10 Mai 2013
May 10, 2013
Tokyo Electric Power Co. will demolish and replace the makeshift canopy covering a badly damaged reactor building at its Fukushima No. 1 nuclear power plant in order to remove rubble and radioactive material.
TEPCO, which announced the plan on May 9, said it will take about four years to complete a new cover for the No. 1 reactor building before removing fuel rods from the reactor's pool.
Although the amount of radioactive substances released from the reactor into the air will increase between the time the current cover is removed and the new one is installed, TEPCO said that it will not likely have a significant impact on the exposure assessment.
TEPCO will start demolishing the current cover this winter and then remove concrete and other rubble on the top floor of the building. After that, a crane and other equipment for fuel removal will be installed and a new cover put in place over the building.
The roof and walls of the No. 1 reactor building were destroyed in a hydrogen explosion that occurred on March 12, 2011, the day after the Great East Japan Earthquake and tsunami. The protective cover, made of polyester fiber panels, is 47 meters long, 42 meters wide and 54 meters high. It was built over the reactor building in October 2011.
TOKYO (Kyodo) -- The operator of the crippled Fukushima Daiichi nuclear power plant said Thursday it plans to temporarily take off a cover placed around the damaged No. 1 reactor building to prepare for the removal of fuel in the spent fuel pool.
Tokyo Electric Power Co. installed the cover in October 2011 to prevent the further release of radioactive substances into the air, given that a hydrogen explosion destroyed the roof and walls of the building housing the stricken No. 1 reactor.
A TEPCO official said that dismantling the cover -- work which will start in the fall -- is expected to lead to a "slight rise" in the radiation level but the impact will be "little."
After removing the cover, workers will clean the upper floor of the building where debris is scattered, and place a crane and other equipment necessary to take out fuel from the pool.
A cover will be reinstalled after the work finishes. The whole process is expected to take about four years, according to TEPCO.
TEPCO will continue to measure the radiation level of the upper floor while there is no outer cover.
The Nos. 1, 3 and 4 reactor buildings were badly damaged by hydrogen explosions that occurred in the early stage of the nuclear crisis, trigged by a huge earthquake and tsunami on March 11, 2011. The Nos. 1 to 3 reactors suffered core meltdowns.
Under a road map toward the decommissioning of the four reactors, TEPCO plans to start taking out fuel assemblies from the spent fuel pool at the No. 4 reactor building later this year and move on to the removal of fuel at the spent fuel tanks of other units.