Validation of the applicability of the best-fit fatigue curves for 550C in Mod.9Cr-1Mo steel to 110 cycles

Toyota, Kodai; Imagawa, Yuya; Onizawa, Takashi; Kato, Shoichi; Furuya, Yoshiyuki*

Nihon Kikai Gakkai Rombunshu (Internet), 89(928), p.23-00206_1 - 23-00206_15, 2023/12

https://doi.org/10.1299/transjsme.23-00206

In order to design fast reactors, it is necessary to consider high cycle fatigue of structural materials up to 110 cycles; to evaluate high cycle fatigue at 110 cycles, it is necessary to develop a best-fit fatigue curve applicable up to 110 cycles. In this study, high cycle fatigue tests were conducted under strain-controlled conditions and ultrasonic fatigue tests were also conducted to develop a high cycle fatigue evaluation method for Mod.9Cr-1Mo steel, which is a candidate material for fast reactor structural materials. Based on the test results, the best-fit fatigue curves were extended and the applicability of the JSME best-fit fatigue curves up to 110 cycles was verified.

Shapiro steps in charge-density-wave states driven by ultrasound

Mori, Michiyasu; Maekawa, Sadamichi

Applied Physics Letters, 122(4), p.042202_1 - 042202_5, 2023/01

https://doi.org/10.1063/5.0132454

Restoration of oxygen vacancies on an anatase TiO(001) surface with supersonic seeded oxygen molecular beam

Katsube, Daiki*; Ono, Shinya*; Inami, Eiichi*; Yoshigoe, Akitaka; Abe, Masayuki*

Vacuum and Surface Science, 65(11), p.526 - 530, 2022/11

https://doi.org/10.1380/vss.65.526

The oxidation of oxygen vacancies at the surface of anatase TiO (001) was investigated by synchrotron radiation photoelectron spectroscopy and supersonic O beam (SSMB). The oxygen vacancies at the top surface and subsurface could be eliminated by the supply of hyperthermal oxygen molecules. Oxygen vacancies are present on the surface of anatase TiO(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the ambient condition, could also be effectively eliminated by using oxygen SSMB. This result is promising as a surface processing for various functional oxides.

Development on ultrasonic hydrogen monitor; For the realization of a hydrogen society

Ara, Kuniaki; Hirabayashi, Masaru*

CROSS T&T, (71), p.10 - 14, 2022/07

https://www.cross.or.jp/tsukuba/reference/cross-tt

Development of hydrogen concentration monitors based on the application of ultrasonic technology applicable to severe accidents in nuclear reactor facilities was conducted. This paper introduces the principle and features of the application of ultrasonic technology. This paper introduces the principles and features of the ultrasonic application, and describes the performance (measurement accuracy, time response, etc.) and environmental resistance of the prototype as development results. In addition, the application of the developed technology would be introduced.

Introduction of application examples of ultrasonic simulation in the development of nuclear reactor measurement technology

Abe, Yuta; Otaka, Masahiko; Sekiya, Naoki*; Makuuchi, Etsuyo*

Hihakai Kensa, 71(2), p.69 - 74, 2022/02

no abstracts in English

Revisit of XPS studies of supersonic O molecular adsorption on Cu(111); Copper oxides

Hayashida, Koki*; Tsuda, Yasutaka; Yamada, Takashi*; Yoshigoe, Akitaka; Okada, Michio*

ACS Omega (Internet), 6(40), p.26814 - 26820, 2021/10

https://doi.org/10.1021/acsomega.1c04663

We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk CuO(111) surface and 8-type and 29-type oxide structures on Cu(111) prepared by using 0.5 eV O supersonic molecular beam (SSMB) source. We propose a new structural model for the 8-type oxide structure and also confirmed the previously proposed model for the [29] oxide structure on Cu(111), based on the O1s XPS spectra. The detection-angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the (X)R30 CuO(111). We also report the electronic excitations which O1s electrons suffer.

Gas barrier properties of chemical vapor-deposited graphene to oxygen imparted with sub-electronvolt kinetic energy

Ogawa, Shuichi*; Yamaguchi, Hisato*; Holby, E. F.*; Yamada, Takatoshi*; Yoshigoe, Akitaka; Takakuwa, Yuji*

Journal of Physical Chemistry Letters (Internet), 11(21), p.9159 - 9164, 2020/11

https://doi.org/10.1021/acs.jpclett.0c02112

Atomically thin layers of graphene have been proposed to protect surfaces through the direct blocking of corrosion reactants such as oxygen with low added weight. The long term efficacy of such an approach, however, is unclear due to the long-term desired protection of decades and the presence of defects in as-synthesized materials. Here, we demonstrate catalytic permeation of oxygen molecules through previously-described impermeable graphene by imparting sub-eV kinetic energy to molecules. These molecules represent a small fraction of a thermal distribution thus this exposure serves as an accelerated stress test for understanding decades-long exposures. The permeation rate of the energized molecules increased 2 orders of magnitude compared to their non-energized counterpart. Graphene maintained its relative impermeability to non-energized oxygen molecules even after the permeation of energized molecules indicating that the process is non-destructive and a fundamental property of the exposed material.

Nonreciprocal surface acoustic wave propagation via magneto-rotation coupling

Xu, M.*; Yamamoto, Kei; Puebla, J.*; Baumgaertl, K.*; Rana, B.*; Miura, Katsuya*; Takahashi, Hiromasa*; Grundler, D.*; Maekawa, Sadamichi*; Otani, Yoshichika*

Science Advances (Internet), 6(32), p.eabb1724_1 - eabb1724_4, 2020/08

https://doi.org/10.1126/sciadv.abb1724

Reactor physics experiment in graphite moderation system for HTGR, 1

Fukaya, Yuji; Nakagawa, Shigeaki; Goto, Minoru; Ishitsuka, Etsuo; Kawakami, Satoru; Uesaka, Takahiro; Morita, Keisuke; Sano, Tadafumi*

KURNS Progress Report 2018, P. 148, 2019/08

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2018/ProgRep2018.html

The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs). The objectives are to introduce generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to introduce reactor noise analysis to High Temperature Engineering Test Reactor (HTTR) experiment. To achieve the objectives, the reactor core of graphite moderation system named B7/4"G2/8"p8EUNU+3/8"p38EU(1) was newly composed in the B-rack of Kyoto University Critical Assembly (KUCA). The core plays a role of the reference core of the bias factor method, and the reactor noise was measured to develop the noise analysis scheme. In addition, training of operator of HTTR was also performed during the experiments.

Influence of ultrasonic irradiation on cesium retention ability of biotite

Arisaka, Makoto

JAEA-Research 2018-014, 27 Pages, 2019/02

JAEA-Research-2018-014.pdf:1.21MB

Influence of ultrasonic irradiation on cesium (Cs) retention ability of biotite was examined in order to support of management of wastes generated by the Fukushima Daiichi Nuclear Power Station accident. Suspensions of Cs exchanged biotite were ultrasonically irradiated at three frequencies of 200, 430, and 950 kHz. The concentration of Cs in the aqueous phase increased, when the irradiation frequency of the ultrasonic is 430 kHz, compared with that without irradiation. This result means decrease of Cs retention ability of biotite. In addition, we observed two phenomena, that (i) the stability of suspension decreased after ultrasonic irradiation and (ii) the Cs concentration continued to increase after the irradiation. However, phenomena were hardly reproducible with a limited of experiments.