NEWS Japan earthquake: Fukushima nuclear plant remains the gap in a wall of disaster defences

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Japan has the most sophisticated earthquake detection network in the world — a system of 4,235 seismometers can detect the very first waves from a quake, before estimating its focus, magnitude and seismic intensity.

Phone alerts are then sent out, giving people precious seconds to prepare themselves for the shaking to come.
The earthquake today off Fukushima underlines how important these early warning systems are, in a country that has more large earthquakes than any other, and from where the word "tsunami" — meaning harbour wave — originates.

But like the tsunami stones that dot the Japanese coast, warnings are only effective if people heed them
Fukushima nuclear plant remains a gap in Japan's disaster defences

 

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so in just 40 years the site will be safe?

 

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Five Years Later, Cutting Through the Fukushima Myths

Radiation expert Andrew Karam, who covered the disaster for Popular Mechanics in 2011 and later traveled to study the site, explains everything you need to know about Fukushima's legacy and danger five years later.


By Andrew Karam
Mar 11, 2016


Nuclear reactor accidents are so devastating and world-changing that you know them by one name: Three Mile Island (1979), Chernobyl (1986), and Fukushima.

March 11, 2011 was a day of unimaginable tragedy in northern Japan, a tragedy exacerbated by the reactor meltdowns and release of contamination. But the nuclear part of this horrible day was, if the longest-lasting, certainly the least lethal event. Yet it's the part that still engenders so much fear. With the fifth anniversary of the Fukushima accident upon us this month, let's take a look at where things stand today with recovering from this calamity, and what might be happening next.


What Happened
You know the outline of the disaster by now: A powerful earthquake caused a massive tsunami that crashed into Fukushima Daiichi Nuclear Power Plant and caused multiple nuclear reactor meltdowns. But to really understand what happened at the nuclear plant that day, you need to know a little more.

At the site of the earthquake, stress had been building up in the Earth's crust for decades. When it released, that stress caused one of the most damaging quakes on record. The earth moved more than 20 meters over a 500-mile zone and the resulting earthquake released as much energy as a 45-megaton hydrogen bomb (to put this in perspective, this is 30,000 times more powerful as the bomb that leveled Hiroshima). It was the fourth-strongest earthquake recorded since 1900 and the strongest earthquake to strike Japan in recorded history. The quake shifted the Earth's axis by somewhere between 4 and 10 inches, altering the length of a day by nearly 2 microseconds.
Fukushima Five Years Later

 

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The multiple nuclear reactor units involved in the Fukushima Daiichi nuclear disaster were close to one another and this proximity triggered the parallel, chain-reaction accidents that led to hydrogen explosions blowing the roofs off reactor buildings and water draining from open-air spent fuel pools. This situation was potentially more dangerous than the loss of reactor cooling itself. Because of the proximity of the reactors, plant workers were put in the position of trying to cope simultaneously with core meltdowns at three reactors and exposed fuel pools at three units.

Automated cooling systems were installed within 3 months. A fabric cover was built to protect the buildings from storms and heavy rainfall. New detectors were installed at the plant to track emissions of xenon gas. Filters were installed to reduce contaminants from escaping the area of the plant into the area or atmosphere. Cement has been laid near to the seabed to control contaminants from accidentally entering the ocean. The biggest costs for the cleanup will be the final decommissioning of the reactors, a process estimated to take 10–30 years.

Cleanup costs will not be fully known until the cleanup is completed and the decommissioning is complete. No strontium was released into the area from the accident;[1] however, in September 2013 it was reported that the level of strontium-90 detected in a drainage ditch located near a water storage tank from which around 300 tons of highly toxic water was found to have leaked was believed to have exceeded the threshold set by the government.[2]

Decommissioning the plant is evaluated to cost tens of billions of dollars and last 30–40 years.[3][4] Initial fears that contamination of the soil was deep have been reduced with the knowledge that current crops are safe for human consumption and the contamination of the soil was not serious;[5] however, in July and August 2013, it was discovered that radioactive groundwater has been leaking into the sea.
Fukushima disaster cleanup - Wikipedia