A robot will start working in the damaged nuclear reactor in Fukushima to remove the remnants of nuclear fuel and debris. The first test mission will take 2 weeks, AP News reports.
Sending the robot into the reactor is an important initial step in the complex and lengthy process of decommissioning the plant. It will take decades and involve handling large volumes of highly radioactive molten fuel inside the three reactors, which were damaged by the massive earthquake and tsunami in 2011.
The nuclear fuel in the reactor cores melted, causing the nuclear power plant's cooling systems to fail. The molten fuel flowed out of the cores and mixed with internal reactor materials such as zirconium, stainless steel, electrical cables, broken grids, and concrete around the support structure and at the bottom of the primary containment tanks.
The reactor meltdown caused the highly radioactive lava-like material to fly in all directions, making cleanup much more difficult. Tokyo Electric Power Company Holdings (TEPCO), which operates the plant, says that approximately 880 tons of molten fuel debris remains in the three reactors.
Workers will use five 1.5-meter-long pipes connected in series to launch the robot inside. The robot itself will be able to go about 6 meters deep. Once inside, it will be controlled remotely by operators in another building of the station.
The front part of the robot, equipped with tongs, a flashlight, and a camera, will be lowered on a cable to a pile of molten fuel. Then it will cut off and collect some debris - about 3 grams. This small amount of collection is due to minimizing the radiation hazard.
The robot will then return to the point where it entered the reactor, a round trip that will take about two weeks. TEPCO is also limiting daily operations to two hours to minimize radiation risk to workers in the reactor building. Eight teams of six people will take turns working, and each team is allowed to stay near the reactor for no more than 15 minutes.