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Journal Articles

Mechanical and thermal properties of Zr-B and Fe-B alloys

Sun, Y.*; Abe, Yuta; Muta, Hiroaki*; Oishi, Yuji*

Journal of Nuclear Science and Technology, 57(8), p.917 - 925, 2020/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Low temperature heat capacity of Cs$$_{2}$$Si$$_{4}$$O$$_{9}$$

Suzuki, Eriko; Nakajima, Kunihisa; Osaka, Masahiko; Oishi, Yuji*; Muta, Hiroaki*; Kurosaki, Ken*

Journal of Nuclear Science and Technology, 57(7), p.852 - 857, 2020/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

The low temperature heat capacity of Cs$$_{2}$$Si$$_{4}$$O$$_{9}$$, which is one of the cesium chemisorbed compounds onto stainless steel during severe accident of the light water nuclear reactor, was experimentally determined for the first time in the temperature range of 1.9 - 302 K. The experimentally determined heat capacity, $$C_{p}$$$$^{o}$$ (298.15K), and the standard entropy, $$S^{o}$$ (298.15K), were 249.4 $$pm$$ 1.1 J K$$^{-1}$$ mol$$^{-1}$$ and 322.1 $$pm$$ 1.3 J K$$^{-1}$$ mol$$^{-1}$$, respectively. The standard Gibbs energy of formation of Cs$$_{2}$$Si$$_{4}$$O$$_{9}$$ at high temperatures, $$Delta$$$$_{f}$$$$G^{o}$$($$T$$), were reevaluated by using the presently obtained $$S^{o}$$ (298.15K) and the previously reported experimental results of the standard enthalpy of formation, $$Delta$$$$_{f}$$$$H^{o}$$ (298.15K), and the standard enthalpy increments at high temperatures, $$H^{o}$$($$T$$)-$$H^{o}$$ (298.15K).

Journal Articles

Chemical trapping of Sr vapor species by Zircaloy cladding under a specific chemical condition

Mohamad, A.*; Nakajima, Kunihisa; Suzuki, Eriko; Miwa, Shuhei; Osaka, Masahiko; Oishi, Yuji*; Muta, Hiroaki*; Kurosaki, Ken*

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05

In the accident of Fukushima Daiichi Nuclear Power Station, formation of a volatile SrCl$$_{2}$$ could have occurred by the sea-water injection into the core. This can cause the release of non-volatile group Sr from the fuel to induce chemical reactions with reactor structural materials, such as stainless steel and Zircaloy (Zry) cladding. Such reactions could cause the changes in distribution of Sr in the reactor. Chemical reactions between Sr species and Zry were therefore investigated experimentally. As the result, it can be said that Sr vapor species were chemically trapped right after the release from fuel. This trapping effect of Sr by Zry-cladding implies a possibility of preferable Sr retention in the oxide phase of debris.

Journal Articles

Synthesis and characterization of CeO$$_{2}$$-based simulated fuel containing CsI

Takamatsu, Yuki*; Ishii, Hiroto*; Oishi, Yuji*; Muta, Hiroaki*; Yamanaka, Shinsuke*; Suzuki, Eriko; Nakajima, Kunihisa; Miwa, Shuhei; Osaka, Masahiko; Kurosaki, Ken*

Nippon Genshiryoku Gakkai Wabun Rombunshi, 17(3/4), p.106 - 110, 2018/12

In order to establish the synthesis method of simulated fuel contacting Cesium (Cs) which is required for the evaluation of physical/chemical characteristics in fuel and release behavior of Cs, sintering tests of the cerium dioxide (CeO$$_{2}$$) based simulated fuels containing Cesium iodide (CsI) are performed by using spark plasma sintering (SPS) method. The sintered CeO$$_{2}$$ pellets with homogeneous distribution of several micro meter of CsI spherical precipitates were successfully obtained by optimizing SPS conditions.

Journal Articles

Effect of hydrogenation conditions on the microstructure and mechanical properties of zirconium hydride

Muta, Hiroaki*; Nishikane, Ryoji*; Ando, Yusuke*; Matsunaga, Junji*; Sakamoto, Kan*; Harjo, S.; Kawasaki, Takuro; Oishi, Yuji*; Kurosaki, Ken*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 500, p.145 - 152, 2018/03

 Times Cited Count:3 Percentile:40.19(Materials Science, Multidisciplinary)

Journal Articles

Thermophysical properties of americium-containing barium plutonate

Tanaka, Kosuke; Sato, Isamu; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*

Journal of Nuclear Science and Technology, 52(10), p.1285 - 1289, 2015/10

 Times Cited Count:2 Percentile:74.39(Nuclear Science & Technology)

Polycrystalline specimens of americium-containing barium plutonate have been prepared by mixing the appropriate amounts of (Pu$$_{0.91}$$Am$$_{0.09}$$)O$$_{2}$$ and BaCO$$_{3}$$ powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. The elastic moduli were determined from the longitudinal and shear sound velocities. The Debye temperature was also determined from the sound velocities and lattice parameter measurements. The thermal conductivity was calculated from the measured density at room temperature, literature values of heat capacity, and thermal diffusivity measured by laser flash method in vacuum. The thermal conductivity of americium-containing barium plutonate was roughly independent of the temperature and was almost the same magnitude as that of BaPuO$$_{3}$$ and BaUO$$_{3}$$.

Journal Articles

Thermophysical properties of BaUO$$_{4}$$

Tanaka, Kosuke; Tokushima, Kazuyuki*; Kurosaki, Ken*; Oishi, Yuji*; Muta, Hiroaki*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 443(1-3), p.218 - 221, 2013/11

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

Polycrystalline specimens of barium uranate, BaUO$$_{4}$$, were prepared and several properties such as the thermal expansion coefficient, elastic moduli, thermal conductivity, and Debye temperature were evaluated.

Journal Articles

Thermophysical properties of perovskite type alkaline-earth metals and plutonium complex oxides

Tanaka, Kosuke; Sato, Isamu; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 422(1-3), p.163 - 166, 2012/03

 Times Cited Count:7 Percentile:43.25(Materials Science, Multidisciplinary)

Polycrystalline specimens of strontium plutonate, SrPuO$$_{3}$$, have been prepared by mixing the appropriate amounts of PuO$$_{2}$$ and SrCO$$_{3}$$ powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. The elastic moduli of SrPuO$$_{3}$$ were determined from the longitudinal and shear sound velocities. The Debye temperature was also determined from the sound velocities and lattice parameter measurements. The thermal conductivity of SrPuO$$_{3}$$ was calculated from the measured density at room temperature, literature values of heat capacity, and thermal diffusivity measured by laser flash method in vacuum.

Journal Articles

Preparation and characterization of the simulated burnup americium; Containing uranium-plutonium mixed oxide fuel

Tanaka, Kosuke; Osaka, Masahiko; Miwa, Shuhei; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 420(1-3), p.207 - 212, 2012/01

 Times Cited Count:4 Percentile:61.15(Materials Science, Multidisciplinary)

In order to investigate the effect on fuel thermophysical properties when adding americium and selected fission products to uranium-plutonium mixed fuel, simulated low decontamination MOX fuel with high burn-ups to 250 GWd/t, has been prepared and subjected to characterization tests, elastic moduli measurements, melting temperature measurement.

Journal Articles

Actinide-handling experience for training and education of future expert under J-ACTINET

Osaka, Masahiko; Konashi, Kenji*; Hayashi, Hirokazu; Li, D.*; Homma, Yoshiya*; Yamamura, Tomoo*; Sato, Isamu; Miwa, Shuhei; Sekimoto, Shun*; Kubota, Takumi*; et al.

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Summer schools for future experts have successfully been completed under Japan Actinide Network (J-ACTINET) for the purpose of development of human resources who are expected to be engaged in every areas of actinide-research/engineering. The first summer school was held in Ibaraki-area in August 2009, followed by the second one in Kansai-area in August 2010. Two summer schools have focused on actual experiences of actinides in actinide-research fields for university students and young researchers/engineers as an introductory course of actinide-researches. Several quasi actinide-handling experiences at the actinide-research fields have attracted attentions of participants at the first school in Ibaraki-area. The actual experiments using actinides-containing solutions have been carried out at the second school in Kansai-area. Future summer schools will be held every year for the sustainable human resource development in various actinide-research fields.

Journal Articles

Thermal conductivity of BaPuO$$_{3}$$ at temperatures from 300 to 1500 K

Tanaka, Kosuke; Sato, Isamu; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 414(2), p.316 - 319, 2011/07

 Times Cited Count:12 Percentile:26.02(Materials Science, Multidisciplinary)

Polycrystalline specimens of barium plutonate, BaPuO$$_{3}$$, have been prepared by mixing the appropriate amounts of PuO$$_{2}$$ and BaCO$$_{3}$$ followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The thermal conductivity of BaPuO$$_{3}$$ was almost the same magnitude as that of BaUO$$_{3}$$.

Journal Articles

Effect of americium and simulated fission products addition on oxygen potential of uranium-plutonium mixed oxide fuels

Tanaka, Kosuke; Osaka, Masahiko; Kurosaki, Ken*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.95 - 100, 2010/10

In order to investigate the effect of MAs and FP addition on the oxygen potential of MOX fuels, thermogravimetric analysis (TGA) were carried out. MOX fuels with Am and 26 kinds of fission product elements (FPs), simulating low-decontamination MOX fuel and high burn-up to 250 GWd/t, were prepared by a conventional powder metallurgical route in a glove box. The oxygen potentials for simulating low-decontamination MOX fuels were higher than the fuels without FPs and increased positively with increasing simulated burn-up.

Journal Articles

Thermal conductivities of Cs-$$M$$-O ($$M$$ = Mo or U) ternary compounds

Tokushima, Kazuyuki*; Tanaka, Kosuke; Kurosaki, Ken*; Gima, Hiromichi*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.151 - 156, 2010/10

The thermal diffusivities of Cs$$_{2}$$MoO$$_{4}$$ and Cs$$_{2}$$UO$$_{4}$$ using samples fabricated by hot press and SPS techniques were measured by a laser flash method in the range from room temperature to 823 K for Cs$$_{2}$$MoO$$_{4}$$ and to 900 K for Cs$$_{2}$$UO$$_{4}$$. The thermal conductivities of these cesium ternary oxides were quite low compared with UO$$_{2}$$ and MOX fuel. This is consistent with previous findings. These results would be useful for evaluating the thermal performance of MOX fuels at the high burn-up region in the fast reactors.

Journal Articles

Chemical states of fission products and actinides in irradiated oxide fuels analyzed by thermodynamic calculation and post-irradiation examination

Kurosaki, Ken*; Tanaka, Kosuke; Osaka, Masahiko; Oishi, Yuji*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 4 Pages, 2010/10

It is important to understand the behavior of fission products and actinides under irradiation. In the present study, the chemical states of fission products and actinides in irradiated oxide fuels were evaluated by both thermodynamic equilibrium calculation and post-irradiation examination.

Oral presentation

Molecular dynamics simulations of MOX fuels containing minor actinides (MA: Np, Am)

Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Osaka, Masahiko; Miwa, Shuhei; Tanaka, Kenya; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

no journal, , 

no abstracts in English

Oral presentation

Oral presentation

Study on the physical properties of nuclear fuels with multi phase system; Toward establishment of the closed cycle system with low-decontaminated oxide fuel, 4; Synthesis and physical properties of low-decontaminated oxide fuel

Tanaka, Kosuke; Osaka, Masahiko; Miwa, Shuhei; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*; Uno, Masayoshi*

no journal, , 

In order to invesitigate the effect of MA and FP addition on MOX fuel performance, pahse relation was evaluated and physical properties were measured.

Oral presentation

Development of common and fundamental technologies on the eveluation of fuel behavior for realizing MA recycling, 6; Outline of the results obtained in FY2008

Arai, Yasuo; Akabori, Mitsuo; Serizawa, Hiroyuki; Kosaka, Yuji*; Uno, Masayoshi*; Muta, Hiroaki*

no journal, , 

It is indispensable for realizing recycling minor actinides (MA) to understand and control the peculiar behavior of MA-bearing fuels, which could not be extrapolated from the present LWR fuel cycle technologies. In particular, the behavior of He produced in the irradiation and strage periods of MA-bearing fuels, and the effect of addition of Am and Cm on the fuel properties of oxide fuel have not been satisfactorily clarified so far. From these viewpoints, a three-years R&D program "Development of common and fundamental technologies on the evaluation of fuel behavior for realizing MA recycling" was started in JFY2007 under the "Innovative Nuclear Research and Development Program" entrusted by MEXT. The outline of the results obtained in JFY2008 is introduced in the presentation.

Oral presentation

Study on the physical properties of nuclear fuels with multi phase system; Toward establishment of the closed cycle system with low-decontaminated oxide fuel, 3; Thermal conductivity analysis on the high-burnup low-decontaminated oxide fuel

Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*; Uno, Masayoshi*; Tanaka, Kosuke; Osaka, Masahiko

no journal, , 

The thermal conductivity of low decontaminated MOXs fuel which were simulated the high burn-up was calculated using FEM analysis.

53 (Records 1-20 displayed on this page)