*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. 
 At 10:15 am on February 25, as the amount of water injected to reactor 
 changes are observed, we changed the water injection volume from the core 
 spray system changed from approx.1.6m3/h to approx. 2.0m3/h (the reactor 
 feed water system stays the same: approx.4.5m3/h). The current water 
 injection amount from the reactor feed water system is approx. 4.5 m3/h 
 and that from the core spray system is approx. 2.0 m3/h. 
 
-At 1:31 am on April 7, 2011, we commenced injection of nitrogen gas into 
 Primary Containment Vessel. 
 At 9:40 am on February 24, we started the work to add the flow-meters to 
 the nitrogen injection line at the side of Primary Containment Vessel of 
 Unit 1 in order to improve the reliability of nitrogen injection activity. 
 Due to this work, we suspended the nitrogen injection task temporarily (*). 
 After the completion of the installation, we restarted the nitrogen 
 injection. At 1:10 pm, it was confirmed that there was no significant 
 variation in the parameters. 
 *In the Chapter 12 of Nuclear Reactor Facilities Security Regulation "The 
  Way of Ensuring Mid-term Security", as the treatments like "Operational 
  limitation" or "Measures required in case of not satisfying the 
  operational limitation" are determined, it is supposed the operator act 
  per the required measures if it fails to satisfy the operational 
  limitation. This time, to implement maintenance works, we have suspended 
  the work of nitrogen injection at the side of Primary Containment Vessel 
  of Unit 1 by conducting a planned shift beyond the range of operational 
  limitation (from 9:40 am to 1:10 pm on February 24). 
-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. 
 At 10:15 am on February 25, as the amount of water injected to reactor 
 changes are observed, we changed the water injection volume from the 
 reactor feed water system changed from approx.2.6 m3/h to approx. 3.0m3/h 
 (the core spray system stays the same: approx.6.0m3/h). The current water 
 injection amount from the reactor feed water system is approx. 3 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 0:21 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. 
  ·At 5:00 am on February 25, the temperature of the lower part of the RPV 
   (top of the lower head)(135°) : approximate 45.2 °C 
 (Reference) 
  ·At 5:00 am on February 25, the temperature of the lower part of the RPV 
   (top of the lower head)(270°) : approximate 39.5 °C 
 The current water injection amount from the reactor feed water system is 
 approx. 2.9m3/h and that from the core spray system is approx. 6.0 m3/h. 
-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. 
 At 10:05 am on February 24, as the change in the injected water amount 
 was observed, the injected water amount was adjusted from approx. 1.6m3/h 
 to 2.0m3/h in the feed water system and from approx. 5.2m3/h to 5.0m3/h 
 in the core spray system. 
 The current water injection amount from the reactor feed water system is 
 approx. 2.0m3/h and that from the core spray system is approx. 5.0 m3/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. On February 23, we conducted gas sampling survey 
 of the PCV gas control system of Unit 3 and confirmed that Xenon 135 was 
 below the detection limit (9.4 x 10-2Bq/cm3) at the inlet of the system 
 and also below 1 Bq/cm3 that is a threshold of recriticality. 
-At 4:26 pm on November 30, 2011, we started operation to inject nitrogen 
 into the reactor pressure vessel. 
-At 3:18 pm on January 14, we started operation of the radioactive 
 material removal instrument for the spent fuel pool in Unit 3 
 
 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 3:11 pm on February 23, in the alternative cooling system of the spent 
 fuel pool of Unit 4, as the inhale pressure of the primary circulating 
 pump showed the tendency of decrease, we stopped the pump in order to 
 conduct flushing of the strainer on its entry side and suspended cooling 
 of the spent fuel pool (the temperature of the pool at the time of the 
 suspension was approx. 25°C) After the flushing, at 5:18 pm on the same 
 day we resumed the cooling of the spent fuel pool and confirmed the 
 recovery of the inhale pressure of the pump. (the temperature of the pool 
 at the time of the resuming was approx. 26°C) 
-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. 
-At 6:00 am on February 24, in order to change the delivery valve of the 
 pump (A) of the reactor sea water system of Unit 5, we stopped the pump 
 (C) of the reactor sea water system. As a result, the cooling of the 
 spent fuel pool was stopped. (the temperature of the spent fuel pool at 
 the time : approx 17.4°C) At 12:08 pm on the same day, the system was 
 restarted after the completion of the work. Accordingly the cooling of 
 the spent fuel pool was restarted as well. (pool temperature at the time 
 of the cooling restart: approx 18.2°C) 
-At this moment, we don't think there is any reactor coolant leakage 
 inside the primary containment vessel. 
 
 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. 
-As the component cooling sea water system pump (C) of Unit 6 has been 
 restored, we started test operation at 10:05 am on February 22, 2012. 
 Accordingly, the component cooling sea water system pump (A) stopped its 
 operation at 10:07 am on the same day. At 11:25 am on the same day, we 
 confirmed that there was no problem in the operation of the component 
 cooling sea water system pump (C). As a result, two of the component 
 cooling sea water system pumps of Unit 6, (A) and (C), are in operation, 
 
 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. 
-At 9:18 am on January 31, we started transfer of Sub-drain Water of Unit 
 6 to the temporary tank. We will conduct transferring to the temporary 
 tank appropriately. 
-At 2:04 pm on February 23, 2012, we started to transfer accumulated water 
 from underground floor of turbine building of Unit 2 to the centralized 
 radiation waste treatment facility. 
-At 10:20 am on February 25, we started the accumulated water from the 
 basement of Turbine building of Unit 1 to the basement of Turbine 
 building of Unit 2. 
-At 8:30 am Today (Feb. 25), Tepco worker and partner companies'worker 
 found water leakage at welded part of piping at B line of 2nd Cesium 
 adsorption apparatus(SARRY) placed on the 1st floor in Miscellaneous 
 Solid Waste Volume Reduction Treatment Building (High Temperature 
 Incinerator Building) of Fukushima Daiichi Nuclear Power Station. The 
 leakage is just a drop per second and the amount of water leaked is 
 approx. 10 litters (2m x 5m x 1mm).  Those leaked water are stayed in 
 barrier in the building and it did not leaked to out of the building. At 
 10:44 am, we stopped operation of SARRY and closed valve positioned in 
 the upstream of leaked point to prevent further leakage of the water. We 
 confirmed that the leakage was stopped at 11:10 am. Surface radiation is 
 approx. 4-5mSv/h (2mSv/h in the back ground). We will sample the leaked 
 water and analyze the radioactivity concentration. The treatment of 
 accumulated water is not affected by suspending the SARRY, and there is a 
 lot of purified water that there is no effect injecting water to the 
 reactor.