*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. 
- 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. 
- From 7:35 pm, April 12th, we started transferring the high level 
  radioactive accumulated water in the trench of the turbine building to 
  the condenser by an underwater pump. At 5:04pm, April 13th, the scheduled 
  transfer was completed. 
 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01am 
  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, March 19th, we started the Residual Heat Removal System Pump 
  (C) in order to cool the spent fuel pool. 
- At 2:30 pm, March 20th, the reactor achieved reactor cold shutdown. At 
  around 5:24 pm on March 23rd, when we switched the temporary Residual 
  Heat Removal System Seawater Pump, it has stopped automatically. At 
  around 4:14 pm, March 24th we replaced the pump, and restarted cooling 
  of reactor at around 4:35 pm. 
- 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, 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, March 20th, the reactor achieved reactor cold shutdown. 
- In relation to the two seawater side pumps of the Residual Heat Removal 
  System, we switched the power source from temporary to permanent at 3:38 
  pm and 3:42 pm, Mar 25 respectively. 
- 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 
- We measured radioactive materials (iodine etc.) inside of the nuclear 
  power station area (outdoor) by monitoring car and confirmed that 
  radioactive materials level is getting higher than ordinary level. As 
  listed below, we have determined that specific incidents stipulated in 
  article 15, clause 1 of Act on Special Measures Concerning Nuclear 
  Emergency Preparedness (Abnormal increase in radiation dose measured 
  at site boundary) have occurred. 
  · Determined at 4:17 pm Mar 12th (Around Monitoring Post 4) 
  · Determined at 8:56 am Mar 13th (Around Monitoring Post 4) 
  · Determined at 2:15 pm Mar 13th (Around Monitoring Post 4) 
  · Determined at 3:50 am Mar 14th (Around Monitoring Post 6) 
  · Determined at 4:15 am Mar 14th (Around Monitoring Post 2) 
  · Determined at 9:27 am Mar 14th (Around Monitoring Post 3) 
  · Determined at 9:37 pm Mar 14th (Around main entrance) 
  · Determined at 6:51 am Mar 15th (Around main entrance) 
  · Determined at 8:11 am Mar 15th (Around main entrance) 
  · Determined at 4:17 pm Mar 15th (Around main entrance) 
  · Determined at 11:05 pm Mar 15th (Around main entrance) 
  · Determined at 8:58 am Mar 19th (Around MP5) 
  Hereafter, if the measured figure fluctuates and goes above and below 
  500 micro Sv/h, we deem that as the continuous same event and will not 
  regard that as a new specific incidents stipulated in article 15, clause 
  1 of the Act on Special Measures Concerning Nuclear Emergency 
  Preparedness (Abnormal increase in radiation dose measured at site 
  boundary) has occurred. In the interim, if we measure a manifestly 
  abnormal figure and it is evident that the event is not the continuous 
  same event, we will determine and notify. 
- The national government has instructed evacuation for those local 
  residents within 20km radius of the periphery and evacuation to inside 
  for those residents from 20km to 30km radius of the periphery, because 
  it is possible that radioactive materials are discharged. 
- From April 2nd, we began to transfer the radioactive water we collected 
  from the Central Environmental Facility to the Unit 4 turbine building. 
  On April 4th, water level of the pit in the trench of Unit 3 increased 
  by 15cm from previous day. Pathway of water flow is unknown. We can not 
  deny the possibility that water in the turbine building of Unit 4 flows 
  into the trench of Unit 3. So, we stopped transferring water to the Unit 
  4 turbine building to make assurance. Present water level of the pit in 
  the trench of Unit 3 is not changed from the time we stopped transferring, 
  and is being stable. 
- From 7:03 pm, April 4, we started to discharge to the sea approximately 
  ten thousand tons of the accumulated low level radioactive water in the 
  Central Radioactive Waste Disposal Facility. We are confirming the amount 
  of discharged water. From 9:00 pm on April 4, we conducted discharging a 
  total of 1,500 tons of the low level radioactive subsurface water stored 
  in the sub drain pits of Unit 5 and 6. The amount of discharged water 
  was approximately 1,323 tons. 
- From 3:00 pm to 4:30 pm, April 5th, in order to prevent diffusion of 
  radioactive contaminated water out from the site port facility to 
  breakwater area which is south to the power station, we began repair of 
  breakwater by founding the large sandbag around it to replace damaged 
  steel water bar. We will continue the operation to prevent diffusion. 
  From 8:45 am to 10:45 am, April 11, in order to prevent water containing 
  radioactive material from spilling from a plant's port to the sea, we 
  conducted works to install 120m wide double silt fences around a 
  breakwater on the south of the station. At 1:50 pm, April 13, we 
  installed silt fence (double layered) in front of Unit 3 and 4 screen. 
- We will continue to take all measures to ensure the safety and to 
  continue monitoring the surrounding environment around the Power Station.