Explosion at Japan's Fukushima Dai-ichi nuclear power plant
Radiation was leaking from an unstable nuclear reactor north of Tokyo on Saturday, the Japanese government said, after an explosion blew the roof off the facility following a massive earthquake. The development has led to fears of a disastrous meltdown. Here are comments from experts about what might have happened.
TIMOTHY ABRAM, PROFESSOR OF NUCLEAR FUEL TECHNOLOGY AT BRITAIN'S MANCHESTER UNIVERSITY
"By sampling the air around the station, you'd be able to tell how much radioactivity has been released. The thing they'll be looking for more than anything is whether there's any evidence of the fuel actually degrading," he told Reuters.
"If the fuel is substantially intact, then there'll be a much, much lower release of radioactivity and the explosion that's happened might be just due to a build-up of steam in the reactor circuit.
"The most probable (cause of the explosion) is the coolant, particularly if it's water, can overheat and turn to steam more rapidly than it was designed to cope with."
He said it was unlikely it would develop into anything more serious, but this would depend on the integrity of the fuel, which contains nearly all the radioactivity of the plant. He said he thought it would be "pretty unlikely" that the fuel itself had been significantly damaged.