We are exerting our utmost effort in establishing the stable cooling of 
Reactors and Spent Fuel Pools and contain release of radioactive 
substances at Fukushima Daiichi Nuclear Power Station. As for Unit 2, to 
achieve stabilization of the Reactor, it is necessary to improve the 
working environment in the Reactor Building for the workers.

As to the Reactor Building of Unit 2, from the evaluation result of the 
figures measured on June 4, the total density of radioactive substances 
was 1.6 x 10-1 Bq/cm3 and the humidity was 99.9%. Therefore, we will 
install the ambient air filtration system to Unit 2 also and circulate the 
air inside the Building in order to reduce the density further. 

Subsequently, we will open the airlock of the Reactor Building for the 
workers to enter the Building and undertake necessary work. In doing so, 
we will measure the density of radioactive substances inside the Building 
to confirm that the impact to the outside environment is sufficiently low.

As for the humidity inside the Building, the Building will be ventilated 
when we open the airlock thus will become lower.

Regarding this matter, on June 8th, TEPCO have received an order* from the 
Minister of Economy, Trade and Industry (METI) to submit reports related 
to improvements to the work environment, evaluation of the impact of 
radioactive substance to the outside environment and radiation management 
plan for the workers.

                               (Previously announced on June 8th and 16th)

Afterward, we have been operating local exhausters and circulating the air 
in the reactor building, which should lead to removing radioactive 
materials and decrease the density of the radioactive materials inside the 
reactor building. With regard to our report to METI on June 15th, METI 
informed us on June 17th that the contents of the report are valid. 
Considering this notice, we have decided that we are going to begin to 
open the airlock in the reactor building gradually, preventing the dust in 
the building from stirring up, and finally open it all from 8 pm today to 
4 am tomorrow.
We have monitoring posts that monitor the radiation in the air around the 
site borders of the plant, but, as a result of evaluation of the influence 
of this opening the airlock, we have confirmed that the influence is not 
the level that changes the instrument reading (the latest one is 
approximately several dozenμSv/h) of the monitoring posts .

                                                                       END

Attachment:Influence evaluation on the radiation after operating local 
           exhausters in the Reactor Building of Unit 2 at Fukushima 
           Daiichi Nuclear Power Station(PDF 60.6KB) 

Order to report to METI

* We have provided a Japanese press release version of the instruction 
document received from NISA. However, at this time we have reserved the 
right to not provide an English version due to potential misunderstandings 
that may arise from an inaccurate rendering of the original Japanese text.

We may provide the English translation that NISA releases in our press 
releases. However, in principle we would advise you to visit the NISA 
website for timely and accurate information.