Highly radioactive water has been detected outside one of the reactors at Japan’s crippled nuclear plant at Fukushima for the first time.
On Sunday radiation levels up to 100,000 times above normal were found in water inside reactor Number 2 at the power station, struck by an earthquake and tsunami earlier this month.
A partial meltdown of fuel rods was said to be the cause.
The plant’s operator, Tepco, now says the same level of radiation has been found in water in tunnels used for piping outside the reactor.
The government has strongly criticised Tepco for getting the degree of radiation wrong.
The company initially miscalculated by two decimal places, saying that radiation levels in the reactor were 10 million times above normal, before correcting the figure to 100,000.
“Measuring radiation levels is vital for ensuring safety,” said Chief Cabinet Secretary Yukio Edano. “So mistakes like this are unacceptable.”
Tepco has reportedly appealed to French companies for help. It is already being aided by Chinese equipment, a huge pump truck helping to cool one of the reactors.
Meanwhile environmentalists Greenpeace say their experts have found high radiation levels outside the 20-kilometre evacuation zone, and have called for it to be extended.