomoyuki; Maruyama, Yu

Journal of Nuclear Science and Technology, 55(4), p.363 - 373, 2018/04

 Times Cited Count:3 Percentile:33.17(Nuclear Science & Technology)

Journal Articles

Application of Bayesian approaches to nuclear reactor severe accident analysis

Zheng, X.; Tamaki, Hitoshi; Shiotsu, Hiroyuki; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 11 Pages, 2017/11

Journal Articles

Source term analysis considering B$$_{4}$$C/steel interaction and oxidation during severe accidents

Ishikawa, Jun; Shiotsu, Hiroyuki; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 7 Pages, 2017/07

Journal Articles

Thermochemical analysis for cesium and iodine species and their impact on aqueous pH under severe accident conditions

Shiotsu, Hiroyuki; Ishikawa, Jun; Maruyama, Yu

Proceedings of 2015 International Workshop on Post-Fukushima Challenges on Severe Accident Mitigation and Research Collaboration (SAMRC 2015) (USB Flash Drive), 8 Pages, 2015/11

Journal Articles

Radioactive Cs in the severely contaminated soils near the Fukushima Daiichi Nuclear Power Plant

Kaneko, Makoto*; Iwata, Hajime; Shiotsu, Hiroyuki; Masaki, Shota*; Kawamoto, Yuji*; Yamasaki, Shinya*; Nakamatsu, Yuki*; Imoto, Jumpei*; Furuki, Genki*; Ochiai, Asumi*; et al.

Frontiers in Energy Research (Internet), 3, p.37_1 - 37_10, 2015/09

The mobility of the aggregates of submicron-sized sheet aluminosilicate in the surface environment is a key factor controlling the current Cs migration in Fukushima.

Journal Articles

Effect of minerals on accumulation of Cs by fungus ${{it Saccaromyces cerevisiae}}$

Onuki, Toshihiko; Sakamoto, Fuminori; Yamasaki, Shinya*; Kozai, Naofumi; Shiotsu, Hiroyuki; Utsunomiya, Satoshi*; Watanabe, Naoko*; Kozaki, Tamotsu*

Journal of Environmental Radioactivity, 144, p.127 - 133, 2015/06

 Times Cited Count:7 Percentile:28.24(Environmental Sciences)

The accumulation of Cs by unicellular fungus of ${{it Saccaromyces cerevisiae}}$ in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica $$>$$ smectite, illite $$>>$$ vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.

Journal Articles

Parametric study for impact of in-vessel chemical forms of cesium and iodine on source term and pH of aqueous phase

Shiotsu, Hiroyuki; Ishikawa, Jun; Maruyama, Yu

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05

Journal Articles

Effects of CeO$$_{2}$$ nanoparticles on microbial metabolism

Masaki, Shota*; Shiotsu, Hiroyuki; Onuki, Toshihiko; Sakamoto, Fuminori; Utsunomiya, Satoshi*

Chemical Geology, 391, p.33 - 41, 2015/01

 Times Cited Count:6 Percentile:28.71(Geochemistry & Geophysics)

Distinct organic species and intracellular proteins were expressed after exposure of yeast cells to CeNPs. Although cytotoxicity was not caused by CeNPs, the results of the peptide mass fingerprint analysis of the intracellular protein revealed that Eno2p, a glycolysis enzyme, was expressed after the exposure to CeNPs. These results suggest that nanoparticles have the potential to alter microbial metabolism, leading to changes in the compositions of the released substances in the surrounding environment.

Oral presentation

Mechanism and crystallochemical signature of nano-particle formation by microorganisms

Shiotsu, Hiroyuki; Giang, M.*; Nakamatsu, Yuki*; Onuki, Toshihiko; Utsunomiya, Satoshi*

no journal, , 

Oral presentation

Mechanism and crystallochemical signature of nano-particles formation by microorganisms

Shiotsu, Hiroyuki; Jiang, M.*; Nakamatsu, Yuki*; Onuki, Toshihiko; Utsunomiya, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Formation of rare earth phosphate nano-particles by microorganisms

Shiotsu, Hiroyuki; Jiang, M.*; Nakamatsu, Yuki*; Onuki, Toshihiko; Utsunomiya, Satoshi*

no journal, , 

Oral presentation

Multidisciplinary investigation on radiocesium fate and transport for safety assessment for interim storage and disposal of heterogeneous waste, 10; Effects of microbial activity on migration of Cs

Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Shiotsu, Hiroyuki; Utsunomiya, Satoshi*

no journal, , 

Accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals have been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. With carbon source, higher amounts of Cs was accumulated in the cells than in the resting condition without carbon source. In the presence of mineral in the agar medium, the radioactivity in the yeast cells with different minerals were in the order of the inverse of Kd of minerals. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.

Oral presentation

Impact of chemical forms of cesium and iodine on source term and pH of aqueous phase

Shiotsu, Hiroyuki; Maruyama, Yu; Ishikawa, Jun

no journal, , 

no abstracts in English

Oral presentation

Development and application of methodologies for source term analysis

Maruyama, Yu; Ishikawa, Jun; Zheng, X.; Kido, Kentaro; Matsumoto, Toshinori; Shiotsu, Hiroyuki; Ito, Hiroto; Tamaki, Hitoshi

no journal, , 

Oral presentation

Analysis for impacts of B$$_{4}$$C control material on FP chemistry with VICTORIA code

Shiotsu, Hiroyuki; Ishikawa, Jun; Maruyama, Yu

no journal, , 

no abstracts in English

Oral presentation

Evaluation of FP chemistry for improvement of source term estimation method, 2; Analytical study for B effects on revaporization behavior of Cs and I

Shiotsu, Hiroyuki; Ishikawa, Jun; Ito, Hiroto; Sugiyama, Tomoyuki; Maruyama, Yu

no journal, , 

no abstracts in English

28 (Records 1-20 displayed on this page)