Tepco on Friday cracked open the cover over the reactor 1 building at the Fukushima No. 1 nuclear plant.
The covering was installed in a bid to contain radioactive dust after a hydrogen explosion shattered the building’s exterior structure in March 2011.
Dismantling it is a first step toward removing spent fuel rods stored in a cooling pool above the reactor. That, in turn, must be completed before the reactor core can be opened to remove the melted-down fuel, according to Tokyo Electric Power Co.
On Friday morning, plant workers used a crane to remove a huge panel to see whether anti-dispersal agents are taking effect. They were inserted last week to reduce the risk of radioactive dust blowing out.
No changes in radiation levels have been observed around the plant so far, the company said.
Tepco will continue observations for a month to make sure radioactive materials are not emerging and then put the panel back again. It plans to begin full-fledged work on dismantling the cover next March.
Once the whole cover is removed, Tepco hopes to be able to clear debris lying on the structure’s upper levels.
The company then plans to begin removing spent fuel rods from the pool — in 2019 at the earliest — and later to try to extract the melted fuel from the reactor itself.
The reactor 1 building cover was installed in October 2011 as an emergency response to the rain sluicing radioactive materials down and the wind picking up contaminated dust.
Tepco initially planned to begin removal preparations by the end of last March but was forced to delay the schedule after local residents voiced concern about the contamination of rice fields nearby.