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 3: shut down due to the earthquake
･ Unit 4 to 6: outage due to regular inspections before the earthquake

* On April 11, We conducted gas sampling of PCV gas control system of Unit 2. As a result of the analysis, Xenon 135 was below the detection limit (9.1 x 10^-2Bq/cm³) at the inlet of the system and confirmed it not exceeding the re-criticality criteria of 1 Bq/cm³.

* At 10:00 am on April 10, we started transferring of accumulated water from the basement of T/B of Unit 6 to the temporary tanks. At 4:00 pm on the same day, we stopped transferring. At 10:00 am on April 12, we started transferring and stopped at 4:00 pm on the same day.

* As for Unit 2 Spent Fuel Pool, from January 19 to April 2, we had reduced salinity by the desalting facility using reverse osmosis membrane. In order to further reduction of salinity, we newly installed an ion exchange membrane device. As the preparation was completed, we started the operation from 10:06 am on April 12.

* At around 12:20 pm on April 12, 2012, at the road between Unit2 and Unit3 reactor buildings, we found a leakage of fuel (diesel oil) of heavy machinery (grab bucket) which has been used for removing rubbles of upper part of Unit 3 reactor building on the iron plate under the vehicle in the area of approx. 1.5 m x 1m. At around 12:40 pm on the same day, we informed Tomioka fire station. Afterwards, Futaba wide-area fire-defense headquarters and Tomioka fire station checked the site and confirmed that this oil leakage came under the leakage from dangerous facilities stipulated in the Fire Services Act. This oil leakage was stopped when it was found, and there will be no radiation effects to the outside by this event.

* At 2:44 pm on April 12, 2012, an alarm "excessive leaking flow amount from heat exchange unit" went off and the pumps of the system automatically stopped. As a result of site investigation on leakage from the system, the following events were confirmed. We will investigate their relevance with the automatic stop of cooling system of the spent fuel pool. The water temperature of the spent fuel pool was 28°C and the temperature rising rate was estimated at approx. 0.5 °C/h.
1.During checking leakage from the system, at around 3:04 pm on the same day, we confirmed that hydrazine was leaking at a rate of one drop per 7 seconds from a check-valve installed in the hydrazine injection pipes of the cooling system. We closed the check-valve and the leakage stopped. (We injected hydrazine from 1:35 pm to 2:56 on the same day.) The amount of leaked hydrazine below the check-valve was approx. 20 cc (approx. 10cm x 20 cm x 1 mm).
2.At 3:10 pm on the same day, at the east side of the 1 floor of Unit 4 Waste Treatment Building, we found water leaking at a rate of 1 drop per 2 seconds from the pipe flange of alternative cooling line for the spent fuel pool. Afterwards, at around 3:55 pm on the same day, we retorqued the flange and confirmed that the leakage stopped. We confirmed that the leakage was approx. 20 liters (approx. 1m x 2m x 1-2 cm) around the funnel near the flange. The leaked hydrazine and water were only in the Waste Treatment Building and we confirmed no other leakage than these two places after the investigation.

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

Appendix: Past Progress (As of 5:00 pm, on April 12, 2012) (PDF 288KB)
Appendix: Past Progress (From March 11, 2011 to December 31, 2011) (PDF 460KB)
* Revised past progress