TOKYO (Reuters) - French President Nicolas Sarkozy called on Thursday for a reform of global nuclear standards by the end of the year during a first visit by a foreign leader to Japan since the earthquake and tsunami that triggered its atomic disaster.
Group of 20 chairman Sarkozy said France wants to host a meeting of the bloc's nuclear officials in May to fix new norms in the wake of the crisis at Japan's Fukushima Daiichi plant.
Japan's Prime Minister Naoto Kan supported the idea.
"In order to avoid recurrence of such an accident, it is our duty to accurately share with the world our experience," he said at a joint news conference.
The world's worst atomic crisis since Chernobyl in 1986 is proving hard to contain and has forced an international re-think of the benefits and safety of nuclear power.
It has also compounded an agonizing moment for the Asian nation after the quake and tsunami left more than 27,500 people dead or missing and caused damage that may top $300 billion.
First data on the economic impact of the March 11 disasters showed manufacturing slumped the most on record this month as factories shut and supply chains were disrupted, especially in the car and technology sectors for which Japan is renowned.
France, the world's most nuclear-dependent country, is taking a lead in assisting Japan. As well as Sarkozy's show of solidarity by his personal presence, Paris has flown in experts from state-owned nuclear reactor maker Areva.
"Consider me your employee," Areva Chief Executive Anne Lauvergeon told Japanese officials.
The United States and Germany have weighed in too, offering robots to help repair the damaged nuclear plant.
In a worrying development in Switzerland, two female employees were injured when a parcel bomb exploded in the offices of the local nuclear lobby, police said. It was not known who sent it.
Switzerland has frozen the approvals process for three new nuclear stations pending a safety review after Japan's disaster.
Pressure has been growing on Japan to expand the evacuation zone around the Fukushima Daiichi plant where radiation hit 4,000 times legal limits in nearby sea and hindered the battle to contain the world's worst atomic crisis since Chernobyl.
Both the U.N. nuclear watchdog and Japan's own nuclear safety agency have advised Kan to consider widening the 20-km (12-mile) zone round the plant on the northeast Pacific coast.
High radiation was detected at twice that distance away.
Government officials are pleading for Japanese, and the world, to avoid overreaction to what they say are still low-risk levels of radiation away from the plant.
More than 70,000 people have been evacuated from the 20-km ring. Another 136,000 who live in a 10-km (6-mile) band beyond that have been encouraged to leave or to stay indoors.
U.N. body, the International Atomic Energy Agency (IAEA), said radiation at Iitate village, 40 km (25 miles) from the plant, exceeded a criterion for evacuation.
Japan's chief Cabinet Secretary Yukio Edano said the government was reviewing the issue daily but "at this moment, no decision to expand the evacuation area has been made".
Consistently high levels of radiation found in the sea near the complex could mean radiation is leaking out continuously, Japan's nuclear watchdog said. The source is still unknown, adding to the headaches for engineers on the site.
Radioactive iodine in seawater near drains running from the plant was 4,385 times more than the legal limit, the highest recorded so far during the crisis.
In a sign of the extraordinary times Japan is living, one newborn baby's first medical appointment was not with a pediatrician but a Geiger counter.
"I am so scared about radiation," Misato Nagashima said as she took her baby Rio, born four days after the earthquake and disaster, for a screening at a city in Fukushima prefecture.
Concern over radiation beyond Japan grew further after Singapore detected radiation nine times the limit in cabbages from Japan, while the United States reported "minuscule" levels of radiation in milk samples on its west coast.
Contaminated milk was one of the biggest causes of thyroid cancers after the 1986 nuclear accident in Chernobyl because people near the plant kept drinking milk from local cows.
Several nations have banned milk and produce from areas near the damaged nuclear plant, 240 km (150 miles) north of Tokyo. Japan has itself stopped exports of vegetables and milk there.
While food makes up only 1 percent of Japan's exports, the nuclear emergency poses a risk to an economy burdened with public debt twice the size of its $5 trillion dollar economy and a fast aging population.
Japan has called on World Trade Organization nations not to impose "unjustifiable" import curbs on its goods.
Experts say the battle to control Fukushima's six reactors could take weeks, if not months, followed by a clean-up operation that may drag on for years.
Plant operator Tokyo Electric Power Co could face compensation claims of up to 11 trillion yen ($133 billion) -- nearly four times its equity -- if the nuclear crisis drags on for two years, an analyst at Bank of America Merrill Lynch said.
As operators struggle to regain control of the damaged reactors, nuclear experts said the continued lack of a permanent cooling system was hindering efforts to cool down fuel rods.
Workers have been forced to pump in seawater to cool the rods, but this creates contaminated seawater around the stricken plant and is making it difficult to reconnect the plant's internal cooling system which contains radiation.
Radiation readings around the evacuation zone vary widely.
Daily readings published by the government show that 30 km (19 miles) northwest of the reactors levels are climbing up to 42 microsieverts per hour, about 6 times the cosmic radiation experienced during a Tokyo-New York flight.
Elsewhere at that distance around the reactor it is just 1.0-1.2 microsieverts per hour.
A Reuters reading in downtown Tokyo on Thursday showed a radiation level of 0.18 microsieverts per hour. This is still quite low by global standards as Japan has lower levels of natural background radiation than other places.
(Additional reporting by Chisa Fujioka, Kiyoshi Takenaka and Chizu Nomiyama in Tokyo, Dave Dolan in Fukushima City, Ben Gruber in Koriyama and Sylvia Westall and Fredrik Dahl in Vienna, and Andrew Callus in Geneva; Writing by Michael Perry and Andrew Cawthorne; Editing by John Chalmers)
mochila insert follows