Tokyo Electric Power Company (Tepco) is planning to survey melted fuel debris at unit 2 of the crippled Fukushima Daiichi nuclear plant by the end of March 2019 to explore ways for its removal, Kyodo news reported, citing sources close to the matter.
It will be the first survey by Tepco involving direct contact with the fuel debris at units 1-3, which suffered core meltdowns during the nuclear crisis triggered by the March 2011 earthquake and tsunami. Debris was confirmed at the bottom of the containment vessel at Fukushima Daiichi unit 2 in a January survey using a telescopic arm.
Tepco hopes to collect information to help determine how to extract the debris and develop a container to keep it in. A device will be attached to a pipe with a camera to check whether it can move the debris. Although the debris will not be extracted during the survey, samples may be collected for analysis, the sources said. The roadmap compiled by Tepco and the government for scrapping the damaged reactors schedules the fiscal year ending March 2020 for a decision on the method for debris extraction and from which unit such removal will begin.
In an underwater robot probe conducted last July in unit 3, Tepco found what was believed to be debris, but its extraction will be much more difficult than for unit 2 as it will first require lowering the water level inside the containment vessel. The location of debris inside unit 1 remains unknown. For the time being, Tepco will focus on unit 2 where the work will be less complicated.