*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.
-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 on 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 on April 13th, the scheduled 
 transfer was completed.
 
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 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 on 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 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.
-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.
-From 11:00 am to 3:00 pm on April 19th, we transferred water accumulated 
 at the underground level of the nuclear reactor building of Unit 6 to 
 measure volume of the accumulated water. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 reactor happened.
 
Operation for cooling the spent fuel pools 
-From 10:17 am to 11:35 am on April 19th, we have sprayed water to Unit 4 
 by a concrete pump vehicle.
-From 4:08 pm to 5:28 pm on April 19th, we injected fresh water by a motor 
 driven pump powered by the off-site transmission line. 
-We will conduct further water spray depending on the conditions of spent 
 fuel pools, if needed.
 
Others 
-The national government has instructed evacuation for those local 
 residents within 20km radius of the periphery and shelter in place for 
 those residents from 20km to 30km radius of the periphery, because it is 
 possible that radioactive materials are discharged.
-Currently, a large quantity of radioactive wastewater exists inside the 
 turbine building of Fukushima Daiichi Nuclear Power Station. Particularly, 
 wastewater in Unit 2 is highly radioactive.
 We have been planning to transfer such wastewater to the Centralized 
 Radiation Waste Treatment Facility once measures to prevent leakage are 
 implemented inside the facility buildings. After transfer to the 
 Centralized Radiation Waste Treatment Facility, the wastewater will be 
 stably stored.
 (Previously announced on April 15th, 2011)
 With this regard, on April 10th, we received direction from Minister of 
 Economy, Trade and Industry to report on matters in connection with 
 transfer of high level radioactive wastewater to the Centralized 
 Radiation Waste Treatment Facility, such as necessity, assessment of 
 safety, plans on permanent safety storage of wastewater and treatment 
 facilities.
 Since we completed implementing measures to prevent leakage in the 
 facility buildings, we have compiled the details based on the direction 
 given and reported to Minister of Economy, Trade and Industry. The 
 content of the report has been confirmed by Nuclear and Industrial 
 Safety Agency.
 At 10:08 am on April 19th, based on the method described in the report, 
 we started transferring high level radioactive wastewater to the 
 Centralized Radiation Waste Treatment Facility.
-From 2:30 pm to 3:45 pm on April 15th, we installed 3 sandbags 
 containing zeolite (as an absorbent material) between the screen pump 
 rooms of the Unit 3 and Unit 4.
 Also, from 9:00am to 11:15am, we threw in two sandbags between the screen 
 pump rooms of Unit 1 and 2, and five sandbags between the screen pump 
 rooms of Unit 2 and 3.
-From 10:19 am to 5:00 pm on April 15th, we transferred distribution 
 panels of the pumps to inject water to the reactors of Units 1 to 3 as 
 a countermeasure against tsunami.
-At 2:34pm on April 17th, power supplies to a common spent fuel pool was 
 temporarily stopped because a breaker at the upstream side was released 
 due to an electrical short circuit which was caused by an insufficient 
 treatment of the end of the unused cable which was connected to the power 
 source of the common spent fuel in parallel.  However, after removal of 
 the cable and checkups, at 5:30pm, the power supplies to the common spent 
 fuel pool was restored.
-From 11:30am to 2:00pm, we opened and closed the double doors and 
 conducted surveys of the situation of the inside of the nuclear reactor 
 building of Unit 3 and measured a dose of radiation, etc. by a remote 
 control robot.  Also, from 4:00pm to 5:30pm, we did the same kind of work 
 on Unit 1. From 1:42pm to 2:33pm on April 18th, we opened and closed the 
 double doors, measured a dose of radiation and so on, and conducted 
 surveys of the situation of the inside of the nuclear reactor building of 
 Unit 2, by a remote control robot.
-From 11:50am to 1:05pm on April 18th, we suspended operations injecting 
 water to the reactor of Unit 1 to 3, and replaced hoses for injecting 
 water, to the brand new ones.
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station.