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Nuclear Emergency Declared At 2 Plants In Japan
Hugh Pickens writes "CBC reports that Japan has declared a state of emergency and called for mass evacuations near two nuclear power plants following cooling systems failures that led to radiation escaping from a reactor at one location. The emergency declarations, which include five reactors at the two plants, followed Friday's 8.9-magnitude earthquake off the country's northeast coast. In a troubling announcement, Japan Nuclear and Industrial Safety Agency official Ryohei Shiomi said a monitoring device outside the plant detected radiation that is eight times higher than normal and an evacuation zone has been expanded from three kilometres around the plant to 10 kilometres."
There's a lot of misinformation flying around.
http://www.bbc.co.uk/news/world-asia-pacific-12721498 [bbc.co.uk] (watch the movie)
Steam was released on purpose.
Based on just this discrepancy between the BBC and the CBC articles, /. might be a bit careful on it's reporting right now...
Everyone's getting excited over the nuclear plants, and ignoring the thousands that are still are dying due to just water. Why is radiation so much scarier? Water kills faster. /rant.
The outer walls of the Reactor 1 building have partially blown off, leaving only what looks like a steel frame. NHK is saying that a sensor within 5km of the plant is detecting radiation levels approaching 1015 microsieverts - that is apparently a year's worth of radiation exposure each hour.
People in the danger zones are being told to cover faces with wet towels, avoid eating vegetables and other fresh foods, and refrain from drinking tap water. Things seem to be happening quickly.
Here's video of the reactor exploding.
It will take the media and Japan a while to circle around to what caused the explosion, so I'll explain it now.
The explosion you see in the videos aligns perfectly with the Fukushima Daiichi No.1 reactor building seen here (forth square building from the left.)
The BBC has provided this incredible before/after photo where you can actually see the reactor building structure with the walls removed by the explosion: the metal framework is still intact.
The exact same thing happened with TMI-2 in 1979. The hydrogen burn occurred inside the containment dome. The Fukushima reactor doesn't have such a dome, so the hydrogen accumulated in the reactor building.
Lurking at the bottom of the gravity well, getting old
Except you're completley missing what caused the damage. The damage you can see in the videos was not caused by the earthquake. It was caused by the reactor losing coolant, running too hot, producing hydrogen gas from the fuel essentially burning, and that gas exploding. As others have pointed out, this is exactly what happened at Three Mile Island, although TMI had an extra containment dome which the Japanese reactors lack, which is resulting in higher radiation leakage than TMI experienced.
Now, consider something lime a molten salt reactor. A modern reactor doesn't care if the coolant/heat exchanger cycle shuts down, as this earthquake appears to have caused. Heating up the coolant naturally slows down the reaction. Additionally, the coolant doesn't boil off, so the fuel is never exposed to oxygen or hydrogen. Combustion is impossible. At the very first step of the problem, the chain of events that leads to a loss of containment is cut. This is a monster of a quake, and yet it would have had no significant effect aside from the reactor safely reducing itself to minimal power (generating heat as quickly as it naturally dissipates) when the heat exchange cycle stopped.
There's no place I could be, since I've found Serenity...
What could have happened that the reactor didn't scram?
No, all reactors properly shutdown with fail safes. The problem is, their reactors require active cooling which is something modern reactor designs specifically avoid for exactly these reasons. The problem is, just because the reactor has shutdown does mean the heat instantly goes away nor does it mean the core immediately stops creating heat. Their reactor designs require electric pumps to circulate coolant. When the reactor went down from the quake, their emergency generators started up. Those ran for about an hour until the tsunami reached the plant. The water, from what I've read, got into the generators and caused all of them to shutdown at the same time. The reactor's fail safes then fell back on a large battery bank. The batteries can't last for too long and from what I understand, power only a small subject of coolant pumps. As a result, the core temperature has continued to rise and a lot of water has evaporated. This is why they are working to get replacement batteries until they can get new generators online.
As a result of the heat, a lot of hydrogen formed and caused a massive explosion at one of the plants. Again, from what I've read, the explosion was external to the core's containment. As such, actual containment has not been lost. In order to address building coolant pressures from the rising temperatures, they've been forced to vent filtered yet radiative coolant.
Last I've heard, one worker has died from the explosion and a second was injured. Likewise, they are preparing to issue iodine to the surround population. Seems some of what has been vented is a radioactive form of iodine. Thusly, when the population ingests a non-radioactive source, its prevents absorption of yet additional iodine, including the radioactive iodine which has been released.