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Yoshida, Naoki; Tashiro, Shinsuke; Amano, Yuki; Yoshida, Kazuo; Yamane, Yuichi; Abe, Hitoshi
NEA/CSNI/R(2017)12/ADD1 (Internet), p.293 - 305, 2018/01
The "Evaporation to Dryness due to the Loss of Cooling Functions" (EDLCF) of highly-active liquid waste (HALW) was newly defined as one of the severe accidents in Japan's nuclear safety standard for the reprocessing plant. Studies on accident scenarios and their source terms have led to an increased need for the development of accident management measures and the assessment of their effectiveness. Previous studies have shown that ruthenium was released at a greater rate than other elements because it formed volatile species such as ruthenium tetroxide (RuO
). In addition, ruthenium isotopes, 
Ru and 
Ru, have radiotoxicity. Accordingly, the accident management measures require the experimental information on the release and transport behavior of the gaseous ruthenium (Ru(g)). This paper summarizes our experimental results on the characteristics of Ru(g) in the EDLCF. This work includes the results of the experiments carried out under the agreement among JAEA, Japan Nuclear Fuel Ltd. and Japan Nuclear Energy Safety Organization.
Nojiri, Naoki; Yamashita, Kiyonobu; Fujimoto, Nozomu; Nakano, Masaaki*; Yamane, Tsuyoshi; Akino, Fujiyoshi
JAERI-Tech 97-060, 34 Pages, 1997/11
no abstracts in English
Yamashita, Kiyonobu; Ando, Hiroei; Nojiri, Naoki; Fujimoto, Nozomu; Nakata, Tetsuo*; Watanabe, Takashi*; Yamane, Tsuyoshi; Nakano, Masaaki*
Proc. of SARATOGA 1997, 2, p.1557 - 1566, 1997/00
no abstracts in English
Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Matsushima, Akira
no journal, ,
no abstracts in English
Ando, Koji; Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Matsushima, Akira
no journal, ,
no abstracts in English
Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Asakura, Yamato*; Matsushima, Akira
no journal, ,
no abstracts in English
Yoshida, Naoki; Tashiro, Shinsuke; Amano, Yuki; Yoshida, Kazuo; Yamane, Yuichi; Abe, Hitoshi
no journal, ,
After the Fukushima-Daiichi Nuclear Power Plant accident, Japan's licensing standards of the nuclear fuel cycle facilities were further strengthened and countermeasures against "severe accidents" were newly required as regulatory items. The severe accidents in the licensing standards were defined as accidents that occur under conditions beyond design-basis conditions. The "Evaporation to Dryness due to the Loss of Cooling Functions (EDLCF)" of high-level liquid waste (HLLW) was defined as one of the severe accidents for the reprocessing plant. In the EDLCF, it is assumed that radioactive materials (RM) are released to the gas phase due to evaporation and dryness of HLLW which induced by decay heat derived from fission products. The release behaviour of the RM is affected by the condition of the HLLW and the migration behaviour of RM is affected by the condition of gas phase. We have been conducted experimental studies for these behaviour of the RM. In recent years, behaviour of ruthenium (Ru) has attracted much attention in the field of EDLCF study. Existing studies have shown that Ru was released at a rate greater than other elements because it formed volatile compounds such as ruthenium tetroxide (RuO). For the above reasons, we have been conducting studies focusing on the behaviour of Ru among the radioactive materials that could be released in the accident. In the presentation, we will report a summary of our studies about the release and migration behaviour of gaseous Ru.
