A fuel cask is lowered into the pool in reactor 4, via Tepco
More than two and a half years after the Fukushima Dai-ichi disaster began, cleanup efforts at the crippled plant have hit a milestone: Today, the process of removing spent fuel rods from damaged reactors began successfully, with the first fuel rod assemblies moved from underwater storage pool at the plant's No. 4 reactor pool to portable storage casks.
Tepco, the firm that manages the plant, hopes that the first 22 rod assemblies will be transferred to a huge portable cask by tomorrow, after which it will be decontaminated and transferred to a common storage pool where spent fuel from other reactors resides. With a total of 1,533 fuel rod assemblies stored in just reactor 4's pool, the planned removal of just 22 rod assemblies speaks to how long cleanup efforts will last. Tepco says it expects to have all of reactor 4's fuel transferred by 2014.
Tepco is starting with reactor 4 because its storage pool is located on the fifth floor of the reactor building. Because that reactor, along with three others, was structurally damaged in a hydrogen explosion following the 2011 Tōhoku earthquake and tsunami, getting the fuel out of the plant's upper floors and into a more stable pool has been a huge priority.
Reactor 4's spent fuel pool, via Tepco
Moving reactor fuel isn't exactly an easy undertaking. Tepco has been working on a plan for months, which has boiled down to lowering a portable cask into the pool before engineers use a crane to lift fuel rod assemblies out of storage racks and into the cask for transport. The rods are in the pool for a reason: they need to be submerged in water in order to stay cool, and thus must remain submerged even while being transferred.
The initial 22 rods are some of the reactor's 202 unused fuel rods, which Tepco started with because they're less fragile than used ones. Presumably, the idea is that engineers will get more practice with the maneuvers required before moving on to more dangerous rods. In a video statement, Tepco president Naomi Hirose said that rod removal is a "routine" process that the company has done more than a thousand times.
Workers manipulate one of the 550-pound fuel rods while keeping it submerged, via Tepco
It's a process that Tepco will have to do a thousand more times before it fully cleans up the plant. Reactors 1 through 4 were all damaged and their fuel rods must be removed. (Reactors 5 and 6, which along with reactor 4 did not melt down, have remained in cold shutdown, and are considered more stable. They will likely be decommissioned after the rest, however.) While 4, with its high-flying spent fuel pool, has been the biggest priority, a total of more than 3100 fuel rods are going to be taken away in the course of the plant's cleanup efforts, a process Tepco hopes to complete within five years.
It's a long, slow process necessitated by the inherent danger of removing nuclear fuel from damaged facilities. And if moving a 91-tonne cask of nuclear fuel around a pool some 130 feet in the air wasn't troublesome enough, it's thought that because of their meltdowns, reactors 1, 2, and 3 will pose more difficulties for cleanup. That's not to mention the huge list of other fixes needed to decommission the plant, including stemming the leaks plaguing the facility. No wonder Japanese citizens don't trust their regulators.