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 2:30 PM on June 6, during the investigation of the tanks in the additionally established Unit 2 Waste Underground Storage Facility Building, the accumulated water was confirmed around the Spent Sludge Storage Tank and the Spent Resin Storage Tank. The amount of the accumulated water was estimated to be approx. 830m3. The accumulated water did not flow out to outside of the building, and there is no possibility for it to flow out. The atmosphere dose rate is 0.03mSv/h on the upper side of the tank. Since it is the same level as the background, it is assumed that the groundwater or rainwater flowed in by way of the penetration hole. The on-site investigation will be conducted, and water stop work will be carried out.
* At 10:18 AM on June 6, accumulated water transferring from the on-site Bunker Building to Process Main Building at Central Radioactive Waste Treatment Facility was started. At 5:05 PM on the same day, transferring was stopped.
* At 8:03 PM on June 4, overload trip at the secondary system circulating pump (A) was confirmed by the emergency alarm of the air-fin cooler panel at Unit 4 spent fuel pool alternative cooling system. As a result of site investigation, a burn mark was confirmed near the motor terminal housing, and we reported it to Tomioka fire department (Naraha branch station) at 9:27 PM. Later we accepted the judgment that it was not a fire. As for Unit 4 spent fuel pool alternative cooling system, the secondary system circulating pump (B) was started up at 8:27 PM on the same day, there was no significant change in the pool water temperature. There was no problem with the cooling condition.
At 10:30 AM on June 5, the secondary system circulating pump (B) at Unit 4 spent fuel pool alternative cooling system was temporarily suspended in order to confirm the condition. As a result of the condition confirmation, it was decided to be fixed, since it was confirmed that the terminal connection was not done properly. After fixing the terminal connection, the pump will be restarted. There is no problem with the pool water temperature control as the temperature increase rate is estimated to be approx. 0.3°C/h.
On June 6, the terminal connection of the secondary system circulating pump (B) at Unit 4 spent fuel pool alternative cooling system was fixed, and the pump was restarted at 6:16 PM. The pool water temperature at the start-up was 42°C, and there is no problem with its control.
* At 10:15 AM on June 3, accumulated water transferring from Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building [High Temperature Incinerator Building]) was started. At 8:25 AM on June 7, transferring was stopped.
* At 10:00 AM on June 7, accumulated water transferring from Unit 6 Turbine Building basement to the temporary tank was started.
* On June 7, dust sampling was conducted at the upper part of Unit 3 Reactor Building.
* On June 7, sampling was conducted at the charcoal filter and the particulate filter of Unit 3 PCV gas control system.
* At 2:18 PM on June 7, injection of hydrazine to Unit 4 spent fuel pool utilizing the circulating cooling system was started.
[Fukushima Daini Nuclear Power Station]
Unit 1 to 4: Shutdown due to the earthquake
Appendix
Past Progress (As of 3:00 pm, on June 7, 2012) (PDF 416KB)
The aforementioned attachments are only available in Japanese.
We apologize for any inconvenience this may cause.
Appendix
Past Progress (From March 11, 2011 to December 31, 2011) (PDF 460KB)
*
Revised past progress
