On Friday March 11th, 2011, Japanese nuclear power plant, Fukushima Daiichi was hit by an earthquake following by the tsunami.
The earthquake, Great East Japan Earthquake, had a magnitude 9.0 on Friday. Both the earthquake and tsunami caused severe damage to the cooling system of the reactors. Then comes the overheating and explosions.
Reactor 1, 2, 3, and 4 were hit by explosions and started to release radiation into the air.
Reactor 1 was hit by an explosion on Saturday, which destroyed the roof of the building while the primary containment vessel remained safe.
An explosion that happened on Monday ripped open the the top and the outer walls of Reactor 3. According to the officials, the containment vessel were cracked.
Another explosion on Tuesday also breached the primary containment of Reactor 2. The fuel rods started to melt after the failing efforts of cooling down the reactor with seawater.
Reactor 4, 5, and 6 were shut down for maintenance before the earthquake. But the explosion on Tuesday still caused the temperature of spent fuel pools in Reactor 5 and 6 to rise. It also damaged the building of Reactor 4 and caused the water of spent fuel pools boiling.
The damage raised concerns for the environment and health. The regions close by were reported to have a radiation level of 680 microSieverts per hour. The workers on site were given potassium iodide to prevent thyroid cancer. The amount of tablets needed is huge. And only 2000 workers had been given with the pills.
After this incident, people’s perception about nuclear power plants had been changed. With the proper protection, a natural disaster is still too much to handle. This should be an important record for people to start working harder on the renewable energy, just like how Germany has changed.
an earthquake hits off the Eastern coast of Japan causing the automatic shut down of units 1, 2, and 3. Units 4, 5, and 6 had been shut down previously due to outages, but the emergency diesel generators are activated to provide power to the emergency cooling systems. Soon after a tsunami hits the plant and the EDGs stop working and an evacuation is ordered for people within 3km of the plant. The knock out of the cooling systems and reactors caused meltdowns and
Reference:
http://www.nytimes.com/interactive/2011/03/15/world/asia/daiichi-graphic.html
http://www.world-nuclear.org/info/fukushima_accident_inf129.html
http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant
http://www.scientificamerican.com/article.cfm?id=japan-earthquake-tsunami-radiation