Database for corrosion under irradiation conditions (Contract research)

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.

Summary of development of corrosion database under radiation environment

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.

Development of corrosion database under radiation environment, 2; Development of data set and database for radiolysis calculation

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

Development of corrosion database under radiation environment, 3; Construction of corrosion test environment in gamma-ray irradiation and Influence of gamma irradiation on de-passivation of carbon steel

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.

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

Calculation of corrosion environment using corrosion database under irradiation

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 10mol/L. The effects of Br is negligible at concentration less than 10mol/L. The effects of HCO is negligible at concentration less than 10mol/L.

Visualisation of chlorides in corroded crevice of a stainless steel by using the radioisotope Cl-36

Aoki, So; Abe, Yosuke; Abe, Hiroshi*; Watanabe, Yutaka*; Yamamoto, Masahiro*

no journal, , 

The objective of this study was to visualise chlorides in corroded crevice of a stainless steel by using the radioisotope Cl-36 as a tracer. Chlorides in the corroded crevice were successfully visualised by imaging the luminescence of the imaging plate due to beta rays emitted by Cl-36 adhering to the corroded crevice. In the 72-hour corrosion test, the luminescent areas roughly coincided with the corroded areas on the test surface, suggesting that chlorides were concentrated in the corroded areas inside the crevice. In the test in which the specimen was left in pure water for 360 hours after the 72-hour corrosion test, the area of the luminescent areas was smaller than the corroded areas of the test surface, but high luminance areas were observed locally. SEM observations showed that the crevice corrosion had propagated deeply in such areas. These results suggest that the propagation of crevice corrosion did not stop under this test conditions.