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Press Release (Apr 20,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 0:00 pm, April 20)
 
No updates from 6:00pm, April 19th 
All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down.
 
Unit 1(Shut down) -Explosive sound and white smoke were confirmed after the big quake occurred at 3:36 pm on March 12th. It was assumed to be hydrogen explosion. -At approximately 2:30 am on March 23rd, seawater injection to the nuclear reactor through the feed water system was initiated. -From 3:37 pm on March 25th, we started injecting freshwater and are now injecting fresh water by a motor driven pump powered by the off-site transmission line. -As it is suspected that hydrogen gas is accumulated inside reactor containment vessel, we commenced the valve opening operation concerning injection of nitrogen gas into the reactor container vessel at 10:30 pm April 6th and commenced injection at 1:31am April 7th.
 
Unit 2(Shut down) -At approximately 6:00 am on March 15th, an abnormal noise began emanating from nearby Pressure Suppression Chamber and the pressure within the chamber decreased. -From 10:10 am on March 26th, we started injecting freshwater to the reactor and are now injecting fresh water by a motor driven pump powered by the off-site transmission line.
 
Unit 3(Shut down) -Explosive sound and white smoke were confirmed at approximately 11:01am on March 14th. It was assumed to be hydrogen explosion. -From 6:02 pm on March 25th, we started injecting fresh water to the reactor and are now injecting fresh water by a motor driven pump powered by the off-site transmission line.
 
Unit 4(outage due to regular inspection) -At approximately 6:00 am on March 15th, we confirmed the explosive sound and the sustained damage around the 5th floor rooftop area of the Nuclear Reactor Building. -At this moment, we do not consider any reactor coolant leakage inside the reactor happened.
 
Unit 5(outage due to regular inspection) -Sufficient level of reactor coolant to ensure safety is maintained. -At 5:00 am on March 19th, we started the Residual Heat Removal System Pump (C) in order to cool the spent fuel pool. -At 2:30 pm on March 20th, the reactor achieved reactor cold shutdown. -At this moment, we do not consider any reactor coolant leakage inside the reactor happened.
 
Unit 6(outage due to regular inspection) -Sufficient level of reactor coolant to ensure safety is maintained. -At 10:14 pm on March 19th, we started the Residual Heat Removal System Pump (B) of Unit 6 in order to cool the spent fuel pool. -At 7:27 pm on March 20th, the reactor achieved reactor cold shutdown. -At this moment, we do not consider any reactor coolant leakage inside the reactor happened.
 
Operation for cooling the spent fuel pools -We will conduct further water spray depending on the conditions of spent fuel pools, if needed.
 
Others -The national government has instructed evacuation for those local residents within 20km radius of the periphery and shelter in place for those residents from 20km to 30km radius of the periphery, because it is possible that radioactive materials are discharged. -At 10:08 am on April 19th we started transferring high level radioactive wastewater to the Centralized Radiation Waste Treatment Facility. -From 11:30am to 2:00pm, we opened and closed the double doors and conducted surveys of the situation of the inside of the nuclear reactor building of Unit 3 and measured a dose of radiation, etc. by a remote control robot. Also, from 4:00pm to 5:30pm, we did the same kind of work on Unit 1. From 1:42pm to 2:33pm on April 18th, we opened and closed the double doors, measured a dose of radiation and so on, and conducted surveys of the situation of the inside of the nuclear reactor building of Unit 2, by a remote control robot. -We will continue to take all measures to ensure the safety and to continue monitoring the surrounding environment around the power station.
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