The Japanese quake, which now appears to have been a magnitude 9.0 on the Richter scale, released seismic energy yield equivalent to a 474 megaton atomic blast. This released 39,000 times more energy than the 12 kiloton bomb that devastated Hiroshima, and is equal to the force that flattened Lisbon, Portugal, on All Saints Day in 1755. Make no mistake, this was a catastrophic quake.
Despite this, the 40-year-old Fukushima Daiichi nuclear power plant, built to withstand a 7.9 magnitude quake, stood up to a seismic event that shook it over 30 times more powerfully than it was designed to survive. It held up to the onslaught, and shut down automatically as the tremors began.
It appears that the 10-metre tsunami that followed is what brought the reactors to the brink of meltdown, as back-up diesel generators for the facility's coolant pumps failed, and the cores began to heat up. Attempts to cool the cores were unsuccessful, and containment buildings blew up as the pressure built.
When a 20 km exclusion zone was declared ? a standard emergency protocol ? the global news coverage frothed with ?NUCLEAR CATASTROPHE?, ?ATOMIC CRISIS? and ?MELTDOWN ALERT?. And how did they deal with the 9.0 magnitude quake? ?TSUNAMI CARNAGE? and ?NATURE'S TERROR?.
These are just the headlines. The actual coverage has often been nonsensical, contradictory, overdramatic and occasionally hysterical. No wonder the public often react with fear when they see the word ?nuclear?.
To say - as some news outlets have - that the Fukushima accident was now worse than the Chernobyl disaster in 1986, just shows how bad the coverage can get, and why people get anxious. Chernobyl was a Russian design without a containment vessel and the reactor core was exposed, on fire, and large quantities of the fuel itself released into the air.
The Japanese reactors are designed to prevent this ever happening; fuel is inside a thick steel vessel, itself within a containment structure that is specifically designed to prevent release of core materials even during an accident such as this. Also, boiling water reactors like the ones in Fukushima are cooled by water which, unlike the graphite core at Chernobyl, cannot burn.