Explosion at Fukushima Power Plant triggers fear of meltdown

March 15– Best to read about Fukushima nuclear power plant meltdown explained simply.

3:00 PM – Reuters: FLASH: Japan chief cabinet secretary says risk of explosion at building housing Fukushima Daiichi No. 3 reactor . More updates from Aljazeera live blog

March 13 – Japan’s top government spokesman says a partial meltdown is likely under way at the second damaged reactor of a quake-damaged nuclear complex, as authorities frantically tried to prevent a similar threat from a nearby unit following a catastrophic earthquake and tsunami. (read more)

7:51 PM- From Al-Jazeera: Ian Hore-Lacy, communications director at the World Nuclear Association, a London-based industry body, told Reuters he believed the explosion was due to hydrogen igniting, adding it may not necessarily have caused radiation leakage.

“It is obviously an hydrogen explosion … due to hydrogen igniting …If the hydrogen has ignited, then it is gone, it doesn’t pose any further threat,” he said.

6:00 PM- @adcarreon based at Urawa, saitama, Japan right now alerted me that ” Tokyo Electric Power Company confirm an explosion at one of its nuclear reactors in Fukushima Prefecture. Several were injured.”

Japan’s nuclear agency said that radioactive caesium and iodine had been detected near the number one reactor of the Fukushima 1 plant.

The agency said this may indicate that containers of uranium fuel inside the reactor may have begun melting.

Lets hope it doesn’t come to this….

The spread of radiation in the event of a nuclear fallout at Fukushima power plant is shown in a map below : (via @producermatthew)

A word of caution: the map might not be accurate based on this forum discussion:

However a comment in that video thinks that “That explosion that you see in these videos is exactly what happened to “Chernobyl”. This was the worst case scenario. The rods melted (melt down), and exploded. If you have ever seen pictures of the Chernobyl reactor building you can see the gigantic hole in the top where it blew up. Workers there were killed,? and injured during that explosion as well, as they were working to gain control.”

Is this scenario possible? Let us see the extent of the damage.

Peter Hayes, a nuclear expert, tells Al Jazeera “it’s still possible that the reactor workers can stabilise the situation” at the Fukushima Daiichi nuclear plant “if power is brought back, if coolant is brought into the reactor”, but “we’re really right at the precipice of a massive nuclear crisis”.

CNN reports that ” Japanese nuclear authorities said the cooling system had also failed at three of the four reactors at the Fukushima Daini plant — located in another town in northeaster Japan’s Fukushima prefecture.” A Yahoo article says that radiation is leaking from an unstable Japanese nuclear reactor after an explosion blew the roof off the facility in the wake of a massive earthquake.

The blast came as plant operator Tokyo Electric Power Co (TEPCO) worked desperately to reduce pressures in the core of the reactor.
“An unchecked rise in temperature could cause the core to essentially turn into a molten mass that could burn through the reactor vessel,” risk information service Stratfor said in a report before the explosion. “This may lead to a release of an unchecked amount of radiation into the containment building that surrounds the reactor.”

A BBC report indicates ” the amount of radiation released was “tiny”

In some of the reactors at the two Fukushima plants the cooling systems, which should keep operating on emergency power supplies, failed.

Without cooling, the temperature in the reactor core builds, with the risk that it could melt through its container into the building housing the system.

Analysts say a meltdown would not necessarily lead to a major disaster because light-water reactors would not explode even if they overheated.

But Walt Patterson, of the London research institute Chatham House, said “this is starting to look a lot like Chernobyl”.

He said it was too early to tell if the explosion’s aftermath would result in the same extreme level of radioactive contamination that occurred at Chernobyl.

The nuclear safety agency asserted Saturday that the radiation at the plants did not pose an immediate threat to nearby residents’ health, the Kyodo News Agency said.

@KeithMansfield reports that the Official #Fukishima nuclear exclusion zone quickly widens from 3 to 10 to 20km.

What now?

Things remain unclear at this point. Nuclear experts are unsure if it is a steam explosion. Monitoring is done 5 kilometers away.

Monitoring developments as it happens in here: