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Hojo, Tomohiko*; Shibayama, Yuki; Ajita, Saya*; Koyama, Motomichi*; Akiyama, Eiji*
Materia, 61(7), p.413 - 418, 2022/07
no abstracts in English
Nishimura, Hayato*; Hojo, Tomohiko*; Ajita, Saya*; Shibayama, Yuki*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Akiyama, Eiji*
Tetsu To Hagane, 107(9), p.760 - 768, 2021/09
Times Cited Count：0 Percentile：0(Metallurgy & Metallurgical Engineering)no abstracts in English
Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Ueno, Fumiyoshi; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; et al.
JAEA-Review 2021-001, 123 Pages, 2021/06
JAEA-Review-2021-001.pdf:10.33MB
In the implement of the decommissioning of Fukushima Daiichi Nuclear Power Station (1F), there are many problems to be solved. Specially, the mitigation of the aging degradation by the corrosion of the structural materials is important to implement the decommissioning safely and continuously. However, there are limited data for the environmental factors of corrosion in 1F, and the condition of 1F is continuously changing. So, the literature data for the water radiolysis and the corrosion under irradiation are listed as the database of corrosion under irradiation in this report. And the new obtained radiolysis and corrosion data, which have not been reported in the literature and will be required in the decommissioning of 1F, are reported.
Shibayama, Yuki; Hojo, Tomohiko*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Matsuno, Takashi*; Akiyama, Eiji*
ISIJ International, 61(4), p.1322 - 1329, 2021/04
Times Cited Count：3 Percentile：24.75(Metallurgy & Metallurgical Engineering)Nishimura, Hayato*; Hojo, Tomohiko*; Ajita, Saya*; Shibayama, Yuki*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Akiyama, Eiji*
ISIJ International, 61(4), p.1170 - 1178, 2021/04
Times Cited Count：3 Percentile：24.75(Metallurgy & Metallurgical Engineering)Hojo, Tomohiko*; Akiyama, Eiji*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Kinugasa, Junichiro*; Yuse, Fumio*
Corrosion Science, 177, p.108957_1 - 108957_9, 2020/12
Times Cited Count：18 Percentile：75.61(Materials Science, Multidisciplinary)Hydrogen assisted cracking on hemispherically-stretch-formed specimens of transformation induced plasticity-aided martensitic steel was investigated. Hydrogen charging induced cracking around the foot of the impression formed on the steel sheet, and the cracks propagated along the radial direction toward the hillside and the plains. Distributions of stress, plastic strain and volume fraction of retained austenite were analyzed employing the energy-dispersive X-ray diffraction method utilizing the synchrotron X-ray radiation at SPring-8. It was notable that the crack initiation took place in the region where the measured tensile stress was the highest. Influences of plastic strain and resulted martensitic transformation were also suggested.
Hojo, Tomohiko*; Kumai, B.*; Koyama, Motomichi*; Akiyama, Eiji*; Waki, Hiroyuki*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Nagasawa, Akihiko*
International Journal of Fracture, 224(2), p.253 - 260, 2020/08
Times Cited Count：14 Percentile：66.22(Materials Science, Multidisciplinary)In the study, the pre-strain effect on hydrogen embrittlement property of the ultra-high-strength transformation-induced plasticity -aided bainitic ferrite steel was investigated towards application for automobile frame parts. 3-10% tensile pre-strain suppressed hydrogen-induced mechanical degradation relative to total elongation while 12-15% pre-strained specimen did not exhibit elongation after hydrogen charging. The advantageous effect of the 3-10% pre-strain was attributed to the suppression of crack initiation related to retained austenite. The TRIP by pre-straining decreased the volume fraction of retained austenite before hydrogen charging, thereby reducing existing probabilities of preferential crack initiation sites and propagation paths. Conversely, high pre-strain such as 12-15% does not effectively work due to work hardening resulting in increases in hydrogen embrittlement susceptibility and a significant increase in hydrogen content due to the multiplication of dislocations.
Omori, Atsushi*; Akiyama, Eiji*; Abe, Hiroshi*; Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; et al.
Zairyo To Kankyo, 69(4), p.107 - 111, 2020/04
To evaluate the effect of oxidants, which are formed by radiolysis of water under gamma ray irradiation, on the corrosion of a carbon steel in humid environment, ozone was introduced as a model oxidant in to humidity-controlled air at 50
C in a thermo-hygrostat chamber. Corrosion monitoring was performed by using an Atmospheric Corrosion Monitor-type (ACM) sensor consisting of a carbon steel anode and an Ag cathode. The output current of the ACM sensor was increased with the increase in relative humidity and it was obviously increased with the increase in the introduced ozone concentration at each relative humidity. The results indicate that ozone accelerates the corrosion of the carbon steel. The effect of ozone on the corrosion acceleration is attributed to the fast reduction reaction and fast dissolution reaction in to water compared to that of oxygen.
Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Risk of corrosion degradation for plant materials in Fukushima-Daiichi Nuclear Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure. We will build the corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion in this project. In this presentation, we will describe summary of this project.
Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Since risk of corrosion degradation for plant materials in Fukushima Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we will describe the overview of this research project.
Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
no abstracts in English
Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we describe the overview of this project.
Sato, Tomonori; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Inoue, Hiroyuki*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*; Hata, Kuniki; Kaji, Yoshiyuki
no journal, ,
To develop the database for the corrosion under irradiation, the experimental evaluation for the corrosion under irradiation is necessary. So, the corrosion test environment under irradiation with controlling pH, temperature dissolved O
concentration and ion concentration was constructed in Takasaki Research center, QST. And, influence of gamma irradiation on de-passivation of carbon steel was evaluated. The map for corrosion property of carbon steel in the borate and chloride ions containing water was created based on the experimental data. The corrosion behavior changes with the concentration of borate.
Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion.
Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
no abstracts in English
Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we describe the overview of this project in 2018 fiscal year.
Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*
no journal, ,
Water radiolysis calculations were performed to evaluate corrosion environments under irradiation by using database of corrosion under irradiation. It was confirmed that the dissolved oxygen is one of major factors to determine the generation of hydrogen peroxide, and the concentration of hydrogen peroxide could be controlled by the control of dissolved oxygen concentration. As a result of the calculation for the water radiolysis including impurities, the effects of Cl
on water radiolysis is negligible at concentration less than 10
mol/L. The effects of Br is negligible at concentration less than 10
mol/L. The effects of HCO
is negligible at concentration less than 10
mol/L.
Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
no journal, ,
Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we describe the overview of this project results as a facility sharing excellence award winning lecture in the Takasaki Advanced Radiation Research Institute of National Institutes for Quantum and Radiological Science and Technology.
Ajita, Saya*; Nishimura, Hayato*; Hojo, Tomohiko*; Koyama, Motomichi*; Fujita, Kenichi*; Kakinuma, Hiroshi*; Akiyama, Eiji*; Shibayama, Yuki
no journal, ,
no abstracts in English
