The following is the known status as of Thursday night of each of the six reactors at the Fukushima No. 1 nuclear power plant and the four reactors at the Fukushima No. 2 plant, both in Fukushima Prefecture, which were crippled by Friday's magnitude 9.0 earthquake and the ensuing tsunami.
Fukushima No. 1 plant
-- Reactor No. 1 - Operation suspended after quake, cooling failure, partial melting of core, vapor vented, building housing reactor damaged Saturday by hydrogen explosion, seawater being pumped in.
-- Reactor No. 2 - Operation suspended after quake, cooling failure, seawater being pumped in, fuel rods fully exposed temporarily, vapor vented, building housing reactor damaged Monday by blast at reactor No. 3, damage to containment vessel feared, potential meltdown feared.
-- Reactor No. 3 - Operation suspended after quake, cooling failure, partial melting of core feared, vapor vented, seawater being pumped in, building housing reactor damaged Monday by hydrogen explosion, high-level radiation measured nearby on Tuesday, plume of smoke observed Wednesday and presumed to have come from spent-fuel storage pool, severe damage to containment vessel unlikely, seawater dumped over pool by helicopter on Thursday, water sprayed at it from ground.
-- Reactor No. 4 - Under maintenance when quake struck, fire Tuesday possibly caused by hydrogen explosion at pool holding spent fuel rods, abnormal temperature rise in spent-fuel storage pool, fire observed Wednesday at building housing reactor, pool water level feared receding, renewed nuclear chain reaction feared.
-- Reactors No. 5, 6 - Under maintenance when quake struck, water temperatures in spent-fuel storage pools increased to about 64 C on Thursday.
-- Spent-fuel storage pools at all reactors -- Cooling functions lost, water temperatures or levels unobservable at reactors No. 1 to 4.
Fukushima No. 2 plant
-- Reactors No. 1, 2, 4 - Operation suspended after quake, cooling failure, then cold shutdown.
-- Reactor No. 3 - Operation suspended after quake, cold shutdown.
==Kyodo
Source : http://english.kyodonews.jp/news/2011/03/79046.html