Engineers were rushing against time to run power from the main grid to fire up water pumps needed to cool two reactors and the spent fuel rods considered to pose the biggest risk of spewing radioactivity into the atmosphere.
While Japanese officials were scrambling with a patchwork of fixes, the top U.S. nuclear regulator warned that the cooling pool for spent fuel rods at reactor No.4 may have run dry and another was leaking.
Gregory Jaczko, head of the Nuclear Regulatory Commission, told a parliamentary hearing that radiation levels around the cooling pool were extremely high, posing deadly risks for workers still toiling in the wreckage of the power plant.
“It would be very difficult for emergency workers to get near the reactors. The doses they could experience would potentially be lethal doses in a very short period of time,” he said.
The plant operator said it believed the No.4 reactor spent-fuel pool still had water as of Wednesday, and made clear its priority was the spent-fuel pool at the No.3 reactor. On Thursday morning alone, military helicopters dumped around 30 tonnes of water, all aimed at this reactor.
U.S. officials took pains not to criticise the Japanese government, which has shown signs of being overwhelmed by the crisis, but Washington’s actions indicated a divide with the Japanese about the perilousness of the situation.
“The worst-case scenario doesn’t bear mentioning and the best-case scenario keeps getting worse,” Perpetual Investments said in a note on the crisis.
Japan said the United States would fly a high-altitude drone over the stricken complex to gauge the situation, and had offered to send nuclear experts.
A State Department official said flights would be laid on for Americans to leave and family of embassy staff had been authorised to leave if they wanted.
Health experts said panic over radiation leaks from the Daiichi plant, around 240 km (150 miles) north of Tokyo, was diverting attention from other life-threatening risks facing survivors of last Friday’s 9.0 magnitude earthquake and tsunami, such as cold, heavy snow in parts and access to fresh water.
The latest images from the nuclear plant showed severe damage to some of the buildings after several explosions.
Sebastian Pflugbeil, president of the private German-based Society for Radiation Protection, said Japan’s efforts to pull the Fukushima plant back from the brink signalled “the beginning of the catastrophic phase.”
“Maybe we have to pray,” he said, adding that a wind blowing any nuclear fallout east into the Pacific would limit any damage for Japan’s 127 million people in case of a meltdown or other releases, for instance from spent fuel storage pools.
A stream of gloomy warnings and reports on the Japan crisis from experts and officials around the world triggered a sharp fall in U.S. financial markets, with all three major stock indexes slumping on fears of slower worldwide growth.
Economics Minister Kaoru Yosano told Reuters that Japan’s markets were not unstable enough to warrant joint G7 currency intervention or government purchases of shares.
“I don’t think stock and currency markets are in a state of turmoil,” Yosano said. Reuters