Fukushima cleanup hits a milestone as worker remove nuclear fuel rods

2013_Fukushima_NB-2 A waterlogged radiation and tsunami warning sign found on Fukushima beaches in 2013. (Photo: Nils Bøhmer/Bellona) Photo: Nils Bøhmer

Tokyo Electric Power Co, or Tepco, owner of Japan’s ruined Fukushima Nuclear Power Plant, began removing radioactive fuel rods earlier this month at one of the three reactors that melted down after they were hit by a tsunami in 2011, marking a major milestone in the arduous cleanup operation.

Thousands of former residents have been barred from returning to areas around the plant for years as crews carry out an enormous radioactive waste cleanup operation in the wake of the worst nuclear accident since Chernobyl in 1986. The process of removing the spent nuclear fuel rods at Fukushima’s Number 3 reactor had been delayed since 2014, as crews battled equipment malfunctions, high levels of radiation and radioactive debris.

In an April 14th release, Tepco said that work had begun to remove the first of 566 used and unused fuel rods from the No 3 reactor building. The rods were first located in 2017 by a radiation-resistant robot.

“Thanks to their training, the work has been going smoothly,” Tomohiko Isogai, the director of the nuclear plant, was quoted as saying by the Japanese broadcaster NHK, referring to workers involved in the fuel cleanup. He added that plant officials were “very sorry” over the delays in the process.

The announcement is a major benchmark in the cleanup and decontamination efforts that Japan has undertaken since the disaster struck. More difficult still will be removing the molten uranium fuel that melted down in the three stricken reactors – a task Tepco is expected to accomplish with the help of robots, though the timeframe for the operation is still unclear.

2013_Fukushima_NB-1 A clock stopped at the time the tsunami gushed in from the sea found in the destruction of a beach community in Fukushima. Photo: Nils Bøhmer - Credit: Nils Bøhmer/Bellona

The devastation caused by the Fukushima disaster left an area the size of Hawaii to decontaminate. And while Japan claims progress, the costs of that progress are astronomical. Estimated costs for the cleanup range from $75.4 billion to much as $660 billion. The whole effort is expected to last for another 40 years.

The fuel rods stored in the third reactor’s cooling pools were not damaged during the 2011 disaster. Tepco said the operation to remove the rods – whose pools are not covered – would take two years.

The uncovered pools have long been a concern, and fears were high that another earthquake in seismically active Japan could cause them to spill their radioactive liquids. Tepco said that moving the rods would keep them safe should another earthquake strike the region.

Tepco is using remotely operated cranes to raise the fuel from storage racks in the Number 3 reactor’s pool and placing them in protective casks. The process occurs underwater to prevent radiation leaks.

This procedure will then be repeated in the other melted down reactors. All told, the three reactors contain 1,573 fuel rods within their structures, the Kyodo News Agency said.

Tepco’s announcement comes a few days after people began moving back to Okuma, a town near the ruined plant. Earlier this month, the government partially lifted the evacuation order over the town, saying radiation levels there had fallen to a safe level.

But the residents remain skeptical, according to the Kyodo agency. Only 367 of the town’s original 10,341 residents have registered as having moved back to the area. Overall, the Fukushima disaster displaced more than 160,000 people, all of whom were evacuated in the days following the disaster.

In 2014, workers removed and stored hundreds of fuel assemblies in reactor building No 4, which was one of three reactors not in operation when the plant was struck by a towering tsunami.

Robotic probes have photographed and detected traces of melted nuclear fuel in all three reactors that suffered meltdowns, but experts have yet to develop robots capable of locating and removing the fuel while exposed to dangerously high radiation levels.

In February a probe made physical contact with melted fuel at the bottom of a reactor for the first time since the disaster.

 

Charles Digges

charles@bellona.no