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

- As for transferring the accumulated water from Unit 2 Turbine Building basement to the Central Radioactive Waste Treatment Facility, we laid the pipe (polyethylene pipe) from Unit 2 Turbine Building basement to Unit 3 Turbine Building basement and switched the operation to pass through Unit 3 Turbine Building basement for reliability improvement. Since we completed the work, we started the transfer of the accumulated water from Unit 2 Turbine Building basement to Unit 3 Turbine Building basement at 6:10 PM on August 8.

- At 6:24 AM on June 30, the alarm of the spent fuel pool alternative cooling system of unit 4 went off, showing that there was a system error, and the cooling system automatically stopped. After that we confirmed that there was no leakage at the site. During the investigation on the same day it was assumed that there was a problem in the UPS (Uninterruptible Power Supply) so we started bypassing works around the suspected UPS from 1:35 PM on July 1 and completed the bypass line at 2:45 PM on the same day. The cooling system was restarted at 3:07 PM. At 11:58 AM on July 5 we stopped the cooling system in order to remove the UPS and analyze the reason of malfunction. At 1:15 PM on the same day we restarted the cooling system (temperature of the pool at the time the cooling system stopped and the time it restarted was both 32°C) . Since we identified soot in the removed UPS, we reported to Tomioka fire Department at 5:20 PM on the same day. At 10:35 AM on July 6, the investigation by the Tomioka Fire Department concluded that it was not caused by a fire. Since the installation environment improvement work of control panel which UPS is installed and the preparation was completed, we stopped the spent fuel pool alternative cooling system at 6:51 AM on August 9. We started the UPS replacement accordingly. Since the work was completed on 10:23 AM on the same day, we started up the pump of the system and restarted cooling. (Spent fuel pool temperature at the time of stopping and restarting: 36 °C) By this work, the UPS bypass condition was restored to the normal condition.

- At around 6:20 PM on July 20, 2012, a worker of TEPCO on patrol found a leakage of fuel oil (light oil) around the diesel generator for the auxiliary nitrogen supply unit (nitrogen gas separator on the hill). Since it sets down that the auxiliary nitrogen supply unit (including the diesel generator) is operable in Technical Specification for the Nuclear Reactor Facility, we judged that it was not satisfied with "Operational Requirements" defined by Technical Specification for the Nuclear Reactor Facility at 7:14 PM on the same day. We fixed the leaked part with the special elastic tape, and confirmed that the leakage was stopped at 7:36 PM. It was confirmed that the leakage was stopped in the presence of the fire department at 9:00 PM on the same day, and we conducted the wiring connections of the auxiliary diesel generator to the nitrogen supply unit subsequently. At 1:48 AM on July 21, 2012, we started up the nitrogen supply unit and confirmed the operation. We confirmed that there was no problem. At 2:29 AM on the same day. We judged that it recovered to the condition that satisfies the Operational Requirements. We started replacing the auxiliary diesel generator to a small diesel generator at 10:00 AM August 9. During this work, we temporarily stopped power supply to the upland nitrogen gas separation apparatus^*. At 11:49 AM on the same day, since we completed the work, we restarted power supply to the apparatus. We installed an auxiliary small diesel generator for multiplexing power source of this apparatus with this replacement work. At starting this work, we started nitrogen injection to PCV and RPV utilizing the treatment water buffer tank bubbling nitrogen gas supply equipment at 9:25 AM on the same day, and switched it parallel running with the nitrogen gas separation apparatus B.

* The equipment management policy in accordance with Chapter 12 of the Technical Specification for the Nuclear Reactor Facility ("Policy on the Mid-term Security") stipulates the "Operational requirements" and "Measures required to be implemented when the operational requirements are not fulfilled". In the case that the operational requirements are not fulfilled, the required measures must be implemented. In this case, intentional transition out of the scope of the operational requirements was done to allow maintenance work (From 10:00 AM to 11:49 AM on August 9), and the power supply to the nitrogen gas separator on the hill was temporarily suspended.

- At 10:10 AM on August 9, we started transferring the accumulated water from Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Process Main Building).

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

Appendix: Past Progress (As of 3:00 pm, on August 9, 2012) (PDF 472KB)
Appendix: 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.