23 Septembre 2014
September 23, 2014
IWAKI, FUKUSHIMA PREF. – Tokyo Electric Power Co. will begin removing hydrogen explosion debris from the reactor 1 building at the Fukushima No. 1 nuclear plant in winter 2015, officials said.
Prior to the move, the utility will soon start dismantling the building’s cover, the officials said Monday during a meeting with government officials in Iwaki, Fukushima Prefecture.
A hydrogen explosion tore apart the reactor 1 building on March 12, 2011, the second day of the crisis.
Tepco and the government vowed to take steps to prevent radioactive materials from being spread during the debris removal and protect local residents from possible exposure.
Similar work at reactor 3 last year is believed to have spread radioactive contaminants in nearby areas. The removal work raised dust containing radioactive materials, causing radiation levels to rise at monitoring posts at the plant. Critics say the dust spread, polluting rice paddies in some parts of Fukushima Prefecture.
Tepco also plans to start removing nuclear fuel rods from the spent fuel storage pool inside the reactor 1 building in the latter half of fiscal 2017. The planned debris removal is necessary to start that work. At present, a cover encloses the whole of the destroyed reactor building. Tepco said it would take about one year to remove the cover.
But the process may not go as smoothly as planned, given the problems Tepco has been facing on another front: dealing with tainted water at the plant.
Tepco said Monday that it now expects a further delay in work to remove highly radioactive water from an underground trench at the plant.
To enable the removal, Tepco plans next month to halt the radioactive water’s flow between the trench and the No. 2 reactor’s turbine building by injecting filler materials, including cement, into the section connecting the trench and the building, officials said.
The company hopes to complete the operation by January. Tepco previously aimed to finish the injection by the end of this month.
The trench, used to place cables and other equipment, holds some 5,000 tons of highly radioactive water, some of which may be leaking into the ground and the sea.
In preparation for the removal, Tepco in late April began an attempt to freeze radioactive water in a section that connects the tunnel to create a wall of ice to block the flow of water between the turbine building and the tunnel. The process would have made it easier to pump out highly radioactive water from the tunnel.
However, after the utility was unable to sufficiently freeze the water by the initially set deadline of mid-August, it switched to the use of fillers in an attempt to stop the flow by the end of this month.
The No. 2 reactor is one of the three that suffered a core meltdown.
A similar trench at reactor 3, which also had a meltdown, holds some 6,000 tons of radioactive water. It remains uncertain when work to remove that water will begin.