*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. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 reactor happened. 
 
Operation for cooling the spent fuel pools 
-From 2:30 pm to 6:29 pm on April 15th, we conducted spraying water to 
 Unit 4 by the concrete pumping vehicle. 
-From 10:13 am to 11:54 am on April 16th, we conducted injecting fresh 
 water to Unit 2 by a temporary motor driven pump. 
-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 evacuation to inside 
 for those residents from 20km to 30km radius of the periphery, because it 
 is possible that radioactive materials are discharged. 
-From 7:03 pm on April 4th to 5:40 pm, April 10th, we discharged to the 
 sea approximately 9,070 tons of the accumulated low level radioactive 
 water stored in the Centralized Radiation Waste Disposal Facility. Also 
 from 9:00 pm on April 4th to 6:52 pm, April 9th, we discharged to the 
 ocean approximately 1,323 tons of the low level radioactive subsurface 
 water stored in the sub drain pits of Unit 5 and 6. 
 Regarding radioactive concentrations at measuring points including those 
 adjacent to the power station due to the discharge of the low level 
 radioactive stored water to the ocean, no significant change has been 
 found, though we compared them with the transition of concentrations for 
 a week before the discharge. 
 The total amount of emitted radioactivity is approximately 1.5 x 1011 
 Becquerel. We evaluate approximately 0.6 mSv of effective radioactive 
 doses per year per an adult as the impact on the discharge of the low 
 radioactive stored water to the ocean if an adult eats adjacent fish and 
 seaweeds every day. The amount (0.6 mSv of effective radioactive doses 
 per year) is one-forth of annual radioactive dose (2.4 mSv) to which the 
 general public is exposed from nature and equivalent to that when we 
 evaluated before discharging the water to the ocean. 
-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. 
-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. 
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station.