Tepco Says Reports On Fukushima Unit 2 Fuel Debris ‘May Be Premature’

8 Feb (NucNet): A camera placed inside the primary containment vessel (PCV) of Unit 2 at the Fukushima-Daiichi nuclear power station has captured “intriguing” images that may be fuel debris from the March 2011 accident, but further examination is necessary before that can be verified, station owner and operator Tokyo Electric Power Company (Tepco) has said. In a statement posted on its website Tepco said media reports that fuel debris had been found “may be premature”. The images could turn out to show fuel debris, but could also show the result of missing paint or rust discoloration. The operator said more analysis would be needed before it could confirm that the images were of melted fuel, but confirmed that the lumps were not there before Fukushima-Daiichi was hit by a powerful earthquake and tsunami on 11 March 2011. Locating the fuel is the first step towards removing it. If Tepco can confirm that the black mass comprises melted fuel, it would represent a significant breakthrough in the recovery and decontamination effort. Using a remotely controlled camera attached to the end of a 10.5-metre-long telescopic arm, Tepco technicians located black lumps on wire-mesh grating just below the reactor’s pressure vessel, local media reported. The company plans to send a robot equipped with cameras, radiation measuring equipment and a temperature gauge into the Unit 2 PCV next month, according to the Asahi Shimbun. Three previous attempts to use robots to locate melted fuel inside the same reactor ended in failure when the devices were rendered useless by radiation. Units 1, 2 and 3 at the six-unit plant were in commercial operation at the time of the earthquake and tsunami and all suffered reactor core, fuel and containment damage. The other three units did not suffer fuel damage. Unit 4 was offline and was not loaded with fuel, but the reactor building was severely damaged by a hydrogen explosion. Units 5 and 6 were offline, but were still fuelled. The images are online: http://bit.ly/2lqi32p