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
- With the initial water injection amounts to Unit 1-3 reactors*, the temperatures of RSV and PCV are expected to gradually increase along with the ambient temperature increase in the summer, and it is predicted that the Unit 3 temperature will be slightly higher than that of Unit 1 and 2. As a result, the operational requirement margin specified by the technical specification will decrease for Unit 3. At 3:45 PM on June 12, the amount of water injection from the reactor core spray system to Unit 2 reactor was adjusted from approx. 6.0m3/h to approx. 5.5m3/h (The amount of water injection from the water supply system was adjusted from approx. 2.7m3/h to approx. 3.0m3/h). The amount of water injection from the water supply system to Unit 3 reactor was also adjusted from approx. 2.8m3/h to approx. 3.5m3/h. (The amount of water injection from the reactor core spray system remain the same at the rate of approx. 5.0m3/h.)
* Unit 1: 6.5m3/h, Unit 2: 9.0m3/h, Unit 3: 7.0m3/h (as of May 29)
- As the fluctuation in the amount of water injection for Unit 1 reactor was confirmed at 3:45 PM on June 12, the amount of water injection from the water supply system was adjusted from approx. 3.3m3/h to approx. 3.5m3/h, the amount of water injection from the reactor core spray system was adjusted from approx. 1.8m3/h to approx. 2.0m3/h.
- At 10:00 AM on June 13, 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 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. 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) 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. As the terminal connection of the secondary system circulating pump (B) was fixed, the pump was restarted at 6:16 PM on June 6. The power cables were reconnected and the motors were replaced for the secondary system circulating pump (A). The secondary system circulating pump (B) was suspended at 11:27 AM on June 13, and the secondary system circulating pump (A) was restarted. Since there was no problem with the operation, it was switched to continuous operation.
- As for the Cesium Adsorption Apparatus which was suspended at 9:50 AM on April 26, the modification was started for reliability improvement on May 15, and the work was completed. This apparatus was started up at 2:44 PM on June 13, and achieved the steady flow (approx. 19.5m3/h) at 3:08 PM on the same day.
- The emission from Unit 2 PCV gas control system was adjusted from approx. 24m3/h to approx. 34m3/h at 3:10 PM on June 13, and the amount of the nitrogen gas injection into Unit 3 PCV was adjusted from approx. 28m3/h to approx. 18m3/h at 3:55 PM on the same day, in order to keep the balance between the amount of the nitrogen gas injection into Unit 2 and 3 RPV and PCV and the emission from PCV gas control system.
[Fukushima Daini Nuclear Power Station]
Past Progress (As of 4:00 pm, on June 13, 2012) (PDF 420KB)
· Unit 1 to 4: Shutdown due to the earthquake
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.