search



Corporate Information

 
Press Release (Jul 17,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, July 17)
*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. 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. 
 At 10:06 am on July 17, as we confirmed that the rate of water injected 
 into the reactor decreased to approx 3.0 m3/h,  we adjusted the water 
 injection rate at approx 3.8 m3/h. After that, at 2:25 pm, we adjusted 
 the water injection rate at approximately 4.0 m3/h as we changed the 
 water injection line. 
 Water is currently injected at approx. 4.0m3/h through reactor feed water
 system piping arrangement.
-We commenced injection of nitrogen gas into Primary Containment Vessel at
 1:31am on 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. At 6:27 pm on June 23, we changed the water injection line so
 that we could inject water to Unit 1 and 2 by a motor driven pump by
 which we had been injecting water into Unit 1 (the motor driven pump for 
 Unit1) and suspended a motor driven pump by which we had been injecting
 water into Unit 2 (the motor pump for Unit 2). 
 At 2:25 pm July 17, we stopped the motor pump for Unit 1 and started the 
 motor pump for Unit 2 so that we would change the power source of the 
 suspended water injection line to the motor pump for Unit 2. We also 
 adjusted the water injection rate at approximately 4.0 m3/h. 
 Water is currently injected at approx. 4.0m3/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.
-At 8:01 pm on July 14, injection of nitrogen gas into the Primary
 Containment Vessel started. 
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.
-Regarding the Residual Heat Removal System, we had been utilizing
 temporary sea water cooling pump, however, at 10:16 am on July 15, we
 recovered the original Residual Heat Removal System Pump (B) and started
 it at 2:45 pm.
-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. 
-At 7:47 pm on June 30, we started cyclic cooling of the spent fuel pool
 in Unit 3 using alternative cooling system for fuel pool cooling and
 filtering system.
-We will continuously conduct further water spray depending on the
 conditions of spent fuel pools, if needed. 
Others 
-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 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 10:50 am on July 16, we started transfer of the accumulated water from
 the Turbine Building of Unit 3 to the Process Main Building of the
 Centralized Radiation Waste Treatment Facility.
-At 10:56 am on July 16, we started transfer of the accumulated water from
 the Turbine Building of Unit 2 to the Process Main Building of the
 Centralized Radiation Waste Treatment Facility.
-From 11:22 am to 3:52 pm on July 16, we injected fresh water into the
 Reactor Well and the Drier Separator Pit of Unit 4, in order to reduce
 the radiation dose at the 5th floor of the Unit 4 Reactor Building.
-At 4:24 am on July 17, in accordance with the work for transmission
 rerouting of the offsite power for Unit 5 and 6 (enhancement of offsite
 power), we switched the on-site power for Unit 5 and 6 to power receiving
 from two diesel generators. At 1:20 pm, after completing the work, we 
 restored receiving offsite power as on-site power for Unit 5 and 6. 
-We will continue to take all measures to ensure the safety and to
 continue monitoring the surrounding environment around the power station. 
back to page top


to TOP