SOMA, Japan —
Fourteen pumps have been brought in to get seawater into the other reactors. They are not yet pumping water into Unit 4 but are trying to figure out how to do that.
In Tokyo, slightly higher-than-normal radiation levels were detected Tuesday but officials insisted there are no health dangers.
"The amount is extremely small, and it does not raise health concerns. It will not affect us," Takayuki Fujiki, a Tokyo government official said.
Kyodo reported that radiation levels nine times higher than normal were briefly detected in Kanagawa prefecture near Tokyo and that the Tokyo metropolitan government said it had detected a small amount of radioactive materials in the air.
Edano said the radiation readings had fallen significantly by the evening.
Japanese government officials are being rightly cautious, said Donald Olander, professor emeritus of nuclear engineering at University of California at Berkeley. He believed even the heavily elevated levels of radiation around Dai-ichi are "not a health hazard." But without knowing specific dose levels, he said it was hard to make judgments.
"Right now it's worse than Three Mile Island," Olander said. But it's nowhere near the levels released during Chernobyl.
On Three Mile Island, the radiation leak was held inside the containment shell — thick concrete armor around the reactor. The Chernobyl reactor had no shell and was also operational when the disaster struck. The Japanese reactors automatically shut down when the quake hit and are encased in containment shells.
Olander said encasing the reactors in a concrete sarcophagus — the last-ditch effort done in Chernobyl — is far too premature. Operators need to wait until they cool more, or risk making the situation even worse.
Millions of people spent a fourth night with little food, water or heating in near-freezing temperatures as they dealt with the loss of homes and loved ones. Asia's richest country hasn't seen such hardship since World War II.