JOPSS - Search Results

Search Results: Records 1-20 displayed on this page of 27

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Journal Articles

Anisotropic creep property related to non-spherical shape of mechanically alloyed powder of oxide dispersion strengthened F82H

Sakasegawa, Hideo; Nakajima, Motoki*; Kato, Taichiro*; Nozawa, Takashi*; Ando, Masami*

Materials Today Communications (Internet), 40, p.109659_1 - 109659_8, 2024/08

https://doi.org/10.1016/j.mtcomm.2024.109659

Times Cited Count：1 Percentile：0.00(Materials Science, Multidisciplinary)

Nanometric oxide particles play an important role in improving the creep property of Oxide Dispersion Strengthened (ODS) steels. In our previous research, we examined a microstructural feature known as prior particle boundary (PPB). PPB refers to the surface of mechanically alloyed (MA) powders before consolidation. We revealed that the ODS steel with fine PPBs produced from smaller MA powders, exhibited shorter creep rupture times, compared to that with coarse PPBs produced from larger MA powders. The size of MA powders had an impact on the creep property. In this study, we examined the shape of MA powders, which were non-spherical shapes. Such shapes have the potential to induce anisotropic creep behavior. We conducted small punch creep tests on specimens with two different orientations to study the possible anisotropy. The results revealed that the creep rupture times varied depending on the orientation of specimen, thus indicating anisotropic creep property.

Journal Articles

Sintering behavior analysis of compacted dry recycled U $_{0.7}$ Pu $_{0.3}$ O $_{2}$ powder using master sintering curve theory

Nakamichi, Shinya; Sunaoshi, Takeo*; Hirooka, Shun; Vauchy, R.; Murakami, Tatsutoshi

Journal of Nuclear Materials, 595, p.155072_1 - 155072_11, 2024/07

https://doi.org/10.1016/j.jnucmat.2024.155072

Times Cited Count：1 Percentile：72.25(Materials Science, Multidisciplinary)

Journal Articles

Liquid phase sintering of alumina-silica co-doped cerium dioxide CeO $_{2}$ ceramics

Vauchy, R.; Hirooka, Shun; Watanabe, Masashi; Yokoyama, Keisuke; Sunaoshi, Takeo*; Yamada, Tadahisa*; Nakamichi, Shinya; Murakami, Tatsutoshi

Ceramics International, 49(2), p.3058 - 3065, 2023/01

https://doi.org/10.1016/j.ceramint.2022.09.295

Times Cited Count：11 Percentile：68.83(Materials Science, Ceramics)

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

Effect of B $_{4}$ C absorber material on melt progression and chemical forms of iodine or cesium under severe accident conditions

Hidaka, Akihide

Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.341 - 356, 2021/10

Journal Articles

The Evaluation of the properties of the collision-plate-type jet mill for dry recycling of MOX powder

Kawaguchi, Koichi; Segawa, Tomoomi; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Ishii, Katsunori

Funtai Kogakkai-Shi, 57(9), p.478 - 484, 2020/09

https://doi.org/10.4164/sptj.57.478

A collision plate type jet mill is assumed to be a pulverizer that can control the particle size for nuclear fuel fabrication. The collision plate type jet mill consists of two modules, a classifier and a mill chamber. Coarse component of powder is cycled in the equipment and finally pulverized into objective particle size. In this report, simulated crushed powders were classified and pulverized step by step, and particle size distribution were compared. The collision plate type jet mil can produce objective size particles with low overgrinding.

Journal Articles

Effect of B $_{4}$ C absorber material on melt progression and chemical forms of iodine or cesium under severe accident conditions

Hidaka, Akihide

Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(1), p.51 - 61, 2015/03

https://doi.org/10.3327/taesj.J14.021

B $_{4}$ C used mainly for BWR and EPR absorbers could cause phenomena which never happen in PWR with Ag-In-Cd absorbers during severe accident. B $_{4}$ C would make a eutectic interaction with stainless steel and enhance melt relocation. Boron oxidation could increase H $_{2}$ generation and change of liberated carbon to CH $_{4}$ could enhance CH $_{3}$ I generation. HBO $_{2}$ generated during B $_{4}$ C oxidation could be changed to CsBO $_{2}$ by combining with Cs. This may increase Cs deposition in reactor coolant system. There could be differences in configuration, surface area, stainless steel-B $_{4}$ C weight ratio between B $_{4}$ C powder and pellet absorbers. Present issue is to clarify effect of these differences on full scale melt progression, B $_{4}$ C oxidation and source term. Advancement of this research domain could contribute to further sophistication of prediction tool for melt progression and source terms, and treatment of organic iodide formation in safety evaluation.

Journal Articles

Development of a criticality evaluation method considering the particulate behavior of nuclear fuel

Sakai, Mikio; Yamamoto, Toshihiro; Murazaki, Minoru; Miyoshi, Yoshinori

Nuclear Technology, 149(2), p.141 - 149, 2005/02

https://doi.org/10.13182/NT05-A3586

Times Cited Count：3 Percentile：23.78(Nuclear Science & Technology)

In the conventional criticality evaluation of the nuclear powder system, the effects of particulate behavior have not been considered. In other words, it is difficult to reflect the particle behavior into the conventional criticality evaluation. We have developed a novel criticality evaluation code to resolve this issue. The criticality evaluation code, coupling a Discrete Element Method simulation code with a continuous-energy Monte Carlo transport code, makes it possible to study the effect of the particulate behavior on a criticality evaluation. The criticality evaluation code has been applied to the powder system of the MOX fuel powder agitation process. The criticality evaluations have been performed under mixing the MOX fuel powder in a stirred vessel to investigate the effects of the powder boundary deformation and particulate mixture conditions on the criticality evaluation. The evaluation results revealed that the powder uniformity mixture condition and the boundary deformation could make the neutron effective multiplication factor decrease.

Journal Articles

Effect of mixing condition of MOX powder and additives on criticality safety

Yamamoto, Toshihiro; Miyoshi, Yoshinori

Transactions of the American Nuclear Society, 91, p.583 - 584, 2004/11

MOX powder and additives are mixed in the process of MOX fuel fabrication. A non-uniform mixing state of MOX powder and additives occurs during the homogenization mixing process. However, ordinary criticalit safety evaluations for mixtures assume that the mixtures have a uniform distribution of the mixing state. A non-uniform distribution of the mixing state in a sphere, which maximizes the effective neutron multiplication factor, was obtained using a concept of the fuel importance. As a result, the central portion of the sphere is composed of an optimal moderation region, and the surrounding region is composed of pure MOX powder. While keff is 0.545 for the uniform distribution, keff for the optimal non-uniform distribution is 0.590. That is, keff increases by 0.045.

Journal Articles

Addendum to $lqlq Doping-Dependent Magnetic Structure of Tb$_{1-x}$$ Ca $_{x}$ MnO $_{3}$ rqrq

Machida, Akihiko; Moritomo, Yutaka*; Oyama, Kenji*

Journal of the Physical Society of Japan, 72(5), P. 1312, 2003/05

In order to investigate interrelation between the lattice structure and the magnetic structure, we have performed Rietveld structural analysis on the neutron powder patterns for Tb $_{1-x}$ Ca $_{x}$ MnO at low temperature. In the concentration range of , we observed the Bragg reflections due to the CE-like- and C-type structures. In this range, the powder patterns were reproduce by the two-phase model with and $P2_{1}/m$ symmetries. The fractions of these phases change against concentration . This variation of the fraction for the phase is similar to the variation of the integrated intensities of the CE-like-type magnetic Bragg reflections. This indicates that the phase is responsible for the CE-like spin-ordering. Furthermore, we discussed interrelation between the detailed lattice structure and magnetic structure.