30 Janvier 2017
Possible Nuclear Fuel Find Raises Hopes
of a Fukushima Plant Breakthrough
Operator says it has seen what may be fuel debris
beneath badly damaged No 2 reactor, destroyed
six years ago in triple meltdown
Justin McCurry in Tokyo, The Guardian, Monday, 30 January 2017
Hopes have been raised for a breakthrough in the decommissioning of the wrecked Fukushima Daiichi nuclear plant after its operator said it may have discovered melted fuel beneath a reactor, almost six years after the plant suffered a triple meltdown.
Tokyo Electric Power (Tepco) said on Monday that a remote camera appeared to have found the debris beneath the badly damaged No 2 reactor, where radiation levels remain dangerously high. Locating the fuel is the first step towards removing it.
The operator said more analysis would be needed before it could confirm that the images were of melted uranium fuel rods, but confirmed that the lumps were not there before Fukushima Daiichi was hit by a powerful earthquake and tsunami on 11 March 2011.
The tsunami, triggered by a 9.0-magnitude quake, killed more than 18,500 people along the coast of north-east Japan and destroyed the backup power supply at Fukushima Daiichi, triggering the world’s worst nuclear accident since Chernobyl 25 years earlier.
If Tepco can confirm that the black mass comprises melted fuel, it would represent a significant breakthrough in a recovery effort that has been hit by mishaps, the buildup of huge quantities of contaminated water, and soaring costs.
“This is a big step forward as we have got some precious data for the decommissioning process, including removing the fuel debris,” a Tepco official said.
Using a remotely controlled camera attached to the end of a 10.5-metrelong telescopic arm, Tepco technicians located black lumps on wire-mesh grating just below the reactor’s pressure vessel, local media reported.
The company plans to send a scorpion-like robot equipped with cameras, radiation measuring equipment and a temperature gauge into the No 2 reactor containment vessel next month, according to the Asahi Shimbun.
Three previous attempts to use robots to locate melted fuel inside the same reactor ended in failure when the devices were rendered useless by radiation.
Developing the means to remove the fuel – a task Tepco has said will become easier once it can gauge its condition – would be the biggest step forward in the mission to clean up Fukushima Daiichi since the removal of hundreds of spent fuel rods from a damaged reactor building in late 2013.
The delicate, potentially dangerous task of decommissioning the plant has barely begun, however.
Japanese media said last week that plans to remove spent fuel from the No 3 reactor building had been delayed, while decommissioning the entire plant was expected to take at least 40 years.
In December, the government said the estimated cost of decommissioning the plant and decontaminating the surrounding area, as well as paying compensation and storing radioactive waste, had risen to 21.5 trillion yen ($187bn), nearly double an estimate released in 2013.
A government committee estimated that 2.4 trillion yen of the total cost would be passed on to consumers through higher electricity bills.