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 1:41 PM on May 31, hydrazine injection to Unit 3 spent fuel pool utilizing the circulating cooling system was started. At 3:17 PM on the same day, injection was completed.

* At 8:36 AM on May 31, Second Cesium Adsorption Apparatus was temporarily stopped to backwash the filter. At 3:35 PM on the same day, the apparatus was restarted and the steady flow rate (approx. 40.0m³/h) was achieved.

* At 12:30 PM on May 29, data reading was failing on the Main Anti-Earthquake Building monitoring panel of the portable monitoring post at the west entrance. The same issue was occurring on the Main Anti-Earthquake Building monitoring panel of the wireless monitoring post used for alternative monitoring. The data from 12:30 PM to 7:30 PM was acquired by the alternative measurement done by a worker at the site. At 7:39 PM on the same day, the wireless monitoring system was recovered after resetting the equipment which transmits from the receiver to the terminal. As the data after 8:00 PM was acquired by the recovered wireless monitoring system, there is no data missing due to this issue. In the morning of May 31, the transmission cable of the monitoring post was repaired as it was disconnected. Also, the transmission cable connector was removed since its terminal was corroded. At around 1:00 PM on the same day, the monitoring post was recovered after directly connecting the cable (with its connector removed) and resetting the receiving terminal panel. At 6:00 PM on the same day, data acquisition utilizing the portable MP was restarted as no problem was found with it.

* At 10:00 AM on June 1, we started transferring the accumulated water in Unit 6 Turbine Building basement to the temporary tank.

* At 8:56 AM on June 1, Unit 4 spent fuel pool primary cooling system was temporarily suspended in order to replace the pump suction strainer (pool water temperature at the time it was stopped: approx. 31°C). The system will be suspended until June 3, however there is no problem with pool water temperature control as the temperature increase rate is estimated to be approx. 0.3°C/h.

* At 9:15 on May 19, 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 9:58 AM on June 1, we stopped transferring.

* On June 1, sampling was conducted at the charcoal filter and the particulate filter in unit 1 PCV gas control system

* On June 1, dust sampling was conducted at the upper part of Unit 1 reactor building at the emission filter of Unit 1 reactor building cover.

* At 10:33 AM on May 29, we started up Unit 5 PCV fan which had been stopped after the earthquake in order to exhaust the air directly from PCV (Until now we have been opening the equipment hatch to exhaust the air). The fan continued operating for a short period of time until 10:30 AM on May 30. Upon our analysis of γ nuclides measurement result (at the main exhaust stack), it was confirmed that the fan operation did not negatively affect the detection level. At 10:30 AM on June 1, the fan was restarted for a continuous run.

* At 2:22 PM on June 1, we started transferring the accumulated water from Unit 1 Turbine Building basement to Unit 2 Turbine Building basement.

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

Appendix: Past Progress (As of 3:00 pm, on June 1, 2012) (PDF 334KB)
Appendix: Past Progress (From March 11, 2011 to December 31, 2011) (PDF 460KB)
* Revised past progress