*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 reactor feed water system was initiated. 
-From 3:37 pm on March 25, we started injecting freshwater by a motor 
 driven pump powered by the off-site transmission line. We are now 
 injecting freshwater by a motor driven pump powered by the off-site 
 transmission line. 
 The current rate of water injection is approx. 5 m3/h 
 through reactor feed water system piping arrangement. 
-As it was suspected that hydrogen gas had been 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 on 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. 
 The current rate of water injection is approx. 5 m3/h 
 through the reactor feed water system piping arrangement. 
 
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. 
 The current rate of water injection is approx. 11.5 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 has occurred. 
 
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 has occurred. 
 
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 has occurred. 
 
Operation for cooling the spent fuel pools 
-At 5:21 pm on May 31, we started cyclic cooling of the spent fuel 
 pool in Unit 2 using alternative cooling system for fuel pool 
 cooling and filtering system. 
-From 2:23 pm to 7:45 pm on June 4, we started water spray to Unit 4 
 by a concrete pumping vehicle (from 2:51pm, also injected hydrazine 
 [corrosion inhibitor] at the same time). 
-From 10:16 am to 10:48 am on June 5, we started the water 
 injection to the spent fuel pool of Unit 1 by a temporary motor 
 driven pump. 
-At 1:08 pm on June 5, we started the water injection to the spent 
 fuel pool of Unit 3 by a temporary motor driven pump (from 1:14 pm 
 to 2:16 pm, we added hydrazine (antioxidant)). 
-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. 
 On May 27, we started spraying dust inhibitor to Turbine Building of 
 Units 1. We will implement spraying the dust inhibitor to other 
 turbine and reactor buildings of Units 1 to 4. 
-At 2:00 pm on May 1, we started transferring accumulated water in 
 the turbine building of Unit 6 to temporary tanks. 
-At 11:00 am on May 10, we started transferring accumulated water 
 from the underground level of reactor building to the radiation 
 waste treatment facility of Unit 6. 
-At 8:00 am on May 31, 2011, we confirmed oil leakage to the sea 
 around the curtain wall of the water intake canal of Unit 5 and 6, 
 Fukushima Daiichi Nuclear Power Station. As a result of our 
 investigation, we confirmed that oil leaked from pipes around 
 seawall to the port through holes of steel sheet piles and that the 
 leakage has already stopped. Since the diffused area was just around 
 the curtain wall and the surface of the sea around Shallow Draft 
 Quay and the oil film was very thin, we confirmed that there is no 
 spread to the outer sea. We completed installing oil-absorbing mat 
 around seawall at approximately 2:00 pm and also installed oil 
 fences at 4:50 pm. We plan to protect pipes around seawall and 
 collect the oil. 
-From 12:50 pm on June 2 to 9:56 pm on June 4, we transferred 
 accumulated water from the condenser of turbine building of Unit 3 
 to the condensate storage tank of Unit 3. 
-At 6:39 pm on June 4, we started transferring accumulated water 
 from vertical shafts (trenches) of turbine building of Unit 2 to 
 Process Main Building. 
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power 
 station.