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 (previously announced on March 11). 
 
At 7:15 pm 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 (previously announced on March 15). 
 
<Updates from previous press release are underlined.> 
 Reactor cooling and filtering system of Unit 4 was restored at 10:00pm on
June 4th.
We have been cooling the reactor by residual heat removal system (B). We
expect that the restoration of the reactor cooling system, which functions
to cool the reactor, will contribute to securing further reliability of
Unit 4, which has been in cold shutdown,
At the same time, we will endeavor to restore the facilities, aiming for
further reliability of cold shutdown in the rest of the units 
 
 
* Reactor cooling and filtering system
A system to remove impurities from reactor water and to maintain its
quality. During the regular inspections or reactor shutdowns, it can be
utilized to discharge surplus water in the reactor and to control the
water level.
The reactor cooling and filtering systems of Units 1 to 4 at the Fukushima
Daini Nuclear Power Station had been unusable due to shutdown of sea water
cooling systems, which serve to cool the reactor cooling and filtering
systems, as a result of tsunami caused by Tohoku-Chihou-Taiheiyou-Oki
Earthquake. 
 
As of 3:00 pm on June 4, the reactors of Unit 1 to 4 are in cold shutdown 
(please refer to the appendix). We continue to make our endeavors to 
stabilize each plant. 

 
 
 Appendix: TEPCO Plant Status of Fukushima Daini Nuclear Power Station 
                                                          (PDF 17.0KB)