First visual confirmation that melted nuclear fuel broke through a pressure vessel at the Fukushima No. 1 plant reactor, following the 2011 Tōhoku earthquake
First visual confirmation that melted nuclear fuel broke through a pressure vessel at the Fukushima No. 1 plant reactor, following the 2011 Tōhoku earthquake
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Excerpt from the linked content^1 by Keitaro Fukuchi, Ryo Sasaki and Takuro Yamano:
>“It was big progress that we could clearly see inside,” Akira Ono, who heads the cleanup project as chief of TEPCO’s decommissioning unit, said at a news conference on March 30. “We hope to thoroughly analyze the collected information.”
>The inspection by the robot started on March 29. It was the first such study at the No. 1 reactor, one of the three reactors that melted down at the plant following the Great East Japan Earthquake and tsunami in 2011.
>More than 90 percent of the nuclear fuel at the No. 1 reactor is believed to have fallen from the pressure vessel.
>The robot found a large amount of melted fuel debris under the pressure vessel.
>The cylindrical pedestal, which supports the 440-ton pressure vessel, is about 6 meters in diameter, and its walls are about 1.2 meters thick.
>The high-temperature fuel debris apparently melted the concrete of the pedestal, leaving its reinforcing bars exposed.
>The robot’s recorded images from the inner wall of the pedestal showed bare bars in the lower part of the pedestal.
>The International Research Institute for Nuclear Decommissioning estimates the No. 1 reactor building contains 279 tons of melted fuel debris.
^1 Keitaro Fukuchi, Ryo Sasaki, and Takuro Yamano for the Asahi Shimbun, 31 Mar. 2023, https://www.asahi.com/ajw/articles/14874722