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Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamamoto, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.345 - 353, 2023/10
no abstracts in English
Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamaki, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.49 - 57, 2023/02
and 
X-ray diffractions of corrosion products freshly formed on the surface of an iron-silicon alloySuzuki, Shigeru*; Matsubara, Eiichiro*; Komatsu, Takuya*; Okamoto, Yoshinori*; Kanie, Kiyoshi*; Muramatsu, Atsushi*; Konishi, Hiroyuki; Mizuki, Junichiro; Waseda, Yoshio*
Corrosion Science, 49(3), p.1081 - 1096, 2007/03
Times Cited Count：32 Percentile：80.42(Materials Science, Multidisciplinary) X-ray diffraction measurements of a small amount of samples extracted from wet corrosion products freshly formed on a pure iron and iron-2 mass% silicon surfaces have been conducted using synchrotron radiation. The results showed that 
-FeOOH was formed on the outer side of wet corrosion products formed on the pure iron by sodium chloride solution, while -FeOOH, 
-FeOOH, Fe
O
, and green rusts were formed on the inner side. In comparison to the case of the pure iron, a significant formation of 
-FeOOH was observed in the iron-silicon alloy. Furthermore, in-situ diffraction measurements by a conventional X-ray source were conducted for analyzing corrosion products formed on the pure iron and iron-silicon alloy surfaces by cyclic exposure to wet and dry atmospheres. The results obtained by the diffraction and 
diffraction measurements on the corrosion products were consistent.
Kawamura, Hiroyuki; Takahashi, Masamitsu; Hojo, Nobuhiko*; Miyake, Masao*; Murase, Kuniaki*; Tamura, Kazuhisa*; Uosaki, Kohei*; Awakura, Yasuhiro*; Mizuki, Junichiro; Matsubara, Eiichiro*
Journal of the Electrochemical Society, 149(2), p.C83 - C88, 2002/02
Times Cited Count：6 Percentile：21.78(Electrochemistry)The structure of a Te layer formed on a Au(111) substrate by underpotential deposition (UPD) in an electrolytic solution has been studied using in-situ surface X-ray diffraction technique. The measurements were carried out for a series of samples which were kept at UPD potential for 4 to 59 hours. The results revealed that the Te UPD layer is unstable. The top layer is analyzed to consist of the UPD Te atoms and Au atoms which diffuse from the Au(111) substrate. Also, the Te UPD layer does not have the structure with periodicity reported in previous works, such as (
) R30
after ample time elapses. Stripping voltammetry for the Te UPD layer shows that the interaction between Te and Au increases with time, supporting the finding that the top layer is a mixture of Te and Au.
Goto, Takahiro*; Matsubara, Ryuta*; Hamamoto, Takafumi*; Fujisaki, Kiyoshi*; Mitsui, Seiichiro; Taniguchi, Naoki
no journal, ,
For the purpose of improvement of long-term glass corrosion model, we conducted immersion tests with specimens of carbon steel and simulated waste glass at 50C and 80C under nitrogen gas atmosphere. We also conducted control immersion tests with a specimen of carbon steel or simulated waste glass under the same conditions. After the immersion tests, we determined glass corrosion rates and secondary phases on the surface of carbon steel specimen. Glass corrosion rates for the immersion tests with specimens of carbon steel and simulated waste glass were three times larger than those for the control immersion tests with simulated waste glass specimen. With X-ray diffraction, several peaks associated with an iron silicate mineral were identified. This observation is consistent with the results of geochemical calculation based on solution data and published study using carbon steel and simulated waste glass.
Goto, Takahiro*; Matsubara, Ryuta*; Hamamoto, Takafumi*; Fujisaki, Kiyoshi*; Mitsui, Seiichiro; Taniguchi, Naoki
no journal, ,
To improve long-term glass corrosion model, immersion tests with specimens of carbon steel and simulated waste glass were conducted at 50C and 80C under nitrogen gas atmosphere for 131 days. Control tests with a specimen of carbon steel or glass under the same conditions were also conducted. After the tests, the element concentration in the solution was analyzed to determine glass corrosion rates. We also analyzed the surface of specimens with XRD and TEM/ED (electron diffraction)/EDX to identify secondary phases. Glass corrosion rates for the tests with specimens of carbon steel and glass were two times larger than those for the control tests with glass specimen. With XRD and TEM/ED/EDX, we determined iron silicates on the surface of both carbon steel and glass. These observations are consistent with the results of geochemical calculation and published studies. The results indicate that glass corrosion could be enhanced by the precipitation of iron silicates.
Matsubara, Ryuta*; Fujisaki, Kiyoshi*; Ishida, Keisuke*; Ishiguro, Katsuhiko*; Inagaki, Yaohiro*; Okubo, Takahiro*; Mitsui, Seiichiro; Iwata, Hajime; Sekine, Nobuyuki*
no journal, ,
Restriction of radionuclide release by low dissolution rate is expected for the vitrified waste as a one of safety functions of the geological disposal system. In order to assess the performance of vitrified waste, it is important to understand how its safety function works under the environmental condition of a deep geological repository. This presentation provides the recent progress on the R&D to improve the current understanding of the key processes affecting glass dissolution rate and the predictive modeling of long-term behavior of the vitrified waste.
Matsubara, Ryuta*; Fujisaki, Kiyoshi*; Ishida, Keisuke*; Ishiguro, Katsuhiko*; Inagaki, Yaohiro*; Okubo, Takahiro*; Mitsui, Seiichiro; Iwata, Hajime; Sekine, Nobuyuki*
no journal, ,
Since the performance of vitrified High-level Radioactive Waste depends on thermal, hydraulic, mechanical, and chemical (THMC) conditions, NUMO, as the implementer of geological disposal, has been promoting R&D of operational model the long-term performance of vitrified High-level Radioactive Waste in consideration of THMC conditions. NUMO has identified R&D issues regarding the glass dissolution and planed the R&D program through FEP (Features, Events, and Processes) analysis and parametric study with numerical model to evaluate relative importance of relevant processes. At present, three R&D programs are ongoing as joint researches with JAEA and two universities: long term glass dissolution experiment to understand evolution of glass dissolution kinetics, glass dissolution experiment at various environmental conditions to assess the performance under several potential repository conditions with the time evolution, and molecular dynamics simulation to understand elemental migration at the interface between glass surface and groundwater. The current status of R&D programs will be introduced in this presentation.
