Expert says Chernobyl-style disaster 'highly-unlikely'
Published 15/03/2011 | 11:56
Nuclear power experts today claimed it was "highly unlikely" that Japan's Fukushima Dai-ichi plant would cause a Chernobyl-style disaster, but warned it could be months before the complex is fully under control.
Despite a third explosion rocking the plant early this morning, it is hoped the amount of radiation released can be kept to a minimum.
Professor Mike Fitzpatrick from the Open University said automatic precautions prevented a more serious situation by shutting down the reactors after the earthquake.
"Within one second of the earthquake hitting, the control rods had been inserted and the nuclear reaction had stopped. The initial safety procedures went according to plan."
He said the latest explosion was the most worrying of the three because it was inside the concrete container vessel, and the damage could make it more likely that radioactive by-products are released, although there was no evidence of this yet.
Japanese authorities must stop the temperature inside the reactors from reaching levels high enough to cause a blast which would send nuclear fuel into the air.
Cooling is being done with sea water so it is vital that the pumping system is maintained.
John Large of the British Nuclear Engineering Society said that a meltdown could occur if the heat cannot be controlled.
"If you remove the cooling, the temperature of the rods goes up to 1200C.
"What you get is a bubbling mass and after a couple of hours you finish with a molten mass."
Professor Fitzpatrick added that he did not believe the crisis would deepen to the extent of Chernobyl.
"It's very unlikely," he said. "At Chernobyl there was an enormous explosion.
"It's hard to see a chain of events that would distribute radioactive material to such an extent. It's not like a nuclear bomb."
But he warned that the temperature would not be completely lowered immediately.
"Everything will gradually get better. For exactly how long it will take until you get cold shutdown, that is by weeks to months of cooling. But it gets cooler as time goes on," he said.