*Updates are underlined

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 12. It was assumed to be hydrogen explosion.
-At approximately 2:30 am on March 23, seawater injection to the reactor 
 through the feed water system was initiated.
-From 3:37 pm on March 25, we started injecting freshwater. We are now 
 injecting freshwater by a motor driven pump powered by the off-site 
 transmission line at 6 m3/h.
-As it is suspected that hydrogen gas is accumulated inside Primary 
 Containment Vessel, we commenced the valve opening operation concerning 
 injection of nitrogen gas into the primary containment vessel at 10:30 pm 
 April 6 and commenced injection at 1:31am April 7.

Unit 2 (Shut down) 
-At approximately 6:00 am on March 15, an abnormal noise began emanating 
 from nearby Pressure Suppression Chamber and the pressure within the 
 chamber decreased. 
-From 10:10 am on March 26, we started injecting freshwater to the reactor 
 and are now injecting freshwater by a motor driven pump powered by the 
 off-site transmission line at 7 m3/h.

Unit 3 (Shut down) 
-Explosive sound and white smoke were confirmed at approximately 11:01am 
 on March 14. It was assumed to be hydrogen explosion.
-From 6:02 pm on March 25, 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.
-At 4:53 pm on May 12, as a part of work to switch the water injection 
 line to the reactor from the fire extinction system to the reactor feed 
 water system, we started water injection through the reactor feed water 
 system in addition to through the fire extinction system. 
-On May 23rd, we changed the rate of water injection to Unit 3 through the 
 fire extinction system piping arrangement from approximately 4 m3/h to 
 approximately 3 m3/h at 5:19 Pm. The current rate of water injection is 
 approximately 3 m3/h through the fire extinction system piping 
 arrangement and approximately 12 m3/h through the reactor feed water 
 system piping arrangement .

Unit 4 (Outage due to regular inspection) 
-At approximately 6:00 am on March 15, we confirmed the explosive sound 
 and the sustained damage around the 5th floor rooftop area of Reactor 
 Building.
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel happened.

Unit 5 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 5:00 am on March 19, we started the Residual Heat Removal System Pump 
 (C) in order to cool the spent fuel pool.
-At 2:30 pm on March 20, the reactor achieved cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel happened.

Unit 6 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 10:14 pm on March 19, 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 20, the reactor achieved cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel happened.

Operation for cooling the spent fuel pools 
-On May 23rd , from 4:00pm to 7:09pm we sprayed water to the spent fuel 
 pool of Unit 4 by the concrete pumping vehicle (from 2:17 pm to 2:37 pm , 
 we sampled, on a trial basis, radioactive materials in the ambient air at 
 the opening of the Reactor Building. We added hydrazine (antioxidant) 
 from 4:08pm to 6:30pm). 
-On May 24th, from 10:15 am to 1:35 pm we injected water to Unit 3 by 
 temporary pumps (we added hydrazine (antioxidant) from 10:20 am to 12:56 
 pm). 
-We will continuously conduct further water spray depending on the 
 conditions of spent fuel pools, if needed.

Others 
-At 1:30 pm on April 26, we started spraying the dust inhibitor inside the 
 site.
-At 10:08 am on April 19, we started transfer of high level radioactive 
 wastewater from the vertical shaft near the turbine building of Unit 2 to 
 the Centralized Radiation Waste Treatment Facility.
-At 2:00 pm on May 1, we started transferring the accumulated water in 
 turbine building of Unit 6 to temporary tanks.
-At 11:00 am on May 10, we started transferring the accumulated water from 
 the underground level of reactor building to the radiation waste 
 treatment facility of Unit 6.
-At 6:04 pm on May 17, we started transfer of high level radioactive waste 
 water from the underground level of the turbine building of Unit 3 to the 
 Centralized Radiation Waste Treatment Facility.
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station.