Radiation levels are so high near the crippled Fukushima Daiichi nuclear power plant that Japanese officials were forced to suspend the latest attempt to keep reactors cool on Thursday, which included helicopters spraying water over the plant, ABC News reports.
Though the two helicopters dropped about 30 tons of water on the plant overnight, Michio Kaku, a theoretical physicist, told ABC that the attempts to keep the plants cool were not only foiled, but also minimally effective.
"It's like a squirt gun, using a squirt gun against a raging forest fire. They're overwhelmed, they're floundering, they don't know what to do," Kaku said.
Crews were forced to evacuate amid efforts to cool the overheating reactors due to radiation exposure. So far, cooling problems have resulted in fires, explosions, and other damage at four of the plant’s reactors.
Meanwhile, following reviews by the Nuclear Regulatory Commission, the Department of Energy, and other nuclear experts, the U.S. Embassy in Tokyo advised U.S. citizens who live within 50 miles of the crippled plant to evacuate the area as soon as they can.
In an advisory, Ambassador John Roos underscored the risk of radioactive contamination in that 50-mile radius.
Those recommendations are based on computer calculations of radiation levels made by the NRC. The NRC says that while the average American is exposed to approximately 620 millirems, or 0.62 rem, of radiation each year from natural and manmade sources, radiation doses exceeding 1 rem to the body or 5 rem to the thyroid could be harmful.