Status of TEPCO's Nuclear Power Stations after the Tohoku-Chihou-Taiheiyou-Oki Earthquake (Daily Report as of 6:00 PM on July 16)

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

- At around 1:20 PM on July 11, in the upper part of Unit 3 Reactor Building, a worker found hydraulic oil leaking from unmanned heavy equipment used for debris removal. At around 1:43 PM, this incident was reported to the fire department. This heavy equipment was lifted down to the ground from the upper part of Unit 3 Reactor Building. Then, at 1:55 PM, oil leakage was confirmed to have stopped. Further, the heavy equipment was placed on a drain pan temporarily just in case. Later, we checked the heavy equipment, and found out that oil leaked from the hydraulic hose joint above the hydraulic cutter. Through a camera, no trace of leakage was found in the operation floor. We consider that there was no inflow of the oil into the spent fuel pool, since the unmanned heavy equipment and the spent fuel pool are distant from each other. Later, the hydraulic oil leakage from a jig (hydraulic cutter) of the unmanned heavy equipment was determined to have been caused by loosening of the hydraulic hose joint above the cutter. Accordingly, the joint was retightened, and measures were taken against loosening of the joint. On July 16, use of the unmanned heavy equipment was restarted since no abnormality was found in an operation test of the jig (hydraulic cutter) of the unmanned heavy equipment conducted after the measures were thus taken.

- While the 9 temporary tanks outside of Units 5 and 6 contain seawater and groundwater (megafloat water) that flowed into the buildings of Units 5 and 6 at the Earthquake, we started transfer of the water in these temporary tanks to the F area tanks north of Unit 6 at1:00 PM on July 16 in order to apply a desalination process (RO) to this water as in the case of accumulated water in Unit 6 Turbine Building. At 1:06 PM on the same day, a patrol was conducted, and any abnormality such as leakage was not found. We plan to carry out this transfer during the daytime until late August.

- 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>
On June 19, since the decrease of all-β radioactivity density in the leakage detection hole (northeast) at the underground reservoirs No.1 has been slow, an operation to dilute the underground reservoir No.1 by transferring desalination-system (RO) treated water (the all-β radioactivity density: approx. 1×10¹Bq/cm³) into the reservoir was started (the all-β radioactivity density of residual water in the underground reservoir No.1: 6.6×10⁴Bq/cm³).
[Recent dilution operation] On July 5, approx. 40m³ of filtered water was injected.
On June 27, since the decrease of all-β radioactivity density in the leakage detection hole (northeast) at the underground reservoirs No.2 has been slow, an operation to dilute the underground reservoir No.2 by transferring filtered water into the reservoir was started.
[Recent dilution operation] On July 13, approx. 20m³ of desalination-system (RO) treated water was injected. On July 16, approx. 60m³ of the water was transferred to a temporary tank.

On July 16, 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 reservoir No.1 was transferred into this underground reservoir.

<Sampling>
On July 15, 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 8 in the observation holes on the sea side (5)-(8) and on July 14 in the other locations).

- 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.

- In a sample taken on July 15 of seawater at the Unit 3 screen (inside the silt fence), cesium-134, cesium-137 and all-β were detected at 350Bq/2L, 770Bq/L, and 1,000Bq/L, respectively, which are higher than the previous values. However, no significant changes were found compared to the past values. We are continuing to accumulate and assess data on water in this location and data on groundwater, etc. in the other observation locations.
Analysis for γ nuclides was conducted on water sampled on July 15 in the groundwater observation hole No.1-2 after filtering. The analysis result showed a trend similar to those shown in the past.

* Revised past progress

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