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Press Release (Jun 30,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, June 30)
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. It was assumed to be hydrogen explosion.
-At approximately 2:30 am on March 23, seawater injection to the reactor 
 through the reactor feed water system was initiated.
-From 3:37 pm on March 25, we started injecting freshwater by a motor 
 driven pump which is now powered by the off-site transmission line. 
 Water is currently injected at approx. 3.5m3/h through reactor feed water 
 system piping arrangement.
-We commenced injection of nitrogen gas into Primary Containment Vessel at 
 1:31am April 7.
Unit 2 (Shut down) 
-At approximately 6:00 am on March 15, an abnormal noise began emanating 
 from nearby Pressure Suppression Chamber and the pressure within the 
 chamber decreased. 
-From 10:10 am on March 26, we started injecting freshwater to the reactor 
 and are now injecting freshwater by a motor driven pump powered by the 
 off-site transmission line. 
 At 6:27 pm on June 23, we changed the water injection line so that we can 
 inject water to Unit 1 and 2 by the motor driven pump for Unit 1 and 
 stopped the motor driven pump for Unit 2. 
 Water is currently injected at approx. 3.5m3/h through reactor feed water 
 system piping arrangement. 
-At 8:06 pm on June 28, we started injecting nitrogen gas into the Primary 
 Containment Vessel.
Unit 3 (Shut down) 
-Explosive sound and white smoke were confirmed at approximately 11:01am 
 on March 14. It was assumed to be hydrogen explosion.
-From 6:02 pm on March 25, 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.
 Water is currently injected at approx. 9 m3/h through reactor feed water 
 system piping arrangement.
Unit 4 (Outage due to regular inspection) 
-At approximately 6:00 am on March 15, we confirmed the explosive sound 
 and the sustained damage around the 5th floor rooftop area of Reactor
 Building.
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred.
Unit 5 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 5:00 am on March 19, we started the Residual Heat Removal System Pump 
 (C) in order to cool the spent fuel pool.
-At 2:30 pm on March 20, the reactor achieved cold shutdown.
-From 10:02 am to 11:48 am on June 30, we stopped cooling the reactor 
 through the Residual Heat Removal System to switch the power source of 
 ancillary equipment. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred.
Unit 6 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 10:14 pm on March 19, 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 20, the reactor achieved cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred.
Operation for cooling the spent fuel pools 
-At 5:21 pm on May 31, we started cyclic cooling of the spent fuel pool in 
 Unit 2 using alternative cooling system for fuel pool cooling and 
 filtering system. 
-From 2:45 pm to 3:53 pm on June 29, we injected water into Unit 3 using a 
 temporary motor driven pump.
-From 11:30 am to 11:55 am on June 30, we injected water into Unit 4 using 
 a temporary spraying equipment. 
-We will continuously conduct further water spray depending on the 
conditions of spent fuel pools, if needed.
Others 
-At 1:30 pm on April 26, we started spraying the dust inhibitor inside the 
 site. 
-At 11:00 am on May 10, we started transferring accumulated water from the 
 underground level of reactor building to the radiation waste treatment 
 facility of Unit 6.
-At approximately 10:00 am on June 13, we started the operation of the 
 circulating seawater purification facility installed at the screen area 
 of Unit 2 and 3.
-From 8:00 pm on June17, we started operation of water treatment of 
 accumulated water at accumulated water treatment facility. 
-At 9:56 am on June 22, we started transferring accumulated water in 
 turbine building of Unit 2 to central waste treatment facility building.
-At approximately 12:00 pm on June 28, since we found the water level 
 indicator (manometer) of the temporary tank to which the accumulated 
 water of the turbine building of Unit 6 was transferred fallen down, we 
 closed the valve and stopped the water leakage from the indicator. 
-In light of the water leakage event at the drain of lower part of the 
 primary storage tank for water desalinations reverse osmosis membrane 
 concentrated water in the accumulated water treatment system at around 
 9:30 am on June 29, during the survey for the existence of similar event, 
 at 5:40 pm, we found small leakage of water from lower part of stoppage 
 flange of another storage tank, we stopped the leakage and installed a 
 saucer at the lower part of the flange.
-Since an alarm showing water leakage was sounded in the On-site Bunker 
 Building at 2:49 pm, the accumulated water treatment system was manually 
 stopped at 2:53 pm.
 The cause of this incident is estimated that treated water, overflowed 
 from the tank to the saucer, triggered the alarm when the manhole was 
 opened during the inspection of the treated water tank of the coagulation 
 settling facility.
 At 6:45 we swiped the accumulated water in the saucer and restart the 
 facility after stopping the alarm. However, we manually stopped it again 
 at 6:54 pm, since equipments that constituted the facility did not work 
 well.
 At 9:15 pm, we restarted the facility after confirming no abnormal issues 
 on that.
-At 8:56 am on June 30, we started transferring the accumulated water from 
 the basement of the turbine building of Unit 3 to Centralized Radiation 
 Waste Treatment Facility (Process Building).
-At 9:00 am on June 30, we stopped the water desalination system to treat 
 the concentrated saltwater in the storage tank of the system.
-At 10:46 am on June 30, we stopped the Accumulated Water Treatment 
 Facility, for flushing with exchanging the Cesium Adsorption Instruments. 
 After exchanging its Instruments, although we restarted the Instruments, 
 we re-stopped the Instruments due to the defect of Coagulation Setting 
 Facility. 
-At 1:00 pm on June 30, we started transferring of low radioactive stored 
 water from temporary tank to Mega Float. Although a water blow was found 
 on the surface of the transferring hose, we cure it and confirmed no 
 leakages to outside. 
-At 3:00 pm on June 30, we started transferring of accumulated water from 
 inside of turbine building of Unit 6 to temporary tank. 
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station. 
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