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)