Status of TEPCO's Nuclear Power Stations after the Tohoku-Chihou-Taiheiyou-Oki Earthquake(Daily Report as of 3:00 PM on August 6)

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 Fukushima Daiichi Nuclear Power Station.

* 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

-Contaminated water transfer from the underground reservoirs was all completed as of July 1. However, we are continuing to take measures to prevent the expansion of contaminated water, and to conduct sampling activities.

<Measures to prevent the expansion of contaminated water>
·Since the decreases of all-β radioactivity densities in the leakage detection holes (at the northeast side of the underground reservoir No.1, the northeast side of the underground reservoir No.2, and the southwest side of the underground reservoir No.3) have been slow, operations to dilute the underground reservoirs No.1-No.3 by transferring filtered water or desalination-system (RO) treated water (the all-β radioactivity density: approx. 1×10¹Bq/cm³) into these reservoirs have been conducted as appropriate.
[Recent dilution operations]
Underground reservoir No.1 (since June 19): On August 3, approx. 60m³ of filtered water was injected.
Underground reservoir No.2 (since June 27): On August 1, approx. 60m³ of filtered water was injected.
Underground reservoir No.3 (since July 24): On August 5, approx. 60m³ of filtered water was injected.

·On August 5 and 6, leaked water in the leakage detection holes at the underground reservoirs No.1-No.3 was transferred to the temporary aboveground tank, and leaked water in the drain holes at the underground reservoirs No.1 and No.2 was transferred into these underground reservoirs.

<Sampling>
On August 5, sampling was performed in the drain holes of the underground reservoirs No.1-No.7 (14 locations), the leakage detection holes of the underground reservoirs No.1-No.4 and No.6 (sample could not be collected at 2 out of 10 locations), the observation holes of the underground reservoirs (22 locations), and the observation holes on the sea side (5)-(8). As a result of the analysis, no significant change was found compared to the analysis results from the sampling performed previously (on July 29 in the observation holes on the sea side (5)-(8) and on August 4 in the other locations).

-At around 4:13 PM on August 5, a fire alarm went off at the third floor area of the Auxiliary Operation Shared Facility (Common Pool Building). At 4:22 PM, the incident was reported to the fire department. Later, we confirmed through a webcam that there had been no abnormality such as smoke around the ceiling at the site. Further, at 4:48 PM, a TEPCO employee confirmed on-site that there had been no abnormality. We therefore determined that the incident occurred due to malfunction of the fire alarm. The incident has caused no impact on the plant conditions so far, and the common pool cooling has been continued. No significant change has been found in the monitoring post readings.

-We installed observation holes east of the Unit 1-4 Turbine Buildings, and have been conducting sampling and analysis of groundwater from the observation holes. On June 19, we announced that tritium and strontium were detected at high densities in the observation hole located between Units 1 and 2. Therefore, we have been conducting intensified monitoring.

The γ nuclide and all-β densities in water sampled on August 5 in the groundwater observation hole No.1-5 (west of the groundwater observation hole No.1-3) were measured. The γ nuclide and all-β densities this time were all detected higher than the previous densities (in the sample taken on July 31).
<Groundwater observation hole No.1-5>
- Sampling on August 5:
Cesium-134 310Bq/L
Cesium-137 650Bq/L
All-β 56,000Bq/L
- Sampling on July 31 (previously announced):
Cesium-134 21Bq/L
Cesium-137 44Bq/L
All-β 1,200Bq/L

-At around 8:00 AM on August 6, steam was again found coming from the vicinity of the central part of the Unit 3 Reactor Building fifth floor (equipment storage pool side), through a camera. The plant status, the monitoring post readings, etc. obtained as at 8:00 AM showed no abnormality. (From the weather data as at 8:00 AM, the air temperature and humidity were 26.3℃ and 92.0%.)

* Revised past progress

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