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).

* 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

* On May 16, while installing the data logger (data collection equipment used for measuring the thermometer direct current resistance) in Unit 1, we found that the wiring (positive) for RPV upper cover flange thermometer (TE-263-66B1) connected to the digital recorder and the stud bolt thermometer (TE-263-67A1) is done in an opposite manner. The wiring was redone properly. These temperatures are not included in the monitoring list of the technical specification (Article 138 and 143).

* At 10:00 AM on May 16, we started transferring the accumulated water in Unit 6 Turbine Building basement to the temporary tank. At 4:00 PM on the same day, we stopped transferring.

* At 1:30 PM on May 16, we found that data was missing in the portable monitoring post at the main entrance of the power station. Upon investigation, it was assumed that the issue is caused by abnormality of the transmission system between the Main Anti-Earthquake Building and the monitoring post, as the reading was confirmed. At 3:00 PM on the same day, the monitoring panel was reset for recovery and the monitoring post started working properly. The missing data (at 2:00 PM and 2:30 PM) was acquired by dose rate measurement, and the result showed the same level of dose rate as that of before the issue arose (Approx. 22μSv/h). At around 4:30 PM on the same day, data reading was failing on the Main Anti-Earthquake Building monitoring panel of the portable monitoring posts at the main entrance and west entrance. At 6:00 PM on the same day, the transmission of the portable monitoring post at the main gate was recovered. As for the monitoring post at the west entrance, alternative measurement was done by a worker, and monitoring was continued utilizing a wireless monitoring post system during the night. At 11:35 AM on May 17, the monitoring post at the west entrance was recovered after a worker wiped off the water on the cable connection part and removed and inserted the cable. At 12:30 PM on the same day, the data reading on the Main Anti-Earthquake Building monitoring panel failed again. At 12:55 PM, the issue was resolved by resetting the monitoring panel. As the data acquired at 12:30 PM and later was confirmed on the wireless monitoring post system, there was no missing data. The cause of the issue on the monitoring post at the main entrance is considered to be a temporary transmission system issue. The issue on the monitoring post at the west entrance seems to be caused by a bad cable connection and a temporary transmission system issue. All data except for that of 1:30 PM on May 16 was acquired by an alternative measurement (at both the main entrance and west entrance). We will continue to monitor these equipments by checking the data updates every 30 minutes.

* At 8:58 AM on May 15, we started transferring the accumulated water from Unit 3 Turbine Building basement to the Centralized Radiation Waste Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building [High Temperature Incinerator Building]). At 8:11 AM on May 17, we stopped transferring.

* At 1:20 PM on May 17, hydrazine injection into Unit 4 spent fuel pool using the circulating cooling system was started. At 2:50 PM on the same day, injection has completed.

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

* At 1:03 PM on May 16, Iwaito line 2 was suspended in order to investigate the Unit 2 gas transformer issue at Shin Fukushima Power Substation. At 8:21 PM on the same day, Iwaito line 2 was recovered upon completing the investigation

Appendix: Past Progress (As of 3:00 pm, on May 17, 2012) (PDF 519KB)
Appendix: Past Progress (From March 11, 2011 to December 31, 2011) (PDF 460KB)
* Revised past progress