*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 5:39pm to 9:22 pm on April 17th, we have sprayed water to Unit 4 by
 a concrete pump vehicle.
-From 2:17pm to 3:02 pm on April 18th, we have sprayed water to Unit 3 by 
 a concrete pump vehicle. 
-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.
 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.