*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 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.
- At 10:02 am on April 27th, in order to examine an appropriate amount of 
  water to make nuclear reactor flooded, the gradual operation to change 
  the amount of injecting freshwater from 6m3/h to approximately 14m3/h 
  was initiated  
- 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  
- From 4:50 am to 8:35 pm on April 26th, water was sprayed to the spent
  fuel pool of Unit 4 by the concrete pumping vehicle.
- From 12:18 pm on April 27th, water spray to the spent fuel pool of Unit 
  4 by the concrete pumping vehicle was initiated.  
- We will continuously conduct further water spray depending on the
  conditions of spent fuel pools, if needed. 

Others  
- We have been confirming the exposure dose of each worker during the 
  emergency work at Fukushima Daiichi Nuclear Power Station. On April 
  27th,2011, we have confirmed that the effective exposure dose from 
  January 1st, 2011 to March (Fourth quarter of the 2010 fiscal year) of a 
  female employee who has been in the restoration work after the 
  Tohoku-Chihou-Taiheiyou-Oki Earthquake is 17.55 mSv, which is an excess 
  of statutory dose limits (5 mSv / 3 months). With regard to the female 
  employee, we have confirmed that there is no impact on her health 
  according to medical diagnosis.  
- In accordance with the reinforcement work for power supply line
  (switching internal power from unit 3 and 4 to unit 1 and 2), power
  panels (480V) were off lined from 10:23 am on April 26th for unit 4 and
  from 3:56 pm to 4:34 pm on April 26th for common pool.
- From 1:30pm on April 26th, we started spraying dust inhibitor in order
  to prevent diffusion of radioactive materials.
- At 10:08 am on April 19th we started transferring high level radioactive
  wastewater 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.