search



Corporate Information

 
Press Release (Apr 09,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 6:00 pm, April 9)
*Updates 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 12th. It was assumed to be hydrogen 
 explosion.
-At approximately 2:30 am on March 23rd, seawater injection to the 
 nuclear reactor through the feed water system was initiated.
-From 3:37 pm on March 25th, we started injecting freshwater.
-As it is suspected that hydrogen gas is accumulated inside reactor 
 containment vessel, we commenced the valve opening operation concerning 
 injection of nitrogen gas into the reactor container vessel at 10:30 pm 
 April 6th and commenced injection at 1:31am April 7th. 
Unit 2 (Shut down) 
-At approximately 6:00 am on March 15th, an abnormal noise began 
 emanating from nearby Pressure Suppression Chamber and the pressure 
 within the chamber decreased. 
-From 10:10 am on March 26th, 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. 
Unit 3 (Shut down) 
-Explosive sound and white smoke were confirmed at approximately 11:01am 
 March 14th. It was assumed to be hydrogen explosion.
-From 6:02 pm on March 25th, 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. 
Unit 4 (outage due to regular inspection) 
-At approximately 6:00 am on March 15th, we confirmed the explosive sound 
 and the sustained damage around the 5th floor rooftop area of the 
 Nuclear Reactor Building.
-At this moment, we do not consider any reactor coolant leakage inside 
 the reactor happened. 
Unit 5 (outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 5:00 am, March 19th, we started the Residual Heat Removal System Pump 
 (C) in order to cool the spent fuel pool.
-At 2:30 pm, March 20th, the reactor achieved reactor cold shutdown. At 
 around 5:24 pm on March 23rd, when we switched the temporary Residual 
 Heat Removal System Seawater Pump, it has stopped automatically. At 
 around 4:14 pm, March 24th we replaced the pump, and restarted cooling 
 of reactor at around 4:35 pm.
-At this moment, we do not consider any reactor coolant leakage inside 
 the reactor happened. 
Unit 6 (outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 10:14 pm, March 19th, we started the Residual Heat Removal System 
 Pump (B) of Unit 6 in order to cool the spent fuel pool.
-At 7:27 pm, March 20th, the reactor achieved reactor cold shutdown.
-In relation to the two seawater side pumps of the Residual Heat Removal 
 System, we switched the power source from temporary to permanent at 3:38 
 pm and 3:42 pm, Mar 25 respectively.
-At this moment, we do not consider any reactor coolant leakage inside 
 the reactor happened. 
Operation for cooling the spent fuel pools 
-From 6:23 pm to 7:40 pm on April 7th, spraying water to Unit 4 by 
 concrete pump vehicle was conducted. 
-From 5:07 pm on April 9th, spraying water to Unit 4 by concrete pump 
 vehicle was conducted. 
-We will conduct further water spray depending on the conditions of spent 
 fuel pools, if needed. 
Draining water from underground floor of turbine buildings 
-At 1:55 pm April 3rd, in Unit 1, water transfer from a condensate 
 storage tank to a suppression pool water surge-tank was initiated.
-At 5:10 pm, April 2nd, in Unit 2, water transfer from a condensate 
 storage tank was to a suppression pool water surge-tank was initiated. 
Injured 
-At 9:19 am April 9th, worker of a cooperative firm who was wearing 
 full-face mask became sick during cable work conducted at the 
 water-treatment facility. The worker accidently stepped into an open 
 manhole located outside of the building and injured the leg. After being 
 transferred to the hospital, the worker was diagnosed with "contusion of 
 right knee" and "suspected medial collateral ligament injury of right 
 knee". Meanwhile, physical survey was conducted and no contamination was 
 detected. 
Others 
-We measured radioactive materials (iodine etc.) inside of the nuclear 
 power station area (outdoor) by monitoring car and confirmed that 
 radioactive materials level is getting higher than ordinary level. As 
 listed below, we have determined that specific incidents stipulated in 
 article 15, clause 1 of Act on Special Measures Concerning Nuclear 
 Emergency Preparedness (Abnormal increase in radiation dose measured at 
 site boundary) have occurred.
 ·Determined at 4:17 pm Mar 12th (Around Monitoring Post 4 )
 ·Determined at 8:56 am Mar 13th (Around Monitoring Post 4 )
 ·Determined at 2:15 pm Mar 13th (Around Monitoring Post 4 )
 ·Determined at 3:50 am Mar 14th (Around Monitoring Post 6 )
 ·Determined at 4:15 am Mar 14th (Around Monitoring Post 2 ) 
 ·Determined at 9:27 am Mar 14th (Around Monitoring Post 3 ) 
 ·Determined at 9:37 pm Mar 14th (Around main entrance ) 
 ·Determined at 6:51 am Mar 15th (Around main entrance ) 
 ·Determined at 8:11 am Mar 15th (Around main entrance ) 
 ·Determined at 4:17 pm Mar 15th (Around main entrance ) 
 ·Determined at 11:05 pm Mar 15th (Around main entrance )
 ·Determined at 8:58 am Mar 19th (Around MP5)
 Hereafter, if the measured figure fluctuates and goes above and below 
 500 micro Sv/h, we deem that as the continuous same event and will not 
 regard that as a new specific incidents stipulated in article 15, clause 
 1 of the Act on Special Measures Concerning Nuclear Emergency 
 Preparedness (Abnormal increase in radiation dose measured at site 
 boundary) has occurred. In the interim, if we measure a manifestly 
 abnormal figure and it is evident that the event is not the continuous 
 same event, we will determine and notify.
-The national government has instructed evacuation for those local 
 residents within 20km radius of the periphery and evacuation to inside 
 for those residents from 20km to 30km radius of the periphery, because 
 it is possible that radioactive materials are discharged.
-In total 12 fire engines are lent for the water spraying to the spent 
 fuel pools and water injection to the nuclear reactors by various 
 regional fire departments* as well as Tokyo Fire Department. Also, 
 instruction regarding the setting and operation of large scale 
 decontamination system was provided by Niigata City Fire Headquarter and 
 Hamamatsu City Fire Headquarter.
 *:Koriyama Fire Department, Iwaki Fire Brigade Headquarters, Fire 
 Headquarters of Sukagawa District Wide Area Fire-fighting Association, 
 Yonezawa City Fire Headquarters, Utsunomiya City Fire Headquarters, Fire 
 Headquarters of Aizu-Wakamatsu wide area municipal association, Saitama 
 City Fire Bureau, and Niigata City Fire Bureau.
-At around 11:35 am April 1st, a worker fell into the sea when he got 
 into a barge of the U.S. Forces to repair a hose of the ship. The worker 
 was rescued immediately, and was not injured and not contaminated. The 
 worker will be checked using the whole-body counter to ensure his health.
-From April 2nd, we began to transfer the radioactive water we collected 
 from the Central Environmental Facility to the Unit 4 turbine building. 
 On April 4th, water level of the pit in the trench of Unit 3 increased 
 by 15cm from previous day. Pathway of water flow is unknown. We can not 
 deny the possibility that water in the turbine building of Unit 4 flows 
 into the trench of Unit 3. So, we stopped transferring water to the Unit 
 4 turbine building to make assurance. Present water level of the pit in 
 the trench of Unit 3 is not changed from the time we stopped 
 transferring, and is being stable.
-As a countermeasure against outflow of radioactive water into the sea 
 near the cooling water intake at Unit 2 of Fukushima Daiichi Nuclear 
 Power Station, we have injected coagulant into the pit from April 5th 
 and we have observed stoppage of spilling of water from the crack on the 
 concrete lateral of the pit at 5:38 am, April 6th. We have put 6,000 
 litters of coagulant into the breakage and surrounding ground after 
 investigation of the leakage route by putting tracer into the 9 holes 
 drilled around electrical conduit and the pit. On April 6th, we 
 installed rubber boards and jigs as a countermeasure against the outflow 
 from the intake. We will further investigate if there is any other 
 leakage.
-From 7:03 pm, April 4, we started to discharge to the sea approximately 
 ten thousand tons of the accumulated low level radioactive water in the 
 Central Radioactive Waste Disposal Facility. From 9:00 pm, April 4, we 
 started to discharge a total of 1,500 tons of the low level radioactive 
 subsurface water stored in the sub drain pits of Unit 5 and 6. 
-From 3:00 pm to 4:30 pm, April 5th, in order to prevent diffusion of 
 radioactive contaminated water out from the site port facility to 
 breakwater area which is south to the power station, we began repair of 
 breakwater by founding the large sandbag around it to replace damaged 
 steel water bar. We will continue the operation to prevent diffusion.
-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