UPDATED 11:44 a.m. -- A Japanese TV station has obtained this video of the damaged Fukushima Daiichi nuclear plant taken from a nearby helicopter:
Japanese defense forces enlisted lead-shielded helicopters to drop water into the damaged roof of Fukushima Daiichi unit 3 Wednesday night, with water cannon trucks also standing by to replenish the reactor's spent-fuel tank.
Government and Tokyo Electric Power Co. officials said that securing the spent fuel pools in units 3 and 4 has become the top priority at the nuclear plant, which has struggled with a loss of cooling systems and potential core damage in three reactors following a magnitude 9 earthquake last week. Two helicopters made four attempts to drop water into unit 3 with mixed success. Radiation readings taken from a smaller helicopter beforehand indicated levels of 4.13 millisieverts per hour at 1,000 feet above the unit and 87.7 millisieverts at 300 feet. Although crews were equipped with protective gear, radiation levels limited the amount of time the helicopters could work in the area, and they did not hover directly above the unit.
Tepco and government officials decided to focus on the tank in unit 3, where reports indicated water levels were extremely low. Nuclear Regulatory Commission Chairman Gregory Jaczko told a congressional panel on Wednesday that the spent-fuel tank in unit 4 was completely dry. But citing observations from a helicopter the day before, Tepco officials said the tank did have water in it, and that refilling unit 3's tank took priority.
White steam or smoke could be see rising from unit 3 Wednesday. It was unclear whether the substance came from the reactor coolant suppression system or from the spent-fuel tank, both of which may have been damaged in a blast Monday.
Some promising news also emerged Wednesday, as Tepco reported an electric line to supply AC power to units 1 and 2 was almost complete. Japanese regulatory authorities at a press conference late Wednesday said workers would begin installing temporary pumps in the reactor cooling system, as the original equipment had been damaged by seawater used to cool the cores of reactors 1, 2 and 3. Once the pumps and the electricity come online, officials are hopeful the cooling systems will be able to bring temperatures and pressures within the reactors under control.
For more information, and our most recent updates on each of the reactors at Fukushima Daiichi, please visit our new plant status page.
87.7 millisieverts at 300 feet measure is quite okay! While the ground level of area near unit 3 can be restricted from ordinary public.
Oops! on my previous comment. I misread milli-sieverts as micro sieverts.