Le blog de fukushima-is-still-news

April 27, 2018

Full extent of melted fuel in Fukushima No. 2 reactor revealed

http://www.asahi.com/ajw/articles/AJ201804270041.html

By CHIKAKO KAWAHARA/ Staff Writer

Inside the bottom of the containment vessel in the No. 2 reactor of the Fukushima No. 1 nuclear power plant in January, revealed fully by new image processing. (Provided by the International Research Institute for Nuclear Decommissioning)

The bottom of the containment vessel in the No. 2 reactor of the Fukushima No. 1 nuclear power plant, as captured on Jan. 19, 2018. Fused materials thought to be melted nuclear fuel debris is attached to pillars and the floor. (Provided by the International Research Institute for Nuclear Decommissioning)

The bottom of the inside of Fukushima No. 1 nuclear plant’s crippled No. 2 reactor has been revealed in a much clearer and wider range in footage released by plant operator Tokyo Electric Power Co. on April 26.

The film shows the clearest pictures yet inside the containment vessel just below the pressure vessel of the nuclear reactor, which went into meltdown due to the 2011 earthquake and tsunami disaster.

Melted nuclear fuel debris is seen attached to pillars, walls and the ceiling, and accumulations between approximately 40 and 70 centimeters thick are piled up and cover the whole floor.

TEPCO captured the footage on Jan. 19 by attaching a remote-controlled camera to an extendable rod with a span of 16 meters into the containment vessel from an opening in its side.

Excerpts were released at the time, but new processing of the footage has revealed a much clearer picture.

In the bottom of the containment vessel, fuel debris has fused to some areas particularly thickly. It is possible that the bottom of the reactor has several holes that caused the debris to fall and solidify as it cooled.

The improved knowledge of the nuclear reactor’s state will help to calculate an estimate of the amount of the debris inside, and suggest at how it could be removed in the future.

TEPCO hopes to start its next investigation inside the reactor within this fiscal year.

TEPCO footage shows deposits inside damaged Fukushima reactor

https://mainichi.jp/english/articles/20180427/p2a/00m/0na/016000c

TOKYO -- Tokyo Electric Power Co. (TEPCO) on April 26 released footage taken inside the containment vessel of the No. 2 reactor at the disaster-hit Fukushima No. 1 Nuclear Power Plant, showing spots where molten fuel appears to have fallen through the reactor pressure vessel.

• 【Related】TEPCO unveils footage of deposits inside Fukushima reactor
• 【Related】Once severely damaged Fukushima reactor building opened to media to showcase progress
• 【Related】First samples of Fukushima plant nuclear fuel debris to be collected in FY 2019

Photos and video footage show deposits -- believed to be fuel debris -- at the bottom of the containment vessel. In two spots, the debris is piled higher than in other places. TEPCO officials said they suspect that the bottom of the pressure vessel, situated at the upper part of the containment vessel, was damaged in more than one place, which allowed melted fuel to fall into the containment vessel.

TEPCO captured the images in January using a camera attached to a pipe inserted into the containment vessel, and found deposits spread across the bottom of the vessel. The nuclear plant operator will use a robot arm to analyze the containment vessel in more detail.

(Japanese original by Ei Okada and Riki Iwama, Science & Environment News Department)