Effects of a corrosion inhibitor on the corrosion of steels under thin solution layers

Momma, Yuichiro*; Sakairi, Masatoshi*; Ueno, Fumiyoshi; Otani, Kyohei

Zairyo To Kankyo, 71(5), p.133 - 137, 2022/05

https://doi.org/10.3323/jcorr.71.133

The effect of the corrosion inhibitor on the corrosion of steel under a thin solution layer was investigated. As a result of forming a thin solution layer with a thickness of 1.0-0.2 mm on the specimen, adding a mixed solution of sodium molybdate and aluminum lactate as a corrosion inhibitor, and performing electrochemical measurement, the corrosion inhibitor suppresses the anodic reaction. And in the thin solution layer, it was suggested that the morphology of the protective layer structure by the corrosion inhibitor changed according to the amount of liquid as compared with the bulk immersion.

Novel strain induces severe corrosion by retrieving electrons from Fe under a freshwater environment

Hirano, Shinichi*; Ihara, Sota*; Wakai, Satoshi*; Dotsuta, Yuma; Otani, Kyohei; Kitagaki, Toru; Ueno, Fumiyoshi; Okamoto, Akihiro*

Microorganisms (Internet), 10(2), p.270_1 - 270_12, 2022/02

https://doi.org/10.3390/microorganisms10020270

To understand the role of methanogens in corrosion under anoxic conditions in freshwater, we investigated the corrosion activities of methanogens in samples collected from groundwater and rivers. We enriched microorganisms that can grow with CO/NaHCO and Fe as the sole carbon source and electron donor, respectively, in ground fresh water. Electrochemical analysis revealed that strain can uptake electrons from the cathode at lower than -0.61 V vs SHE and has a redox-active component with electrochemical potential different from those of other previously reported methanogens with extracellular electron transfer ability. This study indicated the corrosion risk by methanogens capable of taking up electrons from Fe in anoxic freshwater environments and the necessity of understanding the corrosion mechanism to contribute to risk diagnosis.

A Task of microbiologically influenced corrosion in Fukushima Daiichi Decommissioning

Wakai, Satoshi*; Hirano, Shinichi*; Ueno, Fumiyoshi; Okamoto, Akihiro*

Zairyo To Kankyo, 70(12), p.491 - 496, 2021/12

https://doi.org/10.3323/jcorr.70.491

After Fukushima Daiichi Nuclear Power Station accident, various corrosion mitigating activities have been treated, and severe corrosion incident have never taken placed. On the other hand, the facilities were exposed sea water, and some of them have continuously exposed to ground water. The exposure of metal materials to environmental water has a risk of microbiologically influenced corrosion (MIC). In this paper, we summarize the latest knowledge of MIC and the task of MIC in the decommissioning of Fukushima Daiichi Nuclear Power Station.

sp. nov., a mesophilic sulfate-reducing deltaproteobacterium isolated from a deep siliceous mudstone formation

Ueno, Akio*; Tamazawa, Satoshi*; Tamamura, Shuji*; Murakami, Takuma*; Kiyama, Tamotsu*; Inomata, Hidenori*; Amano, Yuki; Miyakawa, Kazuya; Tamaki, Hideyuki*; Naganuma, Takeshi*; et al.

International Journal of Systematic and Evolutionary Microbiology, 71(2), p.004683_1 - 004683_10, 2021/02

https://doi.org/10.1099/ijsem.0.004683

A novel mesophilic sulfate-reducing bacterium, designated strain HN2, was isolated from groundwater sampled from the subsurface Miocene Wakkanai Formation located in Horonobe, Hokkaido, Japan. The cells were Gram-negative rods, with motility conferred by a single polar flagellum. The isolate expressed desulfoviridin, but no catalase or oxidase activities was detected. Strain HN2 grew in a temperature range of 5-43 C (optimum, 35 C) and in a pH range of 6.5-7.5 (optimum, pH 7.0-7.3). It used sulfate, thiosulfate, dimethyl sulfoxide, anthraquinone-2,6-disulfonate, Fe, and manganese oxide as electron acceptors, but not elemental sulfur, nitrite, or nitrate. The bacterium showed very weak growth with sulfite as the electron acceptor. The strain fermented pyruvate and cysteine in the absence of sulfate, but not malate or succinate. The bacterium did not require NaCl, but tolerated up to 4% NaCl (w/v). Strain HN2 did not require vitamins. The G+C content of the genomic DNA was 56.66 mol%. A 16S rRNA gene sequence analysis showed that the closest recognized relative of strain HN2 is JS1 (97.0% similarity). The average nucleotide identity (ANI) value between strain HN2 and D. JS1 was 79.8%. Based on the phenotypic and molecular genetic evidence, the isolate is assigned to the new species sp. nov. The type strain is HN2 (=DSM 101010 =NBRC 112213).

Local structure analysis of KNbO nanocrystals with cubic shape

Yoneda, Yasuhiro; Kunisada, Ryoichi*; Chikada, Tsukasa*; Ueno, Shintaro*; Ohara, Koji*; Wada, Satoshi*

Transactions of the Materials Research Society of Japan, 43(2), p.93 - 96, 2018/04

https://doi.org/10.14723/tmrsj.43.93

KNbO nanocrystals were grown by solvothermal technique assisted by a microwave treatment. We performed high-energy X-ray diffraction to extract average and local structural parameters. The particle size can be evaluated by the Scherrer's equation. The unit cell size was reduced as the particle size increased. The local structure was found to be a rhombohedral structure, which was similar to that of the bulk KNbO.

Radiolysis of mixed solutions of Cl and Br and its effect on corrosion of a low-alloy steel

Hata, Kuniki; Inoue, Hiroyuki*; Kojima, Takao*; Kasahara, Shigeki; Hanawa, Satoshi; Ueno, Fumiyoshi; Tsukada, Takashi; Iwase, Akihiro*

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.304 - 314, 2017/09

A model simulation of radiolysis of mixed solutions of NaCl and NaBr was carried out. The simulation result agreed well with the experimental result, and Br played an important role in determining the amounts of products from water radiolysis. The simulation result also showed that, in highly pure NaCl solutions, the steady-state concentration of a radolytic product, HO, was mainly controlled by three reactions (Cl + OH ClOH, ClOH Cl + OH, and ClOH + H Cl + HO), which indicated that accurate evaluation of the rate constants of these reactions was very important in improving the radiolysis simulation of solutions containing Cl. An immersion test using a low-alloy steel, SQV2A, in the mixed solutions was also carried out under irradiation. The corrosion rate increased or decreased depending on the pH or the concentrations of the halide ions in a similar way to the change in concentration of HO produced from water radiolysis, which is affected by the presence of Cl and Br. However, at high pH values (12), the corrosion rate was almost zero even though the concentration of HO was high. This could be attributed to enhancement of the passivity of test specimens at higher pH values.

Report on recent meetings of the young researchers association and the students association of the Japan Health Physics Society

Sakoda, Akihiro; Kataoka, Noriaki*; Ueno, Satoshi*; Matsuyama, Tsugufumi*

Hoken Butsuri, 51(3), p.191 - 195, 2016/09

https://doi.org/10.5453/jhps.51.191

This article briefly overviews two recent meetings (December 2015 and July 2016) of the Young Researchers Association and the Students Association of the Japan Health Physics Society.

Hydrogen peroxide production by radiolysis of sodium chloride solutions containing a small amount of bromide ion

Hata, Kuniki; Inoue, Hiroyuki*; Kojima, Takao*; Iwase, Akihiro*; Kasahara, Shigeki; Hanawa, Satoshi; Ueno, Fumiyoshi; Tsukada, Takashi

Nuclear Technology, 193(3), p.434 - 443, 2016/03

https://doi.org/10.13182/NT15-32

Evaluation of dose level in a laser-driven ion accelerator using PHITS code

Sakaki, Hironao; Fukuda, Yuji; Nishiuchi, Mamiko; Jinno, Satoshi; Kanasaki, Masato; Yogo, Akifumi; Kondo, Kiminori; Saito, Fumihiro; Fukami, Tomoyo; Ueno, Masayuki; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.182 - 185, 2014/04

http://www.aesj.or.jp/publication/pnst004/data/182_185.pdf

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ions acceleration. In the development of many applications of laser-accelerated ions, it is necessary for securing the radiation safety to calculate the dose evaluation. The dose was measured with the radio-photoluminescent (RPL) glass dosimeter on the test beamline of at laser-driven accelerator. The Monte Carlo code, PHITS (Particle and Heavy Ion Transport code system) simulation is shown to be reasonably predictive at the test beamline for measured with the RPL glass dosimeter. We compare of the measured dose level on the laser-driven accelerator with the result of PHITS code in this report.

Status of J-PARC muon science facility at the year of 2005

Miyake, Yasuhiro*; Nishiyama, Kusuo*; Kawamura, Naritoshi*; Makimura, Shunsuke*; Strasser, P.*; Shimomura, Koichiro*; Beveridge, J. L.*; Kadono, Ryosuke*; Fukuchi, Koichi*; Sato, Nobuhiko*; et al.

Physica B; Condensed Matter, 374-375, p.484 - 487, 2006/03

https://doi.org/10.1016/j.physb.2005.11.136

The construction of the Materials and Life Science building was started in the beginning of the fiscal year of 2004. After commissioning of the accelerator and beam transport sections in 2008, muon beams will be available for users in 2009. In this letter, the latest construction status of the J-PARC Muon Science Facility is reported.