Toshiba Corp.’s energy systems unit has unveiled a long telescopic pipe carrying a pan-tilt camera designed to gather crucial information about the situation inside the reactor chambers at the tsunami-wrecked Fukushima nuclear plant.
The device is 13 meters long and designed to give officials a deeper view into the nuclear plant’s Unit 2 primary containment vessel, where details on melted fuel damage remain largely unknown.
The Fukushima plant had triple meltdowns following the 2011 Great East Japan Earthquake. Finding details about the fuel debris is crucial to determining the right method and technology for its removal at each reactor, the most challenging process to safely carry out the plant’s decadeslong decommissioning.
The nation’s stricter, post-Fukushima safety standards also require nuclear plant operators elsewhere to invest more time and money into safety measures.
On Dec. 22, Kansai Electric Power Co. announced that it would decommission two idle reactors at the Oi Nuclear Power Plant in western Japan, citing the difficulty of adding all the safety requirements at the nearly 40-year-old reactors that would be needed to get approval for their restart.
Reports have said it would cost about ¥58 billion and take 30 years to decommission a reactor, about half the estimated cost to restart one.
Also on Dec. 22, Japan Nuclear Fuel said that it was postponing the planned launch of its trouble-plagued spent fuel reprocessing plant by three more years until 2021. It cited delayed approval by the authorities. It also said it was postponing the planned manufacturing of fuel from recycled plutonium and uranium.
The mission involving Toshiba’s new probe at Fukushima’s Unit 2 reactor could come as soon as late January. Company officials said the new device will be sent inside the pedestal, a structure directly below the core, to investigate the area and hopefully to find melted debris.
The device looks like a giant fishing rod about 12 centimeters in diameter, from which a unit housing the camera, a dosimeter and thermometer slowly slides down. The probe, attached by a cable on the back, can descend all the way to the bottom of the reactor vessel if it can avoid obstacles, officials said.
Two teams of several engineers will be tasked with the mission, which they will remotely operate from a radiation-free command center at the plant.
A simpler predecessor to the pipe unveiled on Dec. 22 had captured a limited view of the vessel during a preparatory investigation in February. A crawling robot sent later in February struggled with debris on the ground and stalled in the end due to higher-than-expected radiation, its intended mission incomplete.
The upgraded probe has been co-developed by Toshiba ESS and International Research Institute for Nuclear Decommissioning, a government-funded unit of construction and nuclear technology companies over the past nine months.