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 2:54 PM on July 27, we confirmed that there was no flow indication of Unit 1-3 nitrogen supply equipment (nitrogen gas separation apparatus A). Since we conducted the on-site investigation at 3:20 PM, we confirmed that this equipment was stopped. We confirmed the message "problem on compressor" and "severe problem on inverter" on site accordingly. Since we could have reset the alarm gone off and could have restarted the system, we assumed that it was unlikely to be a breakdown of inverter and was likely to be a malfunction of inverter. As a result of the evaluation by a diagnostic equipment, we judged that we could implement a test run. At 8:02 AM on August 2, we started the nitrogen gas separation apparatus A. We started nitrogen supply at 8:23 AM, and started the operational status confirmation. When we manually stopped the diagnostic equipment on 9:13 AM, we suspended the operational status confirmation due to the inverter stopping. Since the malfunction of inverter was not the cause, we restarted the nitrogen gas separation apparatus A on 12:10 PM. At 12:27 PM, we started nitrogen supply, and we restarted the operational status confirmation accordingly. At 2:03 PM, we confirmed that an alarm went off at the Main Anti-Earthquake Building, and we confirmed the site at 2:25 PM. Since we confirmed the apparatus stopping, we stopped the operational status confirmation. We confirmed the message "problem on compressor" and "severe problem on inverter" on site accordingly. Since a similar event occurred subsequently, we reevaluated the cause using a diagnostic equipment to confirm whether there was a cause at the inverter. As a result of reevaluation, we judged that there was a problem at the substrate inside the inverter. We replaced the inverter on August 24. We conducted a continuous test operation from August 27. Since there was no problem, we completed the test operation on August 29. (The continuous operation is under going.)

-As for the injection of nitrogen, we conducted a parallel run (3 equipments) by the filtrate water tank bubbling nitrogen gas supply equipment with the nitrogen gas separation apparatus B until the completion of test operation of nitrogen gas separation apparatus A. Since the test operation of the nitrogen gas separation apparatus A was completed, we stopped the filtrate water tank bubbling nitrogen gas supply equipment.

-At 10:26 AM on August 28, we started transferring the accumulated water from Unit 2 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Process Main Building). At 8:47 AM on August 30, we stopped transferring.

-At 1:09 PM on August 24, we started transferring the accumulated water from Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Process Main Building). At 11:06 AM on August 29, transfer was temporarily suspended due to the replacement work of the accumulated water transferring pipes to polyethylene pipes. As the work was completed, we restarted transferring at 12:52 PM. At 8:52 AM on August 30, we stopped transferring.

-Since the restoration of the Unit 5 residual heat removal seawater system pump (A) and (C) which we had not been able to use due to the tsunami was completed, we conducted the test operation on August 23 and 24 and confirmed that there was no problem. We stopped the residual heat removal system (B) at 9:29 AM on August 30, and started the residual heat removal system (B) at 11:33 AM on the same day. Since there was no problem with the operating condition, we started the full-scale operation of the residual heat removal system (A). Both the original residual heat removal system (A) and (B) at Unit 5 were restored.

-At 10:00 AM on August 30, we started transferring the accumulated water in Unit 6 Turbine Building basement to the temporary tank. At 3:00 PM on the same day, we stopped transferring.

-A worker of TEPCO confirmed that the fluctuation in the amount of water injection for Unit 1 - 3 reactor at 3:00 PM on August 30 at the regular data confirmation.

Unit 1: The amount of water injection from 4.9m³/h (at 2:00 PM) to 4.0m³/h.
(The required amount of water injection was 4.3m³/h.)

Unit 2: The amount of water injection from 7.0m³/h (at 2:00 PM) to 5.5m³/h.
(The required amount of water injection was 6.1m³/h.)

Unit 3: The amount of water injection from 7.0m³/h (at 2:00 PM) to 5.6m³/h.
(The required amount of water injection was 6.1m³/h.)

The shift supervisor judged that it was not satisfied with "Operational Requirements"^*2 defined by Technical Specification^*1 for Unit 2 at 3:00 PM, for Unit 3 at 3:05 PM and for Unit 1 at 3:07 on the same day. We are keeping the amount of water injection at each unit at the current level, and preparing to increase the amount of water injection at site. For reference, a significant change at the monitor posts at NPS was not confirmed.

*1 Technical Specification for the Nuclear Reactor Facility:

In accordance with the technical specification for the nuclear reactor facility, operational requirements are stipulated to ensure safety and stability of power stations (such as the number of available equipments, temperatures and pressures). In the case that an issue arises with an equipment subject to the technical specification and the operational requirements cannot be satisfied temporarily, appropriate measures must be implemented.

*2 Operational Requirements:

Government-approved fundamental rules for nuclear power station operators to follow in order to maintain safe operation and stable condition of nuclear power stations (including operation management, fuel management, radiation management, emergency measures and equipment/facility management based on the "Policy on the Mid-term Security"), which are stipulated by Article 37 Section 1 of the Act on the Regulations of Nuclear Source Material, Nuclear Fuel Material and Reactors.

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

Appendix: Past Progress (As of 4:00 pm, on August 30, 2012) (PDF 507KB)
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.