11.09am: The Guardian's energy editor, Terry Macalister, writes that"there is no immediate suggestion that Fukushima could turn into a Chernobyl-sized nuclear crisis."
"Some say its impossible anyway given the design of the reactor. But I was down at Chernobyl two weeks ago to survey the clean-up there and it was certainly a sobering insight into how devastating an atomic accident can be.
"The Chernobyl plant is still highly radioactive - 25 years after that accident - and far from fully dismantled or decommissioned. The nearby town of Pripyat lies completely empty. 50,000 people were evacuated from there and told they would be back the following weekend. They never returned."