*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. 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. 
- 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. 
  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 2:35 pm to 9:15 pm on June 3, we sprayed water to Unit 4 by a 
  concrete pumping vehicle (from 2:44pm to 6:58, injected hydrazine 
  [corrosion inhibitor] at the same time). 
- 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. 
  Since May 27, we have started spraying dust inhibitor to Unit 1's turbine 
  building. We will implement spraying the dust inhibitor to other 
  buildings including Unit 1 to 4's turbine buildings as well as reactor 
  buildings one by one. 
- Since 10:08 am on April 19, we have been transferring high level 
  radioactive wastewater from the vertical shaft near the turbine building 
  of Unit 2 to the Centralized Radiation Waste Treatment Facility. At 4:01 
  pm on May 26, a transferring operation was stopped. 
- 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. 
- Since 6:04 pm on May 17, we have been transferring high level radioactive 
  waste water from the underground level of the turbine building of Unit 3 
  to the Centralized Radiation Waste Treatment Facility, but the transfer 
  was suspended due to an inspection on transmission lines and buildings at 
  9:10 am, on May 25. 
- 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. 
- At 12:50 pm on June 2, we started transferring the accumulated water in 
  condenser of turbine building of Unit 3 to condensate storage tank of 
  Unit 3. 
- At 6:39 pm on June 3, we started transferring the accumulated water in 
  the trench of turbine building, Unit 2 to the condenser inside of turbine 
  building. 
- We will continue to take all measures to ensure the safety and to 
  continue monitoring the surrounding environment around the power station.