* Updates from previous press release 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 12, 2011. It was assumed to be hydrogen
 explosion.
- At 3:37 pm on March 25, 2011, 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. 
- At 10:11 am on December 10, 2011, in addition to water injection from
 water feeding system, we started water injection from piping of core
 spray system to the reactor.
 The current water injection amount from the reactor feed water system is
 approx. 4.8 m3/h and that from the core spray system is approx. 1.8 m3/h.
- At 1:31 am on April 7, 2011, we commenced injection of nitrogen gas into
 Primary Containment Vessel.
- At 11:22 am on August 10, 2011, we started cyclic cooling for the water
 in the spent fuel pool by an alternative cooling equipment of the Fuel
 Pool Cooling and Filtering System. 
- On October 28, 2011, we completed installation of the cover for the
 Reactor Building in order to contain dispersion of radioactive
 substances.
- At 4:04 pm on November 30, 2011, we started operation to inject nitrogen
 into the reactor pressure vessel.
- At 6:00 pm on December 19, 2011, a full-scale operation of the PCV gas
 management system started. 
 
Unit 2 (Shut down) 
- At approximately 6:00 am on March 15, 2011, an abnormal noise began
 emanating from nearby Pressure Suppression Chamber and the pressure
 within the chamber decreased. 
- At 10:10 am on March 26, 2011, 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. 
- At 2:59 pm on September 14, 2011, in addition to water injection from
 feed water system, we started water injection from piping of core spray
 system to the reactor. 
 The current water injection amount from the reactor feed water system is
 approx. 2.9 m3/h and that from the core spray system is approx. 6 m3/h.
- With regard to the water injection volume for Unit 2 reactor, which was
 increased with temperature figure raising, we have gradually adjusted it
 to the original volume before temperature increasing (Feed water system:
 approx. 3.0m3/h, core spray system: approx. 6.0m3/h). During our
 observing the plant parameter after decreasing the flow rate of feed
 water system on February 22, we found that one thermometer in the lower
 part of the RPV (top of the lower head 135°) indicated the different
 movement from others. From 12:21 pm to 2:48 pm on February 23, we
 investigated the concerned device. As the result of the measurement of
 DC resistance, we found no breaking wire and availability of the
 thermometer. But we confirmed that the DC resistance of it became higher
 than the previous measurement test data. We will evaluate the soundness
 of the concerned device and examine correspondence in future. We make
 sure no re-criticality state because there were no significant changes
 at the monitoring post and as the result of the sampling for the Gas
 Control System of the Unit 2; we confirmed that the concentration of
 Xe-135 was below the detectible limit. Through the investigation, we
 confirmed the concerned device is soundness. We submitted the report on
 the soundness of concerned device and the alternative method for
 monitoring temperature inside the Reactor of Unit 2 at Fukushima Daiichi
 Nuclear Power Station to NISA on March 1. We continue the observation of
 the concerned device.
 ·At 5:00 am on March 11, the temperature of the lower part of the RPV 
  (top of the lower head 135°) : approximately 41.4 °C  
 ·At 5:00 am on March 11, the temperature of the lower part of the RPV 
  (top of the lower head 270°) : approximately 40.1 °C (Reference)
- At 5:21 pm on May 31, 2011, we started cyclic cooling for the water in
 the spent fuel pool by an alternative cooling equipment of the Fuel Pool
 Cooling and Filtering System.
- At 8:06 pm on June 28, 2011, we started injecting nitrogen gas into the
 Primary Containment Vessel.
- At 6:00 pm on October 28, 2011, a full operation of the PCV gas control
 system started. 
- At 10:46 am on December 1, 2011, we started the nitrogen injection to
 the Reactor Pressure Vessel.
- At 11:50 am on January 19, 2012, we started the operation of the spent
 fuel pool desalting facility. 
 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01 am
 on March 14, 2011. It was assumed to be hydrogen explosion.
- At 6:02 pm on March 25, 2011, 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.
- At 2:58 pm on September 1, 2011, we started water injection by core
 spray system in addition to water injection by the reactor feed water
 system piping arrangement. 
 The current water injection amount from the reactor feed water system is
 approx. 1.8 m3/h and that from the core spray system is approx. 5.1m3/h.
- At 7:47 pm on June 30, 2011, we started cyclic cooling for the water in
 the spent fuel pool by an alternative cooling equipment of the Fuel Pool
 Cooling and Filtering System.
- At 8:01 pm on July 14, 2011, injection of nitrogen gas into the Primary
 Containment Vessel started. 
- As installation works of the PCV gas control system was completed, we
 started a test operation at 11:38 am on February 23, 2012. We confirmed
 that an exhaust flow amount was stable at 33Nm3/h at 2:10 pm and started
 an adjustment operation.
- At 4:26 pm on November 30, 2011, we started operation to inject nitrogen
 into the reactor pressure vessel. 
 
Unit 4 (Outage due to regular inspection) 
- At around 6 am on March 15, 2011, we confirmed the explosive sound and
 the sustained damage around the 5th floor rooftop area of Reactor
 Building.
- At 12:44 pm on July 31, 2011, we started cyclic cooling for the water in
 the spent fuel pool by an alternative cooling equipment of the Fuel Pool
 Cooling and Filtering System. 
- At 10:58 am on November 29, 2011, in order to decrease more salinity, we
 installed Ion exchange equipment and started the operation of such
 equipment.
- At this moment, we don't think there is any reactor coolant leakage
 inside the primary containment vessel. 
 
Unit 5 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 5:00 am on March 19, 2011, we started the Residual Heat Removal
 System Pump in order to cool the spent fuel pool.
- At 2:45 pm on July 15, 2011, we started the operation of the original
 Residual Heat Removal System (System B) by its original seawater pump.
- At 10:11 am on December 22, 2011, since we finished the recovery work of
 seawater pump (System B) of equipment water cooling system, we made a
 trial run. At 11:25 am on the same day, we confirmed no abnormalities
 and restarted the operation. 
 
Unit 6 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 10:14 pm on March 19, 2011, we started the Residual Heat Removal
 System Pump of Unit 6 to cool down Spent Fuel Pool.
- At 2:33 pm on September 15, 2011, we started separately cooling the
 reactor through the Residual Heat Removal System and the spent fuel pool
 through Equipment Cooling Water System and Fuel Pool Cooling System. 
 
Others 
- At around 10:00 am on June 13, 2011, we started the operation of the
 circulating seawater purification facility installed at the screen area
 of Unit 2 and 3.
- At 8:00 pm on June 17, 2011, we started operation of Water Treatment
 Facility against the accumulated water. At 6:00 pm on July 2, we started
 the circulating injection cooling to inject the water, which was treated
 by the accumulated water treatment system, to the reactors through the
 buffer tank.
- At 7:41 pm on August 19, 2011, we started treatment of accumulated water
 by parallel operation of one line from the cesium adsorption instrument
 to the decontamination instrument and the other treatment line of the
 cesium adsorption instrument No.2.
- At 2:06 pm on October 7, 2011, we started to spray purified accumulated
 water brought from Unit 5 and 6 continually in order to prevent dust
 scattering and potential fire outbreaks from the cut down trees.
- On October 28, 2011, we started installation of the water proof wall at
 the sea side, in front of the existing shore protection, Units 1-4, in
 order to contain marine pollution by underground water.
- At 12:25 pm on December 13, 2011, we started the re-circulating
 operation of desalination facility (reverse osmosis membrane type) for
 the purpose of suppression of condensed water after desalination
 treatment.
- From 1:55 pm on March 7, 2012 to 8:30 am on March 11, we transferred the
 accumulated water from the underground of Unit 2 turbine building to the
 centralized radiation waste treatment facility process main building.
- At 8:47 am on March 11, we started transferring the accumulated water 
 from the basement of Turbine Building of Unit 2 to the centralized 
 radiation waste treatment facility (Miscellaneous Solid Waste Volume 
 Reduction Treatment Building [High Temperature Incinerator Building]). 
- At 10:10 am of March 10, 2012, we started transferring the accumulated
 water from the basement floor of the turbine building of Unit 3 to the
 centralized radiation waste treatment facility (Miscellaneous Solid
 Waste Volume Reduction Treatment Building [High Temperature Incinerator
 Building]).
- In order to conduct the work to improve the reliability of water
 treatment facilities, we are planning to stop water treatment facilities
 one after another. At 8:45 am on March 1, we stopped the cesium
 adsorption apparatus. It will be out of service until March 15. We
 calculated the estimated water level increase at each building due to
 the stop o the facilities, and confirmed that the water levels in each
 building will be maintained within the limits. We also have sufficient
 volume of treated water therefore there will be no impact on the water
 injection to the reactors. At 8:07 am on March 2, we stopped the 2nd
 cesium adsorption apparatus. At 5:00 pm on March 10, we started the 2nd 
 cesium adsorption apparatus after the improvement works. At 6:34 pm on 
 March 10, the water injection volume reached at normal level (approx.42 
 m3/h).