Images taken by miniature drones from inside a badly damaged reactor at the Fukushima nuclear power plant show displaced control equipment and deformed materials, but leave many questions unanswered and highlight the daunting task of decommissioning the reactor…
TOKYO – Images taken by miniature drones from inside a badly damaged reactor at the Fukushima nuclear power plant show displaced control equipment and deformed materials, but leave many questions unanswered and highlight the daunting task of decommissioning the plant.
The 12 photos released by the plant’s operator are the first from inside the key structural support, called the base, in the primary containment of the hardest-hit No. 1 reactor, an area directly beneath the reactor core. Officials had long hoped to reach the area to examine the core and molten nuclear fuel that dripped there when the power plant’s cooling systems were damaged by a major earthquake and tsunami in 2011.
Previous attempts with robots have failed to reach the area. The two-day investigation using tiny drones was completed last week by Tokyo Electric Power Company Holdings (TEPCO), which released the photos on Monday.
About 880 tons of highly radioactive, molten nuclear fuel remain in the three damaged reactors. TEPCO is trying to learn more about its location and condition to facilitate removal and decommissioning of the facility.
The high-resolution color images captured by the drones show brown objects of different shapes and sizes dangling from various locations in the base. Parts of the control rod drive mechanism that controls the nuclear chain reaction and other devices attached to the core were detached.
TEPCO officials said they could not tell from the images whether the dangling blobs were melted fuel or equipment without obtaining other data such as radiation levels. The drones did not carry dosimeters to measure radiation because they had to be light and maneuverable.
The drone cameras could not see the bottom of the reactor core, in part because of the darkness of the containment, officials said. The probe’s information could aid future studies of the melted debris, which is critical to developing technology and robots to remove it, they said.
But the vast amount still unknown about the inside of the reactors suggests how difficult it will be. Critics say the 30- to 40-year goal set by the government and TEPCO for renovating the power plant is too optimistic.
The daunting decommissioning process has been delayed for years by technical hurdles and a lack of data.