JOPSS - Search Results

Journal Articles

Analysis of pulverization property of the collision-plate-type jet mill

Kawaguchi, Koichi; Segawa, Tomoomi; Ishii, Katsunori

Funtai Kogakkai-Shi, 59(6), p.283 - 290, 2022/06

https://doi.org/10.4164/sptj.59.283

In the Japan Atomic Energy Agency, in order to effectively use the out-of-standard pellets in the fuel manufacturing process for high-speed furnaces, we are developing techniques for crushing and reusing them with raw material powder. By analyzing in detail the particle size distribution before and after grinding, it was shown that the grinding powder is composed of three different component particles having different characteristics of the particle size distribution. In addition, we examined the method of predicting pulverized powder particle size distribution from the supply powder particle size distribution.

Journal Articles

Analytical study on removal mechanisms of cesium aerosol from a noble gas bubble rising through liquid sodium pool, 2; Effects of particle size distribution and agglomeration in aerosols

Miyahara, Shinya*; Kawaguchi, Munemichi; Seino, Hiroshi; Atsumi, Takuto*; Uno, Masayoshi*

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 6 Pages, 2021/08

https://doi.org/10.1115/ICONE28-63286

In a postulated accident of fuel pin failure of sodium cooled fast reactor, a fission product cesium will be released from the failed pin as an aerosol such as cesium iodide and/or cesium oxide together with a fission product noble gas such as xenon and krypton. As the result, the xenon and krypton released with cesium aerosol into the sodium coolant as bubbles have an influence on the removal of cesium aerosol by the sodium pool in a period of bubble rising to the pool surface. In this study, cesium aerosol removal behavior due to inertial deposition, sedimentation and diffusion from a noble gas bubble rising through liquid sodium pool was analyzed by a computer program which deals with the expansion and the deformation of the bubble together with the aerosol absorption considering the effects of particle size distribution and agglomeration in aerosols. In the analysis, initial bubble diameter, sodium pool depth and temperature, aerosol particle diameter and density, initial aerosol concentration in the bubble were changed as parameter, and the results for the sensitivities of these parameters on decontamination factor (DF) of cesium aerosol were compared with the results of the previous study in which the effects of particle size distribution and agglomeration in aerosols were not considered. From the results, it was concluded that the sensitivities of initial bubble diameter, the aerosol particle diameter and density to the DF became significant due to the inertial deposition of agglomerated aerosols. To validate these analysis results, the simulation experiments have been conducted using a simulant particles of cesium aerosol under the condition of room temperature in water pool and air bubble systems. The experimental results were compared with the analysis results calculated under the same condition.

Journal Articles

Swelling of radiation-cured polymer precursor powder for silicon carbide by pyrolysis

Takeyama, Akinori; Idesaki, Akira; Sugimoto, Masaki; Yoshikawa, Masahito

Journal of Asian Ceramic Societies (Internet), 3(4), p.402 - 406, 2015/12

https://doi.org/10.1016/j.jascer.2015.08.003

Journal Articles

Effect of flow obstacle on droplet sizes in vertical annular air-water flow in a small diameter pipe

Shibamoto, Yasuteru; Sun, Haomin; Yonomoto, Taisuke

Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 10 Pages, 2014/12

Journal Articles

Micro-PIXE for the study of atmospheric environment

Kasahara, Mikio*; Ma, C.-J.*; Okumura, Motonori*; Kojima, Takuji; Hakoda, Teruyuki; Taguchi, Mitsumasa; Sakai, Takuro; Ohara, Yoshihiro

JAEA-Review 2005-001, TIARA Annual Report 2004, p.293 - 295, 2006/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2005-001-p0268-p0412.pdf

Artificial cloud generation experiment was performed using a huge vertical pit located in Kamaishi iron-copper mine to investigate the characteristics of cloud. The physical and chemical properties of individual cloud droplets were examined by microscopic analysis at Kyoto university and micro-PIXE analysis at TIARA. The process of growth of cloud was clarified based on the result on droplet size, its distribution, droplet number concentration, and the change in distribution of chlorine in droplet as the function of size.

JAEA Reports

Coarse break-up of a stream of oxide and steel melt in a water pool (Contract research)

Moriyama, Kiyofumi; Maruyama, Yu; Usami, Tsutomu*; Nakamura, Hideo

JAERI-Research 2005-017, 173 Pages, 2005/08

JAERI-Research-2005-017.pdf:11.17MB

A series of experiments on the break-up of high temperature oxide and steel melt jets in a water pool was conducted. The objective was to obtain data for the jet break-up length and size distribution of the droplets produced by the jet break-up, and information on the influence of material properties. Also, we tried to obtain additional information giving a clue to the mechanism governing the melt jet break-up, such as flow intensity of the steam column surrounding the melt jet, and its relation with the droplet size. In the experiments, zirconia-alumina mixture and stainless steel melt jets with diameter 17mm and velocity 7.8m/s at the water surface were dropped into a deep (2.1m) or shallow (0.6m) water pool with various subcool. From the results of the present experiments and also by referring other experimental data from literature, we obtained empirical correlation equations for the jet break-up length, the fraction of jet broken-up in a shallow pool where the jet was not completely broken-up, and the droplet size.

Journal Articles

Seasonal characteristics of chemical compositions of the atmospheric aerosols collected in urban seaside area at Tokaimura, eastern central Japan

Fu, F.; Watanabe, Kazuo; Yabuki, Sadayo*; Akagi, Tasuku*

Journal of Geophysical Research, 109(20), p.D20212_1 - D20212_9, 2004/10

Size-separated aerosol samples were collected at Tokaimura urban seaside area of Japan using an Andersen type sampler during July 2002 to July 2003. The size-separated aerosols were divided into water-soluble and insoluble fractions, and chemical compositions (Na $^{+}$ , Cl $^{-}$ , NH $_{3}$ $^{+}$ , NO $_{3}$ $^{-}$ , SO $_{4}$ $^{2-}$ , Al, Ca, Mg, Fe, Pb, Th and U) in both water-soluble and insoluble fractions were analyzed. Then, the seasonal variations and the size-distribution in mass concentration and chemical composition have been investigated in detail. Our results showed that the atmospheric aerosol in Tokaimura was obviously affected by dust storm in China, and that sea-salt particles were bigger than those in the Antarctic and were deficient in chlorine.

Journal Articles

Particle size analysis of radioactive aerosols formed by irradiation of argon using 65MeV quasi-monoenergetic neutrons

Endo, Akira; Noguchi, Hiroshi; Tanaka, Susumu; Kanda, Yukio*; Oki, Yuichi*; Iida, Takao*; Sato, Kaoru; Tsuda, Shuichi

Applied Radiation and Isotopes, 56(4), p.615 - 620, 2002/04

https://doi.org/10.1016/S0969-8043(01)00236-6

Times Cited Count：3 Percentile：23.39(Chemistry, Inorganic & Nuclear)

Formation mechanism and size distribution of radioactive aerosol particles generated in a high-energy neutron field were studied in order to evaluate a particle size parameter for internal dose evaluation in high-energy accelerator facilities. Argon gas containing DOP aerosols was irradiated by a 65MeV quasi-monoenergetic neutron beam of TIARA. The number size distribution of the DOP aerosols and the activity-weighted size distribution of $^{38}$ Cl and $^{39}$ Cl aerosols, formed from the (n, 2np) and (n, np) reactions of $^{40}$ Ar, were measured using an electrical low-pressure impactor. The activity-weighted size distribution of the radioactive aerosols was well explained by the simple attachment model of the radioactive atoms to the DOP aerosols.