A sleek shape-changing robot sent to probe a highly radioactive containment vessel of the crippled Fukushima No. 1 nuclear power plant got stuck hours after it was deployed, dealing a major blow to decommissioning work.
A sleek shape-changing robot sent to probe a highly radioactive containment vessel of the crippled Fukushima No. 1 nuclear power plant got stuck hours after it was deployed, dealing a major blow to decommissioning work.
Tokyo Electric Power Co., the plant operator, said April 10 that the tubular-shaped robot stalled inside the first floor of the No. 1 reactor's containment vessel. TEPCO has yet to determine why the device became immovable or when it will be able to recover the robot.
“There is the possibility that the (robot's) cable got entangled, but we have yet to know what caused this,” a TEPCO official said.
The robot was developed by the International Research Institute for Nuclear Decommissioning (IRID) to chart areas inside the containment vessel where humans cannot enter because of high radiation levels.
Measuring 60 centimeters long in its normal state, the robot is able to change its shape depending on the space it is trying to enter and is controlled remotely via a connecting cable.
The robot entered the containment vessel through piping on April 10 at 9:30 a.m. It began its journey around the netted first floor of the vessel at 11:20 a.m. to measure the temperature and radiation levels while transmitting images of the surrounding conditions. But after covering about two-thirds of its planned route, the robot came to a standstill after 2 p.m.
According to an IRID official, the operators tugged on the robot's cable and sent instructions for it to change shape, but it still would not move. The robot’s camera, dosimeter and temperature gauge were not damaged, and the robot was still capable of transmitting data.
The robot is essential to carrying out preliminary studies ahead of a full-blown investigation scheduled for the end of this fiscal year. It is part of preparations to retrieve melted nuclear fuel, the toughest part of the decommissioning process.