An underwater remotely operated vehicle named ROV-A2 was sent inside the Unit 1 pedestal, a supporting structure right under the core. The area inside the pedestal is where traces of the melted fuel can most likely be found. About 880 tons of highly radioactive melted nuclear fuel remain inside the three reactors. Robotic probes have provided some information, but the status of the melted debris is still largely unknown. Trial removal of melted debris is expected to begin in Unit 2 later this year after a nearly two-year delay.

Source: The Guardian April 05, 2023 14:00 UTC