The operator of the disaster-hit Fukushima Daiichi nuclear power plant on Wednesday began its first attempt to touch the melted fuel accumulating at the bottom of one of the crippled reactors, using a remote-controlled device.
Tokyo Electric Power Company Holdings Inc. plans to insert the device — which carries a camera, radiation meter and tong-like grips to hold objects — into the primary containment vessel during its survey at the No. 2 reactor.
The findings from the survey, such as whether the fuel is in a condition that is easily extractable or not, will provide important information in the process of decommissioning the Nos. 1 to 3 reactors that suffered core meltdowns in the nuclear crisis that began in March 2011, according to TEPCO.
The No. 2 reactor was in operation when the crisis began and some fuel is believed to have melted through the reactor pressure vessel, a container that is supposed to hold the fuel, and accumulated at the bottom of the outer primary containment vessel.
In the latest survey, TEPCO will focus on checking the nature of the deposits and will not take a sample outside. A sample extraction is planned in the second half of the next fiscal year starting April, the plant operator said.
The device, which is 30 centimeters tall and 10 cm wide, will be inserted from a penetration hole that gives access to the primary containment vessel. It is capable of holding an object weighing up to 2 kilograms.
If the fuel debris is in an extractable condition, TEPCO will have a better chance of removing the deposits. But if it is too hard to be picked up, TEPCO may have to consider developing tools capable of cutting the debris for removal.
TEPCO said it plans to look at two or three locations in the survey.
In the decommissioning road map compiled by TEPCO and the Japanese government, they are scheduled to decide from which reactor they will start removing the fuel and the method for extraction within fiscal 2019. The actual removal is expected to start in 2021.
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All — Kyodo News+