Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 83

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 ...

Save select records

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

Oxygen non-stoichiometries in (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$

Osaka, Masahiko; Miwa, Shuhei; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 408(3), p.285 - 288, 2011/01

 Times Cited Count:3 Percentile:69.54(Materials Science, Multidisciplinary)

Oxygen non-stoichiometry in (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were investigated from a viewpoint of features of Ce reduction in several oxide solid solutions. Oxygen non-stoichiometry was experimentally determined by means of thermogravimetric analysis as a function of oxygen potential at 1173, 1273 and 1373 K. The similar features of isotherms of oxygen non-stoichiometry in (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ with those in actinide and/or lanthanide-oxygen dioxides were observed. Oxygen non-stoichiometry in (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were compared with those of CeO$$_{2-x}$$ and (U$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$. It was concluded that features of Ce reduction have some relationships with defect forms and their transformations in the solid solutions.

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

Oxygen potential of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$

Osaka, Masahiko; Tanaka, Kosuke; Miwa, Shuhei; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.199 - 203, 2010/10

Oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were experimentally determined by means of thermogravimetric analysis as a function of non-stoichiometry at 1173 and 1273 K. Oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ at each temperature increased with increase of O/M ratio (= 2-x) and steep increases of the oxygen potentials toward O/M = 2 were observed. These characteristics are typical for non-stoichiometric fluorite-type actinides dioxides. The oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were similar to those of CeOO$$_{2-x}$$ when they were plotted as a function of average Ce valence.

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.

Journal Articles

Mechanical properties at sub-microscale and macroscale of polycrystalline uranium mononitride

Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*; Takano, Masahide; Akabori, Mitsuo; Minato, Kazuo

Journal of Nuclear Materials, 384(1), p.6 - 11, 2009/01

 Times Cited Count:5 Percentile:65.85(Materials Science, Multidisciplinary)

The indentation hardness, Vickers hardness, fracture toughness, and Young's modulus of polycrystalline uranium monontride (UN) at sub-microscale and macroscale were evaluated by an indentation test, Vickers hardness test, and the ultrasonic pulse echo method. The Young's modulus and Vickers hardness were in good agreement with the literature values. The fracture toughness of UN was about three times that of UO$$_{2}$$. In addition, we revealed the indentation size effect on the indentation hardness of UN.

Journal Articles

Modeling and simulation of thermophysical properties of minor actinides-containing oxide fuels

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

Materials Research Society Symposium Proceedings, Vol.1043, p.190 - 195, 2008/00

The molecular dynamics (MD) calculation was performed on minor actinides (MA)-containing mixed oxide (MOX) fuels, (U$$_{0.7-x}$$Pu$$_{0.3}$$MA$$_{x}$$)O$$_{2}$$ (x = 0, 0.016, 0.03, 0.05, 0.1, 0.15), and the lattice parameter, heat capacity and thermal conductivity were evaluated. The calculated thermal conductivity data are comparable in (U$$_{0.7-x}$$Pu$$_{0.3}$$MA$$_{x}$$)O$$_{2}$$ at any temperature and any x value, indicating that the thermal conductivity of MA-containing MOX fuels is scarcely influenced by adding MA up to 15 %. The present study shows that the MD calculation can be usefully applied to determine the thermophysical properties of MA-containing MOX fuels.

Journal Articles

Molecular dynamics study on defect structure of gadolinia-doped thoria

Osaka, Masahiko; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Journal of Nuclear Science and Technology, 44(12), p.1543 - 1549, 2007/12

 Times Cited Count:5 Percentile:59.58(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Phase behavior of PuO$$_{2-x}$$ with addition of 9% Am

Miwa, Shuhei; Osaka, Masahiko; Yoshimochi, Hiroshi; Tanaka, Kenya; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Journal of Alloys and Compounds, 444-445, p.610 - 613, 2007/10

 Times Cited Count:14 Percentile:34.33(Chemistry, Physical)

no abstracts in English

Journal Articles

Prediction of oxygen potential in americium thorium oxides phase of a cermet fuel

Osaka, Masahiko; Kurosaki, Ken*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 362(2-3), p.374 - 382, 2007/05

 Times Cited Count:5 Percentile:59.58(Materials Science, Multidisciplinary)

A new concept of americium-containing target is proposed as a high performance transmutation device for use in fast reactors. The target is designed so as to achieve high irradiation performance. It also meets requirements of reduction of environmental burden and effective use of resources at the same time. Form of the target is a composite of a mixed oxide of (Th, Am)O$$_{2-x}$$ and metallic molybdenum matrix. Various advantages are expected in the present target as the transmutation device for fast reactor. In particular, overcome of problems derived from high oxygen potential caused by Am oxide is focused on. The oxygen potential, which is one important property especially in views of irradiation behavior, is expected to be maintained as a reasonable level by dissolving it into ThO$$_{2}$$ to form (Th, Am)O$$_{2-x}$$ solid solution for stabilization of trivalent Am. Structural stability and enhanced thermal properties could also be expected by the formation of (Th, Am)O$$_{2-x}$$. Furthermore, the support matrix Mo can give a buffering effect of oxygen potential increase during irradiation, together with enhanced thermal conductivity. Aspects of oxygen potentials are predicted by a chemical thermodynamic model. Fabricability of the target by a conventional powder metallurgy is investigated with surrogate non-radioactive material as a replacement of Am. In addition, as one marked characteristics of the present target, use of recovered Mo from the spent nuclear fuel is envisaged. Neutronic aspects of the target-loaded fast reactor core, which are critical issues since recovered Mo is neutron absorber, together with mass balance of the nuclides such as transmutation rate of Am, are also given.

83 (Records 1-20 displayed on this page)