Tokyo Electric Power Company (Tepco) has said that an aquatic robot recently sent into the unit 3 reactor of the Fukushima Daiichi nuclear plant Japan has captured images of what appears to be melted fuel.
The images released on 20 July show a substance around a control rod drive attached to the bottom of the pressure vessel. The remote-controlled robot was sent into the reactor to try to locate fuel debris as a step towards decommissioning the plant. The reactors in units 1, 2 and 3 of the Fukushima Daiichi plant experienced meltdowns as a result of failures of the cooling systems after the March 2011 earthquake and tsunami.
Tepco used a small radiation-hardened, submersible robot to investigate inside the unit 3 primary containment vessel, which had been flooded to a depth of around 6m.
Knowing the exact status of the fuel is essential to handling and removing them, Tepco said. Prior photographic inspection of unit 3 reactor suggests that, during the accident, fuel assemblies melted, dropping down to the pedestal area. The recent inspection aimed to acquire images and data to provide a better understanding of those conditions.
Photo: Inside of Unit 3 PCV, Bottom of the CRD housing (Credit: Tepco/IRID)