Due to the Tohoku-Taiheiyou-Oki Earthquake which occurred on March 11th
2011, TEPCO's facilities including our nuclear power stations have been
severely damaged. We deeply apologize for the anxiety and inconvenience
Below is the status of TEPCO's major facilities.
*new items are underlined
[Nuclear Power Station]
Fukushima Daiichi Nuclear Power Station:
Units 1 to 3: shutdown due to earthquake
(Units 4 to 6: outage due to regular inspection)
* The national government has instructed to evacuate for those local
residents within 20km radius of the site periphery and to remain indoors
for those local residents between 20km and 30km radius of the site
* The level of radioactive materials ( iodine etc.) inside the nuclear
power station area (outdoor) measured by the monitoring car exceeded the
normal level. We have determined that 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) have occurred.
-Determined at 8:58am, Mar 19th (Around Monitoring Post 5)
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.
* Unit 1
The explosive sound and white smoke was confirmed near Unit 1 when
the big quake occurred at 3:36pm, March 12th. We have started injection
of sea water at 8:20 pm and then boric acid into the reactor afterwards.
* Unit 2
At 1:25 pm, March 14th, since the Reactor Core Isolation Cooling System
has failed, it was determined that a specific incident stipulated in
article 15, clause 1 of Act on Special Measures Concerning Nuclear
Emergency Preparedness occurred (failure of reactor cooling function).
At 5:17 pm, while the water level in the reactor reached the top of
the fuel rod, we have restarted the water injection with the valve
At approximately 6:14 am, March 15th, the abnormal sound was confirmed
near the suppression chamber and the pressure inside the chamber
decreased afterwards. It was determined that there is a possibility
that something happened in the suppression chamber. While sea water
injection to the reactor continued, TEPCO employees and workers from
other companies not in charge of injection work started tentative
evacuation to a safe location.
Sea water injection to the reactor is still under operation.
As of March 18th, power from offsite transmission line has received until
temporary substation for backup power. We completed laying cable to unit
receiving facility on March 20 and at 3:46 pm and the load-side power
panel of the receiving facility started to energize.
From 3: 05 pm to 5: 20 pm on March 20th, 40 tons of seawater was injected
into Unit 2 by TEPCO employees.
* Unit 3
At 6:50 am, March 14th, while water injection to the reactor was under
operation, the pressure in the reactor containment vessel increased to
530 kPa. As a result, at 7:44 am, it was determined that a specific
incident stipulated in article 15, clause 1 occurred (abnormal increase
of the pressure of reactor containment vessel). Afterwards, the pressure
has gradually decreased (as of 9:05 am, 490 kPa).
We continue injecting water into a reactor.
* We announced in our past reports that "On March 14, the pressure in the
primary containment vessel increased and it was determined that a
specific incident stipulated in the Article 15, the Clause 1 of Act on
Special Measures Concerning Nuclear Emergency Preparedness occurred".
However, we made a mistake in the calculation of the pressure value and
the status of Unit 3 did not fall under the above-mentioned specific
incidents. We will delete the related description from our latest report.
At approximately 11:01 am, March 14th, an explosion followed by white
smoke occurred near Unit 3. 4 TEPCO employees and 3 workers from other
companies (all of them are conscious) have sustained injuries and they
were already dispatched to the hospital by ambulances.
As the temperature of water in the spent fuel pool rose, spraying water
by helicopters with the support of the Self Defense Force was considered,
however the works on March 16th was cancelled.
At 6:15 am, March 17th, the pressure of the Suppression Chamber
temporally increased, but currently it is stable in a certain range.
Today, March 20th, we were preparing to implement a measurement 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 take a
measure immediately to discharge air containing radioactive material to
outside.We will continue to monitor the status of the pressure of the
reactor containment vessel. Monitoring will be continued.
In order to cool spent fuel pool, water discharge by helicopters has been
conducted on March 17th with the cooperation of Self-Defense Force.
At approximately past 7:00 pm, March 17th, Self-Defense Forces and
the police had started water discharge by water cannon trucks upon our
request for the cooperation. At 8:09 pm, March 17th, they had finished
At 2:00 pm, March 18th , water discharge by fire engine has started with
the cooperation of Self-Defense Forces and Military of United States of
America. At 2:45 pm, March 18th , they had finished water discharge.
At 0:45 am, March 19th, water discharge by the hyper rescue troop has
started with the cooperation of Tokyo Fire Department. At 1:10 am,
March 19th, they finished water discharge. Again, the hyper rescue troop
began the water discharge at 2:10 pm. At approximately 3:40 am,
March 20th, they had finished water discharge.
* Unit 4
At approximately 6:00 am, March 15th, an explosive sound occurred and
the damage in the 5th floor roof of Unit 4 reactor building was
confirmed. At 9:38 am, the fire near the north-west part of 4th floor of
Unit 4 reactor building was confirmed. At approximately 11:00 am,
TEPCO employee confirmed that the fire was off.
At approximately 5:45 am, a TEPCO employee discovered a fire at
the northwest corner of the Nuclear Reactor Building. TEPCO immediately
reported this incident to the fire department and the local government
and proceeded with the extinction of fire. At approximately 6:15 am,
TEPCO staff confirmed at the site that there are no signs of fire.
At approximately 8:21 am, March 20th, water discharge by fire engine has
started with the cooperation of Self-Defense Forces and they finished
water discharge at 9:40 am.
*On March 18th, regarding the spent fuel in the common spent fuel pool,
we have confirmed that the water level of the pool is secured.
A detailed inspection is under preparation.
*common spent fuel pool: a spent fuel pool for common use set in
a separate building in a plant site in order
to preserve spent fuel which are transferred
from the spent fuel pool in each
*On March 17th, we patrolled buildings for dry casks and found no signs
of abnormal situation for the casks by visual observation. A detailed
inspection is under preparation.
*dry cask: a measure to store spent fuel in a dry storage casks in
storages. Fukushima Daiichi Nuclear Power Station started
to utilize the measure from August 1995.
* The restoration work of electricity supply from external source for
Unit 3, 4, 5 and 6 are being implemented. And the repair of emergency
diesel generator A of Unit 6 is completed.
* At 5 am, Mar 19th, we started the Residual Heat Removal System Pump
(C ) of Unit 5 in order to cool the spent fuel pool. At 10:14 pm,
we started the Residual Heat Removal System Pump (B ) of Unit 6 in order
to cool the spent fuel pool.
* Unit 5 has been in reactor cold shutdown since 2:30 pm on March 20th.
* 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
*We will continuously endeavor to securing safety, and monitoring of
the surrounding environment.
Fukushima Daini Nuclear Power Station:
Units 1 to 4: shutdown due to earthquake
* The national government has instructed evacuation for those local
residents within 10km radius of the periphery.
* In order to achieve cold shutdown, reactor cooling function was
restored and cooling of reactors was conducted. As a result, all
reactors achieved cold shutdown: Unit 1 at 5:00 pm, March 14th, Unit 2
at 6:00 pm, March 14th, Unit 3 at 0:15 pm, March 12th, Unit 4
at 7:15 am, March 16th.
*Since March 12th, we had been preparing measures for reducing
the pressure of reactor containment vessels (partial discharge of air
containing radioactive materials to outside), but on March 17th,
we released such preparation in all Units.
* (Unit 1)
As it is confirmed that the temperature of the Emergency Equipment
Cooling Water System *1 has increased, at 3:20 pm, March 15th, we stopped
the Residual Heat Removal System (B) for the inspection. Subsequently,
failure was detected in the power supply facility associated with
the pumps of the Emergency Equipment Cooling Water System. At 4:25 pm,
March 15th, after replacing the power facility, the pumps and
the Residual Heat Removal System (B) have been reactivated.
* (Unit 4)
As it is confirmed that the pressure at the outlet of the pumps of
the Emergency Equipment Cooling Water System*1 has been decreased,
at 8:05 pm, March 15th, we stopped the Residual Heat Removal System (B)
for the inspection. Subsequently, failure was detected in the power
supply facility associated with the pumps of the Emergency Equipment
Cooling Water System. At 9:25 pm, March 15th, after replacing
the relevant facility, the pumps and the Residual Heat Removal System (B)
have been reactivated.
*1:emergency water system in which cooling water (pure water) circulates
which exchanged the heat with sea water in order to cool down bearing
pumps and/or heat exchangers etc.
Kashiwazaki Kariwa Nuclear Power Station:
Units 1, 5, 6, 7: normal operation
(Units 2 to 4: outage due to regular inspection)
[Thermal Power Station]
Hirono Thermal Power Station Units 2 and 4: shutdown due to earthquake
Hitachinaka Thermal Power Station Unit 1: shutdown due to earthquake
Kashima Thermal Power Station Units 2, 3, 5, 6: shutdown due to earthquake
Higashi-Ohgishima Thermal Power Station Unit 1: shutdown due to earthquake
[Hydro Power Station]
* All the stations have been restored.
[Transmission System, etc.]
All substation failed due to the earthquake have been restored.
[Blackout in TEPCO's Service Area]
All the blackouts are resolved.
[Supply and Demand Status within TEPCO's Service Area to Secure Stable
Backup supply from Shinshinano Conversion Station: 600MW
Backup supply from Sakuma Conversion Station: 300MW
Backup supply from Higashi Shimizu Conversion Station: 100MW
Considering the critical balance of our power supply capacity and
expected power demand forward, in order to avoid unexpected blackout,
TEPCO has been implementing rolling blackout (planned blackout alternates
from one area to another) since Mar 14th. We will make our utmost to
secure the stable power supply as early as possible.
For customers who will be subject to rolling blackout, please be prepared
for the announced blackout periods. Also for customers who are not
subject to blackouts, TEPCO appreciates your continuous cooperation in
reducing electricity usage by avoiding using unnecessary lighting and
Please do NOT touch cut-off electric wires.
In order to prevent fire, please make sure to switch off the electric
appliances such as hair drier and to shut down the breaker of
distribution board when you leave your house.
For the customer who has in-house power generation, please secure fuel
* Revised past progress