Tokyo: An underwater robot has captured what is believed to be the first images of melted nuclear fuel deposits inside Japan’s stricken Fukushima nuclear plant, its operator Tepco says.
Large amounts of solidified lava-like rocks and lumps in layers were seen underneath its unit three reactor. If confirmed, it would be a major milestone in the clear-up operation.
The power plant was hit by a tsunami in 2011, causing the most serious nuclear accident since Chernobyl. More than 200,000 people were forced to leave their homes because of nuclear contamination concerns when three reactors failed at the plant after it was flooded.
Parts of the damaged reactors are still highly contaminated, with radiation and robotics playing a crucial part in the clean-up.
“There is a high possibility that the solidified objects are mixtures of melted metal and fuel that fell from the vessel,” a spokesman said.
Some of the objects appeared like icicles hanging around a control rod mechanism, which is attached to the bottom of the reactor’s pressure vessel holding the core, the company said.
According to the Japan Times, fuel rod assemblies contained in the pressure vessel melted into a puddle and burned through the bottom after the tsunami six years ago.
Lumps of material that appeared to have melted and re-solidified near the wall of the pedestal, a concrete structure supporting the pressure vessel, were also captured on camera.
The company said more time was needed to analyse the debris further. The deposits were found underneath the core inside the primary containment vessel of Fukushima’s unit 3 reactor.
Locating the fuel debris in each of the damaged reactors is an important part of the decommissioning process, which is expected to take decades.
