By Shinichi Saoshiro and Kazunori Takada
TOKYO (Reuters) - Global anxiety rose over radiation from Japan's earthquake-crippled nuclear plant, where rising smoke and haze from two of the most threatening reactors suggested the battle to avert a disastrous meltdown was far from won.
Although there appear to have been more advances than setbacks at the Fukushima power complex over the past 48 hours, Japanese Trade Minister Banri Kaieda said it would be hard to claim that the situation was heading in the right direction.
The world's worst atomic crisis in 25 years playing out 240 km (150 miles) north of Tokyo was triggered by a massive earthquake and tsunami that left at least 21,000 people dead or missing.
Technicians working inside an evacuation zone around the stricken plant on Japan's northeast Pacific coast have managed to attach power cables to all six reactors and start a pump at one of them to cool overheating nuclear fuel rods.
"We see a light for getting out of the crisis," an official quoted Prime Minister Naoto Kan as saying, allowing himself some rare optimism in Japan's toughest moment since World War Two.
However, Kyodo News reported that steam appeared to be rising from reactor No. 2 and white haze was detected above reactor No. 3. There have been several blasts of steam from the reactors during the crisis which experts say probably released a small amount of radioactive particles into the atmosphere.
Away from the plant, mounting evidence of radiation in vegetables, water and milk stirred concerns among Japanese and abroad despite officials' assurances levels were not dangerous.
Plant operator Tokyo Electric Power Co (TEPCO) said radiation was found in the Pacific nearby, not surprising given rain and the hosing of reactors with seawater. Some experts said it was unclear where the seawater was ultimately being disposed.
"Where does all the seawater go?" said Najmedin Meshkati, a Professor of Civil and Environmental Engineering at the University of Southern California.
"Some of the seawater is escaping as radioactive steam but we don't know what TEPCO is doing with the rest of it.
Radioactive iodine in the sea samples was 126.7 times the allowed limit, while caesium was 24.8 times over, Kyodo news agency said. That still posed no immediate danger, TEPCO said.
"It would have to be drunk for a whole year in order to accumulate to one millisievert," a TEPCO official said, referring to the standard radiation measurement unit. People are generally exposed to about 1 to 10 millisieverts each year from background radiation caused by substances in the air and soil.
Japan has urged some residents near the plant to stop drinking tap water after high levels of radioactive iodine were detected. It has also stopped shipments of milk, spinach and another local vegetable called kakina from the area.
"What I want the people to understand is that their levels are not high enough to affect humans," Chief Cabinet Secretary Yukio Edano said.
Experts say readings are much lower than around Chernobyl after the 1986 accident in Ukraine. Some warned against panic.
"You would have to eat or drink an awful lot to get any level of radiation that would be harmful," said British nuclear expert Laurence Williams.
"We live in a radioactive world: we get radiation from the earth, from the food we eat. It's an emotive subject and the nuclear industry and governments have got to do a lot more to educate people."
The World Health Organization (WHO) said the radiation impact was becoming more serious than first thought, when it was expected to be limited to 20-30 km (12-19 miles) from the plant.
However, Peter Cordingley, spokesman for the WHO's regional office, told Reuters there was no evidence of contaminated food reaching other countries from the Fukushima complex, which lies 240 km (150 miles) north of Tokyo.
In the city of 13 million, many residents have remained indoors. Some expatriates and locals left after the accident but are now starting to return.
Japan is a net importer of food but has substantial exports -- mainly fruit, vegetables, dairy products and seafood -- with its biggest markets in Hong Kong, China and the United States.
China said it is monitoring food imports from Japan but also took a swipe against panic by jailing a man for 10 days for spreading rumors about contamination of its waters.
State media said the computer company worker, who had urged people to avoid sea products for a year, was also fined 500 yuan ($76) and had confessed to "deep awareness of his mistake."
South Korea is expanding inspection of Japanese food.
And in Taiwan, one Japanese restaurant is offering diners a radiation gauge in case they are nervous about the food.
PLANT SITUATION MAY BE STABILISING
Despite the smoke and steam detected at the Fukushima plant on Tuesday, experts said the situation appeared to be improving.
"Things are beginning to trend in the right direction. TEPCO will need to get electrical power back on line to all six reactors and they will have to make sure that components are working," Mark Prelas, Director of Research for the Nuclear Science and Engineering Institute at the University of Missouri.
The priority on Tuesday will be patching up the No. 2 reactor so electricity, already connected, can be turned on. By Tuesday morning, reactor No. 1 was receiving power. Reactor No. 5 has both electricity and working cooling pumps.
The U.S. Nuclear Regulatory Commission said the crisis appeared close to stabilizing. "I would say optimistically that things appear to be on the verge of stabilizing," said Bill Borchardt, chief of operations at the NRC
The United States said it was distributing potassium iodide to American personnel in Japan "out of an abundance of caution" should the radiation treatment be needed.
BUFFETT: "A BUYING OPPORTUNITY"
The prospects of a nuclear meltdown in the world's third-biggest economy -- and its key position in global supply chains especially for the automobile and technology sectors -- rattled investors worldwide last week and prompted rare joint currency intervention by the G7 group of rich nations.
U.S. nuclear developer NRG Energy Inc has all but stopped work on a $10 billion project in Texas that was to be developed with the Japanese plant operator, the first U.S. company to slow ambitious growth plans after the crisis.
Damage from Japan's earthquake and tsunami is estimated at $250 billion, making it the world's costliest natural disaster.
Tokyo stocks rose 2.1 percent on Tuesday after a holiday on Monday, following a rise in global stocks as progress in the nuclear crisis revived risk appetite. The yen slid on speculation of more Group of Seven intervention.
In a symbolic boost for Japan, billionaire investor Warren Buffett said on Monday that the quake and tsunami were an "enormous blow" but also presented a "buying opportunity" given recovery prospects.
The official death toll - 8,805 by Tuesday morning - is certain to keep rising, with another 12,654 reported missing.
Police say more than 15,000 people probably died in Miyagi prefecture, one of four that took the brunt of the tsunami.
The 9.0-magnitude quake and ensuing 10-meter (32-ft) tsunami obliterated towns, which are now wastelands of mud and debris, leaving more than 350,000 people homeless.
Japanese are famed for resilience though, and there was none of the chaos or looting that major global disasters often spark.
In one devastated northern town, Rikuzentakata, rebuilding has even begun to help families living on mats in cramped shelters, separated from neighbors only by cardboard.
Steel structures, with walls and wood floors, have been erected at a hilltop school, to provide temporary housing.
Nearly 9.5 million foreigners visited Japan last year.
But, like Korean housewife Jin Hye-ryun who canceled a planned visit in May, many tourists are re-thinking.
"Safety is not guaranteed," she said. "Besides, think about people dying there. No one wants to go there to have fun."
There is widespread admiration for the workers facing high radiation dosages on the front line at Fukushima. Some have wept with tension and relief after finishing their shifts.
Other tales of heroism and horror abound, including a fire chief traumatized after sending a team to close a faulty sea-wall manually just as the tsunami struck, killing them all.
(Additional reporting by Paul Eckert in Tokyo, Jon Herskovitz and Chisa Fujioka in Kamaishi, Sui-Lee Wee in Beijing; Jungyoun Park in Seoul, Alister Doyle in Oslo, Scott DiSavino in New York and Kate Kelland in London; Writing by Andrew Cawthorne and Jason Szep; Editing by John Chalmers)