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 around 5:21 AM on October 24, an alarm indicating "mobile desalination system abnormality" (warning) went off at the desalination system (mobile RO system) at Unit 3 spent fuel pool which was under suspension. The warning indicated was "desalination system unit leakage detection". At around 6:15 AM, yellowish liquid was found to be accumulated in the drain pan located in the lower part of the system which was placed on the back of a truck. The area affected by the leakage was approx. 2.5m x 3m x 1cm, and continuous leakage had already been stopped at the time of site investigation. The leaked liquid remains in the drain pan and has not flowed outside. At 6:32 AM, the incident was reported to the Futaba Fire Fighting Head Office. There was a tank filled with 25% hydrochloric acid in the upper part of the leakage area and the analysis results of the leaked liquid were as follows. PH: less than 1, conductivity: less than 200mS/cm, chloride concentration: 250,000ppm, specific gravity: 1.119. Based on the results, the leaked liquid was identified to be hydrochloric acid of the tank. The amount of leakage was approx. 75L. There was no injury due to the incident. The cause of this incident is currently being investigated.

-At 8:46 AM on October 23, we stopped transferring the accumulated water from Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building [High Temperature Incinerator Building]) for transfer pipe replacement. At 1:07 PM on the same day, the transfer was restarted. At 8:11 AM on October 24, the transfer was stopped.

-At 10:00 AM on October 24, we started transferring the accumulated water in Unit 6 Turbine Building basement to the temporary tank. At 3:00 PM on the same day, the transfer was stopped.

-On October 24, nitrogen gas injection to Unit 1 PCV and suppression chamber was temporarily stopped for switching the power supply and was restarted afterwards. The nitrogen injection was suspended from 10:10 to 10:48 AM for the PCV and from 9:16 to 10:56 AM for the suppression chamber. The nitrogen injection to the RPV was not suspended.

-At 9:36 AM on October 22, Unit 4 spent fuel pool alternative cooling system secondary cooling system was stopped for replacing its pipe with polyethylene pipe. At 1:30 PM on October 24, the system was restarted after the pipe replacement and no problem was found with its operation. Though the spent fuel pool temperature increased to approx. 42°C from approx. 29°C during suspension, there is no problem with the spent fuel pool water temperature control considering that there is a sufficient margin to the maximum allowed temperature (65°C).

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

Appendix: Past Progress (As of 3:00 pm, on October 24, 2012) (PDF 728KB)
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.