When the Fukushima Daiichi nuclear disaster began on 11 March 2011, reactor unit 4, 5 and 6 were all shut down. An explosion damaged unit 4 four days after the 2011 Tōhoku earthquake and tsunami. Damages from the earthquake and tsunami on unit 5 and 6 are relatively minor. Reactors 5 and 6 were also shut down when the earthquake struck although, unlike reactor 4, they were still fueled. The reactors have been closely monitored, as cooling processes were not functioning well.
When the Fukushima Daiichi nuclear disaster began on 11 March 2011, reactor unit 4, 5 and 6 were all shut down. An explosion damaged unit 4 four days after the 2011 Tōhoku earthquake and tsunami. Damages from the earthquake and tsunami on unit 5 and 6 are relatively minor. The unit 4 was shut down and all fuel rods had been transferred to the spent fuel pool on an upper floor of the reactor building. On 15 March, an explosion damaged the fourth floor rooftop area of the unit 4 reactor; the source of the explosion is still unknown, although it is speculated to be due to hydrogen generation in the spent fuel pool. Japan's nuclear safety agency NISA reported two large holes in a wall of the outer building of unit 4 after the explosion. It was reported that water in the spent fuel pool might be boiling. Radiation inside the unit 4 control room prevented workers from staying there permanently. Visual inspection of the spent fuel pool of reactor 4 on 30 April showed that there was no significant visible damage to the fuel rods in the pool. Reactors 5 and 6 were also shut down when the earthquake struck although, unlike reactor 4, they were still fueled. The reactors have been closely monitored, as cooling processes were not functioning well. (en)
When the Fukushima Daiichi nuclear disaster began on 11 March 2011, reactor unit 4, 5 and 6 were all shut down. An explosion damaged unit 4 four days after the 2011 Tōhoku earthquake and tsunami. Damages from the earthquake and tsunami on unit 5 and 6 are relatively minor. Reactors 5 and 6 were also shut down when the earthquake struck although, unlike reactor 4, they were still fueled. The reactors have been closely monitored, as cooling processes were not functioning well. (en)
