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 4:00 pm on October 17, 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.

<Updates are underlined> 
○ Unplanned radiation exposure of a partner company worker at Unit 4 
Today, we confirmed at 2:50 pm that a worker of partner company who was
engaged in cleaning inside of Primary Containment Vessel of Unit 4 was 
exposed to an unplanned radiation amount more than 1 mSv*1, 1.58 mSv per
day.
We will investigate the cause.
The radiation exposure amount of the worker is not more than the exposure
limit*2 prescribed by law and it does not cause physical harm and no
radioactive materials were attached to the worker.

*1: 1 mSv per day
It is prescribed by an official notice of Industrial Safety and Health Act,
"Reinforcement of measures for safety and health in radiation work at
nuclear power facilitiy", that work which may exceed 1 mSV per day shall be
notified to Labor Standards Office. As for this work, the planned exposurev
was 0.9 mSv/day and it was not subject to notification.

*2: exposure limit
The exposure limit prescribed by law for workers who engage in radiation 
work is 100 mSv/5years and 50 mSv/year. 

Appendix: TEPCO Plant Status of Fukushima Daini Nuclear Power Station 
                                                         (PDF 14.8KB)