Press Releases 2013

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 4:09 AM on January 30, a cooperative company worker reported to a TEPCO employee that water leakage was found in the temporary warehouse where desalination system No.2 (reverse osmosis membrane) is installed at Fukushima Daiichi Nuclear Power Station. Since the pressure of the system was high, a cooperative company worker performed flushing. When flushing was completed at 4:00 AM, the worker found water leakage around the system while he was preparing to start the system. At 5:00 AM, a TEPCO employee confirmed that the leakage had stopped. The area affected by the leakage was approx. 1.5mx20mx1mm. The leaked water remains in the system dam and has not flowed outside of the temporary warehouse. The amount of leaked water was approx. 30L. As a result of atmosphere dose rate measurement, γ+β was 0.1mSv/h and γ was 0.035mSv/h. The radioactivity density measurement results were as follows. Cesium 134: 7.0×10^-1Bq/cm³, cesium 137: 1.3×10⁰Bq/cm³, stibium 125: 9.4×10⁰Bq/cm³, which are equivalent with those of water sampled at the entrance of the desalination system. Upon site investigation, the leakage location was identified to be the outlet of the safety valve installed on the discharge side of the high pressure pump of the desalination system. The leakage has no impact on reactor water injection considering that there is a sufficient amount of desalinated water and other desalination systems are available for operation.

- At 6:57 AM on January 29, as part of restoration of Unit 1 condensate water storage tank, we started transferring the water stored in the tank to Unit 1 Waste Treatment Building. At 5:30 PM on the same day, the transfer was stopped. At 6:48 AM on January 30, we started transferring the water stored in the tank to Unit 1 Waste Treatment Building.

- On October 10, 2012, during a regular inspection of Unit 5 reactor core spray system (B), one of the two valve elements was found to be removed when the minimum flow rate bypass valve was opened for inspection. As a result of overhaul inspection performed on the valve, the gap between the valve element guide and the valve box guide was found to have increased due to abrasion. The abrasion is considered to have progressed faster since the edge of the valve element guide was touching the valve box guide during operation due to the edge of the valve element being lifted up by water flow. As countermeasures, the valve box was repaired and the valve element (comprised of two elements) was replaced with a new one with a single valve element. On January 30, 2013, no problem was found with the system as a result of trial operation. Thus, the system is now available for operation.

- At 11:00 AM on January 29, Unit 3 PCV gas control system was suspended^* for partial duct replacement with steel pipe and control panel modification. At 2:58 PM on the same day, the system was restarted after the work was completed. At 5:00 PM on the same day, the measurement utilizing the noble gas monitor was restarted. No problem was found with the monitoring parameters during the period the system was suspended.
* The facility management policy based on Chapter 12 of the technical specification for the nuclear reactor facility "Policy on the Mid-term Security" stipulates "operational requirements" and "necessary measures to be implemented in the case that the operational requirements are not fulfilled" (When the operational requirements are not fulfilled, the required measures must be implemented). In this case, Unit 3 PCV gas control system was suspended intentionally for maintenance (transition out of the scope of operational requirements).

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

* Revised past progress

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We apologize for any inconvenience this may cause.