The decades-long decommissioning process at the crippled Fukushima No. 1 plant is about to take what Tokyo Electric Power Co. says is “an important step,” as the utility starts removing fuel rod assemblies from the spent fuel pool high up in reactor building 4 .
“Usually, spent fuel rods are safely stored in sturdy reactor buildings, but reactor building 4 experienced a hydrogen explosion, so it has lost its full containment capability,” said Kiyoshi Takasaka, an adviser on nuclear issues to Fukushima Prefecture.
The hydrogen blast occurred March 15, 2011, four days after the earthquake and tsunami, blowing the roof off the building and showering debris into the pool.
The pool has 1,533 fuel rod assemblies
It will take about two days to remove the first 22 fuel rod assemblies, plant operator Tepco says.
The more then ‘1,500 assemblies must be be removed in what correspondents describe as a risky and dangerous operation set to take a year”
"At 15:18 [06:18 GMT], we started to pull up the first fuel assembly with a crane," a spokesman for Tepco (Tokyo Electric Power Company) said.
How will the rods be removed?
A very 'matter of fact' video presentation by TEPCO regarding the removal of spent fuel
Fuel Discharge from Reactor 4 Spent Fuel Pool in Fukushima Daiichi NPS(3:51)
The operation will entail lifting bundles of the 4-meter-long uranium and plutonium rods out of the storage pool where they were being kept when the earthquake-triggered tsunami struck Fukushima in 2011.Unknown territory
The rods will then be individually transferred into a water-filled cask and loaded onto a truck to be transported to a more secure site on the territory of the power station. TEPCO has assured that the 18-month process will go off without a hitch and that the necessary measures have been taken to ensure safety.
The company has reinforced the storage pool where the rods are being held with steel and concrete and claim that it can withstand an earthquake of the same magnitude as the one in 2011.
In addition, a steel shell has been constructed to block radiation leaks while the rods are being moved.
Doubts have been raised over TEPCO’s initiative. Scientists have urged caution as such an operation has never been undertaken.
“Handling spent fuels involves huge risks," said Shunichi Tanaka, chairman of the Nuclear Regulation Authority. "It would be a disaster if radioactive materials come out of the metal rods during the work.”
"This is the first practical milestone for the project," said Hiroshi Miyano, a nuclear systems expert and visiting professor at Hosei University in Tokyo.
"Any trouble in this operation will considerably affect the timetable for the entire project," he said to AFP. "This is an operation TEPCO cannot afford to bungle."