*There is no update from the previous press release.
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 12. It was assumed to be hydrogen explosion.
- At approximately 2:30 am on March 23, seawater injection to the reactor
through the reactor feed water system was initiated.
- From 3:37 pm on March 25, we started injecting freshwater by a motor
driven pump which is now powered by the off-site transmission line.
Water is currently injected at approx. 3.8m3/h through reactor feed
water system piping arrangement.
- We commenced injection of nitrogen gas into Primary Containment Vessel
at 1:31am April 7.
Unit 2 (Shut down)
- At approximately 6:00 am on March 15, an abnormal noise began emanating
from nearby Pressure Suppression Chamber and the pressure within the
chamber decreased.
- From 10:10 am on March 26, we started injecting freshwater to the
reactor. At 6:27 pm on June 23, we changed the water injection line so
that we can inject water to Unit 1 and 2 by the motor driven pump for
Unit 1 and stopped the motor driven pump for Unit 2.
Water is currently injected at approx. 3.5m3/h through reactor feed
water system piping arrangement.
- At 8:06 pm on June 28, we started injecting nitrogen gas into the
Primary Containment Vessel.
Unit 3 (Shut down)
- Explosive sound and white smoke were confirmed at approximately 11:01am
on March 14. It was assumed to be hydrogen explosion.
- From 6:02 pm on March 25, 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.
Water is currently injected at approx. 9 m3/h through reactor feed water
system piping arrangement.
Unit 4 (Outage due to regular inspection)
- At approximately 6:00 am on March 15, we confirmed the explosive sound
and the sustained damage around the 5th floor rooftop area of Reactor
Building.
- At this moment, we do not consider any reactor coolant leakage inside
the primary containment vessel has occurred.
Unit 5 (Outage due to regular inspection)
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 5:00 am on March 19, we started the Residual Heat Removal System Pump
(C) in order to cool the spent fuel pool.
- At 2:30 pm on March 20, the reactor achieved cold shutdown.
- At this moment, we do not consider any reactor coolant leakage inside
the primary containment vessel has occurred.
Unit 6 (Outage due to regular inspection)
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 10:14 pm on March 19, we started the Residual Heat Removal System
Pump (B) of Unit 6 in order to cool the spent fuel pool.
- At 7:27 pm on March 20, the reactor achieved cold shutdown.
- At this moment, we do not consider any reactor coolant leakage inside
the primary containment vessel has occurred.
Operation for cooling the spent fuel pools
- At 5:21 pm on May 31, we started cyclic cooling of the spent fuel pool
in Unit 2 using alternative cooling system for fuel pool cooling and
filtering system.
- At 7:47 pm on June 30, we started cyclic cooling of the spent fuel pool
in Unit 3 using alternative cooling system for fuel pool cooling and
filtering system.
- From 3:10 pm to 5:30 pm on July 5th, we injected water into unit1
through fuel pool cooling and filtering system.
- We will continuously conduct further water spray depending on the
conditions of spent fuel pools, if needed.
Others
- At 1:30 pm on April 26, we started spraying the dust inhibitor inside
the site.
- At 11:00 am on May 10, we started transferring accumulated water from
the underground level of reactor building to the radiation waste
treatment facility of Unit 6.
- At approximately 10:00 am on June 13, we started the operation of the
circulating seawater purification facility installed at the screen area
of Unit 2 and 3.
- From 8:00 pm on June17, we started operation of water treatment of
accumulated water at accumulated water treatment facility.
- At 9:56 am on June 22, we started transferring accumulated water in
turbine building of Unit 2 to central waste treatment facility building.
- At 8:56 am on June 30, we started transferring the accumulated water
from the basement of the turbine building of Unit 3 to Centralized
Radiation Waste Treatment Facility (Process Building).
- At 6:00 pm on July 2, we started the circulating injection cooling to
inject the water, which was treated by the accumulated water treatment
system, to the reactors through the buffer tank.
- From 10:00 am to 5:00 pm on July 5, we transferred low radioactive
stored water from outdoor temporary tank to Mega Float.
- From 10:30 am to 4:00 pm on July 5, we transferred accumulated water
from inside of turbine building of Unit 6 to temporary tank. We started
transferring water again at 10:00 am on July 6.
- We will continue to take all measures to ensure the safety and to
continue monitoring the surrounding environment around the power station.