Robot succeeds in lifting molten fuel at Fukushima plant

/ Technology & Smart Cities / Sunday, 17 February 2019 12:38

A robot dispatched into a reactor at the ravaged plant in Fukushima, northeastern Japan, managed to lift small pieces of molten nuclear fuel, a test of crucial importance for future extraction operations.

The machine, remotely controlled from a control room and equipped with various measuring instruments, has managed to catch, with a kind of clamp, pieces of these “debris” and lift them about 5 cm, before putting them back.

“We were able to confirm that moving them was possible,” said a spokesman for the company that manages the plant, Tokyo Electric Power (TEPCO).

The bottom of the containment building of reactor 2, one of the three where the fuel melted, was being observed from six different locations. The uplift test was successfully completed in five locations, but failed in a location where, according to Tepco, different means will have to be deployed.

This time, the technicians are not planning to take samples, but such an operation should take place by March 2020.

Previous investigations had been carried out in the containment in which the fuel failed, but only remote observations with cameras and robots. This had identified some of the molten fuel.

It is the removal of these “debris”, characterized with an exceptional level of radioactivity, which will be the most difficult task of installations dismantling, put at risk almost eight years ago, on March 11, 2011, by a gigantic tsunami on the northeast coast of Japan.

The hearts of reactors 1 to 3 melted at the time of the accident and must be cooled continuously. TEPCO is still studying the means necessary to extract the fuel, trying to collect as much data as possible on its condition, which differs according to each reactor.

This operation will not begin at best until 2021 in a first tranche, as Tepco also has many other problems to solve, including the massive amounts of partially contaminated water stored in tanks installed on the site.

The Fukushima accident, the worst since that of Chernobyl (Ukraine) in 1986, caused the evacuation of thousands of people, many of whom cannot or will not return because of radiation. Part of the area is for at least decades uninhabitable.

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