Status of TEPCO's Nuclear Power Stations after the Tohoku-Chihou-Taiheiyou-Oki Earthquake (Daily Report as of 3:00 PM, April 4)

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 3:55 PM on April 3, an alarm indicating high-high radiation dose went off at the continuous dust monitor installed at the main gate. Due to this, an instruction has been given to put on full-face mask in the power station site. As a result of sampling of dust in the air, the radioactivity density was confirmed to be less than the detection limit (5.4×10^-6 Bq/cm³). Since no problem was found with the dust sampling analysis result and the reading of the continuous dust monitor which has been replaced, the alarm going off was determined to be due to the continuous dust monitor failure. As a result of radioactivity density analysis of the continuous dust monitor filter paper, no significant nuclide was detected which indicates that radioactive materials had not been collected. Since the reading of the replaced continuous dust monitor was 1.8×10^-5 Bq/cm³ which is of no problem, the instruction to put on full-face mask was cancelled at 8:10 PM on the same day. No problem was found with the readings of the continuous dust monitors installed at locations other than the main gate and no significant change was found with the monitoring post readings as well.

- At around 5:23 AM on April 4, the multi-nuclide removal equipment (ALPS) for which hot testing using waste liquid treated by the contaminated water treatment facility was being performed has been suspended due to incorrect operation. Since no abnormality was found as a result of site investigation performed after the incident, the treatment of water remaining in the system was started at 6:33 AM on the same day. No problem has been found with its operation after starting the treatment of the remaining water.

- On April 4, sampling was conducted at the charcoal filter and the particulate filter of Unit 2 PCV gas control system.

- On April 4, dust sampling was conducted at the exhaust facility of Unit 2 Reactor Building.

- On April 4, a dry storage cask inspected in the Common Pool Building has been transported from the Common Pool Building to the Temporary Cask Storage Facility.

- On April 4, one out of 8 dry storage casks stored in the Cask Storage Building has been transported to the Common Pool Building.

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

* Revised past progress

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