The UK government’s chief scientific adviser John Beddington today outlined the worst case scenario in Fukushima following a third explosion at the nuclear plant this morning.
Professor Beddington said that a containment vessel around the reactor that exploded this morning may be ruptured, which would mean the temperature could not be controlled.
“At that stage… you get meltdown,” he told BBC Radio 4’s Today programme. “In that situation, radioactive material is going to react with the concrete on the base of the reactor and that is likely to cause an explosion.
Prof Beddington said that such a blast would put “more radioactivity into the atmosphere” in the form of a plume, which he would expect to be around 500 metres high.
But while extremely serious, he said this radioactive plume would be small compared those of other nuclear explosion, particularly the 1986 accident at Chernobyl , where the plume was 30,000 feet high.
A 500 metre plume would be too small to be carried by wind to Tokyo, he stressed.
Prof Beddington said that engineers at Fukushima were doing everything right in terms of trying to contain the problems, in particular by pouring seawater into the reactors to cool them.