SENDAI, Japan (AFP) – Japan said on Thursday its stricken Fukushima Daiichi nuclear plant will have to be scrapped, while pressure also grew for the evacuation zone around the crippled facility to be expanded.
With no end in sight to the world's worst nuclear crisis in 25 years, the US ordered a Marine emergency response unit to Japan, and French nuclear group Areva said it was likely to step up assistance to the plant's operator.
Japanese Prime Minister Naoto Kan said the facility at the centre of the worst atomic accident since Chernobyl in 1986 must be decommissioned, Kyodo news reported.
Officials have previously hinted the plant would be retired once the situation there is stabilised, given the severe damage it has sustained including likely partial meltdowns and a series of hydrogen blasts.
However, there were no plans to widen a 20-kilometre (12-mile) exclusion zone around the Fukushima plant despite the UN atomic watchdog saying radiation in one village 40 kilometres away had reached evacuation levels.
Japan's top government spokesman Yukio Edano, asked whether further evacuations should be ordered, told a press conference: "I don't think that this is something of a nature which immediately requires such action.
"But... we will continue monitoring the level of radiation with heightened vigilance and we intend to take action if necessary."
His comments came after the International Atomic Energy Agency added its voice to that of Greenpeace, which has warned for several days that residents, especially children and pregnant women, should leave Iitate village.
The IAEA's head of nuclear safety and security, Denis Flory, told reporters in Vienna that radiation levels there had exceeded the criteria for triggering evacuations.
He said the IAEA -- which has no mandate to order nations to act -- had advised Japan to "carefully assess the situation, and they have indicated that it is already under assessment."
The reading in Iitate was two megabecquerels per square metre -- a "ratio about two times higher than levels" at which the IAEA recommends evacuations, said the head of its Incident and Emergency Centre, Elena Buglova.
Iodine-131 in the Pacific Ocean waters near the plant has risen to a new high of 4,385 times the legal level, the power station operator TEPCO said.
Elevated radiation levels have also been detected in the air near the nuclear plant, and in regional farm produce as well as in Tokyo drinking water.
Some 155 Marines of the US Chemical Biological Incident Response Force were due to arrive Friday, although there were no plans for them to take part in the emergency work to stabilise Fukushima, US defence officials told AFP.
They will not penetrate a 50-mile (80-kilometer) radius around the stricken plant, a zone which the US has advised its citizens to avoid, officials said.
French nuclear group Areva is assisting Tokyo Electric Power Company (TEPCO), which runs the Fukushima Daiichi plant, and the Japanese utility has asked it to provide more help, said Areva Japan president Remy Autebert.
"We'll need a bit of time, but our actions will probably increase in response to their requests," he told AFP.
French President Nicolas Sarkozy arrived in Tokyo on Thursday in a show of solidarity with the disaster-hit nation, and called on nuclear authorities in the Group of Twenty to establish an international safety standard.
"We ask the independent authorities of G20 members to meet, if possible in Paris, to fix the international nuclear safety standard," he said in a speech at the French embassy in Tokyo.
At the plant itself, workers pushed on with the high-stakes battle to stabilise reactors, into which water has been poured to submerge and cool fuel rods that are assumed to have partially melted down.
They are also struggling to safely dispose of thousands of tons of highly contaminated run-off water.
Japan has considered a range of high-tech options -- including covering explosion-charred reactor buildings with fabric, and bringing in robots to clear the irradiated rubble.
A US military barge carrying more fresh water to be pumped into the reactors was expected to arrive near the plant Thursday, the Yomiuri daily said.
Workers also plan to spray an industrial resin at the plant to trap settled radioactive particles, although plans to start Thursday were delayed because of weather conditions.