I think four of the six on site, but they have not all had the same problems. The explosions were actually in the reactor buildings, not inside the reactor pressure vessels, and these explosions were due to hydrogen accumulating and forming an explosive mixture with air
During the Fukushima Daiichi nuclear disaster in Japan, three of the reactors experienced hydrogen explosions. These explosions occurred in Reactors 1, 3, and 4.
The Fukushima nuclear power plant is a complex of six nuclear reactors located in Fukushima, Japan. It experienced a severe nuclear disaster in March 2011 after a tsunami triggered by an earthquake caused meltdowns in three of its reactors, releasing a significant amount of radioactive material into the environment.
There are six total and as far as I know from press reports four have been damaged. I think Nos 1,3, and 4 have had hydrogen explosions damaging the buildings. All four have probably had partial meltdown or at least damage to some of the fuel. The state of the primary pressure vessels is unknown but from the figures of high activity water in the basements it does appear there may have been some damage (cracking) of at least one vessel. Nos 5 and 6 reactors have not been reported as far as I know. I suspect this may be because they had already been shutdown a while before the incident so had less decay heat to remove, but this is only a guess.
Fukushima is not an event that happened, it is a place, a prefecture, or district, in Japan. There are two Fukushima nuclear power plants. The plant where the accident took place, Fukushima Daiichi, is located in Okuma, Fukushima, Japan.
Nuclear reactors use controlled nuclear fission reactions to generate heat, which is then used to produce steam that drives turbines to generate electricity. The heat is produced in the reactor core where nuclear fuel rods containing uranium or plutonium undergo fission reactions. The reactor's cooling system helps regulate the temperature and prevent overheating.
During the Fukushima Daiichi nuclear disaster in Japan, three of the reactors experienced hydrogen explosions. These explosions occurred in Reactors 1, 3, and 4.
General Electric
The Fukushima nuclear power plant is a complex of six nuclear reactors located in Fukushima, Japan. It experienced a severe nuclear disaster in March 2011 after a tsunami triggered by an earthquake caused meltdowns in three of its reactors, releasing a significant amount of radioactive material into the environment.
Some examples of nuclear disasters include the Chernobyl disaster in 1986 where a reactor at the Chernobyl Nuclear Power Plant in Ukraine exploded, releasing a significant amount of radioactive material. Another example is the Fukushima Daiichi nuclear disaster in 2011, where a series of equipment failures and a tsunami caused meltdowns at multiple reactors in the Fukushima Daiichi Nuclear Power Plant in Japan. These disasters have had long-lasting environmental and health impacts.
Those reactions that take place in functioning nuclear reactors (i.e not Chernobyl or Fukushima when the accidents happened).
Present 2013. None. All are active. Fukushima has been 'Decommissioned'.
It exploded because, seawater into the cores of the wrecked reactors fast enough to keep up with the steady heating.
Though Fukushima has lost 4 of its Nuclear Reactors, There are many more Nuclear Reactos running in Japan, Secondly Japan is mostly using Coal and Gas to compesate for fukushima.
Before the Fukushima Daiichi Disaster, there were 54 operational nuclear reactors in Japan. Three of those melted down, and one had problems that rendered it inoperable. The government has decided the other two reactors at Fukushima Daiichi cannot be restarted. Also, as other reactors have been shut down for maintenance or refueling, they have not been restarted, with the result that now, in early December 2011, only eight Japanese reactors remain in operation.
The solidified fuel and debris that melted in a meltdown is often called lava.
There are six total and as far as I know from press reports four have been damaged. I think Nos 1,3, and 4 have had hydrogen explosions damaging the buildings. All four have probably had partial meltdown or at least damage to some of the fuel. The state of the primary pressure vessels is unknown but from the figures of high activity water in the basements it does appear there may have been some damage (cracking) of at least one vessel. Nos 5 and 6 reactors have not been reported as far as I know. I suspect this may be because they had already been shutdown a while before the incident so had less decay heat to remove, but this is only a guess.
Yes. That's how the diesel generators were damaged at Fukushima Daiichi, leading to the current crises there. Note that the reactors themselves were not touched by the tsunami because of the containment structures in place.