First drone probe of melted fuel inside Fukushima Daiichi reactor halted due to equipment glitch

TOKYO (AP) — Japanese authorities said they were forced to abandon plans Thursday to send in drones for a second day to probe one of the damaged reactors at the Fukushima Daiichi nuclear power plant because of equipment failure.

Two drones successfully flew inside the reactor for the first time on Wednesday, to examine some of the molten fuel debris and other damages in areas where earlier robots failed to reach. Thursday’s development delayed the probe further and underscored the difficulty of the task.

The government and TEPCO plan to remove the massive amount of fatally radioactive melted nuclear fuel that remains inside each reactor since a magnitude 9.0 quake and tsunami in March 2011 destroyed the plant’s power supply and cooling systems, causing a triple meltdown.

The daunting decommissioning process has already been delayed for years and mired by technical hurdles and a lack of data.

TEPCO had prepared since July to fly a fleet of four drones, one at a time, inside the hardest-hit No. 1 reactor’s primary containment vessel, in which most of the fuel in the core melted and fell to the concrete bottom, experts say.

The first two drones Wednesday captured images showing enough space for the other two to reach the particular area that TEPCO’s experts wanted to examine.

Thursday’s flights were canceled after a snake-shaped crawling robot, designed to transmit data from a drone’s high-definition camera to the control room, stalled before reaching a targeted position, said TEPCO spokesperson Kenichi Takahara.

The cause of its failuire is under investigation, Takahara said without elaborating or saying when the next drone flight might take place.

Fukushima Daiichi decommissioning chief Akira Ono was cautiously optimistic.