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Corporate Information

 
Press Release (Mar 28,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 2:00 PM Mar 28th)
[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 Mar 12th. It was assumed to be hydrogen explosion.
- At approximately 2:30 am on March 23rd, seawater was started to be 
  injected to the nuclear reactor through the feed water system.
- At approximately 10:50 am on March 24th, white fog-like steam arising
  from the roof part of the reactor building was observed.
- At approximately 11:30 am on March 24th, lights in the main control
  room was restored. 
- We had been injecting sea water into the reactor, but from 3:37 pm on
  March 25th, we started injecting freshwater into it. 
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 this chamber decreased. 
- At 6:20 pm on March 21st, white smoke was confirmed arising from the
  top of the reactor building. As of 7:11 am on March 22nd, smoke
  decreased to the level to nearly non-existent.
- We have been injecting sea water into the reactor, but from 10:10 am on
  March 26th, we started injecting fresh water (with boric acid) into it.
- At approximately 4:46 pm on March 26nd, the light in the main control
  room was turned on.
- Previously, we have been injecting fresh water in to the reactor
  utilizing fire pump, however, we have switched over to utilizing
  temporary electrical pump from 6:31 pm on March 27th. 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at 11:01am March 4th.
  It was assumed to be hydrogen explosion.
- At 8:30am on March 16th, fog like steam was confirmed arising from
  the reactor building.
- At approximately 6:15 am on March 17th the pressure of the Suppression
  Chamber has temporarily increased. We were preparing to implement
  measures to reduce the pressure of the reactor containment vessel
  (partial discharge of air containing radioactive material to outside)
  in order to fully secure safety. However, at present, it is not
  a situation to immediately implement measures and discharge air
  containing radioactive material to outside. We will continue to 
  monitor the status of the pressure of the reactor containment vessel.
- At approximately 4:00 pm, March 21st, light gray smoke was confirmed
  arising from the floor roof of the Unit 3 building. On March 22nd, 
  the color of smoke changed to somewhat white and it is slowly 
  dissipating.
- At approximately 10:45 pm on March 22nd, the light in the main control
  room was turned on.
- At around 4:20 pm on March 23rd, our staff confirmed light black smoke
  belching from the Unit 3 building. At approximately 11:30 pm on
  March 23rd and 4:50 am on March 24th, our employee found no signs
  of smoke.
- We had been injecting sea water into the reactor pressure vessel, but
  from 6:02 pm on March 25th, we started injecting freshwater into it. 
Unit 4 (outage due to regular inspection) 
- At approximately 6 am on March 15th, we confirmed the explosive sound
  and the sustained damage around the 5th floor rooftop area of
  the Nuclear Reactor Building.
- On March 15th and 16th, we respectively confirmed the outbreak of fire
  at the 4th floor of the northwestern part of the Nuclear Reactor
  Building. We immediately reported this matter to the fire department
  and the related authorities. TEPCO employees confirmed that each fire
  had already died down by itself. 
- 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 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 containment vessel happened. 
Unit 6 (outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- We completed the repair work on the emergency diesel generator (A).
- 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 3:42PM, Mar 25 respectively.
- At this moment, we do not consider any reactor coolant leakage inside
  the reactor containment vessel happened. 
Today's work for cooling the spent fuel pools 
- We are considering further spraying subject to the conditions of spent
  fuel pools. 
Casualty 
- 2 workers of cooperative firm were injured at the occurrence of
  the earthquake, and were transported to the hospital on March 11th.
- Presence of 2 TEPCO employees at the site is not confirmed on
  March 11th.
- 1 TEPCO employee who was not able to stand by his own holding left chest
  with his hand, was transported to the hospital by an ambulance on
  March 12th.
- 4 workers were injured and transported to the hospital after explosive
  sound and white smoke were confirmed around the Unit 1on March 12th.
- 1 subcontract worker at the key earthquake-proof building was
  unconscious and transported to the hospital by an ambulance on
  March 12th.
- The radiation exposure of 1 TEPCO employee, who was working inside
  the reactor building, exceeded 100mSv and he was transported to
  the hospital on March 12th.
- 2 TEPCO employees felt bad during their operation in the central
  control rooms of Unit 1 and 2 while wearing full masks, and were
  transferred to Fukushima Daini Nuclear Power Station for consultation
  with a medical advisor on March 13th.
- 11 workers were injured and transported to Fukushima Daini Nuclear
  Power Station etc. after explosive sound and white smoke were confirmed
  around the Unit 3. One of the workers was transported to the Fukushima
  Medical University Hospital on March 14th.
- At approximately 10 pm on March 22nd, 1 worker who had been working
  on setting up a temporary power panel in the common pool was injured
  and transported to Fukushima Daini Nuclear Power Station where
  the industrial doctor is.
- At approximately 1:30 am on March 23rd, 1 worker who had been working
  on transporting a temporary power panel in the common pool was injured
  and transported to Fukushima Daini Nuclear Power Station where
  the industrial doctor is.
- On March 24th, it was confirmed that 3 workers from cooperative
  companies who were in charge of cable laying work in the 1st floor and
  the underground floor of turbine building were exposed to
  the radiation dose of more than 170 mSv. 2 of them were confirmed that
  their skins on legs were contaminated. Although they were
  decontaminated, since there was a possibility of beta ray burn injury,
  they were transferred to Fukushima Medical University Hospital.
  The third worker was also transferred to Fukushima Medical University
  Hospital on March 25th. After that, the 3 workers were transferred
  to National Institute of Radiological Sciences in Chiba Prefecture.
  Regarding this event, TEPCO has reported to the related government
  ministries and agencies on measures to be taken to assure appropriate
  radiation dose control and radiation exposure related operations.
  Before today's restoration work, we will make notification to
  the concerned parties and continue to take all possible measures to
  future management. 
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)
 From now on, 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.
- At approximately 10am on March 15th, we observed 400mSv/h at the inland
  side of the Unit 3 reactor building and 100mSv/h at the inland side of
  the Unit 4 reactor building.
- At around 10:37 am March 21st, water spraying to common spent fuel pool
  and finished at 3:30 pm (conducted by TEPCO).
- At around 3:37 pm, March 24th, electricity supply to common spent fuel
  pool has started from external power source. At around 6:05 pm, fuel 
  pool cooling pump was started to cool the pool.
- We found no signs of abnormal situation for the casks by visual
  observation during the patrol activity. A detailed inspection is under
  preparation.
- At Units 5 and 6, in order to prevent hydrogen gas from accumulating
  within the buildings, we have made three holes on the roof of
  the reactor building for each unit.
- 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.
- By March 22nd, Units 1 through 6 were started to be energized from
  the external power source.
- At 3:30PM, March 27th, we found that there was water in the trenches of 
  Units 1 to 3. The radioactive emission at the surface of the water was 
  0.4mSv/h for Unit 1 and over 1,000mSv/h for Unit 2. As for Unit 3, we 
  couldn't have access to the surface because of rubbles. We will 
  continue to monitor water in the trenches. 
- 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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