Tepco: radiation from Fukushima plant declines further (Reuters)

TOKYO (Reuters) – The operator of Japan's tsunami-hit Fukushima nuclear power plant Monday said the amount of radiation being emitted from the complex has halved from a month ago, in the latest sign that efforts to bring the plant under control are progressing.

The Fukushima Daiichi plant, 240 kilometers (150 miles) northeast of Tokyo, was damaged in March by a devastating earthquake and tsunami in the world's worst nuclear accident since the Chernobyl disaster 25 years ago.

"Our latest measurements show that radiation from the damaged reactors is 100 million becquerels per hour, which is one eight-millionth of the amount measured soon after the accident," Tokyo Electric Power's (Tepco) vice president Zengo Aizawa told reporters during a monthly review.

Aizawa said that this translates to about 0.2 millisievert per year of radiation measured at the fringes of the plant, below the 1 millisievert safety limit according to government guidelines.

The amount is half of what Tepco announced at its review a month ago.

In light of the progress being made in cooling its damaged reactors, which suffered nuclear fuel meltdowns in the first days of the crisis, Tepco formally brought forward its plan to bring the plant to a state of "cold shutdown" within this year, instead of by January as initially planned.

It had said last month it was hoping to achieve a cold shutdown within the year but had not made a formal declaration.

Technically, a cold shutdown is a state in which water used to cool nuclear fuel rods remains below 100 degrees Celsius, preventing the fuel from reheating.

With the help of newly built cooling systems, Tepco's efforts to cool the reactors have progressed steadily, with temperatures at all three of the damaged reactors falling below 100 degrees late in September.

But despite this development, Tepco and the government have been cautious about immediately declaring a cold shutdown.

"We still need to proceed with care. We need to continue monitoring whether the temperatures of the reactors and radiation levels being emitted remain stable going forward," Yoshinori Moriyama, deputy director-general of the government watchdog Nuclear Industrial and Safety Agency, told the same news conference.

Declaring a cold shutdown will have repercussions well beyond the plant as it is one of the criteria the government said must be met before it begins allowing about 80,000 residents evacuated from within a 20 km (12 mile) radius of the plant to go home.

Japan faces a massive cleanup task if these residents are to be returned home -- the environmental ministry says about 2,400 square km (930 square miles) of land surrounding Daiichi may need decontamination, an area roughly the size of Luxembourg.

Even if a cold shutdown is declared Tepco has acknowledged that it may not be able to remove the fuel from the reactors for another 10 years and that the cleanup at the plant could take several decades.

It also has to decontaminate tens of thousands of tonnes of contaminated water pooled at the plant, a result of its efforts to cool the reactors early in the crisis by pumping in vast amounts of water, much of it from the ocean.

(Reporting by Shinichi Saoshiro; Editing by Sanjeev Miglani)

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Tepco confirms meltdowns at 2 more Fukushima reactors (Reuters)

TOKYO (Reuters) – The operator of the nuclear power plant at the center of a radiation scare after being disabled by Japan's earthquake and tsunami confirmed Tuesday that there had been meltdowns of fuel rods at three of its reactors.

Tokyo Electric Power Co said meltdowns of fuel rods at three reactors at the Fukushima Daiichi plant occurred early in the crisis triggered by the March 11 disaster.

The government and outside experts had said previously that fuel rods at three of the plant's six reactors had likely melted early in the crisis, but the utility, also known as Tepco, had only confirmed a meltdown at the No.1 reactor.

Tepco officials said a review since early May of data from the plant concluded the same happened to reactors No.2 and 3.

The preliminary finding, which was reported to Japan's nuclear safety agency, represents part of an initial effort to explain how events at Fukushima spiraled out of control early in the crisis.

Also Tuesday, the government appointed Yotaro Hatamura, a Tokyo University professor of engineering who has studied how complex systems and designs fail, to head a committee that will investigate the cause and handling of the nuclear crisis.

The moves came as a team of investigators from the International Atomic Energy Agency began a two-week visit to Japan to prepare a report on the accident to be submitted to the United Nations agency in June.

Some analysts said the delay in confirming the meltdowns at Fukushima suggested the utility feared touching off a panic by disclosing the severity of the accident earlier.

"Now people are used to the situation. Nothing is resolved, but normal business has resumed in places like Tokyo," said Koichi Nakano, a political science professor at Tokyo's Sophia University.

Nakano said that by confirming the meltdowns now, Tepco may be hoping the news will have less impact. The word "meltdown" has such a strong connotation that when the situation was more uncertain more people would likely have fled Tokyo, he said.

Engineers are battling to plug radiation leaks and bring the plant 240 km (150 miles) northeast of Tokyo under control more than two months after the 9.0 magnitude earthquake and deadly tsunami that devastated a vast swathe of Japan's northeast coastline and tipped the economy into recession.

The disaster has triggered a drop of more than 80 percent in Tepco's share price and forced the company to seek government aid as it faces compensation liabilities that some analysts say could top $100 billion.

Japanese trade minister Banri Kaieda said the government would approve the formation of a committee later Tuesday that will make sure Tepco follows through with restructuring plans.

Tepco officials said damage to the No.2 reactor fuel rods had begun three days after the quake, with much of the fuel rods eventually melting and collecting at the bottom of the pressure vessel containing them.

Fuel rods in the No.3 reactor were damaged by the afternoon of March 13, they said.

TSUNAMI

The Tepco officials repeated that the tsunami had disabled power to the reactors and knocked out their cooling capability.

Hidehiko Nishiyama, a spokesman for the government's Nuclear and Industrial Safety Agency, expressed a similar view.

"We don't think the quake affected the important parts of the plant, such as its cooling capacity," Nishiyama told reporters Tuesday, although he added there were still some aspects that needed to be clarified by inspecting the site directly.

That process is likely to make months because of the high radiation readings in areas of the plant, experts have said.

"It could very well be that Tepco is rushing to conclude that the tsunami is to blame to prevent further questions and give more momentum to the nuclear camp. It's not just Tepco, it's the whole nuclear industry, maybe business circles as a whole. It's highly political," said Sophia University's Nakano.

Others said that from a very early stage the tsunami, not the quake, was the likely cause of the overheating and subsequent damage of the reactors at Daiichi.

"As with the other nuclear reactors, such as Onagawa (in northeastern Japan), those at Daiichi deactivated after the quake. It is our belief that it was the tsunami that knocked out power and took out the systems and pumps that cool the reactors, resulting in their damage and radiation leakage," said Kazuhiko Kudo, a Kyushu University professor who specializes in nuclear engineering.

Despite a steady flow of information on how the clean-up is proceeding -- Tepco and the government's nuclear watchdog hold news conferences twice a day on most weekdays -- the authorities have faced criticism for what some have said is a lack of timely disclosure.

"I am very sorry that the public is mistrustful of the various disclosures made by the government on the accident," Prime Minister Naoto Kan said in parliament Monday.

(Additional reporting by Linda Sieg and Yoko Nishikawa; Editing by Chris Gallagher and Michael Watson)

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