Tokyo Electric Power Co. announced Sunday that it will take six to nine months to complete a cold shutdown of the damaged reactors at the Fukushima No. 1 power plant, while the United States proposed a daring plan to use a remote-controlled helicopter and cranes to pluck out their spent fuel rods.
The “road map” represents the first specific time line Tepco has issued for getting the radiation crisis in Fukushima Prefecture under control.
If all goes well, displaced residents from the evacuation zone should know within six to nine months whether they will be able to go home, trade minister Banri Kaieda said.
The utility and its leaking power plant, which was crippled when the mega-quake and tsunami knocked out its cooling systems, are locked in a vicious cycle in which water being pumped in to cool the reactors is being turned into radioactive runoff that must either be stored or dumped into the sea, while it bleeds off radioactive steam into the atmosphere to cool off the cores.
Beleaguered Tepco Chairman Tsunehisa Katsumata, who hinted he might quit over the accident, said the utility needs three months to achieve a “steady reduction” in radiation and three to six more to get a handle on the emissions. This would be done by covering heavily damaged reactor buildings 1, 3 and 4, he said.
In the meantime, two U.S. robots with moveable arms entered the No. 3 reactor building later in the day to take temperature, radiation and oxygen readings and survey the damage. An test at the No. 5 reactor showed that the robots, each 70 cm long and 53 cm wide, can open the buildings’ doors by themselves.
In another development, the U.S. government has suggested Japan use a special unmanned cargo helicopter to set up cranes to remove the hazardous spent-fuel rods from the plant, Japanese and U.S. sources said Saturday.
Japan is looking to use a K-MAX helicopter developed by Lockheed Martin Corp. and KAMAN Aerospace Group of the U.S. to place cranes at the radioactive plant.
Since the helicopter can be operated remotely, it would allow repair teams to conduct repairs even in areas with lethal levels of radiation, they said.
Spent nuclear fuel is usually left to cool in storage pools for a few years after use and then taken away from nuclear plants inside of steel casks.
The plan would be to lower the casks into the pool and put the spent fuel in them.
The U.S. has proposed using the unmanned helicopter to transport the cranes in partially assembled form to the plant. It has also proposed installing them after radiation levels fall.
The proposal was originally conveyed by Adm. Robert Willard, commander of the U.S. Pacific Command, at a meeting in late March with his Japanese counterpart, Self-Defense Forces Chief of Staff Ryoichi Oriki, the sources said.
The U.S. side is ready to transport the special chopper by plane from the United States to the Air Self-Defense Force’s Matsushima base in Higashimatsushima, Miyagi Prefecture, they said.
The K-MAX helicopters belong to the U.S. Marine Corps and were introduced by the U.S. military after a number of manned helicopters were shot down by insurgents in Afghanistan. The improved version of the K-MAX can lift 1.4 tons.
The proposal was communicated to the unified command headquarters for the crisis, but Japan has not yet responded.
The spent-fuel storage pools on the fifth floors above the reactors are being cooled by hosing them down with water from truck-mounted concrete pumps.
In addition, water- and nitrogen-pumping operations are proceeding to address the more immediate threat of hydrogen explosions emerging in reactors 1 to 3, and toxic water emanating from reactor No. 2.
The Nuclear and Industry Safety Agency recently elevated the crisis to level 7 on the international nuclear incident scale, putting it on par with the 1986 Chernobyl disaster.