On March 11 2011, turbines and reactors of Fukushima Daini Nuclear Power
Station Units 1 to 4 (Boiling Water Reactors, rated output 1,100 Megawatts)
that we had been constantly operating at rated thermal output were
automatically shut down at 2:48 pm due to the Tohoku-Chihou-Taiheiyou-Oki
Earthquake.
(Announced on March 11)
At 7:15 am on March 15, the reactor of Unit 4 achieved cold shutdown. As a
result, all reactors of Units 1 to 4 at Fukushima Daini Nuclear Power
Station achieved cold shutdown.
(Announced on March 15)
As of 3:00 pm on December 21, the reactors of Units 1 to 4 are in cold
shutdown (please refer to the appendix for each reactor status).
We will continue to make our endeavors to further stabilize each plant of
cold shutdown.
<Updates are underlined>
○End of the visual inspection of the reactor containment vessel of unit 4
Regarding the inspection of the reactor containment vessel of unit 4, we
have opened airlock for site workers on August 29 (announced on August 29),
and implemented the cleaning and decontamination on September 7. After
November 21, we have conducted the visual inspection of the reactor
containment vessel and inside facilities.
We finished the inspection today. In the result, there were no reactor
coolant leakages and no damages of facilities, equipments and pipes.
Therefore, we have confirmed that there are no harmful effects for cold
shutdown.
Although there were some removal of paints of equipments due to high
temperature and humidity, we estimated it has no direct impact on the cold
shutdown.
We will conduct detail inspection of the reactor containment vessel
including inside facilities.
Appendix: TEPCO Plant Status of Fukushima Daini Nuclear Power Station
(PDF 16.1KB)