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 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 (previously announced on March 15).

As of 4:30 pm on October 1, the reactors of Units 1 to 4 are in cold
shutdown (please refer to the appendix). We will continue to make our
endeavors to further stabilize each plant of cold shutdown.

<Underlined are new matters> 
Planned shutdown of Residual heat removal system (B) of Unit 1
Regarding the Residual heat removal system (B) of Unit 1, since
restarting on September 26 after its inspection, we have been checked its
operation. And at around 6:00 pm on September 30, we confirmed a bleeding
of oil (grease) at the junction (coupling) between the pump of the
Residual heat removal system (B) and a motor. Therefore, at 9:58 am today,
we conducted a planned shutdown of the Residual heat removal system (B)
just to be safe, and checked the junction.
By the result of the inspection, we assumed that the bleeding of the oil
in operation was caused by too much greasing to the junction on the
inspection on 26 September.
After that, we adjusted the amount of grease and start operation of the
Residual heat removal system (B) at 4:21 pm.

In addition, while stopping the operation of the Residual heat removal
system (B), we continued heat removal and cooling by Clean Up Water
System, and increase in temperature of reactor water was kept to 9°C
during the inspection

<Temperature of reactor water at shutdown and restart of Residual heat
removal system (B) (actual temperature)>
As of the shutdown (9:58 am) : 25°C
As of the restart (4:21 pm) : 34°C 
 

Appendix1: TEPCO Plant Status of Fukushima Daini Nuclear Power Station 
                                                          (PDF 46.7KB) 
Appendix2: Layout of Residual heat removal system (B) of Unit 1 at 
           Fukushima Daini Nuclear Power Station (PDF 14.2KB)