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18 mars 2011 5 18 /03 /mars /2011 22:49

Status of TEPCO's Facilities and its services after Tohoku-Taiheiyou-Oki Earthquake (as of 1:00AM)

 

 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 apologies for the anxiety and inconvenience
caused.

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
periphery.

* 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 operation.

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. Now, cabling to unit
receiving facility is underway.

*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).

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. 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 water
discharge.
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 hyper rescue troop has
started with the cooperation of Tokyo Fire Department. At 1:10 am, March
19th , 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.

*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 Unit building.

*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.

*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.

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