Satellite image captured March 14, 2011 shows a view of the Fukushima Dai Ichi nuclear plant. Japan's nuclear crisis worsened on March 15 following another explosion at the plant northeast of Tokyo, which was damaged Friday during a 9.0-magnitude earthquake and subsequent tsunami.
Credit: AFP
WASHINGTON: Attempts to manually cool the reactor at Japan's earthquake-hit nuclear facilities could fail if radiation levels continue to rise, forcing all remaining workers to evacuate, U.S. scientists said.
Only about 50 nuclear workers have stayed behind to douse the stricken reactors with sea water and authorities were mulling using water-dropping helicopters as the crisis at the aging Fukushima nuclear plant has deepened. Worsening levels of radiation have already forced the company to pull out most of its hundreds of workers who have been battling the emergency since Friday's quake and tsunami knocked out cooling systems.
"I am very concerned that the ongoing activities may become more and more challenging if radiation levels continue to increase for the workers who are engaged in manual actions at the site," said physicist Edwin Lyman, am expert on nuclear plant design.
Radiation detected in capital
"I don't know - if there had to be an evacuation of all workers - if the jerry-rigged cooling that they now have could be maintained," Lyman said.
Tens of thousands of people in the surrounding 20 km of the plant have already fled on government orders to clear the area. Radiation levels around the Fukushima No.1 plant on the eastern coast had "risen considerably," Japan's Prime Minister Naoto Kan said earlier, and his chief spokesman announced it had reached the point where it endangered human health.
In Tokyo, 250 km to the southwest, authorities also said that higher-than-normal radiation levels had been detected in the capital, the world's biggest urban area, but not at harmful levels. Lyman described those reports as "troubling developments."
"They are not unexpected but they do demonstrate the mobility of the fission products that are being released from the site and their ability to travel large distances downwind," he said.
Aerial water won’t cool core
Explosions hit the building's housing reactors one and three Saturday and Monday. On Tuesday, a blast hit reactor two at the plant and there was also an explosion at reactor four, which started a fire.
Tokyo Electric Power (TEPCO) has already taken the drastic measure of using highly corrosive sea water to cool reactor one - where a huge explosion Saturday tore away the outer concrete housing while leaving the steel reactor intact. The plant operator said it may be necessary to use helicopters to pour water into a containment pool for spent fuel rods.
David Lochbaum, head of the Union of Concerned Scientists' (UCS) nuclear safety program, said "the helicopters and aerial water addition won't help core cooling on any of the innards. However some kind of delivery like that might help with the spent fuel pools."
