The operator of the crippled Fukushima Daiichi nuclear plant is planning to survey melted fuel debris at the No. 2 reactor by the end of next March to explore ways for its removal using a device that will come into direct contact with it, sources close to the matter said Wednesday.

It will be the first survey by Tokyo Electric Power Company Holdings Inc. involving direct contact with the debris at the Nos. 1 to 3 units, which saw core meltdowns in the nuclear crisis triggered by the March 2011 earthquake and tsunami.

Tepco is considering extracting debris, the most difficult process of decommissioning, first from the No. 2 unit. Gravel-like debris was confirmed at the bottom of the containment vessel in a January survey using a telescope arm.

[Photo courtesy of the International Research Institute for Nuclear Decommissioning]

The utility aims to collect information in the survey to help determine how to extract the debris and develop a container in which to keep it. A special 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.

In the road map compiled by Tepco and the government for scrapping the damaged reactors, they are scheduled in the fiscal year through March 2020 to decide on the method for debris extraction and from which unit they will start removing debris.

In an underwater robot probe conducted last July at the No. 3 unit, Tepco found what was believed to be debris but its extraction will be much harder compared to the No. 2 unit as the company needs to lower the water level inside the containment vessel.

The location of the debris in the No. 1 unit remains unknown.