*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. 4.7 m3/h and that from the core spray system is approx. 2 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. 
 At 6:20 pm on March 2, 2012, since the flow rate of the water injected to 
 the reactor was dropped, we adjusted the water injection amount from the 
 reactor feed water system from approx. 2.6 m3/h to approx. 3 m3/h and 
 that from the core spray system from approx. 5.7 m3/h to approx. 6 m3/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 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 4, the temperature of the lower part of the RPV 
  (top of the lower head 135°) : approximate 43.9 °C 
 ·At 5:00 am on March 4, the temperature of the lower part of the RPV 
  (top of the lower head 270°) : approximate 41.1 °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. 1.9 m3/h and that from the core spray system is approx. 5m3/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. 
-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. 
-From 1:56 pm on February 28 to 9:54 am on March 4, we transferred the 
 accumulated water from the basement of turbine building of Unit 3 to 
 Miscellaneous Solid Waste Volume Reduction Treatment Building (High 
 Temperature Incinerator Building). 
-At 2:00 pm on February 28, we started transferring accumulated water from 
 basement of unit 2 turbine building to Centralized Radiation Waste 
 Treatment Facility Process Main building. 
-At 9:44 am on March 2, in order to conduct the work to switch the control 
 circuits of on-site power source for operation of southern switching 
 station, we cut the power of on-site power source. The evaporation 
 apparatuses of water desalination facilities and desalination facilities 
 (reverse osmosis membrane type) are out of service due to the work to 
 switch the control circuits. We also have sufficient volume of treated 
 water, therefore there will be no impact on the water injection to the 
 reactors. 
-From 9:43 am to 3:58 pm on March 3, 2012, we transferred the water 
 accumulated in the site banker building to the process main building in 
 the centralized waste treatment facilities.