Due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake which occurred on March 11, 2011, TEPCO's facilities including our nuclear power stations have been severely damaged. We deeply apologize for the anxiety and inconvenience caused.
With regard to the accident at Fukushima Daiichi Nuclear Power Station, on April 17, 2011, we have compiled the roadmap towards restoration from the accident and on July 19 we accomplished the Step1 target "Radiation dose is in steady decline". Then on December 16 we confirmed the accomplishment of the Step 2 target "Release of radioactive materials is under control and radiation doses are being significantly held down".
In addition, on December 21, 2011, we have compiled the "Mid-to-long-Term Roadmap toward the Decommissioning of Fukushima Daiichi Nuclear Power Units 1-4, TEPCO".
In addition to the maintenance of the plant's stable condition, we will implement Mid-to-Long Term countermeasures towards the decommissioning of Fukushima Daiichi Nuclear Power Units 1-4 to enable evacuees to return to their homes as soon as possible and reduce the anxiety of the people in Fukushima and the whole nation as soon as possible.

Below is the status of TEPCO's nuclear power stations (Fukushima Daiichi and Fukushima Daini).

* The updates are underlined.

[Fukushima Daiichi Nuclear Power Station]
･ Unit 1 to 4: Abolishment (April 19, 2012)
･ Unit 5 to 6: Outage due to regular inspections before the earthquake

- At 2:23 PM on December 5, Unit 2 spent fuel pool alternative cooling system was suspended in prior to the suspension of the common M/C1A^* for recovery work (connecting the cable) of M/C1A-2A interconnected line cable damage (the pool water temperature when the system was suspended: 14.5℃). At 3:27 PM on December 7, the system was restarted as the common M/C had recovered (the pool water temperature when the system was suspended: 20.3℃).
* Suspension of the common M/C1A: From 11:20 AM to 11:27 AM on December 6

- At 8:42 AM on December 4, the second cesium absorption apparatus was suspended in order to replace the pressure hose with polyethylene pipe (in the backup line of the accumulated water transfer line) for the purpose of its reliability improvement. In response to this, the cesium absorption apparatus was started at 10:34 AM on the same day and the steady flow rate was achieved at 10:38 AM. At 3:42 PM on December 7, the second cesium absorption apparatus was restarted after the pipe replacement had completed, and the steady flow rate was achieved at 4:42 PM. At 4:46 PM on the same day, the cesium absorption apparatus was suspended accordingly.

- At 5:00 PM on December 7, we started transferring the accumulated water in Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building [High Temperature Incinerator Building]).

- At around 5:18 PM on December 7, a M7.3 earthquake occurred at the offshore of Sanriku. Upon plant checkup, no problem originating from the earthquake was found.

- At 11:40 PM on December 7, Units 1-3 reactor injection water amounts were adjusted since the amounts had decreased.
[Unit 1] Feed water system: Increased from approx. 2.3m³/h to approx. 2.5m³/h, Reactor core spray system: Increased from approx. 1.8m³/h to approx. 2.0m³/h.
[Unit 2] Feed water system: Increased from approx. 1.8m³/h to approx. 2.0m³/h, Reactor core spray system: Increased from approx. 3.8m³/h to approx. 4.0m³/h.
[Unit 3] Feed water system: Increased from approx. 1.7m³/h to approx. 2.0m³/h, Reactor core spray system: Increased from approx. 3.9m³/h to approx. 4.0m³/h.

- At 10:40 AM on December 8, Units 1-3 reactor injection water amounts were adjusted since the amounts had decreased.
[Unit 1] Feed water system: Increased from approx. 2.3m³/h to approx. 2.5m³/h, Reactor core spray system: Increased from approx. 1.8m³/h to approx. 2.0m³/h.
[Unit 2] Feed water system: Increased from approx. 1.8m³/h to approx. 2.0m³/h, Reactor core spray system: Maintained at approx. 4.0m³/h.
[Unit 3] Feed water system: Increased from approx. 1.8m³/h to approx. 2.0m³/h, Reactor core spray system: Maintained at approx. 4.0m³/h.

- At 1:50 PM on December 8, we started transferring the accumulated water in Unit 2 Turbine Building basement to Unit 3 Turbine Building basement.

 [Fukushima Daini Nuclear Power Station]
･ Unit 1 to 4: Shutdown due to the earthquake.

- At around 5:18 PM on December 7, a M7.3 earthquake occurred at the offshore of Sanriku. Upon plant checkup, no problem originating from the earthquake was found. Since the pressure in Unit 1 Reactor Building had turned positive (though the pressure is kept negative to the outdoor air), the standby gas treatment system* was started upon judgment of an operator. The pressure in the Reactor Building increased to 0.05kPa right after the system was started and later the pressure turned back to negative and became stable. In order to investigate the cause of the pressure turning to positive, the standby gas treatment system was suspended and the Reactor Building ventilation air conditioning system was started on December 8. The pressure in the Reactor Building is being maintained in negative after switching the system. The cause of the incident will continue to be investigated.
* Standby gas treatment system: System that purifies the air in the Reactor Building utilizing high performance filter and discharge it to the outside through the exhaust stack. The system is comprised of systems (A) and (B).

Appendix: Past Progress (As of 3:00 pm, on December 8, 2012) (PDF 765KB)
Appendix: Past Progress (From March 11, 2011 to December 31, 2011) (PDF 523KB)
* Revised past progress

The aforementioned attachments are only available in Japanese.
We apologize for any inconvenience this may cause.