Refine your search:     
Report No.
 - 
Search Results: Records 1-7 displayed on this page of 7
  • 1

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

Corrosion monitoring in humidity-controlled environment simulating gamma ray irradiation

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$$^{circ}$$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.

Oral presentation

Effect of concentration of artificial sea water on corrosion behavior of steel in air-solution alternating condition

Otani, Kyohei; Tsukada, Takashi; Ueno, Fumiyoshi; Kato, Chiaki

no journal, , 

Corrosion tests of carbon steel was carried out in air-solution alternating condition in previous study. It has been reported that the corrosion rate of carbon steel exposed in air-solution alternating condition was accelerated compare with the steel exposed in solution. In this study, it was investigated that the effect of concentration of model sea water on corrosion rate of carbon steel in air-solution alternating condition. The mass measurement in corrosion tests clarified that the corrosion rate of carbon steel in the 200 times diluted model sea water is fastest during various model sea water. Cross-sectional analysis of iron rust layer formed on carbon steel after corrosion tests indicated that the corrosion rate of carbon steel in model sea water is decreased by precipitation of metal cations containing in model sea water.

Oral presentation

Development of corrosion database under radiation environment, 2; Development of radiolysis dataset for contaminated stagnant water

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

Oral presentation

Temperature dependence on corrosion behavior of Ta in NaOH solutions

Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi

no journal, , 

In spent nuclear fuel reprocessing plant, SUS304/Ta/Zr dissimilar metal joint is used for connect between different devices. And it is known that Ta corrodes in NaOH solutions. The other hand, it is not clear that the temperature effect on corrosion behavior of Ta in NaOH solutions. This study aims to elucidate the effect on temperature effect for corrosion behavior of Ta in NaOH solutions. Immersion tests and electrochemical measurements were carried out in NaOH solutions. Immersion test results show that corrosion rate in 1mol/L NaOH at 353 K was decreased compared to 333 K. And also the test results show that corrosion rate increased with temperature at above 3 mol/L. From SEM observation, dence film was observed at the surface of specimen after immersion test in 1 mol/L NaOH at 353 K. From these results, it is considered that the decrease of corrosion rate in 1mol/L at 353 K was caused by the dence film suppress the Ta dissolution.

Oral presentation

Development of corrosion database under radiation environment, 1; Overview

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.

Oral presentation

Corrosion of stainless steel in spent Cs adsorption tank containing salt

Kato, Chiaki; Sato, Tomonori; Yamagishi, Isao; Arisaka, Makoto; Terada, Atsuhiko

no journal, , 

Electrochemical test of stainless steel (SUS316L) in zeolite containing artificial seawater under gamma-ray irradiation as a basic study on the local corrosion generation conditions of the used adsorption tower used for contaminated water treatment at the Fukushima Daiichi Nuclear Power Plant Accident. In addition, a drying test using the second Cs adsorption tower (SARRY) mock-up was conducted to report the change of Cl concentration in the tower and to investigate the possibility of local corrosion in the used Cs adsorption tower. The steady natural immersion potential of stainless steel became noble by gamma irradiation, and the potential increased as the absorbed dose rate increased. On the other hand, in the zeolite coexisting system, the potential increase under gamma irradiation was suppressed. The mechanism of increasing the potential of stainless steel under gamma irradiation is that H$$_{2}$$O$$_{2}$$ generated by radiation activates the cathode reaction of stainless steel and that the potential of zeolite decreases to suppress the formation of H$$_{2}$$O$$_{2}$$. Also, from the dry test of the mock-up specimen, as the temperature of the zeolite layer rises, the residual water is sucked up by the dry zeolite layer, so that the salt content of the residual water is precipitated in the heat generating part and the evaporated water condenses on the inner surface of the container. It was confirmed that the residual water Cl concentration decreased due to the heat generation in the adsorption tower, which was confirmed by the mock-up test specimen. It was expected as a mitigation measure.

Oral presentation

Effect of impurities in steel and ppb level of chloride in bulk water on electrical conductivity of stainless steel's crevice solution in high temperature water

Soma, Yasutaka; Komatsu, Atsushi; Kato, Chiaki

no journal, , 

In this study, the effect of impurities in steel and ppb level of chloride in bulk water on electrical conductivity of stainless steel's crevice solution (K) has been studied. Crevice specimens were made of as-polished Type-316L stainless steel (standard-SS), standard-SS exposed to 60% nitric acid to dissolve sulfur containing inclusions (acid-picked SS), and 316EHP steel in which sulfur and phosphorous concentration was decreased compared to standard-SS (EHP-SS). These crevice specimens were immersed into 561 K, 8 MPa water the K values were measured as a function of time with stepwise increase in dissolved oxygen levels. In addition, effect of 50 ppb Cl$$^{-}$$ added to bulk water was investigated using standard-SS crevice. The all of the standard-SS, acid-picked SS, and 316EHP showed similar K vs time curves. It can be concluded that impurities dissolved from the steel itself do not significantly contribute to the increase of K. The effect of 50 ppb Cl$$^{-}$$ on K vs time curve was obvious because maximum K value became more that 2 times larger than the solution without Cl$$^{-}$$ addition. This indicate that small concentration of impurities can be migrated into the crevice.

7 (Records 1-7 displayed on this page)
  • 1