Klystron power supplies system of the J-PARC linac

Kawamura, Masato*; Anami, Shozo*; Fukui, Yuji*; Kubota, Chikashi*; Ono, Masaaki*; Chishiro, Etsuji; Yumino, Yuichi*; Kubo, Hiroshi*

Proceedings of 28th Linear Accelerator Meeting in Japan, p.369 - 371, 2003/07

no abstracts in English

Corrosion behavior of stainless steels simulating radiation-induced segregation

Miwa, Yukio; Tsukada, Takashi

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2003, p.301 - 306, 2003/00

Local composition change at grain boundaries due to radiation-induced segregation (RIS) followed by loss of corrosion resistance is considered to be a key mechanism on irradiation-assisted stress corrosion cracking (IASCC). However it is not clear that the local composition change induces the loss of corrosion resistance at grain boundaries, because RIS results in not only depletion of Cr but also enrichment of Ni and Si. This chemical composition change is different from that of thermally-sensitized stainless steels. In this study, experimental alloys were manufactured simulating the composition at grain boundaries of irradiated type 304 stainless steel and corrosion behavior of the experimental alloys was examined by weight loss measurement in 573 K water and anode polarization measurement in 1N sulfuric acid and 1mol/l sodium sulfate at 303 K. Following results were obtained: (1) In oxygenated water (DO=10ppm) at 573 K, weight loss increased with decreasing the concentration of Cr and did not depend on the concentration of Ni and Si. (2) Results of anode polarization measurements showed that alloys contained lower Cr and higher Ni and Si concentration exhibited lower corrosion potential in oxygenated, lower pH solution. In de-aerated solutions both sulfuric acid and sodium sulfate, however, there was a little influence of chemical composition on the corrosion potential.

Passivation condition of carbon steel in bentonite/sand mixture

Taniguchi, Naoki; Kawakami, Susumu; *

JNC TN8400 2001-025, 27 Pages, 2002/03

JNC-TN8400-2001-025.pdf:1.16MB

It is essential to understand the corrosion type of carbon steel under the repository conditions for the lifetime assessment of carbon steel overpack used for geological isolation of high-level radioactive waste. According to the previous study, carbon steel is hard to passivate in buffer material assuming a chemical condition range of groundwater in Japan. However, concrete support will be constructed around the overpack in the case of repository in the soft rock system and groundwater having a higher pH may infiltrate to buffer material. There is a possibility that the corrosion type of carbon steel will be influenced by the rise of the pH in groundwater. In this study, anodic polarization experiments were performed to understand the passivation condition of carbon steel in buffer material saturated with water contacted with concrete. An ordinary concrete and a low-alkalinity concrete were used in the experiment. The results of the experiments showed that the carbon steel can passivate under the condition that water having pH 13 infiltrate to the buffer material assuming present property of buffer material. If the low-alkalinity concrete is selected as the support material, passivation can not occur on carbon steel overpack. The effect of the factors of buffer material such as dry density and mixing ratio of sand on the passivation of carbon steel was also studied. The results of the study showed that the present property of buffer material is enough to prevent passivation of carbon steel.

None

; Inoue, K.*; Obata, Masamichi*

PNC TN8410 93-299, 26 Pages, 1993/12

PNC-TN8410-93-299.pdf:0.81MB

None