*The updates from the 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 a
big quake occurred at 3:36 pm on March 12, 2011. It was
assumed to be hydrogen explosion.
- At 3:37 pm on March 25, 2011, 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.
- At 10:11 am on December 10, 2011, in addition to water
injection from water feeding system, we started water
injection from piping of core spray system to the
reactor.
The current amount of water injection from the feed water
system is approx. 4.9 m3/h and that from the reactor core
spray system is approx. 2 m3/h.
- At 1:31 am on April 7, 2011, we commenced injection of
nitrogen gas into Primary Containment Vessel.
- At 11:22 am on August 10, 2011, we started cyclic cooling
for the water in the spent fuel pool by an alternative
cooling equipment of the Fuel Pool Cooling and Filtering
System.
- At 4:04 pm on November 30, 2011, we started operation to
inject nitrogen into the reactor pressure vessel.
- At 6:00 pm on December 19, 2011, a full-scale operation
of the PCV gas management system started.
Unit 2 (Shut down)
- At approximately 6:00 am on March 15, 2011, an abnormal
noise began emanating from nearby Pressure Suppression
Chamber and the pressure within the chamber decreased.
- At 10:10 am on March 26, 2011, 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.
- At 2:59 pm on September 14, 2011, in addition to water
injection from feed water system, we started water
injection from piping of core spray system to the
reactor.
The current water injection amount from the reactor feed
water system is approx. 2.8 m3/h and that from the core
spray system is approx. 6m3/h.
- At 5:21 pm on May 31, 2011, we started cyclic cooling for
the water in the spent fuel pool by an alternative cooling
equipment of the Fuel Pool Cooling and Filtering
System.
- At 8:06 pm on June 28, 2011, we started injecting
nitrogen gas into the Primary Containment Vessel.
- At 6:00 pm on October 28, 2011, a full operation of the
PCV gas control system started.
- At 10:46 am on December 1, 2011, we started the nitrogen
injection to the Reactor Pressure Vessel.
- At 11:50 am on January 19, 2012, we started the operation
of the spent fuel pool desalting facility.
Unit 3 (Shut down)
- Explosive sound and white smoke were confirmed at
approximately 11:01 am on March 14, 2011. It was assumed to
be hydrogen explosion.
- At 6:02 pm on March 25, 2011, 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.
- At 2:58 pm on September 1, 2011, we started water
injection by core spray system in addition to water
injection by the reactor feed water system piping
arrangement.
The current water injection amount from the reactor feed
water system is approx 1.8m3/h and that from the core spray
system is approx. 4.9m3/h.
- At 7:47 pm on June 30, 2011, we started cyclic cooling
for the water in the spent fuel pool by an alternative
cooling equipment of the Fuel Pool Cooling and Filtering
System.
- At 8:01 pm on July 14, 2011, injection of nitrogen gas
into the Primary Containment Vessel started.
- At 4:26 pm on November 30, 2011, we started operation to
inject nitrogen into the reactor pressure vessel.
- At 7:00 pm on March 14, 2012, the regular operation of
the PCV gas control system started.
Unit 4 (Outage due to regular inspection)
- At around 6 am on March 15, 2011, we confirmed an
explosive sound and the sustained damage around the 5th
floor rooftop area of Reactor Building.
- At 12:44 pm on July 31, 2011, we started cyclic cooling
for the water in the spent fuel pool by an alternative
cooling equipment of the Fuel Pool Cooling and Filtering
System.
- At 10:58 am on November 29, 2011, in order to decrease
more salinity, we installed Ion exchange equipment and
started the operation of such equipment.
- At this moment, we don't think there is any reactor
coolant leakage inside the primary containment vessel.
Unit 5 (Outage due to regular inspection)
- Sufficient level of reactor coolant to ensure safety is
maintained.
- At 5:00 am on March 19, 2011, we started the Residual
Heat Removal System Pump in order to cool the spent fuel
pool.
- At 2:45 pm on July 15, 2011, we started the operation of
the original Residual Heat Removal System (System B) by its
original seawater pump.
Unit 6 (Outage due to regular inspection)
- Sufficient level of reactor coolant to ensure safety is
maintained.
- At 10:14 pm on March 19, 2011, we started the Residual
Heat Removal System Pump of Unit 6 to cool down Spent Fuel
Pool.
- At 2:33 pm on September 15, 2011, we started separately
cooling the reactor through the Residual Heat Removal
System and the spent fuel pool through Equipment Cooling
Water System and Fuel Pool Cooling System.
Others
- At around 10:00 am on June 13, 2011, we started the
operation of the circulating seawater purification facility
installed at the screen area of Unit 2 and 3.
- At 7:41 pm on August 19, 2011, we started treatment of
accumulated water by parallel operation of one line from
the cesium adsorption instrument to the decontamination
instrument and the other treatment line of the cesium
adsorption instrument No.2.
- At 2:06 pm on October 7, 2011, we started to spray
purified accumulated water brought from Unit 5 and 6
continually in order to prevent dust scattering and
potential fire outbreaks from the cut down trees.
- On October 28, 2011, we started installation of the water
proof wall at the sea side, in front of the existing shore
protection, Units 1-4, in order to contain marine pollution
by underground water.
- At 12:25 pm on December 13, 2011, we started the
re-circulating operation of desalination facility (reverse
osmosis membrane) for the purpose of suppression of
condensed water after desalination treatment.
- At 9:26 on March 30, we started the transfer of the
accumulated water from the basement of Unit 3 T/B to the
Centralized Radiation Waste Treatment Facility (Process
Main Building).
- At around 11:00 am on March 29, 2012, our staff
patrolling at the Turbine Building of Unit 5 and 6 and
checking the water level of the tank was not masked
temporarily. For reference, no radioactive materials were
found to be attached to the worker's body on the same
day. On March 31, 2012, We have confirmed there was no
contamination around his mouth. Since there was a
possibility of the worker taking in radioactive materials,
we conducted a whole counter examination. As a result, we
found out that there was no issue regarding internal
exposure dose.
distributed by | This press release was issued by TEPCO - Tokyo Electric Power Company Inc. and was initially posted at http://www.tepco.co.jp/en/press/corp-com/release/2012/12033103-e.html . It was distributed, unedited and unaltered, by noodls on 2012-03-31 14:36:21 PM. The issuer is solely responsible for the accuracy of the information contained therein. |