The U.N. atomic energy chief said he plans to fly to Japan on Thursday to seek first-hand information of what he called a "very serious" situation at a disaster-stricken nuclear power plant in his home country.

The move suggested growing concern at the International Atomic Energy Agency (IAEA), which is tasked with fostering the safe use of nuclear energy, about the lack of speedy and detailed information from Japan on the unfolding crisis.
"It is different to receive facts by email from Tokyo to sitting down with them and exchanging views," Yukiya Amano, IAEA director general, told a news conference.

"We always need to improve the flow of information," Amano said, adding he hoped to meet high-level Japanese officials but that it was not decided whether he would go the site of the severely damaged Fukushima plant during his one-day trip.

Despite his growing concern, Amano said it was not the time to say whether developments at the site had spiraled out of control, as suggested by a senior European official in remarks that sent shares lower.

European Union energy chief Guenther Oettinger said earlier on Wednesday Japanese authorities appeared to have lost control of the situation, although his spokesman later said his comments were based on media reports and his personal fears.
"It is not the time to say things are out of control," Amano said. "The operators are doing the maximum to restore the safety of the reactor."

The veteran Japanese diplomat spoke after workers briefly withdrew from the stricken power plant because of surging radiation levels and a helicopter failed to drop water on the most troubled reactor.

No Plutonium Concern
Early on Wednesday another fire broke out at the earthquake-crippled facility, which has sent low levels of radiation wafting into Tokyo in the past 24 hours, triggering fear in the capital and international alarm.

"It is a very serious situation," Amano said.

Damage to the cores of units 1, 2 and 3 at the Fukushima Daiichi nuclear reactor had been confirmed, although there had been no serious change there since Tuesday, he said.

In another potentially ominous sign, he suggested the water was at a level that left up to two meters of the cores holding the fuel rods exposed, even though the pressure inside suggested the reactor vessels remained largely intact.

The plant operator described No. 3 - the only reactor at that uses plutonium in its fuel mix - as the "priority."

Plutonium, once absorbed in the bloodstream, can linger for years in bone marrow or liver and lead to cancer.

But Amano's deputy for safety issues, Denis Flory, said the IAEA had not seen any measurements of plutonium release.

"Plutonium is not a concern at the time being," he said.

Japanese media have become more critical of the government's handling of the disaster and have also criticized plant operator Tokyo Electric Power Co. for its failure to provide enough information on the incident.

The IAEA, which has as a mandate to share information with member states when there is a nuclear emergency, has also faced criticism in the media and in comments posted on its Facebook page for providing scant and out-of-date information.

The IAEA says it can only provide the information it receives and verifies.