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 50C 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.
Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko; Mori, Eito*
Nihon Hozen Gakkai Dai-16-Kai Gakujutsu Koenkai Yoshishu, p.221 - 224, 2019/07
Test equipment, containers, and analytical wastes, generated by experiments using spent fuel pieces in hot cell of Operation Testing Laboratory and by analysis of highly active liquid wastes in hot analytical cell line of Tokai Reprocessing Plant, are treated as highly radioactive solid wastes. These wastes are stored in specific shielded containers called waste cask and then transport to the storage facility. The treatment of these highly radioactive solid wastes have been carried out for 40 years with upgrading waste taking out system and transportation device. As a results, automation of several procedures have been achieved utilizing conventional equipment, and work efficiency and safety have been improved.
Yamamoto, Masahiko; Shirozu, Hidetomo; Mori, Eito; Surugaya, Naoki
JAEA-Technology 2016-009, 58 Pages, 2016/05
The panels of glove box installed at Tokai Reprocessing Plant have been deteriorated and transparencies have been decreased due to the long-term use. Therefore, the panels have been replaced from the view point of preventive maintenance. In the new regulation formulated since the Fukushima Daiichi Nuclear Power Plant accident, it is demanded that the glove box consists of incombustible or inflammable materials. In this replacement, new panels have been manufactured with polycarbonate which satisfied the UL94 V-0 incombustible class. The inside of glove box has been contaminated with radioactive materials. Thus, the contamination and operator's exposure have been investigated. Then radiation protection equipment have been selected. Also, it is necessary to maintain the glove box enclosure during the replacement. The replacement has been conducted by covering the opening parts with vinyl sheets. The enclosure function has been verified by the inspection of the new panels and glove box.
Yamamoto, Masahiko; Surugaya, Naoki; Mori, Eito; Taguchi, Shigeo; Sato, Soichi
JAEA-Research 2015-013, 27 Pages, 2015/10
The H concentration generating from Highly Active Liquid Waste (HALW) of Tokai Reprocessing Plant is measured in a closed experimental system. The experimental results show that H concentration gradually increases at first and then approaches a steady-state due to the H consumption reaction by Pd ions. The highest H concentration is 1200 ppm (0.1%) when the solution temperature is at 23C. It is found that H generating from HALW is equilibrated one order of magnitude lower than the H combustion lower limit. Moreover, a model based on H generation from HALW by the radiolysis and H consumption reaction by Pd ions is proposed and applied to evaluate H concentration behavior in the gas phase. The calculated H concentrations from proposed model agreed well with the experimental values. It is demonstrated that the behavior of H generating from HALW can be evaluated quantitatively by applying the proposed model in this study.
Yamamoto, Masahiko; Mori, Eito; Surugaya, Naoki
JAEA-Technology 2015-024, 19 Pages, 2015/09
Environmental Sampling from the hot cell in the Operating Testing Laboratory (OTL) of the Tokai Reprocessing Plant is implemented as an inspection of International Atomic Energy Agency (IAEA) for the first time. The specified sampling place requested from IAEA inspector is a device inside the hot cell. Since it is expected to be highly radioactive, the dose rates of samples and inside the hot cell are evaluated in advance. Also, the threshold dose rates of samples are determined. Subsequently, the sampling procedure describing radiation protection has been prepared. The environmental sampling from OTL hot cell is safely performed in accordance with the procedure and the radioactivity of sample is measured. The samples are categorized as Excepted Package according to the transport regulation and are transported to Safeguards Analytical Services of IAEA.
Mori, Eito; Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Kitao, Takahiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.132 - 138, 2014/07
The contamination of the radioactive material was observed on the filter casing surface of the glove box installed at the analytical laboratory in Tokai Reprocessing Plant. The cause of the contamination was investigated with visual inspection, penetrant testing and ultrasonic thickness measurement. It was found that a micro through-hole due to the corrosion of stainless-steel was generated in the glove box filter casing. The repair work of the filter casing was performed keeping the glove box negative pressure. The corrosion part of filter casing was replaced and newly fabricated casing was connected to the glove box with Tungsten Inert Gas welding method.
Seito, Hajime; Kojima, Takuji; Takei, Taro*; Ide, Takashi*; Mori, Ichiro*
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 198, 2008/03
no abstracts in English
Ono, Takahiro*; Kazama, T.*; Hashimoto, T.*; Hattori, Tomomi*; Kanamori, Miwa*; Seito, Y.*
JNC TJ1420 2001-008, 295 Pages, 2000/03
Ono, Takahiro*; Higuchi, Takanao*; Kazama, T.*; Hashimoto, T.*; Seito, Y.*; Hattori, Tomomi*; Kanamori, Miwa*
JNC TJ1420 2000-005, 257 Pages, 2000/03
Kazama, T.*; Hashimoto, T.*; Seito, Y.*; *; Kanamori, Miwa*; *; *
JNC TJ1450 2000-001, 160 Pages, 1999/12
no abstracts in English