French agency says 'radioactive plume' but no risk for Tokyo
The Fukushima accident has generated a "radioactive plume" which is likely to expand in coming days but does not present any health threat to Tokyo, the head of a French nuclear safety agency said on Wednesday.
He added, though, that there could eventually be a "strongly contaminated zone" extending up to 60 kilometres (37.5 miles) around the stricken plant.
The cloud's extent "is relatively concentrated on a zone of several dozen kilometres around the site, depending on the fluctuation of the winds, which are generally blowing towards the Pacific Ocean but not always," said Jacques Repussard, from the Institute for Radiological Protection and Nuclear Safety (IRSN).
"In the coming days, this plume will eventually reach a zone of several hundred kilometres, but our calculations show that, for example in Tokyo, exposure will not have any impact on health in any way," he told a parliamentary committee.
The Fukushima No. 1 plant, hit by a quake and tsunami on March 11, lies 250 kilometres (155 miles) northeast of the Japanese capital.
"There will be ionising radiation, there will be radioactive particles, but doses will be at levels that are far far below those that, for instance, would need iodine tablets to be taken," said Repussard said.
Potassium iodine tablets are used in nuclear emergencies to protect the thyroid against radioactive iodine, which can cause cancer.
Eventually, said Repussard, "there will be a strongly contaminated zone, in the order of 50 to 60 kilometres [31-37.5 miles] around the site."
Beyond this, "there will be measurable impacts but not dramatic impacts."
Repussard did not give details about radioactivity levels, nor did he say what he meant by a "strongly contaminated zone" or what scenario of radioactivity emissions would be needed for this to happen.
Japan has set up a 20-km (12-mile) exclusion zone around the plant and warned people living up to 10 kms (six miles) beyond this to stay indoors. More than 200,000 people have already been evacuated.
In Tokyo, the US embassy Thursday warned American citizens living within 50 miles (80 kms) of Fukushima to evacuate or seek shelter.
Repussard added that global atmospheric concentrations of caesium, a long-lasting radioactive element, would remain lower than those that prevailed in the 1950s and 1960s, when the nuclear powers at the time carried out atmospheric tests.
"We have to keep these proportions in mind so that the public does not get alarmed for the wrong reasons," he said.
© 2011 AFP